7. Light Micrograph (LM)
(for viewing living cells)
Light micrograph of a protist, Paramecium
LM
ColorizedSEM
Scanning Electron Micrograph (SEM)
(for viewing surface features)
Scanning electron micrograph of Paramecium
TYPES OF MICROGRAPHS
Transmission Electron Micrograph (TEM)
(for viewing internal structures)
Transmission electron micrograph of Paramecium
ColorizedTEM
Figure 4.1
8. Light Micrograph (LM)
(for viewing living cells)
Light micrograph of a protist, Paramecium
LM
Figure 4.1a
18. 10 m
1 m
10 cm
1 cm
1 mm
100 mm
10 mm
Human height
Chicken egg
Frog eggs
Length of some
nerve and
muscle cells
Unaidedeye
Lightmicroscope
Plant and
animal cells
Most bacteria
Nucleus
Mitochondrion
1 mm
100 nm
10 nm
1 nm
0.1 nm
Smallest bacteria
Viruses
Ribosomes
Proteins
Lipids
Small molecules
Atoms
Electronmicroscope
Figure 4.3
34. (a) Phospholipid bilayer of
membrane
(b) Fluid mosaic model of
membrane
Outside of cell Outside of cell
Hydrophilic
head
Hydrophobic
tail
Hydrophilic
region of
protein
Hydrophilic
head
Hydrophobic
tail
Hydrophobic
regions of
protein
Phospholipid
bilayer
Phospholipid
Proteins
Cytoplasm (inside of cell)
Cytoplasm (inside of cell)
Figure 4.6
35. (a) Phospholipid bilayer of membrane
Outside of cell
Hydrophilic
head
Hydrophobic
tail
Phospholipid
Cytoplasm (inside of cell)
Figure 4.6a
36. (b) Fluid mosaic model of membrane
Outside of cell
Hydrophilic
region of
protein
Hydrophilic
head
Hydrophobic
tail
Hydrophobic
regions of
protein
Phospholipid
bilayer
Proteins
Cytoplasm (inside of cell)
Figure 4.6b
61. Synthesis of
mRNA in the
nucleus
Nucleus
DNA
mRNA
Cytoplasm
mRNAMovement of
mRNA into
cytoplasm
via
nuclear pore
Figure 4.12-2
62. Synthesis of
mRNA in the
nucleus
Nucleus
DNA
mRNA
Cytoplasm
mRNAMovement of
mRNA into
cytoplasm
via
nuclear pore
Ribosome
Protein
Synthesis of
protein in the
cytoplasm
Figure 4.12-3
69. Proteins are
often modified in
the ER.
Secretory
proteins depart in
transport vesicles.
Vesicles bud off
from the ER.
A ribosome
links amino acids
into a
polypeptide.
Ribosome
Transport
vesicle
Polypeptide
Protein
Rough ER
Figure 4.14
72. “Receiving” side of
Golgi apparatus
New vesicle forming
Transport vesicle
from rough ER
“Receiving” side
of Golgi
apparatus
New
vesicle
forming
Transport
vesicle
from the
Golgi
Plasma
membrane
“Shipping” side
of Golgi
apparatus
ColorizedSEM
Figure 4.15
73. Transport vesicle
from rough ER
“Receiving” side of
Golgi apparatus
New
vesicle
forming
Transport
vesicle
from the
Golgi
Plasma
membrane
“Shipping” side of
Golgi apparatus
Figure 4.15a
74. “Receiving” side of Golgi apparatus
New vesicle forming
ColorizedSEM
Figure 4.15b
84. Vacuole filling with water
Vacuole contracting
(a) Contractile vacuole in Paramecium
(b) Central vacuole in a plant cell
Central vacuole
ColorizedTEM
LMLM Figure 4.17
88. Golgi apparatus
Transport vesicle
Plasma membrane
Secretory protein
New vesicle forming
Transport vesicle from
the Golgi
Vacuoles store some
cell products.
Lysosomes carrying digestive
enzymes can fuse with other vesicles.
Transport vesicles carry enzymes
and other proteins from the rough
ER to the Golgi for processing.
Some products
are secreted
from the cell.
Golgi apparatus
Rough ER
Vacuole
Lysosome
Transport
vesicle
TEM
Figure 4.18
111. (a) Flagellum of a human sperm cell
ColorizedSEM
(b) Cilia on a protist
(c) Cilia lining the
respiratory tract
ColorizedSEM
ColorizedSEM
Figure 4.22
131. Prokaryotic Cells Eukaryotic Cells
• Smaller
• Simpler
• Most do not have organelles
• Found in bacteria and archaea
• Larger
• More complex
• Have organelles
• Found in protists, plants,
fungi, animals
CATEGORIES OF CELLS
Figure 4.UN12
132. Outside of cell
Cytoplasm (inside of cell)
Protein
Phospholipid
Hydrophilic
Hydrophilic
Hydrophobic
Figure 4.UN13
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
Figure 4.1 Types of micrographs
Figure 4.1a Types of micrographs (LM)
Figure 4.1b Types of micrographs (SEM)
Figure 4.1c Types of micrographs (TEM)
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
Figure 4.2 Electron microscope
Figure 4.3 The size range of cells
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Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
Figure 4.4 An idealized prokaryotic cell
Figure 4.4a Prokaryotic cell: art
Figure 4.4b Prokaryotic cell: TEM
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Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
<number>
Student Misconceptions and Concerns
1. Students typically cannot distinguish between resolution and magnification. However, pixels and resolution of digital images can help clarify the distinction. Consider printing the same image at high and low resolution or enlarging the same image at two different levels of resolution. Teaching tip #2 below suggests another related exercise.
2. Students frequently equate the functions of mitochondria and chloroplasts as alternate ways to acquire usable energy. This often leads to the conclusion that animal cells have mitochondria but not chloroplasts and that plant cells have chloroplasts but not mitochondria. Plant cells have both.
Teaching Tips
1. Here is a chance to challenge students to identify technology that has extended our senses. Chemical probes can identify what we cannot taste, listening devices detect what we do not normally hear, night vision and ultraviolet (UV) cameras detect or magnify wavelengths beyond our vision, etc. Students could be assigned the task of preparing a short report on one of these technologies.
2. Here is a way to demonstrate resolving power in the classroom. Use a marker and your classroom marker board to make several pairs of dots separated by shorter and shorter distances. Start out with two dots clearly separated apart—perhaps by 4–5 cm—and end with a pair of dots that touch. Label them a, b, c, etc. Ask your students to indicate the letters of the pairs of points that they can distinguish as separate; this is the definition of resolution for their eyes. (They need not state their answers publicly, to avoid embarrassment.)
3. Most biology laboratories have two types of microscopes for student use: a dissection (or stereo-) microscope and a compound light microscope using microscope slides. The way these scopes function parallels the workings of EMs. Dissection microscopes are like a SEM—both rely upon a beam reflected off a surface. As you explain this to your class, hold up an object, identify a light source in the room, and explain that our eyes see most images when our eyes detect light that has reflected off the surface of an object. Compound light microscopes are like TEMs, in which a beam is transmitted through a thin sheet of material. If you have an overhead or other strong light source, hold up a piece of paper between your eye and the light source. You will see the internal detail of the paper as light is transmitted through the paper to your eye . . . the way a compound light microscope or TEM works!
4. Even in college, students still struggle with the metric system. When discussing the scale of life, consider bringing a meter stick to class. The relationship between a meter and a millimeter is the same as a millimeter is to a micron. Each is a difference of 1000.
5. This is a place where a visual image comparing a prokaryotic and eukaryotic cell can be very helpful. These cells are strikingly different in size and composition. A visual reference point instead of just abstract ideas and traits will be a continual reminder for your students during your discussion of these cells.
6. Students might wrongly conclude that prokaryotes are typically one-tenth the volume of eukaryotic cells. A difference in diameter by a factor of ten translates into a much greater difference in volume. Students might be challenged to recall enough geometry to calculate the difference in the volume of two cells with diameters that differ by a factor of ten.
7. Germs—here is a term that we learn early in our lives but that is rarely well defined. Students may appreciate a biological explanation. The general use of germs is a reference to anything that causes disease. This may be a good time to sort the major disease-causing agents into three categories: (1) bacteria (prokaryotes), (2) viruses (not yet addressed), and (3) single-celled and multicellular eukaryotes (athlete’s foot is a fungal infection; malaria is caused by a unicellular eukaryote).
8. Some instructors have reported great success by challenging their students to make analogies to the functions of the many organelles discussed below. Students may wish to construct one inclusive analogy between a society or factory (used in the text) and a cell or to construct separate analogies for each organelle. As with any analogy, it is important to list the similarities and differences/exceptions.
9. This might be a good time to discuss the evolution of antibiotic resistance. Teaching tips and ideas for related lessons can be found at http://www.pbs.org/wgbh/evolution/educators/lessons/lesson6/act1.html.
Figure 4.5 A view of an idealized animal cell and plant cell
Figure 4.5a A view of an idealized animal cell
Figure 4.5b A view of an idealized plant cell
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Student Misconceptions and Concerns
1. Students often think of the function of cell membranes as mainly containment, like that of a plastic bag. Consider relating the functions of membranes to our human skin. (For example, both membranes and our skin detect stimuli, engage in gas exchange, and serve as sites of excretion and absorption.)
Teaching Tips
1. The hydrophobic and hydrophilic ends of a phospholipid molecule naturally create a lipid bilayer. The hydrophobic edges of the layer will seal to other such edges, eventually wrapping a sheet into a sphere that can enclose water (a simple cell). Further, because of these hydrophobic properties, lipid bilayers are naturally self-healing. That all of this organization naturally emerges from the properties of phospholipids is worth sharing with your students.
2. You might wish to share a very simple analogy that seems to work with some students. A cell membrane is a little like a peanut butter and jelly sandwich with jellybeans poked into it. The bread represents the hydrophilic portions of the bilayer (and bread does indeed quickly absorb water). The peanut butter and jelly represent the hydrophobic regions (and peanut butter, containing plenty of oil, is generally hydrophobic). The jellybeans stuck into the sandwich represent proteins variously embedded partially into or completely through the membrane. Transport proteins would be like the jellybeans that poke completely through the sandwich. Analogies are rarely perfect. Challenge your students to critique this analogy to find exceptions. (For example, this analogy does not include a model of the carbohydrates on the cell surface.)
<number>
Student Misconceptions and Concerns
1. Students often think of the function of cell membranes as mainly containment, like that of a plastic bag. Consider relating the functions of membranes to our human skin. (For example, both membranes and our skin detect stimuli, engage in gas exchange, and serve as sites of excretion and absorption.)
Teaching Tips
1. The hydrophobic and hydrophilic ends of a phospholipid molecule naturally create a lipid bilayer. The hydrophobic edges of the layer will seal to other such edges, eventually wrapping a sheet into a sphere that can enclose water (a simple cell). Further, because of these hydrophobic properties, lipid bilayers are naturally self-healing. That all of this organization naturally emerges from the properties of phospholipids is worth sharing with your students.
2. You might wish to share a very simple analogy that seems to work with some students. A cell membrane is a little like a peanut butter and jelly sandwich with jellybeans poked into it. The bread represents the hydrophilic portions of the bilayer (and bread does indeed quickly absorb water). The peanut butter and jelly represent the hydrophobic regions (and peanut butter, containing plenty of oil, is generally hydrophobic). The jellybeans stuck into the sandwich represent proteins variously embedded partially into or completely through the membrane. Transport proteins would be like the jellybeans that poke completely through the sandwich. Analogies are rarely perfect. Challenge your students to critique this analogy to find exceptions. (For example, this analogy does not include a model of the carbohydrates on the cell surface.)
<number>
Student Misconceptions and Concerns
1. Students often think of the function of cell membranes as mainly containment, like that of a plastic bag. Consider relating the functions of membranes to our human skin. (For example, both membranes and our skin detect stimuli, engage in gas exchange, and serve as sites of excretion and absorption.)
Teaching Tips
1. The hydrophobic and hydrophilic ends of a phospholipid molecule naturally create a lipid bilayer. The hydrophobic edges of the layer will seal to other such edges, eventually wrapping a sheet into a sphere that can enclose water (a simple cell). Further, because of these hydrophobic properties, lipid bilayers are naturally self-healing. That all of this organization naturally emerges from the properties of phospholipids is worth sharing with your students.
2. You might wish to share a very simple analogy that seems to work with some students. A cell membrane is a little like a peanut butter and jelly sandwich with jellybeans poked into it. The bread represents the hydrophilic portions of the bilayer (and bread does indeed quickly absorb water). The peanut butter and jelly represent the hydrophobic regions (and peanut butter, containing plenty of oil, is generally hydrophobic). The jellybeans stuck into the sandwich represent proteins variously embedded partially into or completely through the membrane. Transport proteins would be like the jellybeans that poke completely through the sandwich. Analogies are rarely perfect. Challenge your students to critique this analogy to find exceptions. (For example, this analogy does not include a model of the carbohydrates on the cell surface.)
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Figure 4.6a Phospholipid bilayer of membrane
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Figure 4.6b Fluid mosaic model of membrane
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Student Misconceptions and Concerns
1. Students often think of the function of cell membranes as mainly containment, like that of a plastic bag. Consider relating the functions of membranes to our human skin. (For example, both membranes and our skin detect stimuli, engage in gas exchange, and serve as sites of excretion and absorption.)
Teaching Tips
1. The hydrophobic and hydrophilic ends of a phospholipid molecule naturally create a lipid bilayer. The hydrophobic edges of the layer will seal to other such edges, eventually wrapping a sheet into a sphere that can enclose water (a simple cell). Further, because of these hydrophobic properties, lipid bilayers are naturally self-healing. That all of this organization naturally emerges from the properties of phospholipids is worth sharing with your students.
2. You might wish to share a very simple analogy that seems to work with some students. A cell membrane is a little like a peanut butter and jelly sandwich with jellybeans poked into it. The bread represents the hydrophilic portions of the bilayer (and bread does indeed quickly absorb water). The peanut butter and jelly represent the hydrophobic regions (and peanut butter, containing plenty of oil, is generally hydrophobic). The jellybeans stuck into the sandwich represent proteins variously embedded partially into or completely through the membrane. Transport proteins would be like the jellybeans that poke completely through the sandwich. Analogies are rarely perfect. Challenge your students to critique this analogy to find exceptions. (For example, this analogy does not include a model of the carbohydrates on the cell surface.)
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Student Misconceptions and Concerns
1. Students often think of the function of cell membranes as mainly containment, like that of a plastic bag. Consider relating the functions of membranes to our human skin. (For example, both membranes and our skin detect stimuli, engage in gas exchange, and serve as sites of excretion and absorption.)
Teaching Tips
1. The hydrophobic and hydrophilic ends of a phospholipid molecule naturally create a lipid bilayer. The hydrophobic edges of the layer will seal to other such edges, eventually wrapping a sheet into a sphere that can enclose water (a simple cell). Further, because of these hydrophobic properties, lipid bilayers are naturally self-healing. That all of this organization naturally emerges from the properties of phospholipids is worth sharing with your students.
2. You might wish to share a very simple analogy that seems to work with some students. A cell membrane is a little like a peanut butter and jelly sandwich with jellybeans poked into it. The bread represents the hydrophilic portions of the bilayer (and bread does indeed quickly absorb water). The peanut butter and jelly represent the hydrophobic regions (and peanut butter, containing plenty of oil, is generally hydrophobic). The jellybeans stuck into the sandwich represent proteins variously embedded partially into or completely through the membrane. Transport proteins would be like the jellybeans that poke completely through the sandwich. Analogies are rarely perfect. Challenge your students to critique this analogy to find exceptions. (For example, this analogy does not include a model of the carbohydrates on the cell surface.)
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Student Misconceptions and Concerns
1. Students often think of the function of cell membranes as mainly containment, like that of a plastic bag. Consider relating the functions of membranes to our human skin. (For example, both membranes and our skin detect stimuli, engage in gas exchange, and serve as sites of excretion and absorption.)
Teaching Tips
1. The hydrophobic and hydrophilic ends of a phospholipid molecule naturally create a lipid bilayer. The hydrophobic edges of the layer will seal to other such edges, eventually wrapping a sheet into a sphere that can enclose water (a simple cell). Further, because of these hydrophobic properties, lipid bilayers are naturally self-healing. That all of this organization naturally emerges from the properties of phospholipids is worth sharing with your students.
2. You might wish to share a very simple analogy that seems to work with some students. A cell membrane is a little like a peanut butter and jelly sandwich with jellybeans poked into it. The bread represents the hydrophilic portions of the bilayer (and bread does indeed quickly absorb water). The peanut butter and jelly represent the hydrophobic regions (and peanut butter, containing plenty of oil, is generally hydrophobic). The jellybeans stuck into the sandwich represent proteins variously embedded partially into or completely through the membrane. Transport proteins would be like the jellybeans that poke completely through the sandwich. Analogies are rarely perfect. Challenge your students to critique this analogy to find exceptions. (For example, this analogy does not include a model of the carbohydrates on the cell surface.)
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Student Misconceptions and Concerns
1. Students often think of the function of cell membranes as mainly containment, like that of a plastic bag. Consider relating the functions of membranes to our human skin. (For example, both membranes and our skin detect stimuli, engage in gas exchange, and serve as sites of excretion and absorption.)
Teaching Tips
1. The hydrophobic and hydrophilic ends of a phospholipid molecule naturally create a lipid bilayer. The hydrophobic edges of the layer will seal to other such edges, eventually wrapping a sheet into a sphere that can enclose water (a simple cell). Further, because of these hydrophobic properties, lipid bilayers are naturally self-healing. That all of this organization naturally emerges from the properties of phospholipids is worth sharing with your students.
2. You might wish to share a very simple analogy that seems to work with some students. A cell membrane is a little like a peanut butter and jelly sandwich with jellybeans poked into it. The bread represents the hydrophilic portions of the bilayer (and bread does indeed quickly absorb water). The peanut butter and jelly represent the hydrophobic regions (and peanut butter, containing plenty of oil, is generally hydrophobic). The jellybeans stuck into the sandwich represent proteins variously embedded partially into or completely through the membrane. Transport proteins would be like the jellybeans that poke completely through the sandwich. Analogies are rarely perfect. Challenge your students to critique this analogy to find exceptions. (For example, this analogy does not include a model of the carbohydrates on the cell surface.)
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Student Misconceptions and Concerns
1. Students often think of the function of cell membranes as mainly containment, like that of a plastic bag. Consider relating the functions of membranes to our human skin. (For example, both membranes and our skin detect stimuli, engage in gas exchange, and serve as sites of excretion and absorption.)
Teaching Tips
1. The hydrophobic and hydrophilic ends of a phospholipid molecule naturally create a lipid bilayer. The hydrophobic edges of the layer will seal to other such edges, eventually wrapping a sheet into a sphere that can enclose water (a simple cell). Further, because of these hydrophobic properties, lipid bilayers are naturally self-healing. That all of this organization naturally emerges from the properties of phospholipids is worth sharing with your students.
2. You might wish to share a very simple analogy that seems to work with some students. A cell membrane is a little like a peanut butter and jelly sandwich with jellybeans poked into it. The bread represents the hydrophilic portions of the bilayer (and bread does indeed quickly absorb water). The peanut butter and jelly represent the hydrophobic regions (and peanut butter, containing plenty of oil, is generally hydrophobic). The jellybeans stuck into the sandwich represent proteins variously embedded partially into or completely through the membrane. Transport proteins would be like the jellybeans that poke completely through the sandwich. Analogies are rarely perfect. Challenge your students to critique this analogy to find exceptions. (For example, this analogy does not include a model of the carbohydrates on the cell surface.)
Figure 4.7 How MRSA may destroy human immune cells (Step 1)
Figure 4.7 How MRSA may destroy human immune cells (Step 2)
Figure 4.7 How MRSA may destroy human immune cells (Step 3)
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Student Misconceptions and Concerns
1. Students often think of the function of cell membranes as mainly containment, like that of a plastic bag. Consider relating the functions of membranes to our human skin. (For example, both membranes and our skin detect stimuli, engage in gas exchange, and serve as sites of excretion and absorption.)
Teaching Tips
1. The hydrophobic and hydrophilic ends of a phospholipid molecule naturally create a lipid bilayer. The hydrophobic edges of the layer will seal to other such edges, eventually wrapping a sheet into a sphere that can enclose water (a simple cell). Further, because of these hydrophobic properties, lipid bilayers are naturally self-healing. That all of this organization naturally emerges from the properties of phospholipids is worth sharing with your students.
2. You might wish to share a very simple analogy that seems to work with some students. A cell membrane is a little like a peanut butter and jelly sandwich with jellybeans poked into it. The bread represents the hydrophilic portions of the bilayer (and bread does indeed quickly absorb water). The peanut butter and jelly represent the hydrophobic regions (and peanut butter, containing plenty of oil, is generally hydrophobic). The jellybeans stuck into the sandwich represent proteins variously embedded partially into or completely through the membrane. Transport proteins would be like the jellybeans that poke completely through the sandwich. Analogies are rarely perfect. Challenge your students to critique this analogy to find exceptions. (For example, this analogy does not include a model of the carbohydrates on the cell surface.)
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Student Misconceptions and Concerns
1. Students often think of the function of cell membranes as mainly containment, like that of a plastic bag. Consider relating the functions of membranes to our human skin. (For example, both membranes and our skin detect stimuli, engage in gas exchange, and serve as sites of excretion and absorption.)
Teaching Tips
1. The hydrophobic and hydrophilic ends of a phospholipid molecule naturally create a lipid bilayer. The hydrophobic edges of the layer will seal to other such edges, eventually wrapping a sheet into a sphere that can enclose water (a simple cell). Further, because of these hydrophobic properties, lipid bilayers are naturally self-healing. That all of this organization naturally emerges from the properties of phospholipids is worth sharing with your students.
2. You might wish to share a very simple analogy that seems to work with some students. A cell membrane is a little like a peanut butter and jelly sandwich with jellybeans poked into it. The bread represents the hydrophilic portions of the bilayer (and bread does indeed quickly absorb water). The peanut butter and jelly represent the hydrophobic regions (and peanut butter, containing plenty of oil, is generally hydrophobic). The jellybeans stuck into the sandwich represent proteins variously embedded partially into or completely through the membrane. Transport proteins would be like the jellybeans that poke completely through the sandwich. Analogies are rarely perfect. Challenge your students to critique this analogy to find exceptions. (For example, this analogy does not include a model of the carbohydrates on the cell surface.)
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Student Misconceptions and Concerns
1. Noting the main flow of genetic information from DNA to RNA to Protein on the board will provide a useful reference for students when explaining these processes. As a review, have students note where new molecules of DNA, RNA, and proteins are produced in a cell.
2. Consider challenging your students to explain how we can have four main types of organic molecules functioning in specific roles in our cells, yet DNA and RNA only specifically dictate the generation of proteins (and more copies of DNA and RNA). How is the production of specific types of carbohydrates and lipids in cells controlled? (Answer: primarily by the specific properties of enzymes.)
Teaching Tips
Some of your more knowledgeable students may like to guess the exceptions to 46 chromosomes per human cell. These exceptions include gametes, some of the cells that produce them, and red blood cells in non-fetal mammals.
2. If you wish to continue the text’s factory analogy, nuclear pores might be said to function most like the doors to the boss’s office.
3. If you want to challenge your students further, ask them to consider the adaptive advantage of using mRNA to direct the production of proteins instead of using DNA directly. Some biologists suggest that DNA is better protected in the nucleus and that mRNA, exposed to more damaging cross-reactions in the cytosol, is the temporary working copy of the genetic material. In some ways, this is similar to making a working photocopy of an important document, keeping the original copy safely stored away.
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Student Misconceptions and Concerns
1. Noting the main flow of genetic information from DNA to RNA to Protein on the board will provide a useful reference for students when explaining these processes. As a review, have students note where new molecules of DNA, RNA, and proteins are produced in a cell.
2. Consider challenging your students to explain how we can have four main types of organic molecules functioning in specific roles in our cells, yet DNA and RNA only specifically dictate the generation of proteins (and more copies of DNA and RNA). How is the production of specific types of carbohydrates and lipids in cells controlled? (Answer: primarily by the specific properties of enzymes.)
Teaching Tips
Some of your more knowledgeable students may like to guess the exceptions to 46 chromosomes per human cell. These exceptions include gametes, some of the cells that produce them, and red blood cells in non-fetal mammals.
2. If you wish to continue the text’s factory analogy, nuclear pores might be said to function most like the doors to the boss’s office.
3. If you want to challenge your students further, ask them to consider the adaptive advantage of using mRNA to direct the production of proteins instead of using DNA directly. Some biologists suggest that DNA is better protected in the nucleus and that mRNA, exposed to more damaging cross-reactions in the cytosol, is the temporary working copy of the genetic material. In some ways, this is similar to making a working photocopy of an important document, keeping the original copy safely stored away.
Figure 4.8 The nucleus
Figure 4.8a The nucleus: art
Figure 4.8b Nuclear envelope
Figure 4.8c Nuclear pores
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Student Misconceptions and Concerns
1. Noting the main flow of genetic information from DNA to RNA to Protein on the board will provide a useful reference for students when explaining these processes. As a review, have students note where new molecules of DNA, RNA, and proteins are produced in a cell.
2. Consider challenging your students to explain how we can have four main types of organic molecules functioning in specific roles in our cells, yet DNA and RNA only specifically dictate the generation of proteins (and more copies of DNA and RNA). How is the production of specific types of carbohydrates and lipids in cells controlled? (Answer: primarily by the specific properties of enzymes.)
Teaching Tips
Some of your more knowledgeable students may like to guess the exceptions to 46 chromosomes per human cell. These exceptions include gametes, some of the cells that produce them, and red blood cells in non-fetal mammals.
2. If you wish to continue the text’s factory analogy, nuclear pores might be said to function most like the doors to the boss’s office.
3. If you want to challenge your students further, ask them to consider the adaptive advantage of using mRNA to direct the production of proteins instead of using DNA directly. Some biologists suggest that DNA is better protected in the nucleus and that mRNA, exposed to more damaging cross-reactions in the cytosol, is the temporary working copy of the genetic material. In some ways, this is similar to making a working photocopy of an important document, keeping the original copy safely stored away.
Figure 4.9 The relationship between DNA, chromatin, and a chromosome
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Student Misconceptions and Concerns
1. Noting the main flow of genetic information from DNA to RNA to Protein on the board will provide a useful reference for students when explaining these processes. As a review, have students note where new molecules of DNA, RNA, and proteins are produced in a cell.
2. Consider challenging your students to explain how we can have four main types of organic molecules functioning in specific roles in our cells, yet DNA and RNA only specifically dictate the generation of proteins (and more copies of DNA and RNA). How is the production of specific types of carbohydrates and lipids in cells controlled? (Answer: primarily by the specific properties of enzymes.)
Teaching Tips
Some of your more knowledgeable students may like to guess the exceptions to 46 chromosomes per human cell. These exceptions include gametes, some of the cells that produce them, and red blood cells in non-fetal mammals.
2. If you wish to continue the text’s factory analogy, nuclear pores might be said to function most like the doors to the boss’s office.
3. If you want to challenge your students further, ask them to consider the adaptive advantage of using mRNA to direct the production of proteins instead of using DNA directly. Some biologists suggest that DNA is better protected in the nucleus and that mRNA, exposed to more damaging cross-reactions in the cytosol, is the temporary working copy of the genetic material. In some ways, this is similar to making a working photocopy of an important document, keeping the original copy safely stored away.
Figure 4.10 Computer model of a ribosome synthesizing a protein
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Student Misconceptions and Concerns
1. Noting the main flow of genetic information from DNA to RNA to Protein on the board will provide a useful reference for students when explaining these processes. As a review, have students note where new molecules of DNA, RNA, and proteins are produced in a cell.
2. Consider challenging your students to explain how we can have four main types of organic molecules functioning in specific roles in our cells, yet DNA and RNA only specifically dictate the generation of proteins (and more copies of DNA and RNA). How is the production of specific types of carbohydrates and lipids in cells controlled? (Answer: primarily by the specific properties of enzymes.)
Teaching Tips
Some of your more knowledgeable students may like to guess the exceptions to 46 chromosomes per human cell. These exceptions include gametes, some of the cells that produce them, and red blood cells in non-fetal mammals.
2. If you wish to continue the text’s factory analogy, nuclear pores might be said to function most like the doors to the boss’s office.
3. If you want to challenge your students further, ask them to consider the adaptive advantage of using mRNA to direct the production of proteins instead of using DNA directly. Some biologists suggest that DNA is better protected in the nucleus and that mRNA, exposed to more damaging cross-reactions in the cytosol, is the temporary working copy of the genetic material. In some ways, this is similar to making a working photocopy of an important document, keeping the original copy safely stored away.
Figure 4.11 Locations of ribosomes
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Student Misconceptions and Concerns
1. Noting the main flow of genetic information from DNA to RNA to Protein on the board will provide a useful reference for students when explaining these processes. As a review, have students note where new molecules of DNA, RNA, and proteins are produced in a cell.
2. Consider challenging your students to explain how we can have four main types of organic molecules functioning in specific roles in our cells, yet DNA and RNA only specifically dictate the generation of proteins (and more copies of DNA and RNA). How is the production of specific types of carbohydrates and lipids in cells controlled? (Answer: primarily by the specific properties of enzymes.)
Teaching Tips
Some of your more knowledgeable students may like to guess the exceptions to 46 chromosomes per human cell. These exceptions include gametes, some of the cells that produce them, and red blood cells in non-fetal mammals.
2. If you wish to continue the text’s factory analogy, nuclear pores might be said to function most like the doors to the boss’s office.
3. If you want to challenge your students further, ask them to consider the adaptive advantage of using mRNA to direct the production of proteins instead of using DNA directly. Some biologists suggest that DNA is better protected in the nucleus and that mRNA, exposed to more damaging cross-reactions in the cytosol, is the temporary working copy of the genetic material. In some ways, this is similar to making a working photocopy of an important document, keeping the original copy safely stored away.
Figure 4.12 DNA → RNA → Protein (Step 1)
Figure 4.12 DNA → RNA → Protein (Step 2)
Figure 4.12 DNA → RNA → Protein (Step 3)
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Student Misconceptions and Concerns
1. Students might have trouble connecting the diverse functions to the organelles. The pathway of secretory proteins is a good process to use to introduce the primary organelle functions. The movement of information and products extends generally from the central nucleus to the interconnected rough ER, to the more peripherally located Golgi, and finally to the outer plasma membrane. Introducing the steps of this process with the central to peripheral flow may help students better see the interrelationships and recall the sequence.
2. Conceptually, some students seem to benefit from the well-developed factory-like-a-cell analogy developed in the text. The use of this analogy in lecture might help to anchor these relationships.
Teaching Tips
1. The endoplasmic reticulum is continuous with the outer nuclear membrane. This explains why the ER is usually found close to the nucleus.
2. Some people think the Golgi apparatus looks like a stack of pita bread.
3. If you continue the factory analogy, the addition of a molecular tag is like adding address labels in the shipping department of a factory.
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Student Misconceptions and Concerns
1. Students might have trouble connecting the diverse functions to the organelles. The pathway of secretory proteins is a good process to use to introduce the primary organelle functions. The movement of information and products extends generally from the central nucleus to the interconnected rough ER, to the more peripherally located Golgi, and finally to the outer plasma membrane. Introducing the steps of this process with the central to peripheral flow may help students better see the interrelationships and recall the sequence.
2. Conceptually, some students seem to benefit from the well-developed factory-like-a-cell analogy developed in the text. The use of this analogy in lecture might help to anchor these relationships.
Teaching Tips
1. The endoplasmic reticulum is continuous with the outer nuclear membrane. This explains why the ER is usually found close to the nucleus.
2. Some people think the Golgi apparatus looks like a stack of pita bread.
3. If you continue the factory analogy, the addition of a molecular tag is like adding address labels in the shipping department of a factory.
Figure 4.13 Endoplasmic reticulum (ER)
Figure 4.13a Endoplasmic reticulum (ER) art
Figure 4.13b Endoplasmic reticulum (ER) TEM
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Student Misconceptions and Concerns
1. Students might have trouble connecting the diverse functions to the organelles. The pathway of secretory proteins is a good process to use to introduce the primary organelle functions. The movement of information and products extends generally from the central nucleus to the interconnected rough ER, to the more peripherally located Golgi, and finally to the outer plasma membrane. Introducing the steps of this process with the central to peripheral flow may help students better see the interrelationships and recall the sequence.
2. Conceptually, some students seem to benefit from the well-developed factory-like-a-cell analogy developed in the text. The use of this analogy in lecture might help to anchor these relationships.
Teaching Tips
1. The endoplasmic reticulum is continuous with the outer nuclear membrane. This explains why the ER is usually found close to the nucleus.
2. Some people think the Golgi apparatus looks like a stack of pita bread.
3. If you continue the factory analogy, the addition of a molecular tag is like adding address labels in the shipping department of a factory.
Figure 4.14 How rough ER manufactures and packages secretory proteins
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Student Misconceptions and Concerns
1. Students might have trouble connecting the diverse functions to the organelles. The pathway of secretory proteins is a good process to use to introduce the primary organelle functions. The movement of information and products extends generally from the central nucleus to the interconnected rough ER, to the more peripherally located Golgi, and finally to the outer plasma membrane. Introducing the steps of this process with the central to peripheral flow may help students better see the interrelationships and recall the sequence.
2. Conceptually, some students seem to benefit from the well-developed factory-like-a-cell analogy developed in the text. The use of this analogy in lecture might help to anchor these relationships.
Teaching Tips
1. The endoplasmic reticulum is continuous with the outer nuclear membrane. This explains why the ER is usually found close to the nucleus.
2. Some people think the Golgi apparatus looks like a stack of pita bread.
3. If you continue the factory analogy, the addition of a molecular tag is like adding address labels in the shipping department of a factory.
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Student Misconceptions and Concerns
1. Students might have trouble connecting the diverse functions to the organelles. The pathway of secretory proteins is a good process to use to introduce the primary organelle functions. The movement of information and products extends generally from the central nucleus to the interconnected rough ER, to the more peripherally located Golgi, and finally to the outer plasma membrane. Introducing the steps of this process with the central to peripheral flow may help students better see the interrelationships and recall the sequence.
2. Conceptually, some students seem to benefit from the well-developed factory-like-a-cell analogy developed in the text. The use of this analogy in lecture might help to anchor these relationships.
Teaching Tips
1. The endoplasmic reticulum is continuous with the outer nuclear membrane. This explains why the ER is usually found close to the nucleus.
2. Some people think the Golgi apparatus looks like a stack of pita bread.
3. If you continue the factory analogy, the addition of a molecular tag is like adding address labels in the shipping department of a factory.
Figure 4.15 The Golgi apparatus
Figure 4.15a The Golgi apparatus art
Figure 4.15b The Golgi apparatus SEM
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Student Misconceptions and Concerns
1. Students might have trouble connecting the diverse functions to the organelles. The pathway of secretory proteins is a good process to use to introduce the primary organelle functions. The movement of information and products extends generally from the central nucleus to the interconnected rough ER, to the more peripherally located Golgi, and finally to the outer plasma membrane. Introducing the steps of this process with the central to peripheral flow may help students better see the interrelationships and recall the sequence.
2. Conceptually, some students seem to benefit from the well-developed factory-like-a-cell analogy developed in the text. The use of this analogy in lecture might help to anchor these relationships.
Teaching Tips
1. The endoplasmic reticulum is continuous with the outer nuclear membrane. This explains why the ER is usually found close to the nucleus.
2. Some people think the Golgi apparatus looks like a stack of pita bread.
3. If you continue the factory analogy, the addition of a molecular tag is like adding address labels in the shipping department of a factory.
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Student Misconceptions and Concerns
1. Students might have trouble connecting the diverse functions to the organelles. The pathway of secretory proteins is a good process to use to introduce the primary organelle functions. The movement of information and products extends generally from the central nucleus to the interconnected rough ER, to the more peripherally located Golgi, and finally to the outer plasma membrane. Introducing the steps of this process with the central to peripheral flow may help students better see the interrelationships and recall the sequence.
2. Conceptually, some students seem to benefit from the well-developed factory-like-a-cell analogy developed in the text. The use of this analogy in lecture might help to anchor these relationships.
Teaching Tips
1. The endoplasmic reticulum is continuous with the outer nuclear membrane. This explains why the ER is usually found close to the nucleus.
2. Some people think the Golgi apparatus looks like a stack of pita bread.
3. If you continue the factory analogy, the addition of a molecular tag is like adding address labels in the shipping department of a factory.
Figure 4.16 Two functions of lysosomes
Figure 4.16a Lysosome digesting food
Figure 4.16b Lysosome breaking down the molecules of damaged organelles
Figure 4.16c Lysosome micrograph
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Student Misconceptions and Concerns
1. Students might have trouble connecting the diverse functions to the organelles. The pathway of secretory proteins is a good process to use to introduce the primary organelle functions. The movement of information and products extends generally from the central nucleus to the interconnected rough ER, to the more peripherally located Golgi, and finally to the outer plasma membrane. Introducing the steps of this process with the central to peripheral flow may help students better see the interrelationships and recall the sequence.
2. Conceptually, some students seem to benefit from the well-developed factory-like-a-cell analogy developed in the text. The use of this analogy in lecture might help to anchor these relationships.
Teaching Tips
1. The endoplasmic reticulum is continuous with the outer nuclear membrane. This explains why the ER is usually found close to the nucleus.
2. Some people think the Golgi apparatus looks like a stack of pita bread.
3. If you continue the factory analogy, the addition of a molecular tag is like adding address labels in the shipping department of a factory.
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Student Misconceptions and Concerns
1. Students might have trouble connecting the diverse functions to the organelles. The pathway of secretory proteins is a good process to use to introduce the primary organelle functions. The movement of information and products extends generally from the central nucleus to the interconnected rough ER, to the more peripherally located Golgi, and finally to the outer plasma membrane. Introducing the steps of this process with the central to peripheral flow may help students better see the interrelationships and recall the sequence.
2. Conceptually, some students seem to benefit from the well-developed factory-like-a-cell analogy developed in the text. The use of this analogy in lecture might help to anchor these relationships.
Teaching Tips
1. The endoplasmic reticulum is continuous with the outer nuclear membrane. This explains why the ER is usually found close to the nucleus.
2. Some people think the Golgi apparatus looks like a stack of pita bread.
3. If you continue the factory analogy, the addition of a molecular tag is like adding address labels in the shipping department of a factory.
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Student Misconceptions and Concerns
1. Students might have trouble connecting the diverse functions to the organelles. The pathway of secretory proteins is a good process to use to introduce the primary organelle functions. The movement of information and products extends generally from the central nucleus to the interconnected rough ER, to the more peripherally located Golgi, and finally to the outer plasma membrane. Introducing the steps of this process with the central to peripheral flow may help students better see the interrelationships and recall the sequence.
2. Conceptually, some students seem to benefit from the well-developed factory-like-a-cell analogy developed in the text. The use of this analogy in lecture might help to anchor these relationships.
Teaching Tips
1. The endoplasmic reticulum is continuous with the outer nuclear membrane. This explains why the ER is usually found close to the nucleus.
2. Some people think the Golgi apparatus looks like a stack of pita bread.
3. If you continue the factory analogy, the addition of a molecular tag is like adding address labels in the shipping department of a factory.
Figure 4.17 Two types of vacuoles
Figure 4.17a Contractile vacuole in Paramecium
Figure 4.17b Central vacuole in a plant cell
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Student Misconceptions and Concerns
1. Students might have trouble connecting the diverse functions to the organelles. The pathway of secretory proteins is a good process to use to introduce the primary organelle functions. The movement of information and products extends generally from the central nucleus to the interconnected rough ER, to the more peripherally located Golgi, and finally to the outer plasma membrane. Introducing the steps of this process with the central to peripheral flow may help students better see the interrelationships and recall the sequence.
2. Conceptually, some students seem to benefit from the well-developed factory-like-a-cell analogy developed in the text. The use of this analogy in lecture might help to anchor these relationships.
Teaching Tips
1. The endoplasmic reticulum is continuous with the outer nuclear membrane. This explains why the ER is usually found close to the nucleus.
2. Some people think the Golgi apparatus looks like a stack of pita bread.
3. If you continue the factory analogy, the addition of a molecular tag is like adding address labels in the shipping department of a factory.
Figure 4.18 Review of the endomembrane system
Figure 4.18a Review of the endomembrane system: art
Figure 4.18b Review of the endomembrane system: micrograph
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Student Misconceptions and Concerns
1. Students often mistakenly think that chloroplasts are a substitute for mitochondria in plant cells. They may falsely think that cells either have mitochondria or they have chloroplasts. You might wish to emphasize the presence and significance of mitochondria and chloroplasts in plant cells.
2. The evidence that mitochondria and chloroplasts evolved from free-living prokaryotes is further supported by the small prokaryote size of these organelles. Mitochondria and chloroplasts are therefore helpful in comparing the general size of eukaryotic and prokaryotic cells.
Teaching Tips
1. ATP functions in cells much like money functions in modern societies. Each holds value that can be generated in one place and spent in another. This analogy has been very helpful for many students.
2. Mitochondria and chloroplasts are each wrapped by multiple membranes. In both organelles, the innermost membranes are the sites of greatest molecular activity and the outer membranes have fewer significant functions. These outer membranes best correspond to the plasma membrane of the eukaryotic cells that originally wrapped the free-living prokaryotes during endocytosis.
3. Mitochondria and chloroplasts are not cellular structures that are synthesized in a cell like ribosomes and lysosomes. Instead, mitochondria only come from other mitochondria and chloroplasts only come from other chloroplasts. This is further evidence of the independent evolution of these organelles from free-living ancestral forms.
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Student Misconceptions and Concerns
1. Students often mistakenly think that chloroplasts are a substitute for mitochondria in plant cells. They may falsely think that cells either have mitochondria or they have chloroplasts. You might wish to emphasize the presence and significance of mitochondria and chloroplasts in plant cells.
2. The evidence that mitochondria and chloroplasts evolved from free-living prokaryotes is further supported by the small prokaryote size of these organelles. Mitochondria and chloroplasts are therefore helpful in comparing the general size of eukaryotic and prokaryotic cells.
Teaching Tips
1. ATP functions in cells much like money functions in modern societies. Each holds value that can be generated in one place and spent in another. This analogy has been very helpful for many students.
2. Mitochondria and chloroplasts are each wrapped by multiple membranes. In both organelles, the innermost membranes are the sites of greatest molecular activity and the outer membranes have fewer significant functions. These outer membranes best correspond to the plasma membrane of the eukaryotic cells that originally wrapped the free-living prokaryotes during endocytosis.
3. Mitochondria and chloroplasts are not cellular structures that are synthesized in a cell like ribosomes and lysosomes. Instead, mitochondria only come from other mitochondria and chloroplasts only come from other chloroplasts. This is further evidence of the independent evolution of these organelles from free-living ancestral forms.
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Student Misconceptions and Concerns
1. Students often mistakenly think that chloroplasts are a substitute for mitochondria in plant cells. They may falsely think that cells either have mitochondria or they have chloroplasts. You might wish to emphasize the presence and significance of mitochondria and chloroplasts in plant cells.
2. The evidence that mitochondria and chloroplasts evolved from free-living prokaryotes is further supported by the small prokaryote size of these organelles. Mitochondria and chloroplasts are therefore helpful in comparing the general size of eukaryotic and prokaryotic cells.
Teaching Tips
1. ATP functions in cells much like money functions in modern societies. Each holds value that can be generated in one place and spent in another. This analogy has been very helpful for many students.
2. Mitochondria and chloroplasts are each wrapped by multiple membranes. In both organelles, the innermost membranes are the sites of greatest molecular activity and the outer membranes have fewer significant functions. These outer membranes best correspond to the plasma membrane of the eukaryotic cells that originally wrapped the free-living prokaryotes during endocytosis.
3. Mitochondria and chloroplasts are not cellular structures that are synthesized in a cell like ribosomes and lysosomes. Instead, mitochondria only come from other mitochondria and chloroplasts only come from other chloroplasts. This is further evidence of the independent evolution of these organelles from free-living ancestral forms.
Figure 4.19 The chloroplast: site of photosynthesis
Figure 4.19a Chloroplast: art
Figure 4.19b Chloroplast: TEM
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Student Misconceptions and Concerns
1. Students often mistakenly think that chloroplasts are a substitute for mitochondria in plant cells. They may falsely think that cells either have mitochondria or they have chloroplasts. You might wish to emphasize the presence and significance of mitochondria and chloroplasts in plant cells.
2. The evidence that mitochondria and chloroplasts evolved from free-living prokaryotes is further supported by the small prokaryote size of these organelles. Mitochondria and chloroplasts are therefore helpful in comparing the general size of eukaryotic and prokaryotic cells.
Teaching Tips
1. ATP functions in cells much like money functions in modern societies. Each holds value that can be generated in one place and spent in another. This analogy has been very helpful for many students.
2. Mitochondria and chloroplasts are each wrapped by multiple membranes. In both organelles, the innermost membranes are the sites of greatest molecular activity and the outer membranes have fewer significant functions. These outer membranes best correspond to the plasma membrane of the eukaryotic cells that originally wrapped the free-living prokaryotes during endocytosis.
3. Mitochondria and chloroplasts are not cellular structures that are synthesized in a cell like ribosomes and lysosomes. Instead, mitochondria only come from other mitochondria and chloroplasts only come from other chloroplasts. This is further evidence of the independent evolution of these organelles from free-living ancestral forms.
<number>
Student Misconceptions and Concerns
1. Students often mistakenly think that chloroplasts are a substitute for mitochondria in plant cells. They may falsely think that cells either have mitochondria or they have chloroplasts. You might wish to emphasize the presence and significance of mitochondria and chloroplasts in plant cells.
2. The evidence that mitochondria and chloroplasts evolved from free-living prokaryotes is further supported by the small prokaryote size of these organelles. Mitochondria and chloroplasts are therefore helpful in comparing the general size of eukaryotic and prokaryotic cells.
Teaching Tips
1. ATP functions in cells much like money functions in modern societies. Each holds value that can be generated in one place and spent in another. This analogy has been very helpful for many students.
2. Mitochondria and chloroplasts are each wrapped by multiple membranes. In both organelles, the innermost membranes are the sites of greatest molecular activity and the outer membranes have fewer significant functions. These outer membranes best correspond to the plasma membrane of the eukaryotic cells that originally wrapped the free-living prokaryotes during endocytosis.
3. Mitochondria and chloroplasts are not cellular structures that are synthesized in a cell like ribosomes and lysosomes. Instead, mitochondria only come from other mitochondria and chloroplasts only come from other chloroplasts. This is further evidence of the independent evolution of these organelles from free-living ancestral forms.
Figure 4.20 The mitochondrion: site of cellular respiration
Figure 4.20a Mitochondrion: art
Figure 4.20b Mitochondrion: TEM
<number>
Student Misconceptions and Concerns
1. Students often mistakenly think that chloroplasts are a substitute for mitochondria in plant cells. They may falsely think that cells either have mitochondria or they have chloroplasts. You might wish to emphasize the presence and significance of mitochondria and chloroplasts in plant cells.
2. The evidence that mitochondria and chloroplasts evolved from free-living prokaryotes is further supported by the small prokaryote size of these organelles. Mitochondria and chloroplasts are therefore helpful in comparing the general size of eukaryotic and prokaryotic cells.
Teaching Tips
1. ATP functions in cells much like money functions in modern societies. Each holds value that can be generated in one place and spent in another. This analogy has been very helpful for many students.
2. Mitochondria and chloroplasts are each wrapped by multiple membranes. In both organelles, the innermost membranes are the sites of greatest molecular activity and the outer membranes have fewer significant functions. These outer membranes best correspond to the plasma membrane of the eukaryotic cells that originally wrapped the free-living prokaryotes during endocytosis.
3. Mitochondria and chloroplasts are not cellular structures that are synthesized in a cell like ribosomes and lysosomes. Instead, mitochondria only come from other mitochondria and chloroplasts only come from other chloroplasts. This is further evidence of the independent evolution of these organelles from free-living ancestral forms.
<number>
Student Misconceptions and Concerns
1. Students often regard the fluid of the cytoplasm as little more than a watery fluid, which suspends the organelles. The diverse functions of thin, thick, and intermediate filaments are rarely appreciated before college.
2. Students often think that the cilia on the cells lining our trachea function like a comb, removing debris from the air. Except in cases of disease or damage, these respiratory cilia are instead covered by mucus. Cilia lining our trachea do not reach the air to comb it. Instead, these cilia sweep the dirty mucus up our respiratory tracts. (See also Teaching Tip #2 below.)
3. The dynamic, web-like structure of the cytoskeleton is very different from the skeletons that students may already know. Their dynamic structures (see Teaching Tip #2 below) are quite unlike any human designs. Students have much to gain from vivid illustrations of cytoskeletal diversity. Consider sharing some impressive images from a Google image search or other resources.
Teaching Tips
1. Students might enjoy this brief class activity. Have everyone in the class clear their throats at the same time. Wait a few seconds. Have them notice that after clearing, they swallowed. The mucus that trapped debris is swept up the trachea by cilia. When we clear our throats, this dirty mucus is disposed of down our esophagus and amongst the strong acids of our stomach!
2. Analogies between the infrastructure of human buildings and the cytoskeleton are limited by the dynamic nature of the cytoskeleton. Few human structures have their structural framework routinely constructed, deconstructed, and then reformed in a new configuration on a regular basis. (Tents are often constructed, deconstructed, and then reformed repeatedly but typically rely upon the same basic design.) Thus, caution is especially warranted in such analogies.
<number>
Student Misconceptions and Concerns
1. Students often regard the fluid of the cytoplasm as little more than a watery fluid, which suspends the organelles. The diverse functions of thin, thick, and intermediate filaments are rarely appreciated before college.
2. Students often think that the cilia on the cells lining our trachea function like a comb, removing debris from the air. Except in cases of disease or damage, these respiratory cilia are instead covered by mucus. Cilia lining our trachea do not reach the air to comb it. Instead, these cilia sweep the dirty mucus up our respiratory tracts. (See also Teaching Tip #2 below.)
3. The dynamic, web-like structure of the cytoskeleton is very different from the skeletons that students may already know. Their dynamic structures (see Teaching Tip #2 below) are quite unlike any human designs. Students have much to gain from vivid illustrations of cytoskeletal diversity. Consider sharing some impressive images from a Google image search or other resources.
Teaching Tips
1. Students might enjoy this brief class activity. Have everyone in the class clear their throats at the same time. Wait a few seconds. Have them notice that after clearing, they swallowed. The mucus that trapped debris is swept up the trachea by cilia. When we clear our throats, this dirty mucus is disposed of down our esophagus and amongst the strong acids of our stomach!
2. Analogies between the infrastructure of human buildings and the cytoskeleton are limited by the dynamic nature of the cytoskeleton. Few human structures have their structural framework routinely constructed, deconstructed, and then reformed in a new configuration on a regular basis. (Tents are often constructed, deconstructed, and then reformed repeatedly but typically rely upon the same basic design.) Thus, caution is especially warranted in such analogies.
<number>
Student Misconceptions and Concerns
1. Students often regard the fluid of the cytoplasm as little more than a watery fluid, which suspends the organelles. The diverse functions of thin, thick, and intermediate filaments are rarely appreciated before college.
2. Students often think that the cilia on the cells lining our trachea function like a comb, removing debris from the air. Except in cases of disease or damage, these respiratory cilia are instead covered by mucus. Cilia lining our trachea do not reach the air to comb it. Instead, these cilia sweep the dirty mucus up our respiratory tracts. (See also Teaching Tip #2 below.)
3. The dynamic, web-like structure of the cytoskeleton is very different from the skeletons that students may already know. Their dynamic structures (see Teaching Tip #2 below) are quite unlike any human designs. Students have much to gain from vivid illustrations of cytoskeletal diversity. Consider sharing some impressive images from a Google image search or other resources.
Teaching Tips
1. Students might enjoy this brief class activity. Have everyone in the class clear their throats at the same time. Wait a few seconds. Have them notice that after clearing, they swallowed. The mucus that trapped debris is swept up the trachea by cilia. When we clear our throats, this dirty mucus is disposed of down our esophagus and amongst the strong acids of our stomach!
2. Analogies between the infrastructure of human buildings and the cytoskeleton are limited by the dynamic nature of the cytoskeleton. Few human structures have their structural framework routinely constructed, deconstructed, and then reformed in a new configuration on a regular basis. (Tents are often constructed, deconstructed, and then reformed repeatedly but typically rely upon the same basic design.) Thus, caution is especially warranted in such analogies.
Figure 4.21 The cytoskeleton
Figure 4.21a Microtubules in the cytoskeleton
Figure 4.21b Microtubules and movement
<number>
Student Misconceptions and Concerns
1. Students often regard the fluid of the cytoplasm as little more than a watery fluid, which suspends the organelles. The diverse functions of thin, thick, and intermediate filaments are rarely appreciated before college.
2. Students often think that the cilia on the cells lining our trachea function like a comb, removing debris from the air. Except in cases of disease or damage, these respiratory cilia are instead covered by mucus. Cilia lining our trachea do not reach the air to comb it. Instead, these cilia sweep the dirty mucus up our respiratory tracts. (See also Teaching Tip #2 below.)
3. The dynamic, web-like structure of the cytoskeleton is very different from the skeletons that students may already know. Their dynamic structures (see Teaching Tip #2 below) are quite unlike any human designs. Students have much to gain from vivid illustrations of cytoskeletal diversity. Consider sharing some impressive images from a Google image search or other resources.
Teaching Tips
1. Students might enjoy this brief class activity. Have everyone in the class clear their throats at the same time. Wait a few seconds. Have them notice that after clearing, they swallowed. The mucus that trapped debris is swept up the trachea by cilia. When we clear our throats, this dirty mucus is disposed of down our esophagus and amongst the strong acids of our stomach!
2. Analogies between the infrastructure of human buildings and the cytoskeleton are limited by the dynamic nature of the cytoskeleton. Few human structures have their structural framework routinely constructed, deconstructed, and then reformed in a new configuration on a regular basis. (Tents are often constructed, deconstructed, and then reformed repeatedly but typically rely upon the same basic design.) Thus, caution is especially warranted in such analogies.
<number>
Student Misconceptions and Concerns
1. Students often regard the fluid of the cytoplasm as little more than a watery fluid, which suspends the organelles. The diverse functions of thin, thick, and intermediate filaments are rarely appreciated before college.
2. Students often think that the cilia on the cells lining our trachea function like a comb, removing debris from the air. Except in cases of disease or damage, these respiratory cilia are instead covered by mucus. Cilia lining our trachea do not reach the air to comb it. Instead, these cilia sweep the dirty mucus up our respiratory tracts. (See also Teaching Tip #2 below.)
3. The dynamic, web-like structure of the cytoskeleton is very different from the skeletons that students may already know. Their dynamic structures (see Teaching Tip #2 below) are quite unlike any human designs. Students have much to gain from vivid illustrations of cytoskeletal diversity. Consider sharing some impressive images from a Google image search or other resources.
Teaching Tips
1. Students might enjoy this brief class activity. Have everyone in the class clear their throats at the same time. Wait a few seconds. Have them notice that after clearing, they swallowed. The mucus that trapped debris is swept up the trachea by cilia. When we clear our throats, this dirty mucus is disposed of down our esophagus and amongst the strong acids of our stomach!
2. Analogies between the infrastructure of human buildings and the cytoskeleton are limited by the dynamic nature of the cytoskeleton. Few human structures have their structural framework routinely constructed, deconstructed, and then reformed in a new configuration on a regular basis. (Tents are often constructed, deconstructed, and then reformed repeatedly but typically rely upon the same basic design.) Thus, caution is especially warranted in such analogies.
Figure 4.22 Flagella and cilia
Figure 4.22a Flagellum of a human sperm cell
Figure 4.22b Cilia on a protist
Figure 4.22c Cilia lining the respiratory tract
<number>
Student Misconceptions and Concerns
1. Students often regard the fluid of the cytoplasm as little more than a watery fluid, which suspends the organelles. The diverse functions of thin, thick, and intermediate filaments are rarely appreciated before college.
2. Students often think that the cilia on the cells lining our trachea function like a comb, removing debris from the air. Except in cases of disease or damage, these respiratory cilia are instead covered by mucus. Cilia lining our trachea do not reach the air to comb it. Instead, these cilia sweep the dirty mucus up our respiratory tracts. (See also Teaching Tip #2 below.)
3. The dynamic, web-like structure of the cytoskeleton is very different from the skeletons that students may already know. Their dynamic structures (see Teaching Tip #2 below) are quite unlike any human designs. Students have much to gain from vivid illustrations of cytoskeletal diversity. Consider sharing some impressive images from a Google image search or other resources.
Teaching Tips
1. Students might enjoy this brief class activity. Have everyone in the class clear their throats at the same time. Wait a few seconds. Have them notice that after clearing, they swallowed. The mucus that trapped debris is swept up the trachea by cilia. When we clear our throats, this dirty mucus is disposed of down our esophagus and amongst the strong acids of our stomach!
2. Analogies between the infrastructure of human buildings and the cytoskeleton are limited by the dynamic nature of the cytoskeleton. Few human structures have their structural framework routinely constructed, deconstructed, and then reformed in a new configuration on a regular basis. (Tents are often constructed, deconstructed, and then reformed repeatedly but typically rely upon the same basic design.) Thus, caution is especially warranted in such analogies.
<number>
Student Misconceptions and Concerns
1. Students often regard the fluid of the cytoplasm as little more than a watery fluid, which suspends the organelles. The diverse functions of thin, thick, and intermediate filaments are rarely appreciated before college.
2. Students often think that the cilia on the cells lining our trachea function like a comb, removing debris from the air. Except in cases of disease or damage, these respiratory cilia are instead covered by mucus. Cilia lining our trachea do not reach the air to comb it. Instead, these cilia sweep the dirty mucus up our respiratory tracts. (See also Teaching Tip #2 below.)
3. The dynamic, web-like structure of the cytoskeleton is very different from the skeletons that students may already know. Their dynamic structures (see Teaching Tip #2 below) are quite unlike any human designs. Students have much to gain from vivid illustrations of cytoskeletal diversity. Consider sharing some impressive images from a Google image search or other resources.
Teaching Tips
1. Students might enjoy this brief class activity. Have everyone in the class clear their throats at the same time. Wait a few seconds. Have them notice that after clearing, they swallowed. The mucus that trapped debris is swept up the trachea by cilia. When we clear our throats, this dirty mucus is disposed of down our esophagus and amongst the strong acids of our stomach!
2. Analogies between the infrastructure of human buildings and the cytoskeleton are limited by the dynamic nature of the cytoskeleton. Few human structures have their structural framework routinely constructed, deconstructed, and then reformed in a new configuration on a regular basis. (Tents are often constructed, deconstructed, and then reformed repeatedly but typically rely upon the same basic design.) Thus, caution is especially warranted in such analogies.
Figure 4.23 The changing role of antibiotics
Figure 4.23a Penicillin poster
Figure 4.23b CDC poster
Figure UN1 Plasma membrane orientation figure
Figure UN2 Nucleus orientation
Figure UN3 Ribosome orientation
Figure UN4 Endoplasmic reticulum orientation
Figure UN5 Golgi apparatus orientation
Figure UN6 Lysosome orientation
Figure UN7 Vacuole orientation
Figure UN8 Chloroplast orientation
Figure UN9 Mitochondrion orientation
Figure UN10 Cytoskeleton orientation
Figure UN11 Cilia and flagella orientation
Figure UN12 Summary: categories of cells
Figure UN13 Summary: plasma membrane
Figure UN14 Summary: chloroplast and mitochondrion
