1. UNIT 1: THE CELL

2. Hans and Zacharias Janssen
(father and son), late 16th century
- Dutch spectacle makers, inventors
of the first microscope (simple, and
compound).
- Also associated with the invention
of the first telescope.
simple (single-lens)
microscope

3. Robert Hooke (1635-1702)
- observed cork under the
microscope
- used the word CELLS for the first
time, to describe the tiny, empty
chambers he saw.

4. Anton van Leeuwenhoek (1632-1723)
- Dutch cloth merchant.
- “father of microbiology: he used a
simple microscope to observe pond
water... and discoverd a whole new
world of living microorganisms!
- he was the first one to observe
living cells, among them: bacteria,
sperm cells, blood cells, protozoa...

5. Robert Brown (1773-1858)
- he discovered the cell nucleus,
in plant cells.

6. Matthias Jakob Schleiden
(1804-1881)
- German botanist.
- Observed plants under the
microscope, and concluded:
“All plants are made of cells” (1838)

7. Friedrich Theodor Schwann
1810-1882)
- German physiologist and anatomist.
- He studied animal tissues under the microscope,
and concluded:
“All animals are made of cells” (1839)

8. Rudolf Carl Virchow (1821-1902)
- German doctor and pathologist.
- He studied cell reproduction and
concluded:
“All cells come from pre-existing cells”
(1858)
Louis Pasteur refuted one year later for
good the “Spontaneus Generation”

9. The CELL THEORY is the result of the discoveries
of Schleiden, Schwann and Virchow, and consists
on 3 principles:



ALL ORGANISMS ARE MADE OF CELLS
THE CELL IS THE BASIC UNIT OF LIFE IN ALL
LIVING THINGS (structural and functional unit)
ALL CELLS COME FROM THE DIVISION OF
PRE-EXISTING CELLS

10. Santiago Ramón y Cajal
(1852-1934)
- Spanish doctor, who
studied the Nervous System
- He proved that neurons were independent cells,
which finally confirmed the Cell Theory.
- He was awarded the Nobel Prize in
Physiology and Medicine

12. Levels of Organization of the Living Beings

14. The Elements of Life:
Bulk Elements:
C H O N
P
They form aprox. 99% of living matter
They are found in ALL living things
S
Trace Elements:
Ca Na K
Cl Fe Cu
F
I Zn
They form <1% of living matter (if <0.1%
they are called oligo-elements
Some of them are common to all living
beings, some others are specific

15. Elements in the living beings:

16. The Molecules of Life (Biomolecules):
Inorganic:
WATER
MINERALS
(common to non-living and
living matter)
CARBOHYDRATES
LIPIDS
(only in living matter
they all contain C)
Organic:
PROTEINS
NUCLEIC ACIDS

17. WATER:
Most abundant molecule in the cells.
Important biological functions:
“Universal Solvent”
Substance exchange between cell/medium,
transport, removal.
Temperature buffer: moderates the temperature changes
in the cell

18. MINERALS:
Present in two forms:
Precipitated (solid): bones, shells, etc.
Ions (dissolved): regulating several cellular
processes

20. CARBOHYDRATES (I):
- Formed by C, H and O:
- Three main types:
Cn(H2O)n
MONOSACCHARIDES
DISACCHARIDES
Sweet and soluble
Only one molecule:
1: 2: 1
Sweet and soluble
SUGARS
Two molecules of monosaccharides
Sucrose
ENERGETIC
Ribose
Glucose
Lactose

21. CARBOHYDRATES (II):
POLYSACCHARIDES
Not sweet, not soluble
Many molecules of monosaccharides
ENERGY
STORAGE
PLANTS
ANIMALS
STRUCTURAL
Starch
Cellulose
Glycogen
Chitin

22. LIPIDS (I):
All of them formed by C, H and O.
Some of them contain N and P.
None of them are soluble in water.
Triglicerids (fats, oils)
Phospholipids
Types of lipids
Contain
FATTY ACIDS
Waxes
Terpens
Steroids
Do NOT contain FATTY ACIDS

23. LIPIDS (II):
Fatty Acids:
long chains of C, H and O
Triglicerids (fats and oils):
3 fatty acid chains attached to a glycerol molecule
They store
energy.
Phospholipids:
They contain P.
They constitute the cell membranes
(structural)
.

24. LIPIDS (III):
Waxes:
Protect the leaves and fruits in plants, and skin, hair and feathers in
animals. (structural)
Terpenes:
- Aromatic oils and pigments in plants.
- Some vitamins: A,E and K are terpenes.
Steroids:
- Some vitamins: D
(regulatory)
- Some hormones: sex hormones (testosterone, estrogens)
and other hormones (cortisone, aldosterone)
- Biliar acids
- Cholesterol
(structural)

25. PROTEINS (I):
Formed by C, H, O, N (and S)
Long chains (polymers) of basic
units (monomers) called AMINO
ACIDS
There are 20 types of amino acids.
Proteins are different depending
on their sequence (order)
Proteins are folded in space. Their
function depends on this tridimensional structure.

26. PROTEINS (II):
Functions:
Structural: cell membranes, cell organelles.
Catalytic: enzymes make possible cell reactions.
Transportation of oxygen (hemoglobin) and other
substances.
Regulatory: some hormones are proteins (insulin)
Muscular contraction: actin, myosin
Defense: some proteins belong to the IS: antibodies
(energetic)

27. NUCLEIC ACIDS (I):
- Formed by C, H, O, N and P.
- They are chains (polymers) of basic units
(monomers) called nucleotides.
nucleotide
polinucleotide

28. NUCLEIC ACIDS (II):
DNA (DeoxyriboNucleic
Acid)
- carries the hereditary
information of the cell

29. RNA (RiboNucleic Acid)
- takes the information in the
DNA and helps to make
proteins with it

30. Parts of a Compound Light Microscope

32. Prokaryotic cell
No nucleus
Circular DNA floating in the cytoplasm
No membranous organelles
Ribosomes
Mesosomes
Cell wall covering
the Cell Memebrane
Capsule
Flagellum

33. Eukaryotic Cell: Plant Cell

34. Eukaryotic Cell: Animal Cell

35. Viruses
Not cells
DNA or RNA + protein capsid
Some have an envelope
Obligatory parasites of animals,
Bacteriophage
Influenza
plants or bacteria.
TMV

36. Cell Membrane
A phospholipid bilayer with
proteins.
Isolates the cell and controls the
substance exchange with the
medium.
Cytoplasm
Content of the cell:
Cytosol (liquid): water and soluble substances.
Cell Organelles

37. Nucleus
Controls the cell activity.
Double membrane, with pores.
Nucleoplasm.
Nucleolus (RNA+proteins): where
ribosomes are formed.
Chromatin (DNA+proteins)
transforms into chromosomes
when the cell is going to divide.

38. Cell Wall
Only present in plant cells.
It covers and protects the cell membrane.
It gives the cell a fixed shape.
Formed by a matrix of cellulose molecules.

39. Mitochondria
Double membrane (outer and inner
The inner membrane forms cristae.
The inner space (matrix) contains
DNA and ribosomes!
They produce energy in a metabolic
process called cellular respiration.

40. Chloroplasts
Only present in plant cells.
Like mitochondria, they have a double
membrane (outer and inner).
Like mitochondria, they have DNA and
ribosomes.
The inner membrane forms a system of
sacs piled up forming structures called
thylakoids. The stacks of thylakoids are
called grana.
The space inside the inner membrane is
called stroma.
They contain pigments like chlorophyll,
that make photosynthesis possible.

41. Endoplasmic Reticulum
System of membranes that
extend over the cytoplasm.
Two types:
ROUGH ER: with ribosomes
attached. Produces, stores and
trasnports proteins
SMOOTH ER: no ribosomes.
Produces, stores and
transports lipids.

42. Golgi Apparatus (or Complex)
Composed of membranous flat sacs piled
up forming stacks.
It modifies the substances that receives
from the ER, and secrets them outside the
cell.
Lysosomes
Vesicles formed in the Golgi
Complex.
They contain digestive enzymes
that break down large
molecules or cell organelles.
If they broke, the cell would be
destroyed by them.

43. Vacuoles
Vesicles that store substances.
Plant cells usually have 1 or 2 big vacuoles.
Animal cells have many small vacuoles.

44. Ribosomes
Present in all types of cells (prokaryotic and eukaryotic)
Composed of RNA and proteins. Produced in the nucleolus.
Not membranous.
May be floating free in the cytoplasm or attached to the RER
They synthesize (=produce) proteins.

45. Cytoskeleton
Only present in animal cells.
Composed of protein filaments of two types:
Microfilaments
Microtubules
Functions:
Helps the cell to divide (mitosis)
Contraction
Cell movement (form pseudopodia)
Transport inside the cytoplasm.
Form the centriols, cillia and flagella.

46. Centrosome
Only present in animal cells.
Composed of two centrioles,
one perpendicular to the other.
It organizes the cytoskeleton
and helps the cell to divide
(mitotic spindle)

47. Cillia and Flagella
Only found in animal cells (unicellular or multicellular organisms).
Extensions of the cell membrane that are able to move.
They have the same structure, but cillia are shorter and more numerous
than flagella.
They allow the cells to move (protozoa, sperm cells...); they also help the
cell to capture nutrients from the environment, and move the liquids on the
surface of the cells (respiratory epithelia)

48. Transport through
the Cell Membrane

49. Cells need to exchage substances with their environment, in order to get
materials for nutrition and remove wastes.
This exchage can be:
PASSIVE:
ACTIVE:
does NOT require ENERGY
down a gradient (high to low)
requires ENERGY
up a gradient (low to high)

50. Passive Transport (I): DIFFUSION
Small molecules like gases (O2, CO2), water, nutrients move through
the cell membrane from the area of higher concentration to the area
of lower concentration, until the gradient disappears (concentration
equals)
Permeable to
the solute

51. Passive Transport (II): FACILITATED DIFFUSION
Some molecules need the help of a carrier, a protein in the cell
membrane, to enter or exit the cell.

52. Passive Transport (III): OSMOSIS
Special term used for the diffusion of water through a semi-permeable cell
membrane (= only allows the solvent -water – to go through it)
Water moves frome the HYPOTONIC solution to the HYPERTONIC
solution.
Semi-permeable
membrane

56. ACTIVE TRANSPORT
Movement occurs against the concentration
gradient (from low to high concentration)
A carrier protein in the membrane is required, as
well as energy.

57. ENDOCYTOSIS / EXOCYTOSIS
Transport of large particles through the cell membrane, using vesicles.
and requiring energy.
EXOCYTOSIS: waste products are placed in vesicles that then fuse
with the cell membrane, releasing their contents outside the cell.
ENDOCYTOSIS: the cell membrane engulfs a large molecule outside
the cell and releases it inside. There are two types of endocytosis:
PHAGOCYTOSIS: the cell takes solid food particles.
PINOCYTOSIS: the cell takes nutrients dissolved in fluids.