2. From cells to organisms
Human beings are
composed of
biomolecules.
They are made up of
cells.
They perform 3 vital
functions:
◦ Nutrition
◦ Reaction to stimuli
◦ Reproduction
3. Cell size
Microscopic objects are
meassured in:
◦ μm = 10-3 mm
◦ nm = 10-6 mm
These are not visible
with a naked eye.
Eye resolution is 0.2 mm
◦ If two objects are
separated by a smaller
distance, we will see them
as one.
Exercise:
If an object meassures 1
mm, how many
micrometers does it
meassure? And how
many nanometers?
4. Activity
5 cm
Image increased: 1500 times
How large is the
Paramecium in
reality?
5cm
1500
= 0,0033 cm How many µm is that?
33 µm
5. Biomolecules
Rich in carbon
◦ Proteins: give
structure..transport…
muscle.
◦ Lipids: fat
◦ Carbohidrates: sugar
◦ Nucleic acids: form the
nucleus. Genetic
material.
6. What do all cells have in common?
Cellular membrane
Cytoplasm
Nucleus
7. Cell membrane
It is a thin layer that covers the cell and serves
as a boundary between the cell and the
surrounding.
8. Cytoplasm
Inner content of the cell mainly made of
water and where different structures,
called organelles, are found.
9. Organelles: Nucleus
It is the largest and most visible structure in the
cell. It’s shaped like a sphere and normally in the
center of the cell. It contains the material necessary
to control all cell functions.
Nuclear envelope: made of a double membrane which
has pores that allow the exchange of substances
Chromatin: filaments of genetic material which has
the information that controls how the cell functions
Nucleolus: The ribosomes are synthesized in here
It’s structure changes depending on the phase of the
cell cycle. The chromatin condenses into structures
called chromosomes during cell division.
CONTROL
12. Organelles: Mitochondria
• All cells need mitochondria to obtain energy from nutrients
• Mitochondria have an oval shape with a double membrane.
• The cell obtains energy from small organic molecules using
oxygen through a process called cellular respiration
• http://www.shmoop.com/biology-cells/botw/resources?d=http://multimedia.mcb.harvard.edu/
With
OXYGEN
Respiration
http://www.youtube.com/watch?v=xbJ0nbzt5Kw&feature=relmfu
http://www.youtube.com/watch?v=3y1dO4nNaKY&feature=relmfu
13. Organelles: Endoplasmic
Reticulum
• It’s made of membrane
canals and sacks that extend
throughout the cytoplasm
with grain like structures
called ribosomes.
• Rough ER
• In the reticulum many
different substances are
produced.
• The ER without ribosomes is
the Smooth ER.
14. Organelles: Lysosomes
• Membrane bound
vesicles that
transform complex
structures into
simpler ones.
• Some nutrients reach
the cell already
transformed in small
molecules. If not
they are digested
into smaller
molecules by the
lysosomes.
16. Organelles: Ribosomes
Small particles
found loose in the
cytoplasm or
attatched to the
ER membrane.
They synthesize
proteins.
They are produced
in the nucleolus.
17. Organelles: Centrioles
2 hollow ciliders
which walls are
made of
filaments.
They are in
charge of moving
the cytoskeleton
and play a main
role in cell
division.
18. Organelles: cytoskeleton
Group of filaments that are
distributed making a network
around the cytoplasm.
Most of the time cells respond
with movements to stimuli.
The structures responsible for
this movement are the filaments
of the cytoskeleton