1. The Human Body
A multicellular organism.The cell.

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

10. Activity How many cells
do you see in
the image?

11. The cell: organelles

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.

15. Organelles: Vacuoles
 Membranous
vesicles which
store dissolved
substances as
reserves or waste.
Membrane of
vacuoles in plant cells

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