1. Cellular Transport
aka how to molecules move
in/out of the cell?

2. Let’s examine the cell membrane
• The membrane is
selectively permeable
– Allows only certain
molecules to move
into or out of the cell.

3. Molecules that can pass freely
• The cell membrane is permeable to water
molecules and a few other small,
uncharged, molecules like
oxygen (O2) and carbon dioxide (CO2).

4. Types of molecules that are NOT
permeable to the cell membrane
• Macromolecules such as proteins and
RNA.
• Cations such as K+, Na+, Ca+
• Anions such as Cl-
• Hydrophilic molecules such as glucose

5. Passive Movement
• Does not require energy or an action
– Examples: diffusion and osmosis

6. Diffusion
• Movement of a molecule
from a high concentration
to a low concentration.
• Down the concentration
gradient.
• Think of this as rolling a
ball down a hill, going
from a high point to a low
point

7. Diffusion

8. Osmosis
• Diffusion of water, its
the movement from a
high concentration of
solvent to a lower
concentration of
solvent.
• Solvent is typically
water

9. Animation: How Osmosis Works

10. Various osmotic conditions
• Remember osmosis is all about the
concentration of the solvent and
the the solute.
• Knowing this allows for different
osmotic conditions to occur.
• Think about eating a bag of salty
chips… what do your lip feel like
after that??
• FOR THE NEXT SECTION WE WILL DO
ALL THE DRAWINGS TOGETHER

11. Hypertonic
• Hypertonic (above
normal) the cell
is hypertonic to
the
environment,there
is water
movement out of
cell.
• hypertonic
solution="more
solute, less
water"
• The cell shrivels

12. Hypertonic:

13. Hypotonic
• Hypotonic (below
normal) the cell
is hypotonic to the
environment,
there is water
movement into of
cell.
• hypotonic
solution = "less
solute, more
water"
• The cell bursts!

14. Hypotonic

15. Isotonic
• Isotonic is
equilibrium and
there is equal
movement into
and out of the
cell
• isotonic
solution= "equal
solute and water"

16. Isotonic

17. Try to figure out what is going
on in the Carrot video
• It’s kind of corny but • http://www.youtube.co
really gets the point m/watch?v=aiUCeNs
across 4bo4

19. So how does the cell get the other
molecules what is needs to
survive?
• By using other mechanisms of transporting
ions and small molecules across their
membranes that require movement or
ENERGY

20. Facilitated Difffusion
• Uses a protein
embedded in the cell
membrane to “help”
diffuse the molecule
thru a channel
• EX. (+/- )ions, sugars,
and salts

21. Facilitated Diffusion
• http://www.youtube.com/watch?v=I4123h
UU8xo&feature=related

22. Active Transport
• Movement of molecules from a low
concentration to a high concentration with
the use of energy.
• Think of it like moving a boulder up a hill, it
would require a bit of energy to get it up
the hill.

24. Endocytosis
• Engulfing of a solid or
liquid
• -phago (solid)
• -pino (liquid)

25. Phagocytosis

26. Exocytosis
• Opposite of
endocytosis
• The Golgi body
creates a vesicle
around molecules.
• Moves the vesicle
towards the cell
membrane and gets
rid of it.

27. Endo and Exocytosis

28. Difference between each cell
type
Prokaryote Cells Eukaryote Cells
• Do not have a defined nucleus • Contain true nuclei in which
• Chromosomes are dispersed in chromosomes are compacted
the cytoplasm as chromatin
• Contain no membrane-bound • Contain membrane-bound
organelles organelles
• Have circular chromosomes • Have linear DNA called
• Small chromosomes
• Don't undergo meiosis but • Larger
reproduce sexually by the • Reproduce sexually with the
transfer of DNA fragments use of meiosis
through conjugation

30. Examples of each type of cell