The document discusses cellular transport and the cell membrane. It explains that the cell membrane is selectively permeable, allowing small uncharged molecules like oxygen and carbon dioxide to pass freely through diffusion and osmosis. Larger molecules and ions require energy-requiring mechanisms like active transport or facilitated diffusion. The document contrasts passive transport mechanisms like diffusion and osmosis, which move molecules down concentration gradients without energy, with active transport which moves molecules against gradients by using cellular energy. It also briefly discusses endocytosis and exocytosis for transporting larger particles and molecules in and out of cells.

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