Exam 1: lecture 5

Question 1

Types of passive transport

Answer 1

no energy required
1) osmosis: water
2) simple diffusion: small molecules (gases: CO2& O2, H20)
3) ion channel diffusion (Cl- HCO3-)
4) facilitated carrier diffusion (glucose)

Question 2

Rules of membrane diffusion

Answer 2

size rule- small molecules get past
charge rule- no charged molecules get past
polarity rule-nonpolar molecules (hydrophic) get past wile polar molecule do not

Question 3

summary of relative permeabilities

Answer 3

hydrophobic molecule: O2, CO2, N2 (size and polarity)
small, uncharged polar molecules (h2o, glycerol)
large, uncharged polar molecules (glucose, sucrose)
ions (h+, Na+, ca2+)

Question 4

fluidity

Answer 4

allows membrane to adapts its shapes and movement to different condition

Question 5

permeability

Answer 5

the rate of diffusion-only selected ones

Question 6

what changes the fluidity and permeablity of membranes

Answer 6

kinks

bilayer with saturated fatty acids have LOW permeability
bilayer with unsaturated fatty acid have HIGh permeability

Question 7

what does cholesterol do in membranes

Answer 7

fill spaces between phospholipids

*the more cholesterol in the membrane, the less permeable it is

Question 8

cholesterol membrane paradox

Answer 8

cholesterol increases the fluidity but decreases permeability (water) because it causes the membrane to become more hydrophobic

***cholesterol up, fluidity up, permeability down (harder to get across due to it being more nonpolar)