bcm33

Question 1

most important determinants to get through membrane

Answer 1

polarity
charge
concentration gradeitn

Question 2

3 ways to cross membrane

Answer 2

1. passive diffusion down ec conc grad
2. faciliated d down ec conc grad
3. at against conc grad
   - primary = light energy
   - seconadary trade one gradient for another

Question 3

example of faciliated diffusion

Answer 3

ionophores
ion channels
porins
K+ channel vita for gen resting potential

Question 4

what is patch clamping

Answer 4

study transport through membrane
thin quarts glass pippettte with blunt end sealed onto membrane suction applied to seal tight
pore isolated all ions flow into pippete
recorded by silver chloride electrode sensitive amplifier

Question 5

ficks law

Answer 5

diffusion of a chemical occurs in the direction that eliminates its concentration gradient at a rate proportional to the magnitude of this gradient.
j= d [a] out -[a]in / x
j= influx/sec/unit area
d= diffusivity coefficient for a, viscoity of membrane, oil solubility
x= membrane thickness

Question 6

osmosis

Answer 6

facilitated diffusion through aquaporins

mutation of aqua porin 2 causes rare form of diabetes insipidus.

Question 7

what kinetics does fd show?

Answer 7

saturation kinetics

transporters= enzymes

Question 8

ionophores

Answer 8

small non protein molecules that mediate diffusion
eg. valinomycin
antibiotic carries 10^5 K+ accross membrane

Question 9

concentration of ions in blood

Answer 9

K+ is much lower
Na+ is much higher
Cl- is much higher
Ca2+ is much higher

Question 10

uni port

• mechanism
• example

Answer 10

1 way, 1 ion
calcium p type atpase
restores ca2+ gradient accross sarcoplasmic reticulum

Question 11

antiport
mechanism
example

Answer 11

2 ions opposite directions
Na+/K+ type Atpase
maintain resting potential of mammal cells

Question 12

symport
mechanism
example

Answer 12

2 ions same direction
glucose Na+
move glucose into intestine