Dr. Davenport's lecture

Question 1

polar molecule

Answer 1

molecule that does not have an even distribution of charges

Question 2

nonpolar molecule

Answer 2

molecule that has an even distribution of charges

Question 3

lipid bilayer

Answer 3

a double layer of phospholipid molecules that have a polar/hydrophilic region (choline polar head group) and a nonpolar/hydrophobic region (fatty acyl chains), which separates intra and extracellular environments

Question 4

what functions do proteins carry out in the cell membrane?

Answer 4

proteins make channels through the membrane for ions (conformation determines whether the channel is open or closed)

Question 5

what is driving force?

Answer 5

something that provides the energy for a net movement of molecules from one solution to another

Question 6

what is the relationship between cell permeability and lipid solubility?

Answer 6

cell permeability describes the ability of a molecule to cross the membrane. lipophilic molecules readily cross the cell membranes because they can traverse the lipophilic center (they’re nonpolar)

Question 7

what is the resting membrane potential (RMP)?

Answer 7

the static membrane potential of relatively quiescent cell, caused by a semi-permeable membrane and a concentration gradient for ions. There will be a separation of charge if the membrane is impermeable to one ion. The situation will remain as long as the membrane conditions for the ions remain constant.

Question 8

what is an action potential?

Answer 8

gated channels are responsible for pumping Na+ out of the cell and pumping K+ into the cell, against the net electrochemical gradient

Question 9

what is electrochemical equilibrium?

Answer 9

when the concentration gradient equals the electrical gradient, which requires an ion selective semipermeable membrane

Question 10

what is hyperpolarization?

Answer 10

when the RMP is becoming more negative

Question 11

what is depolarization?

Answer 11

when the RMP is becoming less negative