CH. 11: Lecture Questions COMPLETE

Question 1

Which is least likely to diffuse across a lipid bilayer?

A. Hydrophobic molecules
B. H2O
C. Large uncharged polar molecules
D. ions

Answer 1

B. H2O

Question 2

Which is most likely to diffuse across a lipid bilayer?

A. Hydrophobic molecules
B. H2O
C. Large uncharged polar molecules
D. ions

Answer 2

A. Hydrophobic molecules

Question 3

Passive transport:

Answer 3

All channels and some transporters allow
solutes to cross the membrane only “downhill” (i.e. in the
direction of the chemical or electrochemical gradient).

Question 4

Simple diffusion:

Answer 4

movement directly across a membrane without a role of a transmembrane protein

Question 5

Facilitated diffusion
Facilitative transport
Vmax (V for velocity): maximal rate of transport, when all solute-
binding sites are occupied)

True or False

Answer 5

True

Question 6

Secondary active transport:

Answer 6

active transport builds gradient that drives coupled transport

Question 7

What kind of transporter is the cystic fibrosis transmembrane conductance regulator
(CFTR)?

Answer 7

ABC transporter that acts as a gated Cl- channel
and regulates extracellular ion concentrations, including
retention of Na+ in extracellular fluid.

Question 8

Ion pumps and channels create an osmotic gradient
H2O follows through aquaporins.

True or False

Answer 8

True

Question 9

Central asparagine side chains in the pore align water molecules, preventing the normal relay of H+ from one H2O molecule to the next.

True or False

Answer 9

True

Question 10

Which end of a helix is Na+ attracted to:

A. N-terminal end
B. C-terminal end

Answer 10

B. C-terminal end

Question 11

Voltage-gated channels automatically inactivate after opening, and a refractory period prevents rapid, repetitive opening.

True or False

Answer 11

True

Question 12

In skeletal muscle, acetylcholine causes:

A. Depolarization
B. polarization
C. hyperpolarization

Answer 12

A. Depolarization

Question 13

When this gated cation channel opens, Na+ moves:

A. From the extracellular fluid to the cytosol
B. From the cytosol to the extracellular fluid

Answer 13

A. From the extracellular fluid to the cytosol

Question 14

When open, the AMPA receptor mediates:

A. Excitatory postsynaptic potential
B. Inhibitory postsynaptic potential

Answer 14

A. Excitatory postsynaptic potential