Quiz
1 Answer Key
1. The Na ion channel is an example of how
molecules are transferred across the phospholipid bilayer by the process of
a. simple
diffusion
b. facilitated
transport
c. secondary
active transport
d. primary
active transport
ANSWER: b.
2. If you placed one of your cheek cells (given:
The ICF = 150 mM NaCl ) in a solution of 300 mM glucose, and you assume neither
compound could permeate the PL bilayer, through the process of osmosis your
cell would
a. crenate
b.
lyse
c. be
happy as a clam (normal cell volume)
d.
cannot determine by the
provided information
ANSWER: c.
3. The Na/K ATPase pump uses a method called
__________________ __________________
or
successive phosphorylation/dephosphorylation cycles to change its configuration
and pump ions against their concentration gradients.
a. phosphatase
enzymes
b. secondary
active transport
c. molecular
peristalis
d. brownian
movement
e. chemiosmotic
hypothesis
ANSWER: c.
4. T or F
All cells
have a negative resting membrane potential and thus have the capacity to
generate an action potential.
a. TRUE
b. FALSE
ANSWER: b.
5. Which of the following physiological
processes requires no ATP expenditure?
a. endocytosis
b. exocytosis
c. osmosis
d. facilitated
diffusion
e. two
of the above
ANSWER: e.
6. Which of the following organic molecules
would be classified as a protein?
a. glycogen
b. molecules
that contain free fatty acids
c. molecules
that are produced from peptide bond formations
d. steroids
e. DNA
ANSWER: c.
7. If a cell had the following ionic
concentrations and permeabilities, about at what voltage would you predict an
action potential would change polarity (peak of the action potential spike)?
HINT: You
can decide whether to use Nernst or Goldman.
PK = 10
PNa =
10,000
Assume you
are computing for my pug Jack (mammalian temperatures)
[K+]o = 40
mM
[K+]i = 365
mM
[Na+]o =
310 mM
[Na+]i = 55
mM
a. 45
mV
b. 52
mV
c. 58
mV
d. 41
mV
e. -58
mV
ANSWER: a.
8. If the resting potential of the cell in #7
was -85 mV, at what voltage would this action potential fire fully, given the
all-or-none principle? HINT: Threshold.
a. around
-64 mV
b. around
-60 mV
c. around
-66 mV
d. around
-84 mV
e. cannot
be determined with the data provided
ANSWER: c.
9. Which phase of the action potential is driven
by the underlying activity (gated open) of K channels without any contribution
of Na channel conformational changes?
a. depolarization
b. repolarization
c. hyperpolarization
d. latency
e. the
resting membrane potential
ANSWER: c.
10. Which of the following properties is
associated with the Action Potential?
a. they
are an all-or-none process
b. they
decrement in amplitude the further down the axon they travel
c. their
threshold activity is mediated by the space constant or lambda
d. they
have increased frequency when potassium channels are gated open
e. they
can fire during the ARP phase
ANSWER: a.
11. If an action potential (AP) reaches
threshold, where in the neuron will the AP “spike” be initiated?
a. the
dendrite
b. the
soma
c. the
axon hillock
d.
the synaptic terminals
e. the
sodium/potassium ATPase pump
ANSWER: c.