quiz - week two

Question 1

when vesicles in the cytoplasm combine with the plasma membrane and release hormones into the extracellular fluid, this is called-
a) exocytosis
b) active transport
c) simple diffusion
d) endocytosis

Answer 1

a) exocytosis

Question 2

Leak channels are a type of protein channel on the cell membrane that when open allow specific ions to travel through them. This ion movement does not require any energy. Consequently, when ions move through a leak channel this would be an example of-
a) osmosis
b) active transport
c) simple diffusion
d) facilitated diffusion

Answer 2

d) facilitated diffusion

Question 3

if there are 2 ions inside of the cell and -3 ions outside of the cell, what is the membrane potential?

Answer 3

5

Question 4

which of the following is most responsible for a neuron having a resting membrane potential of -70 mV?
a) proteins
b) K+ leak channels
c) Na+/K+ ATPase pump
d) Na+ leak channels

Answer 4

b) K+ leak channels

Question 5

Assume the following

There is a greater concentration of copper (Cu2+) outside of the cell, compared to the inside
There are Cu2+ channels located on the cell membrane
These channels do not open due to a change in membrane potential
These channels do not open due to a hormone binding to a receptor
what is being described?
a __________ channel which is a/n ________ channel

Answer 5

leak, passive

Question 6

which of the following statements is true about a ligand-gated ion channel receptor?
a) they are found on the cell nucleus
b) differences in membrane potential affect whether the channel receptors are open or close
c) neurotransmitters can act as the chemical messengers for these channels
d) they are primarily made of lipids

Answer 6

c) neurotransmitters can act as the chemical messengers for these channels

Question 7

You are working in the lab and you initiate an action potential in a pre-synaptic neuron. You are able to confirm that the voltage-gated calcium channels open correctly. However, the neuron doesn’t release any neurotransmitters

Which of the following statements is a plausible explanation for what you have seen?

a) enzyme is rapidly breaking down the neurotransmitter in the synapse
b) there are no receptors on the post-synaptic neuron
c) the extracellular fluid has a lower than normal concentration of calcium

Answer 7

c) the extracellular fluid has a lower than normal concentration of calcium

Question 8

chromium (Cr6+) moving down its gradient will cause
a) hyperpolarization
b) depolarization
c) need more information

Answer 8

c) need information

Question 9

You have four neurons - A, B, C, and D.

Neuron B repeatedly sends a hyperpolarizing signal to neuron D.

This would be an example of
____________
which would cause ___________

Answer 9

temporal summation, inhibition

Question 10

during an action potential, when calcium moves into the cell to signal exocytosis, what happens to membrane potential?
a) repolarization
b) hyperpolarization
c) depolarization
d) no change in membrane potential

Answer 10

c) depolarization