Cell Communication (Test 1)

Question 1

Can you give examples of transport processes uses ATP most directly?

Answer 1

Transport of Na+ out of cells, transport K+ into cells, transport Ca2+ into ER/SR.

Question 2

What factors cause these opening and closing of ion channels:

Answer 2

Voltage, Ligand-binding, Physical stretch and Phosphorylation

Question 3

Can you give example of transport processes that is not chemical specific?

Answer 3

Gas diffusion through cytoplasmic membrane.

Question 4

Which transport process characterizes Na+/Ca2+ exchanger’s function of moving intracellular Ca2+ out of cells?

Answer 4

Secondary active transport.

Question 5

Which protein provides the highest speed for ions moving across the cytoplasmic membrane?

Answer 5

ion channel

Question 6

What is second messenger?

Answer 6

Few common small intracellular molecules that amplify the hormonal signal inside cell.

Question 7

Is intracellular Ca2+ responsible for action potential propagation alone the neuron axons?

Answer 7

no

Question 8

Is cCMP referred to as a second messenger?

Answer 8

no

Question 9

What are the cellular functions of cAMP?

Answer 9

PKA activation, regulation of ion channels, regulation of proteins containing NBD (nucleotide-binding domain).

Question 10

What is G-protein refers to?

Answer 10

Guanine nucleotide-binding proteins.

Question 11

How does vitamin D (1,25-(OH2)-D) across cytoplasmic membrane?

Answer 11

Simple diffusion because Vitamin D (1,25-(OH)2-D) is a metabolic product of cholesterol.

Question 12

If the two chambers are equal in volume, a diffusible molecule concentration is X in the chamber 1 and 0 in the chamber 2 at beginning, respectively.

1) What is the concentration of this molecule after equilibrium is achieved?
2) What if the volume of chamber 1 is n-time larger than the chamber 2?

Answer 12

(1) X/2.

2) X * n/(n + 1

Question 13

What factors directly determine the amplitude of a voltage gated ion channel current?

Answer 13

Ion concentration gradient and voltage difference across cytoplasmic membrane.

Question 14

What effect of increase in intracellular Na+ concentration will be on the rate of Na+/Ca2+ exchanger?

Answer 14

Decrease

Question 15

How many different kinds of second messengers have been discovered so far?

Answer 15

less than 10

Question 16

What is the function of inositol triphosphate (IP3)?

Answer 16

It triggers Ca2+ release from intracellular calcium store.

Question 17

Which channel plays the most important role in establishing the resting membrane potential:

Answer 17

Voltage-gated K+ channel.

Question 18

Which of the following processes describes CO2 transport in lung?

Answer 18

Simple diffusion through lipid bilayer

Question 19

What is an antagonist?

Answer 19

A molecule binds to a specific receptor, but it does not generate consequential physiological functions as the physiological ligand does.

Question 20

Can you give an example of a nuclear receptor?

Answer 20

Vitamin D

Question 21

Can you give an example of a small G-protein?

Answer 21

G 12&13

Question 22

Heterotrimeric G-protein is consist of α, β and γ subunits. Upon the hormonal stimulation, which of the subunits binds to GTP and is separated from others?

Answer 22

α subunit.