Sodium-Potassium Pump

SODIUM-POTASSIUM PUMP

Q. 1

Cells maintain a low intracellular Na+ concentration and a high intracellular K+ concentration by sodium-potassium pump which is an example of:

 A

Active transport

 B

Passive transport

 C

Facilitated diffusion

 D

Osmosis

Q. 1

Cells maintain a low intracellular Na+ concentration and a high intracellular K+ concentration by sodium-potassium pump which is an example of:

 A

Active transport

 B

Passive transport

 C

Facilitated diffusion

 D

Osmosis

Ans. A

Explanation:

Some carriers transport substances against their electrical and chemical gradients. This form of transport requires energy and is called active transport. In animal cells, the energy is provided almost exclusively by hydrolysis of ATP. One of these ATPases is sodium–potassium adenosine triphosphatase (Na, K ATPase), which is also known as the Na, K pump.

Na, K ATPase catalyzes the hydrolysis of ATP to adenosine diphosphate (ADP) and uses the energy to extrude three Na+ from the cell and take two K+ into the cell for each molecule of ATP hydrolyzed. It is an electrogenic pump in that it moves three positive charges out of the cell for each two that it moves in, and it is therefore said to have a coupling ratio of 3:2.
 
Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 2. Overview of Cellular Physiology in Medical Physiology. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong’s Review of Medical Physiology, 24e.

 


Q. 2

For sodium – potassium pump the coupling ratio is

 A

1 :1

 B

2 : 3

 C

3 : 2

 D

1 : 4

Q. 2

For sodium – potassium pump the coupling ratio is

 A

1 :1

 B

2 : 3

 C

3 : 2

 D

1 : 4

Ans. C

Explanation:

C i.e. 3 : 2


Q. 3

True about Na+ – K+ pump is that:

 A

Involves ATPase activity

 B

It can move Na+ in and out of cell

 C

Electrically neutral

 D

Pumps out one Na+ for one K+

Q. 3

True about Na+ – K+ pump is that:

 A

Involves ATPase activity

 B

It can move Na+ in and out of cell

 C

Electrically neutral

 D

Pumps out one Na+ for one K+

Ans. A

Explanation:

A i.e. Involves ATPase activity


Q. 4

True regarding Na+ – K+ pump

 A

Hetrodimer – homogenous

 B

Hetrodimer – hetrogenous

 C

Homodimer – hetrogenous

 D

Homodimer – homogenous

Q. 4

True regarding Na+ – K+ pump

 A

Hetrodimer – homogenous

 B

Hetrodimer – hetrogenous

 C

Homodimer – hetrogenous

 D

Homodimer – homogenous

Ans. B

Explanation:

B i.e. Hetrodimer hetrogenous


Q. 5

Entracellular binding site on Na+ – K+ pump is

 A

Na+

 B

ATP

 C

PO4

 D

Ouabain

Q. 5

Entracellular binding site on Na+ – K+ pump is

 A

Na+

 B

ATP

 C

PO4

 D

Ouabain

Ans. D

Explanation:

D i.e. Ouabain


Q. 6

Binding site present on p unit of Na+ – K+ pump is

 A

Na+

 B

K+

 C

ATP

 D

Glycosylation

Q. 6

Binding site present on p unit of Na+ – K+ pump is

 A

Na+

 B

K+

 C

ATP

 D

Glycosylation

Ans. D

Explanation:

D i.e. Glycosylation


Q. 7

Which of them is TRUE about Na+-K+ pump:

 A

K+ is pumped against the gradient

 B

2K+ are exchanged with 5Na+

 C

Hypercalcemia causes arrest in Na+ K+ pump

 D

Increase in intracellular Na+ increases action potential.

Q. 7

Which of them is TRUE about Na+-K+ pump:

 A

K+ is pumped against the gradient

 B

2K+ are exchanged with 5Na+

 C

Hypercalcemia causes arrest in Na+ K+ pump

 D

Increase in intracellular Na+ increases action potential.

Ans. A

Explanation:

A i.e. is K+ pumped against the gradient


Q. 8

The sodium- potassium pump is an example of:

 A

Active transport

 B

Passive transport

 C

Facilitated diffusion

 D

Osmosis

Q. 8

The sodium- potassium pump is an example of:

 A

Active transport

 B

Passive transport

 C

Facilitated diffusion

 D

Osmosis

Ans. A

Explanation:

A i.e. Active transport

Calcium Metabolism in mammalian cells
• Concentration of intracellular Ca2+ is 100 nmol/ L and it is about 12000 times less than that in extracellular fluid.Q
• Ca2+ is stored in endoplasmic reticulum and mitochondria & can be released from them to replenish cytoplasmic Ca2+
• Calcium binding proteins bind cytoplasmic Ca2+ and when activated in this fashion, bring about a variety of physiological
effect.
• Ca2+ enter cell via
– Voltage gated Ca2+ channels
– Ligand gated Ca2+ channels (T & L types)
– Store operated Ca2+ channels (SOCCs)
• It is transport out of cell by (Active transport)Q
(i) Ca2+ IP ATPase antiportQ: cause 21-1+ inside & Ca2+ outside() of membrane at the cost of hydrolysis of ATP.
(ii) Na+ Ca2+ antiportQ : It is a counter transport causes 3 Na+ inside & 2Ca2+ outsideQ of membrane.
• Calmodulin is Ca2+ binding protein involved in contraction of smooth muscle.
• Passive transport : when molecules traverse membrane by electro mechanical gradient (Passively)
• Uniport : Form of transport where only one substance is transported.
• Symport: Here binding of more than one substance to transport protein & substances are transported across the membrane together.
• Antiport: The transport exchange one substance for another


Q. 9

Sodium-potassium pump is a type of ‑

 A

Passive transport

 B

Primary active transport

 C

Secondary active transport

 D

Counter transport

Q. 9

Sodium-potassium pump is a type of ‑

 A

Passive transport

 B

Primary active transport

 C

Secondary active transport

 D

Counter transport

Ans. B

Explanation:

Ans. is ‘b’ i.e., Primary active transport



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