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Na+ enters nerve cells through a channel in the cell membrane when the cell is stimulated....

Na+ enters nerve cells through a channel in the cell membrane when the cell is stimulated. What would happen to the rate of Na+ entry if you increased the concentration of Na+ outside the cell while not changing the internal concentration? A. No change B. Increase C. Decrease

A scientist has added a colored molecule to the exposed portion of transmembrane proteins in a small patch on the exterior leaflet (exterior surface) of a membrane. She comes back after a few hours and examines the cells. Where will the color-tagged proteins be?

A. They will they still be in the same small patch but now on both sides (leaflets) of the membrane. B. They will be distributed across the entire outer surface of the membrane. C. They will they be distributed across the entire surface of both sides of the membrane. D. They will still be in the small patch on the exterior of the membrane.

A scientist has added a colored molecule to the head groups of the phospholipids in a small patch on the exterior leaflet (exterior surface) of a membrane. She comes back after a few hours and examines the cells. Where will the color-tagged phospholipids be?

A. They will they be distributed across the entire surface of both sides of the membrane. B. They will they still be in the same small patch but now on both sides (leaflets) of the membrane. C. They will be distributed across the entire outer surface of the membrane. D. They will still be in the small patch on the exterior of the membrane.

Solutions

Expert Solution

1. B) Increase

Since the concentration of Na+ increases outside the cell , the gradient difference will increase. Due to this the rate of sodium entry will increase.

2. D. They will still be in the same patch on the exterior of the membrane

Proteins are in the form of ion channels or transport channels. The localization of these proteins are fixed and these proteins generally are concentrated around the lipid rafts. There is little to no movement of the proteins across the membrane or around the membrane.

3. A) They will be distributed across the entire surface of both sides of the membrane

Due to the action of flippases, floppases and scramblase transport enzymes, the lipid molecules are transported around the membrane and across the membrane to maintain the composition of both the leaflets.. Due to this, lipid molecules of plasma membrane continuously move within the plasma membrane

gladiator answered 2 years ago
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