Question

22. The counter-current exchange mechanism observed in the loop of Henle results in a high efficiency of removing water from the descending loop because: a. the water can be so rapidly taken back up by the ascending loop before the fluid leaves the loop b. fluid in the descending loop is always moving toward tissues that have slightly lower solute e. tissues outside the descending loop always have higher solute potential than the fluid inside the d. no energy needs to be expended anywhere along the loop of Henle in order to establish the of Henle. potential compared to the fluid inside the descending loop. descending loop. counter-current gradient. 23. Proton pumps in root hair cells create a gradient of protons that serves at least two functions -: a. to reduce pH inside the root hair cells, and to increase the pH in the soil outside the root hair b. to reduce the uptake of ions by the root hairs, and to increase the uptake of water by the root c. to create a charge gradient favoring the inward movement of positively charged nutrients, and d. to favor the movement of negatively charged ions to the outside of the root hairs, and to favor cells. hairs. to provide energy for cotransporters for negatively charged nutrients. the movement of positively charged ions to the inside of the root hairs.

Answer 1

1. The countercurrent exchange mechanism in the loop of Henle results in a high efficiency of removing water from the descending loop because

of b. – Fluid in the descending loop is always moving towards tissues that have slightly lower potential compared to the fluid inside the descending loop

c. Tissues outside the descending loop always have higher solute potential than the fluid inside the descending loop.

Both above points are valid.

2. Proton pumps in root hair cells create a gradient of protons that serves below two functions:

b. To reduce the uptake of ions by the root hairs and to increase the uptake of water by the root hairs

d. TO favor the movement of negatively charged ions to the outside of the root hairs, and to favor the movement of positively charged ions to the inside of the root hairs.

Both above points are valid.