MCAT Biology Question 140: Answer and Explanation

Home > MCAT Test > MCAT biology practice tests

Test Information

Question: 140

5. Which of the following statements is FALSE?

  • A. ADH increases water reabsorption in the kidney.
  • B. Aldosterone indirectly increases water reabsorption in the kidney.
  • C. ADH acts directly on the proximal convoluted tubule.
  • D. Aldosterone stimulates reabsorption of sodium from the collecting duct.

Correct Answer: C

Explanation:

All of the answer choices describe ADH or aldosterone. These two hormones ultimately act to increase water reabsorption in the kidney; their respective mechanisms of action, however, are different. ADH increases water reabsorption by increasing the permeability of the collecting duct to water, whereas aldosterone stimulates reabsorption of sodium from the distal convoluted tubule and collecting duct. Using this knowledge, we can now attack the answer choices. Choice (C) is the correct answer because ADH does not act on the proximal convoluted tubule, but rather the collecting duct.

Previous       Next