Which of the Following Molecules CANNOT Freely Cross Biological Membranes

question 38

Multiple Choice

Which of the following molecules CANNOT freely cross biological membranes?

• A) O₂
• B) CO₂
• C) NH4+
• D) N₂
• E) H₂O

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Definitions:

ADH

Antidiuretic hormone, also known as vasopressin, a hormone released by the pituitary gland that regulates water balance in the body.

Aquaporin-2 Channels

Specific water channel proteins in kidney tubules that regulate water reabsorption and urine concentration.

Distal Convoluted Tubules

A portion of the nephron in the kidney where fine tuning of salt and water reabsorption and secretion occurs, aiding in urine formation.

Sympathetic Stimulation

Activation of the sympathetic nervous system, leading to increased heart rate, blood pressure, and energy mobilization.