SAT Subject Biology Practice Question 116: Answer and Explanation

Next steps

Question: 116

6. What prevents ions from crossing the plasma membrane via simple diffusion?

A. Ions are too large.
B. Ions carry a charge.
C. Ions are hydrophobic.
D. Ions do not produce a concentration difference.
E. Ions cannot interact with membrane-bound proteins.

Correct Answer: B

Explanation:

Because ions carry a charge, they cannot cross the hydrophobic cell membrane and so must be transported by facilitated diffusion via ion channels.

Previous       Next