Passive transport molecules
A) allow small molecules across membranes.
B) are peripheral proteins.
C) can transport against a concentration gradient.
D) use the energy of ATP to transport molecules.

Question

Quizplus · Accepted Answer

Passive transport molecules refer to the movement of molecules across biological membranes that do not require energy input. Small molecules, such as ions and gases, can move across the membrane through passive transport mechanisms such as diffusion, facilitated diffusion, and osmosis. Therefore, choice A is the best answer as it correctly states that passive transport molecules allow small molecules to cross membranes. Choices B and D are incorrect as passive transport molecules do not involve peripheral proteins or the energy of ATP, respectively. Choice C is incorrect because passive transport mechanisms can only move molecules down their concentration gradient, not against it.

Passive Transport Molecules