Apentix/AP Biology/Unit 2: Cell Structure and Function/Question
AP Biologymediummcq1 pt

Glucose uptake into human red blood cells runs through GLUT1 carriers in the plasma membrane. Which pattern in measured uptake identifies the process as carrier-mediated facilitated diffusion?

A.Uptake keeps rising without limit as glucose concentration climbs, never leveling off.
B.Uptake climbs with glucose concentration and then plateaus once the finite carrier population saturates.
C.Uptake persists unchanged even when metabolic poison stops all ATP production, proving no protein participates.
D.Cells accumulate glucose far beyond outside levels, showing transport against the gradient.

Explanation

Core Concept

That saturation curve distinguishes mediated transport from the linear rise expected for unhindered diffusion through lipid. Because the driving force remains the concentration gradient, the process still consumes no ATP. Plateau height reflects the number of carriers inserted in the membrane.

Correct Answer

BUptake climbs with glucose concentration and then plateaus once the finite carrier population saturates.

More Unit 2: Cell Structure and Function practice questions

Try a random question →

Practice more AP Biology questions with full explanations

Practice Unit 2: Cell Structure and Function Questions →