Question

In active transport, the affinity of the carrier protein for the molecule being transported is greater on which side of the membrane?

A) always the side facing the intracellular fluid

B) always the side facing the extracellular fluid

C) on the side where the molecule is in lower concentration

D) on the side where the molecule is in greater concentration

E) Neither; it is equal on both sides of the membrane

Answer 1

In active transport, the carrier protein's affinity for the molecule is greater on the side where the molecule is in lower concentration, as the protein functions to transport molecules against their concentration gradient.

Step-by-step explanation:

On the side where the molecule is in lower concentration. During the process of active transport, carrier proteins bind to molecules and use energy, often in the form of ATP (adenosine triphosphate), to move these molecules across the cell membrane against their concentration gradient. This means molecules are transported from an area of lower concentration to an area of higher concentration.

The carrier protein's affinity for the molecule being transported is greater on the side where the molecule is in lower concentration because the protein is designed to pick up molecules in that area and transport them to the other side, where they are in higher concentration. It requires energy because the molecules are moving in a direction opposite to that which would occur naturally by diffusion.