Question

Which mechanism best describes the process by which nutrients are taken up at the apical surface of the epithelial cells that line the guy and released from their basal and lateral surfaces?
a. Proteins are tethered to the cell cortex
b. Proteins are tethered to the extracellular matrix
c. Protista are tethered to the proteins on the surface of another cell
d. Protein movement is limited by the presence of a diffusion barrier

Answer 1

Answer:

The correct answer is option d. "Protein movement is limited by the presence of a diffusion barrier".

Explanation:

There are transportation mechanisms that allow to take up nutrients to the apical surface of the epithelial cells. The transportation process is best describes as protein movement limited by the presence of a diffusion barrier. There are structures known as tight junctions, located just below the apical surface . These tight junctions acts as diffusion barriers, separating the  extracellular fluids surrounding the apical and basolateral membranes.