Question

Which of the following is a way that digestion and absorption of carbohydrates differs from that of proteins?

a) Only carbohydrate absorption involves cotransport driven by Na+ gradients.

b) Only protein absorption involves cotransport driven by H+ gradients.

c) Only carbohydrate absorption involves digestion via brush border enzymes.

d) Only protein absorption involves facilitated diffusion transporters that allow the digested monomers to enter the interstitial fluid across the basolateral membranes of gut epithelial cells.

e) Only during protein absorption are digested monomers packaged into vesicles and secreted into the interstitial fluid across the basolateral membrane of gut epithelial cells

Answer 1

Answer - Only protein absorption involves cotransport driven by H+ gradients.

The small peptides are absorbed into the small intestinal epithelial cell by cotransport with H⁺ ions via a transporter called PepT1.

Cells of the brush border secrete enzymes such as aminopeptidase and dipeptidase, which further break down peptide chains.