Question

Carbohydrates

a. can be absorbed as small polysaccharides.
b. can be absorbed as either disaccharides or monosaccharides.
c. require GLUT proteins to absorb the monosaccharides.
d. require lipoprotein carriers to transport them in the blood.

Answer 1

Carbohydrates are absorbed as monosaccharides via proteins in the small intestine, with glucose and galactose using secondary active transport and fructose using facilitated diffusion.

Step-by-step explanation:

Carbohydrates are primarily absorbed in the form of monosaccharides. The small intestine plays a crucial role in this process, capable of absorbing monosaccharides at a rate of about 120 grams per hour. Carbohydrates such as glucose and galactose are transported into epithelial cells by protein carriers through a mechanism known as secondary active transport, which involves the co-transport with sodium ions. Once inside the cells, these monosaccharides exit via facilitated diffusion and enter the capillaries. Fructose, another monosaccharide, is absorbed differently, solely by facilitated diffusion. Carbohydrate digestion commences in the mouth and completes in the small intestine, with all digestible carbohydrates being absorbed and indigestible fibers discarded in feces. Moreover, glucose is essential for ATP production in cells and, when in surplus, is stored as glycogen or converted into fat.