Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.)
-fat digestion begins
A)mouth
B)stomach
C)small intestine lumen
D)intracellularly in the small intestine brush border
E)colon

Question

Quizplus · Accepted Answer

Fat digestion commences and is completed in the lumen of the small intestine with the help of bile salts and pancreatic lipase.

Answer: A and B
 Digestion of carbohydrates and proteins commences in the mouth and stomach, respectively, through the action of salivary amylase and pepsin. However, digestion of carbohydrates is not completed in the mouth, and digestion of proteins is not completed in the stomach.

Answer: D
 Intracellular digestion of carbohydrates and proteins occurs in the small intestine brush border with the help of enzymes such as maltase, sucrase, lactase, and peptidases.

Answer: E
 The colon is not involved in the digestion of any of the three main categories of foodstuffs. It mainly absorbs water and electrolytes from the remaining undigested material before excretion as feces.

Indicate the Site, Labelled A