Q: Which of the following equations best represents the hydrolysis reaction carried out by digestive enzymes?

$$\text{Polysaccharide} + \text{H}_2\text{O} \rightarrow \text{Monosaccharides}$$

Question 1

Which of the following best describes the process by which monosaccharides are absorbed across the intestinal epithelium?

Accepted Answer

Monosaccharides are cotransported with Na+ across the apical membrane by secondary active transport, then exit via facilitated diffusion across the basolateral membrane.

Question 2

Which enzyme is responsible for the initial breakdown of starch in the digestive tract?

Accepted Answer

Salivary amylase

Question 3

What is the primary mechanism by which lipid molecules are absorbed in the small intestine?

Accepted Answer

Passive diffusion through the membrane

Question 4

Which brush border enzyme is NOT involved in the final breakdown of disaccharides into monosaccharides?

Accepted Answer

Pepsin

Question 5

A patient with lactose intolerance is likely to experience which of the following symptoms after consuming milk?

Accepted Answer

Diarrhea due to an osmotic gradient preventing water absorption

Question 6

Which of the following equations best represents the hydrolysis reaction carried out by digestive enzymes?

Accepted Answer

$$	ext{Polysaccharide} + 	ext{H}_2	ext{O} ightarrow 	ext{Monosaccharides}$$

Question 7

Which statement correctly describes the absorption of amino acids in the small intestine?

Accepted Answer

Amino acids are cotransported with Na+ or H+ across the apical membrane and exit via facilitated diffusion across the basolateral membrane.

Question 8

Which of the following is a correct sequence for the digestion of proteins?

Accepted Answer

Pepsin in the stomach → Pancreatic proteases in the small intestine → Brush border enzymes

Question 9

Which of the following best explains why tight junctions are important in the intestinal epithelium?

Accepted Answer

They force molecules to pass through epithelial cells, ensuring selective absorption.

Question 10

Which of the following is TRUE regarding the absorption of nutrients in the small intestine?

Accepted Answer

Most nutrients are absorbed before chyme reaches the ileum.

Question 11

A patient is given a drug that inhibits the Na+-K+ ATPase pump in intestinal epithelial cells. Which of the following is most likely to occur?

Accepted Answer

Decreased absorption of glucose and amino acids due to loss of Na+ gradient

Question 12

Which of the following is a plausible consequence of undigested lactose remaining in the intestine?

Accepted Answer

Creation of an osmotic gradient that prevents water absorption, leading to diarrhea

Question 13

Which of the following brush border enzymes is responsible for breaking down maltose into glucose?

Accepted Answer

Maltase

Question 14

Which of the following is the correct pathway for glucose absorption in the small intestine?

Accepted Answer

Glucose enters by secondary active transport with Na+ and exits by facilitated diffusion.

Question 15

Which of the following equations represents the cotransport of glucose with sodium across the apical membrane?

Accepted Answer

$$	ext{Glucose}_{	ext{lumen}} + 	ext{Na}^+_{	ext{lumen}} ightarrow 	ext{Glucose}_{	ext{cell}} + 	ext{Na}^+_{	ext{cell}}$$

Question 16

Which of the following is NOT a function of brush border enzymes in the small intestine?

Accepted Answer

Breaking down starch into disaccharides

Question 17

Which of the following best describes the fate of amino acids after absorption in the small intestine?

Accepted Answer

Amino acids enter the capillary blood in the villi and are transported to the liver via the hepatic portal vein.

Question 18

Which of the following is a plausible result of a deficiency in brush border enzymes?

Accepted Answer

Decreased absorption of monosaccharides

Question 19

Which of the following is TRUE regarding the role of pancreatic proteases in protein digestion?

Accepted Answer

Pancreatic proteases cleave proteins into smaller peptides and amino acids.

Physiology of Digestion and Absorption: Carbohydrates and Proteins

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