Q: Which of the following best describes the chemical reaction catalyzed by pepsin in the stomach?

Hydrolysis of peptide bonds: $$ \text{Protein} + \text{H}_2\text{O} \rightarrow \text{Small polypeptides} $$

Question 1

Which of the following best describes the role of hydrochloric acid (HCl) in protein digestion within the stomach?

Accepted Answer

HCl denatures protein molecules, making them more accessible to enzymatic cleavage by pepsin.

Question 2

Pepsin is an enzyme that acts in the stomach. What is its primary function during digestion?

Accepted Answer

Pepsin cleaves peptide bonds, breaking proteins into smaller polypeptides.

Question 3

After mechanical and chemical digestion in the stomach, proteins are primarily converted into which of the following before entering the small intestine?

Accepted Answer

Small polypeptides

Question 4

Which process allows fatty acids and monoglycerides to enter the epithelial cells of the small intestine?

Accepted Answer

Simple diffusion

Question 5

Once inside the small intestine epithelial cells, fatty acids and monoglycerides are reassembled into which molecule before entering the lymphatic system?

Accepted Answer

Triglycerides

Question 6

Which structure is responsible for transporting reassembled triglycerides from the small intestine to the circulatory system?

Accepted Answer

Lacteals

Question 7

A patient has a genetic defect that prevents the formation of lacteals in the small intestine. Which of the following would most likely be impaired?

Accepted Answer

Absorption of triglycerides

Question 8

Which of the following best explains why proteins must be denatured before enzymatic digestion?

Accepted Answer

Denaturation exposes peptide bonds, making them accessible to proteolytic enzymes.

Question 9

If a person’s stomach did not produce enough HCl, which of the following would most likely occur?

Accepted Answer

Pepsin would be less active, leading to incomplete protein digestion.

Question 10

Which of the following correctly traces the path of dietary fat from ingestion to entry into the bloodstream?

Accepted Answer

Mouth → Stomach → Small intestine → Lacteals → Lymphatic system → Bloodstream

Question 11

A patient is unable to produce pepsin. Which of the following would be the most direct consequence?

Accepted Answer

Impaired breakdown of proteins into small polypeptides in the stomach

Question 12

Which of the following best describes the chemical reaction catalyzed by pepsin in the stomach?

Accepted Answer

Hydrolysis of peptide bonds: $$ 	ext{Protein} + 	ext{H}_2	ext{O} ightarrow 	ext{Small polypeptides} $$

Question 13

Which of the following is a correct statement about the absorption of amino acids and fatty acids in the small intestine?

Accepted Answer

Amino acids are absorbed into capillaries, while fatty acids (as triglycerides) enter lacteals.

Question 14

A person consumes a meal high in protein and fat. Which of the following best describes the sequence of events for the digestion and absorption of these macromolecules?

Accepted Answer

Proteins are denatured and cleaved in the stomach; fats are emulsified and digested in the small intestine; amino acids enter capillaries, triglycerides enter lacteals.

Question 15

Which of the following would most likely result from a blockage in the lymphatic system at the level of the lacteals?

Accepted Answer

Decreased absorption of triglycerides

Question 16

Which of the following best explains why triglycerides are reassembled inside epithelial cells before entering the lymphatic system?

Accepted Answer

Reassembly into triglycerides allows packaging into chylomicrons for transport in the lymph.

Question 17

A patient with a mutation that prevents the denaturation of proteins in the stomach would most likely experience which of the following?

Accepted Answer

Impaired protein digestion because pepsin cannot access peptide bonds

Question 18

Which of the following is the correct chemical equation for the hydrolysis of a triglyceride during digestion?

Accepted Answer

$$ 	ext{Triglyceride} + 3\ 	ext{H}_2	ext{O} ightarrow 	ext{Glycerol} + 3\ 	ext{Fatty acids} $$

Question 19

Which of the following best describes the fate of small polypeptides after leaving the stomach?

Accepted Answer

They are further digested by proteases in the small intestine into amino acids.

Protein Digestion and Absorption in the Human Body

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