Question 1

Which enzyme is primarily responsible for the initial hydrolysis of starch in the human digestive system, and where does this process begin?

Accepted Answer

Salivary amylase in the mouth

Question 2

During digestion, proteins are first hydrolyzed into smaller polypeptides. Which combination of substances is directly responsible for this process in the stomach?

Accepted Answer

Hydrochloric acid (HCl) and pepsin

Question 3

A patient is unable to absorb much fructose from their diet. Which of the following best explains this phenomenon?

Accepted Answer

Intestinal epithelial cells lack the specific transporter protein for fructose

Question 4

Which of the following correctly matches the digestive enzyme with its substrate and the location where it acts?

Accepted Answer

Salivary amylase – starch – mouth

Question 5

After hydrolysis in the small intestine, which of the following is the correct sequence for the absorption of glucose into the bloodstream?

Accepted Answer

Glucose passes through epithelial cells lining the intestine, then into capillaries

Question 6

Which of the following best describes the role of insulin in glucose uptake by body cells?

Accepted Answer

Insulin triggers a signal transduction pathway that allows glucose transporter proteins to move glucose into cells

Question 7

A person has a genetic mutation that prevents the production of pancreatic enzymes. Which of the following would most likely be impaired?

Accepted Answer

Hydrolysis of small polypeptides, disaccharides, nucleic acids, and fats in the small intestine

Question 8

Which of the following equations best represents the hydrolysis of a disaccharide into monosaccharides?

Accepted Answer

$$C_{12}H$$_{22}$$O_{11} + H_2O \rightarrow 2C_6H_{12}O_6$

Question 9

If a person’s pancreatic duct is blocked, which of the following digestive processes would be most directly affected?

Accepted Answer

Hydrolysis of fats, nucleic acids, and small polysaccharides in the small intestine

Question 10

Which of the following best explains why not all dietary fructose is absorbed into the bloodstream?

Accepted Answer

Intestinal epithelial cells lack sufficient fructose transporter proteins

Question 11

A patient with a deficiency in small intestine enzymes would have the most difficulty absorbing which of the following?

Accepted Answer

Amino acids and monosaccharides

Question 12

Which of the following is a correct sequence of events for the digestion and absorption of dietary starch?

Accepted Answer

Hydrolysis by salivary amylase in the mouth, further breakdown by pancreatic enzymes in the small intestine, absorption of glucose into the bloodstream

Question 13

Which of the following best describes the fate of nucleic acids during digestion?

Accepted Answer

They are hydrolyzed by pancreatic enzymes in the small intestine into nucleotides, then further broken down into nitrogenous bases, sugars, and phosphates

Question 14

A person with a genetic defect in their glucose transporter proteins would most likely experience which of the following symptoms after eating a carbohydrate-rich meal?

Accepted Answer

Elevated blood glucose levels due to impaired cellular uptake

Question 15

Which of the following best explains why hydrolysis reactions are essential in the digestive process?

Accepted Answer

They break down macromolecules into monomers that can be absorbed by intestinal cells

Question 16

If a person’s stomach did not produce hydrochloric acid (HCl), which of the following would be most directly affected?

Accepted Answer

Activation of pepsin and hydrolysis of proteins in the stomach

Question 17

Which of the following is a correct chemical equation for the hydrolysis of a triglyceride (fat) molecule during digestion?

Accepted Answer

$$C_{55}H$$_{98}$$O_6 + 3H_2O$$ \rightarrow C_3H_8O_3 + 3C_{16}$$H_{32}O_2$

Question 18

A person is unable to digest lactose due to a lack of the enzyme lactase. Which of the following best describes what happens to lactose in their digestive tract?

Accepted Answer

Lactose passes undigested into the large intestine, where it is fermented by bacteria

Question 19

Which of the following best explains why the hydrolysis of macromolecules is necessary before absorption in the small intestine?

Accepted Answer

Macromolecules are too large to pass through the epithelial cell membranes

Overview of Human Digestion and Absorption of Organic Molecules

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