$$30 - 32 \, \text{ATP} / \text{glucose}$$

Question 1

Which of the following best describes the primary function of the small intestine in the digestive process?

Accepted Answer

Mixing chyme with intestinal secretions, digestion and absorption of all biomolecules, ions, and water

Question 2

A patient presents with a deficiency in intrinsic factor. Which of the following nutrients will be most affected in terms of absorption?

Accepted Answer

Vitamin B12

Question 3

Which hormone is secreted in response to fatty chyme in the small intestine and promotes the release of pancreatic enzymes and bile?

Accepted Answer

Cholecystokinin (CCK)

Question 4

Which of the following best explains why most pancreatic enzymes are secreted in an inactive form?

Accepted Answer

To prevent self-digestion of the pancreas and its ducts

Question 5

During the absorptive (fed) state, which hormone is dominant and what is its primary effect?

Accepted Answer

Insulin; increases uptake and storage of glucose

Question 6

Which of the following is a correct sequence for the aerobic metabolism of glucose?

Accepted Answer

Glycolysis → Citric Acid Cycle → Electron Transport Chain

Question 7

Which of the following best describes the role of the enteric nervous system (ENS) in gastrointestinal function?

Accepted Answer

It acts as a 'little brain' capable of integrating local reflexes independently of the CNS

Question 8

A patient is experiencing rapid gastric emptying. Which of the following is a likely consequence?

Accepted Answer

Decreased digestion and absorption due to insufficient processing time

Question 9

Which of the following equations correctly represents the net ATP yield from aerobic respiration of one glucose molecule?

Accepted Answer

$$30 - 32 \, 	ext{ATP} / 	ext{glucose}$$

Question 10

Which of the following best explains why lipids are absorbed into the lymphatic system rather than directly into the blood?

Accepted Answer

Lipids are too large and hydrophobic to enter blood capillaries directly

Question 11

Which of the following is a function of bile salts in digestion?

Accepted Answer

Emulsification of lipids to form micelles

Question 12

Which of the following best describes the process of gluconeogenesis?

Accepted Answer

Synthesis of glucose from non-carbohydrate sources such as amino acids and glycerol

Question 13

Which of the following is the correct order of events for the activation of pancreatic proteases in the small intestine?

Accepted Answer

Enteropeptidase activates trypsinogen to trypsin, which then activates other proteases

Question 14

Which of the following best describes the effect of somatostatin released from D cells in the stomach?

Accepted Answer

It inhibits secretion of gastrin and gastric acid

Question 15

Which of the following best explains why carbohydrate-rich meals are digested and absorbed more quickly than lipid-rich meals?

Accepted Answer

Carbohydrates require fewer types of secretions and less controlled motility

Question 16

Which of the following best describes the role of ATP synthase in the electron transport chain?

Accepted Answer

It uses the diffusion gradient of $$\mathrm{H^+} to $$phosphorylate ADP to ATP

Question 17

A patient with a mutation that prevents GLUT transporter insertion into cell membranes would most likely experience which of the following?

Accepted Answer

Decreased glucose uptake by insulin-sensitive cells

Question 18

Which of the following best describes the fate of excess acetyl-CoA when citric acid cycle activity is low and glucose is abundant?

Accepted Answer

It is converted to fatty acids and stored as triglycerides (lipogenesis)

Question 19

Which of the following best explains why iron absorption is tightly regulated in the small intestine?

Accepted Answer

Free iron is cytotoxic and must be bound to proteins for safe transport

Question 20

Which of the following best describes the effect of aldosterone on ion absorption in the large intestine?

Accepted Answer

It increases active absorption of Na+ and excretion of K+

Digestive System and Metabolism: Structure, Function, and Regulation

Study Guide - Practice Questions