Unit 6a Digestion Absorption

Question 1

How are carbohydrates absorbed in the small intestine?
a) As disaccharides
b) As monosaccharides through transporters
c) Via endocytosis
d) As starch directly

Answer 1

b) As monosaccharides through transporters

Explanation: Only monosaccharides like glucose, galactose, and fructose can be absorbed. Glucose and galactose use SGLT; fructose uses GLUT5.

Question 2

Which transporter moves glucose into intestinal epithelial cells?
a) SGLT
b) Na+/K+-ATPase
c) GLUT5
d) CFTR

Answer 2

a) SGLT

Explanation: The sodium-glucose linked transporter (SGLT) uses secondary active transport to move glucose with sodium into the cell.

Question 3

What is the role of bile salts in fat digestion?
a) Activate proteases
b) Stimulate acid secretion
c) Emulsify fats into smaller droplets
d) Absorb triglycerides

Answer 3

c) Emulsify fats into smaller droplets

Explanation: Bile salts coat fats, increasing surface area for pancreatic lipases to act and form micelles for absorption.

Question 4

How are most dietary fats absorbed?
a) As monoglycerides and fatty acids into lymph
b) As triglycerides directly into blood
c) As cholesterol into bile
d) Via tight junctions

Answer 4

a) As monoglycerides and fatty acids into lymph

Explanation: Lipid digestion products are absorbed, reassembled into triglycerides, and packed into chylomicrons that enter lymph via lacteals.

Question 5

Which vitamin requires intrinsic factor for absorption?
a) Vitamin A
b) Vitamin C
c) Vitamin D
d) Vitamin B12

Answer 5

d) Vitamin B12

Explanation: B12 absorption in the ileum depends on intrinsic factor secreted by gastric parietal cells. Without it, oral B12 isn’t absorbed.