Digestion - Carbohydrates

Question 1

Principal sites

Answer 1

• Mouth
• Intestinal lumen

Question 2

Events in the mouth

Answer 2

• Carbohydrate digestion begins during mastication
• Salivary amylase digests gylcogen and starch → dextrin

Question 3

Events in the stomach

Answer 3

• No CHO digestion
• Low pH inhibits salivary amylase

Question 4

Events in the small intestines

Answer 4

• Pancreatic amylase hydrolyzes complex carbohydrates to disaccharides but not directly to monosaccharides
• Disaccharidases complete the digestive process

Question 5

Amylase can only digest ____

Answer 5

Alpha1-4 glycosidic bonds

Question 6

Disaccharides in the _______ complete the digestive process

Answer 6

Brush border

Question 7

In the small intestines, majority of absoprtion occurs in the ____ and ____

Answer 7

Duodenum and upper jejunum

Question 8

How are the following absorbed from the intestinal lumen?

• Glucose
• Galactose
• Fructose

Answer 8

• Glucose
  
  • Secondary active transport with Na+ ion and galactose via SGLT
  • Requires ATP
• Galactose
  
  • Secondary active transport with Na+ ion and glucose via SGLT
  • Requires ATP
• Fructose
  
  • Facilitated diffusion via GLUT5
  • Does not require ATP

Question 9

How are the following exported from the enterocytes?

• Glucose
• Galactose
• Fructose

Answer 9

In the basement membrane, all are transported via facilitated diffusion by GLUT-2

Question 10

____ is excreted unchanged because it contain ____, which cannot be digested by ____; this constitute the fiber in the diet

Answer 10

• Cellulose
• Beta-glycosidic bond
• Alpha-gylcosidases