CXC CXC - Caribbean Examinations Council Human and Social Biology: The Human Digestive System 1 — Questions and Answers
Question 1: What is the role of amylase in digestion?
- It breaks down proteins into amino acids
- It breaks down fats into fatty acids and glycerol
- It breaks down starch into maltose (Correct answer)
- It breaks down cellulose into glucose
Correct answer: It breaks down starch into maltose
Amylase is a carbohydrase enzyme that catalyzes the breakdown of starch into the disaccharide maltose.
Question 2: Where does chemical digestion of food BEGIN in the human digestive system?
- Stomach
- Small intestine
- Large intestine
- Mouth (Correct answer)
Correct answer: Mouth
Chemical digestion begins in the mouth, where salivary amylase starts breaking down starch while teeth perform mechanical digestion.
Question 3: Which organ produces bile and what is bile's function?
- Pancreas; it digests proteins
- Liver; it emulsifies fats (Correct answer)
- Stomach; it kills bacteria
- Gallbladder; it produces digestive enzymes
Correct answer: Liver; it emulsifies fats
The liver produces bile, which emulsifies large fat droplets into smaller ones, increasing the surface area for lipase to act on.
Question 4: What is the function of villi in the small intestine?
- To produce digestive enzymes
- To absorb water from undigested food
- To increase the surface area for absorption of digested nutrients (Correct answer)
- To kill harmful bacteria in food
Correct answer: To increase the surface area for absorption of digested nutrients
Villi are finger-like projections lining the small intestine that greatly increase the surface area available for absorbing digested nutrients into the bloodstream.
Question 5: Which enzyme found in the stomach breaks down proteins?
- Lipase
- Amylase
- Pepsin (Correct answer)
- Maltase
Correct answer: Pepsin
Pepsin is a protease enzyme secreted in the stomach that breaks peptide bonds in proteins, producing smaller polypeptide chains.
Question 6: What is the main function of the large intestine?
- Digestion of proteins
- Absorption of glucose and amino acids
- Absorption of water and formation of feces (Correct answer)
- Production of digestive enzymes
Correct answer: Absorption of water and formation of feces
The large intestine primarily absorbs water from undigested food residue and compacts the remaining material into feces for elimination.
CXC CXC - Caribbean Examinations Council Human and Social Biology: The Human Digestive System 1
What is the role of amylase in digestion?