CXC CXC - Caribbean Examinations Council Human and Social Biology: The Human Digestive System 2 — Questions and Answers
Question 1: What type of enzyme is lipase, and where is it produced?
- A carbohydrase produced in the mouth
- A protease produced in the stomach
- A fat-digesting enzyme produced by the pancreas (Correct answer)
- A starch-digesting enzyme produced in the liver
Correct answer: A fat-digesting enzyme produced by the pancreas
Lipase is a fat-digesting enzyme (a type of esterase) produced mainly by the pancreas, which breaks triglycerides into fatty acids and glycerol.
Question 2: Where does the majority of nutrient absorption take place in the digestive system?
- Stomach
- Large intestine
- Small intestine (Correct answer)
- Esophagus
Correct answer: Small intestine
The small intestine is the primary site of nutrient absorption, facilitated by villi and microvilli that dramatically increase its absorptive surface area.
Question 3: What is peristalsis?
- The chemical breakdown of food by enzymes
- The wave-like muscular contractions that move food along the digestive tract (Correct answer)
- The secretion of digestive juices into the gut
- The absorption of water in the colon
Correct answer: The wave-like muscular contractions that move food along the digestive tract
Peristalsis is the coordinated, wave-like contraction and relaxation of smooth muscle in the walls of the digestive tract that propels food forward.
Question 4: Which of the following correctly describes the role of hydrochloric acid (HCl) in the stomach?
- It directly digests carbohydrates
- It activates pepsinogen into pepsin and kills bacteria in food (Correct answer)
- It neutralizes bile to aid fat digestion
- It converts maltose into glucose
Correct answer: It activates pepsinogen into pepsin and kills bacteria in food
HCl in the stomach activates the inactive enzyme pepsinogen into pepsin and creates an acidic environment that kills most pathogens in ingested food.
Question 5: What are the end products of protein digestion?
- Fatty acids and glycerol
- Glucose and fructose
- Amino acids (Correct answer)
- Maltose and sucrose
Correct answer: Amino acids
Proteases such as pepsin and trypsin break down dietary proteins through hydrolysis into their monomers, which are amino acids.
Question 6: Which structure prevents food from entering the trachea (windpipe) during swallowing?
- Uvula
- Epiglottis (Correct answer)
- Pyloric sphincter
- Cardiac sphincter
Correct answer: Epiglottis
The epiglottis is a flap of cartilage that folds over the glottis during swallowing, directing food into the esophagus and away from the airway.
CXC CXC - Caribbean Examinations Council Human and Social Biology: The Human Digestive System 2
What type of enzyme is lipase, and where is it produced?