HUN201 Digestion, Absorption & Metabolism 2026/2027 | Jersey College Nutrition HUN 201
Study Guide & Exam Prep | Digestion, Absorption and Metabolism Practice Questions,
Answers & Detailed Rationales | Nutrient Digestion, Macronutrient Metabolism,
Carbohydrate, Protein & Lipid Metabolism, Vitamins & Minerals, Energy Metabolism,
Gastrointestinal Tract, Nutrient Absorption, Enzymes, Hormones, Water & Electrolyte
Balance, Nutrition & Disease
Question 1: Which organ is primarily responsible for the
mechanical and chemical digestion of food, as well as the
absorption of most nutrients?
A. The esophagus
B. The stomach
C. The small intestine
D. The large intestine
CORRECT ANSWER: C. The small intestine
Rationale: The small intestine is the primary site for the digestion and
absorption of most nutrients. While the stomach begins the chemical
digestion of proteins and some mechanical digestion, the small intestine is
where the majority of enzymatic breakdown and nutrient absorption
occurs, facilitated by its large surface area, villi, and microvilli.
Question 2: What is the name of the wave-like muscular
contractions that propel food through the digestive tract?
A. Segmentation
B. Peristalsis
C. Emulsification
D. Hydrolysis
CORRECT ANSWER: B. Peristalsis
Rationale: Peristalsis is the involuntary, wave-like contraction of smooth
muscles that moves food along the digestive tract. Segmentation refers to
localized contractions that mix chyme, emulsification is the breakdown of
fat globules, and hydrolysis is a chemical process of breaking down
compounds using water.
Question 3: Which of the following enzymes is responsible for the
initial digestion of starches in the mouth?
A. Pepsin
B. Trypsin
C. Salivary amylase
D. Lipase
,CORRECT ANSWER: C. Salivary amylase
Rationale: Salivary amylase is an enzyme present in saliva that begins the
chemical digestion of carbohydrates (starches) into smaller polysaccharides
and maltose. Pepsin digests proteins in the stomach, trypsin digests
proteins in the small intestine, and lipase digests fats.
Question 4: The acidic environment of the stomach, crucial for
activating enzymes and killing bacteria, is maintained by the
secretion of what substance?
A. Bicarbonate
B. Mucus
C. Hydrochloric acid
D. Bile
CORRECT ANSWER: C. Hydrochloric acid
Rationale: Parietal cells in the stomach lining secrete hydrochloric acid
(HCl), which lowers the pH of the stomach, creating an acidic environment.
This is necessary to activate pepsinogen into pepsin for protein digestion
and to destroy ingested microorganisms.
Question 5: What is the primary role of bile in the digestive
process?
A. To digest proteins into amino acids
B. To break down carbohydrates into simple sugars
C. To emulsify fats into smaller droplets
D. To neutralize stomach acid in the small intestine
CORRECT ANSWER: C. To emulsify fats into smaller droplets
Rationale: Bile, produced by the liver and stored in the gallbladder, contains
bile salts that act as emulsifiers. They break large fat globules into smaller
ones, increasing the surface area for pancreatic lipase to digest
triglycerides. Bile does not contain digestive enzymes.
Question 6: Where does the majority of nutrient absorption occur?
A. Stomach
B. Duodenum
C. Jejunum
D. Ileum
,CORRECT ANSWER: C. Jejunum
Rationale: The jejunum is the middle section of the small intestine and is
the primary site for the absorption of most nutrients, including
carbohydrates, amino acids, and fatty acids. The duodenum is more
involved in receiving chyme and digestive secretions, while the ileum
primarily absorbs vitamin B12, bile salts, and whatever remains.
Question 7: Which of the following is NOT a function of the large
intestine?
A. Absorption of water and electrolytes
B. Synthesis of certain vitamins by bacteria
C. Digestion and absorption of the majority of proteins
D. Formation and storage of feces
CORRECT ANSWER: C. Digestion and absorption of the majority of
proteins
Rationale: The majority of protein digestion and absorption occurs in the
stomach and small intestine. The large intestine's main functions are to
absorb water and electrolytes, synthesize vitamins like vitamin K and some
B vitamins via gut bacteria, and form and store feces.
Question 8: What are villi and microvilli, and what is their primary
function?
A. Finger-like projections in the stomach that secrete acid
B. Small pouches in the large intestine that house bacteria
C. Microscopic projections in the small intestine that increase surface area
for absorption
D. Valves that prevent backflow of food between digestive organs
CORRECT ANSWER: C. Microscopic projections in the small
intestine that increase surface area for absorption
Rationale: Villi are finger-like projections lining the small intestine, and
microvilli are even smaller projections on the surface of the cells covering
the villi. Together, they dramatically increase the surface area of the small
intestine, maximizing the efficiency of nutrient absorption.
Question 9: Which hormone stimulates the release of hydrochloric
acid from the stomach lining?
, A. Secretin
B. Cholecystokinin (CCK)
C. Gastrin
D. Insulin
CORRECT ANSWER: C. Gastrin
Rationale: Gastrin is a hormone produced by G cells in the stomach in
response to food intake. It stimulates parietal cells to secrete hydrochloric
acid and chief cells to secrete pepsinogen, aiding in protein digestion.
Secretin and CCK are hormones produced by the small intestine.
Question 10: The process of breaking down large food molecules
into smaller ones using water is known as:
A. Condensation
B. Hydrolysis
C. Oxidation
D. Phosphorylation
CORRECT ANSWER: B. Hydrolysis
Rationale: Hydrolysis is a chemical reaction where a molecule of water is
used to break a chemical bond, splitting a large molecule into two smaller
ones. This is the primary mechanism for the enzymatic digestion of
carbohydrates, proteins, and fats.
Question 11: What is the primary function of cholecystokinin (CCK)
in digestion?
A. To stimulate gastric acid secretion
B. To stimulate the release of bile from the gallbladder and pancreatic
enzymes
C. To inhibit intestinal motility
D. To promote water reabsorption in the colon
CORRECT ANSWER: B. To stimulate the release of bile from the
gallbladder and pancreatic enzymes
Rationale: Cholecystokinin (CCK) is released by the small intestine in
response to the presence of fats and proteins. It stimulates the gallbladder
to contract and release bile, and it stimulates the pancreas to secrete
digestive enzymes. It also slows gastric emptying.
Study Guide & Exam Prep | Digestion, Absorption and Metabolism Practice Questions,
Answers & Detailed Rationales | Nutrient Digestion, Macronutrient Metabolism,
Carbohydrate, Protein & Lipid Metabolism, Vitamins & Minerals, Energy Metabolism,
Gastrointestinal Tract, Nutrient Absorption, Enzymes, Hormones, Water & Electrolyte
Balance, Nutrition & Disease
Question 1: Which organ is primarily responsible for the
mechanical and chemical digestion of food, as well as the
absorption of most nutrients?
A. The esophagus
B. The stomach
C. The small intestine
D. The large intestine
CORRECT ANSWER: C. The small intestine
Rationale: The small intestine is the primary site for the digestion and
absorption of most nutrients. While the stomach begins the chemical
digestion of proteins and some mechanical digestion, the small intestine is
where the majority of enzymatic breakdown and nutrient absorption
occurs, facilitated by its large surface area, villi, and microvilli.
Question 2: What is the name of the wave-like muscular
contractions that propel food through the digestive tract?
A. Segmentation
B. Peristalsis
C. Emulsification
D. Hydrolysis
CORRECT ANSWER: B. Peristalsis
Rationale: Peristalsis is the involuntary, wave-like contraction of smooth
muscles that moves food along the digestive tract. Segmentation refers to
localized contractions that mix chyme, emulsification is the breakdown of
fat globules, and hydrolysis is a chemical process of breaking down
compounds using water.
Question 3: Which of the following enzymes is responsible for the
initial digestion of starches in the mouth?
A. Pepsin
B. Trypsin
C. Salivary amylase
D. Lipase
,CORRECT ANSWER: C. Salivary amylase
Rationale: Salivary amylase is an enzyme present in saliva that begins the
chemical digestion of carbohydrates (starches) into smaller polysaccharides
and maltose. Pepsin digests proteins in the stomach, trypsin digests
proteins in the small intestine, and lipase digests fats.
Question 4: The acidic environment of the stomach, crucial for
activating enzymes and killing bacteria, is maintained by the
secretion of what substance?
A. Bicarbonate
B. Mucus
C. Hydrochloric acid
D. Bile
CORRECT ANSWER: C. Hydrochloric acid
Rationale: Parietal cells in the stomach lining secrete hydrochloric acid
(HCl), which lowers the pH of the stomach, creating an acidic environment.
This is necessary to activate pepsinogen into pepsin for protein digestion
and to destroy ingested microorganisms.
Question 5: What is the primary role of bile in the digestive
process?
A. To digest proteins into amino acids
B. To break down carbohydrates into simple sugars
C. To emulsify fats into smaller droplets
D. To neutralize stomach acid in the small intestine
CORRECT ANSWER: C. To emulsify fats into smaller droplets
Rationale: Bile, produced by the liver and stored in the gallbladder, contains
bile salts that act as emulsifiers. They break large fat globules into smaller
ones, increasing the surface area for pancreatic lipase to digest
triglycerides. Bile does not contain digestive enzymes.
Question 6: Where does the majority of nutrient absorption occur?
A. Stomach
B. Duodenum
C. Jejunum
D. Ileum
,CORRECT ANSWER: C. Jejunum
Rationale: The jejunum is the middle section of the small intestine and is
the primary site for the absorption of most nutrients, including
carbohydrates, amino acids, and fatty acids. The duodenum is more
involved in receiving chyme and digestive secretions, while the ileum
primarily absorbs vitamin B12, bile salts, and whatever remains.
Question 7: Which of the following is NOT a function of the large
intestine?
A. Absorption of water and electrolytes
B. Synthesis of certain vitamins by bacteria
C. Digestion and absorption of the majority of proteins
D. Formation and storage of feces
CORRECT ANSWER: C. Digestion and absorption of the majority of
proteins
Rationale: The majority of protein digestion and absorption occurs in the
stomach and small intestine. The large intestine's main functions are to
absorb water and electrolytes, synthesize vitamins like vitamin K and some
B vitamins via gut bacteria, and form and store feces.
Question 8: What are villi and microvilli, and what is their primary
function?
A. Finger-like projections in the stomach that secrete acid
B. Small pouches in the large intestine that house bacteria
C. Microscopic projections in the small intestine that increase surface area
for absorption
D. Valves that prevent backflow of food between digestive organs
CORRECT ANSWER: C. Microscopic projections in the small
intestine that increase surface area for absorption
Rationale: Villi are finger-like projections lining the small intestine, and
microvilli are even smaller projections on the surface of the cells covering
the villi. Together, they dramatically increase the surface area of the small
intestine, maximizing the efficiency of nutrient absorption.
Question 9: Which hormone stimulates the release of hydrochloric
acid from the stomach lining?
, A. Secretin
B. Cholecystokinin (CCK)
C. Gastrin
D. Insulin
CORRECT ANSWER: C. Gastrin
Rationale: Gastrin is a hormone produced by G cells in the stomach in
response to food intake. It stimulates parietal cells to secrete hydrochloric
acid and chief cells to secrete pepsinogen, aiding in protein digestion.
Secretin and CCK are hormones produced by the small intestine.
Question 10: The process of breaking down large food molecules
into smaller ones using water is known as:
A. Condensation
B. Hydrolysis
C. Oxidation
D. Phosphorylation
CORRECT ANSWER: B. Hydrolysis
Rationale: Hydrolysis is a chemical reaction where a molecule of water is
used to break a chemical bond, splitting a large molecule into two smaller
ones. This is the primary mechanism for the enzymatic digestion of
carbohydrates, proteins, and fats.
Question 11: What is the primary function of cholecystokinin (CCK)
in digestion?
A. To stimulate gastric acid secretion
B. To stimulate the release of bile from the gallbladder and pancreatic
enzymes
C. To inhibit intestinal motility
D. To promote water reabsorption in the colon
CORRECT ANSWER: B. To stimulate the release of bile from the
gallbladder and pancreatic enzymes
Rationale: Cholecystokinin (CCK) is released by the small intestine in
response to the presence of fats and proteins. It stimulates the gallbladder
to contract and release bile, and it stimulates the pancreas to secrete
digestive enzymes. It also slows gastric emptying.
