ISSA NUTRITION FINAL EXAM 350
QUESTIONS WITH 100% CORRECT
ANSWERS 2026/ 2027
Section 1: Foundations of Nutrition, Digestion, and Basic Biochemistry
Questions 1–35
1. Which of the following best describes the primary function of the
gastrointestinal (GI) tract's enteric nervous system?
A) To regulate voluntary skeletal muscle movement during eating
B) To control digestive processes independently of the central nervous system
C) To secrete digestive enzymes exclusively from the pancreas
D) To absorb water primarily in the stomach
Correct Answer: B
Rationale: The enteric nervous system (ENS) is a mesh-like system of neurons that
governs GI motility, secretion, and blood flow. It can operate autonomously from
the brain and spinal cord, although it does receive CNS input. Option A is incorrect
because skeletal muscle control is somatic; C is wrong because the ENS regulates
more than just pancreatic secretion; D is wrong because the stomach absorbs very
little water.
2. What is the primary role of hydrochloric acid (HCl) secreted by the parietal cells
of the stomach?
A) To emulsify dietary fats
B) To activate the enzyme pepsinogen into pepsin
C) To absorb vitamin B12
D) To neutralize chyme entering the duodenum
1
,Correct Answer: B
Rationale: HCl creates an acidic environment (pH 1.5-3.5) that denatures proteins
and converts inactive pepsinogen to active pepsin, initiating protein digestion. Bile
emulsifies fats (A); intrinsic factor (not HCl) absorbs B12 (C); bicarbonate from
the pancreas neutralizes chyme (D).
3. In which segment of the GI tract does the majority of macronutrient absorption
occur?
A) Stomach
B) Large intestine
C) Small intestine
D) Esophagus
Correct Answer: C
Rationale: The small intestine (duodenum, jejunum, and ileum) is responsible for
~90% of all nutrient absorption due to its enormous surface area from villi and
microvilli. The stomach absorbs very little, the large intestine absorbs water and
electrolytes, and the esophagus is a conduit.
4. Which macronutrient requires the most water for its metabolic breakdown and
excretion, making adequate hydration particularly important?
A) Carbohydrates
B) Lipids
C) Proteins
D) Alcohol
Correct Answer: C
Rationale: Protein metabolism produces nitrogenous wastes like urea and
ammonia, which require large amounts of water for renal excretion. Carbohydrate
and lipid metabolism primarily produce carbon dioxide and water, requiring less
water for clearance.
2
,5. The "cephalic phase" of digestion is triggered by:
A) The presence of food in the stomach
B) The sight, smell, or thought of food
C) The arrival of chyme in the small intestine
D) Stretching of the large intestine
Correct Answer: B
Rationale: The cephalic phase is the earliest stage, mediated by the vagus nerve,
initiating gastric secretions in response to sensory inputs (sight, smell, taste,
thought) before food enters the stomach. Options A and C describe the gastric and
intestinal phases, respectively.
6. What is the primary transport mechanism for monosaccharides and amino acids
from the intestinal lumen into enterocytes?
A) Passive diffusion
B) Facilitated diffusion via GLUT-2
C) Active transport via sodium-dependent co-transporters
D) Endocytosis
Correct Answer: C
Rationale: Glucose and amino acids are absorbed via secondary active transport,
typically coupled with sodium ions (SGLT-1 for glucose). GLUT-2 is involved in
facilitated exit from the enterocyte into the bloodstream, not entry. Passive
diffusion is not the primary mechanism for these hydrophilic molecules.
7. Which of the following is a catabolic hormone that increases blood glucose
levels by stimulating glycogenolysis?
A) Insulin
B) Glucagon
3
, C) Testosterone
D) Estrogen
Correct Answer: B
Rationale: Glucagon, secreted by pancreatic alpha cells, is a primary catabolic
hormone that signals the liver to break down glycogen (glycogenolysis) and release
glucose. Insulin is anabolic and lowers blood glucose. Testosterone and estrogen
are not directly involved in acute blood glucose regulation.
8. What is the "basal metabolic rate" (BMR) primarily determined by?
A) Physical activity level
B) Lean body mass
C) Dietary fat intake
D) Total body water
Correct Answer: B
Rationale: Lean body mass (muscle, organs) is the most metabolically active tissue
and accounts for 60-70% of BMR. Physical activity is above BMR, fat intake does
not determine BMR, and total body water is a component of lean mass but less
directly predictive.
9. Which enzyme is responsible for breaking down starches into maltose in the
mouth?
A) Lipase
B) Pepsin
C) Amylase
D) Lactase
Correct Answer: C
4
QUESTIONS WITH 100% CORRECT
ANSWERS 2026/ 2027
Section 1: Foundations of Nutrition, Digestion, and Basic Biochemistry
Questions 1–35
1. Which of the following best describes the primary function of the
gastrointestinal (GI) tract's enteric nervous system?
A) To regulate voluntary skeletal muscle movement during eating
B) To control digestive processes independently of the central nervous system
C) To secrete digestive enzymes exclusively from the pancreas
D) To absorb water primarily in the stomach
Correct Answer: B
Rationale: The enteric nervous system (ENS) is a mesh-like system of neurons that
governs GI motility, secretion, and blood flow. It can operate autonomously from
the brain and spinal cord, although it does receive CNS input. Option A is incorrect
because skeletal muscle control is somatic; C is wrong because the ENS regulates
more than just pancreatic secretion; D is wrong because the stomach absorbs very
little water.
2. What is the primary role of hydrochloric acid (HCl) secreted by the parietal cells
of the stomach?
A) To emulsify dietary fats
B) To activate the enzyme pepsinogen into pepsin
C) To absorb vitamin B12
D) To neutralize chyme entering the duodenum
1
,Correct Answer: B
Rationale: HCl creates an acidic environment (pH 1.5-3.5) that denatures proteins
and converts inactive pepsinogen to active pepsin, initiating protein digestion. Bile
emulsifies fats (A); intrinsic factor (not HCl) absorbs B12 (C); bicarbonate from
the pancreas neutralizes chyme (D).
3. In which segment of the GI tract does the majority of macronutrient absorption
occur?
A) Stomach
B) Large intestine
C) Small intestine
D) Esophagus
Correct Answer: C
Rationale: The small intestine (duodenum, jejunum, and ileum) is responsible for
~90% of all nutrient absorption due to its enormous surface area from villi and
microvilli. The stomach absorbs very little, the large intestine absorbs water and
electrolytes, and the esophagus is a conduit.
4. Which macronutrient requires the most water for its metabolic breakdown and
excretion, making adequate hydration particularly important?
A) Carbohydrates
B) Lipids
C) Proteins
D) Alcohol
Correct Answer: C
Rationale: Protein metabolism produces nitrogenous wastes like urea and
ammonia, which require large amounts of water for renal excretion. Carbohydrate
and lipid metabolism primarily produce carbon dioxide and water, requiring less
water for clearance.
2
,5. The "cephalic phase" of digestion is triggered by:
A) The presence of food in the stomach
B) The sight, smell, or thought of food
C) The arrival of chyme in the small intestine
D) Stretching of the large intestine
Correct Answer: B
Rationale: The cephalic phase is the earliest stage, mediated by the vagus nerve,
initiating gastric secretions in response to sensory inputs (sight, smell, taste,
thought) before food enters the stomach. Options A and C describe the gastric and
intestinal phases, respectively.
6. What is the primary transport mechanism for monosaccharides and amino acids
from the intestinal lumen into enterocytes?
A) Passive diffusion
B) Facilitated diffusion via GLUT-2
C) Active transport via sodium-dependent co-transporters
D) Endocytosis
Correct Answer: C
Rationale: Glucose and amino acids are absorbed via secondary active transport,
typically coupled with sodium ions (SGLT-1 for glucose). GLUT-2 is involved in
facilitated exit from the enterocyte into the bloodstream, not entry. Passive
diffusion is not the primary mechanism for these hydrophilic molecules.
7. Which of the following is a catabolic hormone that increases blood glucose
levels by stimulating glycogenolysis?
A) Insulin
B) Glucagon
3
, C) Testosterone
D) Estrogen
Correct Answer: B
Rationale: Glucagon, secreted by pancreatic alpha cells, is a primary catabolic
hormone that signals the liver to break down glycogen (glycogenolysis) and release
glucose. Insulin is anabolic and lowers blood glucose. Testosterone and estrogen
are not directly involved in acute blood glucose regulation.
8. What is the "basal metabolic rate" (BMR) primarily determined by?
A) Physical activity level
B) Lean body mass
C) Dietary fat intake
D) Total body water
Correct Answer: B
Rationale: Lean body mass (muscle, organs) is the most metabolically active tissue
and accounts for 60-70% of BMR. Physical activity is above BMR, fat intake does
not determine BMR, and total body water is a component of lean mass but less
directly predictive.
9. Which enzyme is responsible for breaking down starches into maltose in the
mouth?
A) Lipase
B) Pepsin
C) Amylase
D) Lactase
Correct Answer: C
4
