BIOD 121 Module 3 Exam: Macronutrients, Metabolism & Digestive Enzymes | Verified Questions and Answers | Latest 2025/2026 – Portage Learning

BIOD 121: Module 3 Exam Portage Learning Questions and
Answers 2026



BIOD 121: Module 3 Gastrointestinal System Test Bank

1. The "Alimentary Canal" is another name for the:
A. Respiratory tract
B. Gastrointestinal (GI) tract
C. Urinary system
D. Lymphatic system
Answer: B
Rationale: The alimentary canal is the continuous long tube that runs from the mouth to
the anus through which food passes.
2. Which of the following is considered an "Accessory Organ" of digestion?
A. Esophagus
B. Stomach
C. Pancreas
D. Large Intestine
Answer: C
Rationale: Accessory organs (liver, gallbladder, pancreas) help with digestion by
secreting enzymes and juices but are not part of the actual GI tube.
3. The process of "Mastication" refers to:
A. Swallowing
B. Mechanical chewing of food in the mouth
C. Chemical breakdown of protein in the stomach
D. The movement of food through the esophagus
Answer: B
Rationale: Mastication is the first step of mechanical digestion, breaking food into
smaller pieces to increase surface area for enzymes.
4. Which enzyme in the mouth begins the chemical digestion of starches?
A. Lingual Lipase
B. Pepsin
C. Salivary Amylase
D. Trypsin

,Answer: C
Rationale: Amylase specifically breaks down complex carbohydrates into simpler sugars
like maltose.
5. The wave-like muscular contractions that move food along the GI tract are
called:
A. Segmentation
B. Mastication
C. Peristalsis
D. Emulsification
Answer: C
Rationale: Peristalsis is the involuntary contraction and relaxation of smooth muscle that
propels a bolus forward.
6. What is the role of the "Epiglottis"?
A. To produce saliva
B. To prevent food from entering the trachea (windpipe)
C. To digest protein
D. To absorb water
Answer: B
Rationale: The epiglottis is a flap of cartilage that closes over the larynx during
swallowing to ensure food enters the esophagus.
7. A "Bolus" is formed in which part of the GI tract?
A. Stomach
B. Mouth
C. Duodenum
D. Esophagus
Answer: B
Rationale: A bolus is the soft, rounded mass of chewed food mixed with saliva that is
ready to be swallowed.
8. Which sphincter prevents stomach acid from backing up into the esophagus?
A. Pyloric sphincter
B. Lower Esophageal (Cardiac) sphincter
C. Ileocecal valve
D. Anal sphincter
Answer: B
Rationale: This sphincter sits at the base of the esophagus; if it relaxes inappropriately,
it causes heartburn (GERD).

, 9. "Chyme" is the name given to food after it has been mixed with gastric juices in
the:
A. Mouth
B. Esophagus
C. Stomach
D. Small Intestine
Answer: C
Rationale: Chyme is the semi-liquid, highly acidic mass that is released slowly into the
small intestine.
10. Which cells in the stomach produce Hydrochloric Acid (HCl)?
A. Chief cells
B. Parietal cells
C. Goblet cells
D. G-cells
Answer: B
Rationale: Parietal cells secrete HCl, which lowers the stomach pH to about 2.0 to kill
bacteria and activate enzymes.
11. The primary function of "Pepsin" is to digest:
A. Carbohydrates
B. Lipids
C. Proteins
D. Fiber
Answer: C
Rationale: Pepsin is a protease that breaks long protein chains into smaller polypeptide
fragments.
12. Why doesn't the stomach digest itself?
A. The stomach is made of bone
B. A thick layer of alkaline mucus protects the stomach lining
C. The stomach only produces acid when empty
D. Enzymes are not active in the stomach
Answer: B
Rationale: Mucous neck cells produce a protective barrier that neutralizes the acid in
direct contact with the stomach wall.
13. "Intrinsic Factor" is necessary for the absorption of which nutrient?
A. Iron
B. Vitamin C