Q11. The process by which food is moved through the digestive tract by alternating contraction and relaxation of muscles is called:
a) Osmosis
b) Diffusion
c) Peristalsis
d) Filtration
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Correct Answer: c) Peristalsis
Explanation: Peristalsis is the process of rhythmic, wave-like muscle contractions that move food through the digestive tract. It involves the coordinated contraction and relaxation of circular and longitudinal muscles of the alimentary canal.
Q12. The enzyme pepsin, essential for protein digestion, is active in the:
a) Mouth
b) Stomach
c) Small intestine
d) Large intestine
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Correct Answer: b) Stomach
Explanation: Pepsin is an enzyme that is active in the stomach and is crucial for the digestion of proteins. It is secreted as an inactive precursor, pepsinogen, and is activated by stomach acid into pepsin.
Q13. What is the main role of mucus in the stomach?
a) To digest proteins
b) To emulsify fats
c) To protect the stomach lining
d) To absorb nutrients
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Correct Answer: c) To protect the stomach lining
Explanation: Mucus in the stomach plays a protective role. It coats the stomach lining, creating a barrier that protects the stomach wall from the corrosive effects of stomach acid and digestive enzymes.
Q14. Bile aids in the digestion of fats by:
a) Breaking down fat molecules
b) Emulsifying fats
c) Absorbing fatty acids
d) Converting fats to proteins
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Correct Answer: b) Emulsifying fats
Explanation: Bile aids in the digestion of fats primarily through the process of emulsification. It breaks down large fat globules into smaller droplets, increasing the surface area for enzymes to work, thus enhancing fat digestion and absorption.
Q15. Which part of the digestive system is responsible for absorbing most of the water?
a) Stomach
b) Small intestine
c) Large intestine
d) Liver
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Correct Answer: c) Large intestine
Explanation: The large intestine (colon) is primarily responsible for absorbing most of the water from indigestible food residue. This absorption process concentrates the waste, leading to the formation of feces.
Q16. Lactase is an enzyme that breaks down:
a) Starch
b) Lactose
c) Proteins
d) Lipids
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Correct Answer: b) Lactose
Explanation: Lactase is an enzyme that specifically breaks down lactose, a sugar found in milk and dairy products. It converts lactose into glucose and galactose, which can then be absorbed into the bloodstream.
Q17. The condition known as ‘acid reflux’ occurs when:
a) Acidic gastric contents enter the small intestine
b) Bile leaks into the stomach
c) The lower esophageal sphincter fails to close properly
d) The pancreas stops producing enzymes
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Correct Answer: c) The lower esophageal sphincter fails to close properly
Explanation: Acid reflux, or gastroesophageal reflux disease (GERD), occurs when the lower esophageal sphincter fails to close properly, allowing acidic gastric contents to flow back (reflux) into the esophagus, causing irritation and discomfort.
Q18. The finger-like projections in the small intestine that increase the surface area for absorption are called:
a) Villi
b) Microvilli
c) Plicae circulares
d) Rugae
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Correct Answer: a) Villi
Explanation: Villi are finger-like projections lining the small intestine, which significantly increase the surface area for nutrient absorption. Each villus contains blood vessels and a lacteal, aiding in the transfer of nutrients to the blood and lymphatic system.
Q19. What is the primary digestive function of the liver?
a) To produce digestive enzymes
b) To absorb nutrients
c) To produce bile
d) To grind food
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Correct Answer: c) To produce bile
Explanation: The primary digestive function of the liver is to produce bile, which is important in the digestion and absorption of fats and fat-soluble vitamins in the small intestine. Bile also helps in the elimination of waste products.
Q20. The process of breaking down food into nutrients that the body can absorb is known as:
a) Catabolism
b) Metabolism
c) Digestion
d) Absorption
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Correct Answer: c) Digestion
Explanation: Digestion is the process of breaking down food into smaller components that can be absorbed into the bloodstream. It includes both mechanical digestion (physical breakdown) and chemical digestion (enzymatic breakdown).