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Quiz Chapter 9: Nutrition and the Human Digestive System

10 questions ยท Form 4 Biology Bab 9: Nutrition and the Human Digestive System

Question 1 of 10Score: 0

What is the role of hydrochloric acid in the stomach regarding enzyme activity?

Full Question List & Answer Key

Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.

1. What is the role of hydrochloric acid in the stomach regarding enzyme activity?

  1. A. It denatures pepsin.
  2. B. It activates inactive pepsinogen into active pepsin.
  3. C. It neutralizes pancreatic juice.
  4. D. It breaks down lipids into fatty acids.
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Answer: B

Hydrochloric acid provides an acidic medium and converts the zymogen precursor pepsinogen into active pepsin.

2. What is the optimal pH environment for the enzyme pepsin in the human stomach?

  1. A. pH 1.5 - 2.0
  2. B. pH 6.5 - 7.5
  3. C. pH 8.0 - 8.5
  4. D. pH 11.0 - 12.0
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Answer: A

Pepsin operates in a highly acidic environment (pH 1.5 to 2.0) provided by hydrochloric acid in gastric juice.

3. Fat-soluble vitamins (A, D, E, K) and fatty acids are absorbed into which specific vessel inside a villus?

  1. A. Blood capillary
  2. B. Lacteal
  3. C. Hepatic artery
  4. D. Venule
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Answer: B

Fat-soluble substances enter the central lymphatic vessel of the villus, known as the lacteal.

4. An individual avoiding food due to extreme fear of gaining weight, leading to severe body mass depletion, suffers from:

  1. A. Obesity
  2. B. Anorexia nervosa
  3. C. Type 2 Diabetes
  4. D. Atherosclerosis
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Answer: B

Anorexia nervosa is a psychological eating disorder characterized by extreme food restriction and distorted body image.

5. A patient experiences pain in the stomach lining due to erosion caused by excessive hydrochloric acid secretion. What condition does this describe?

  1. A. Appendicitis
  2. B. Gastritis
  3. C. Anorexia nervosa
  4. D. Bulimia nervosa
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Answer: B

Gastritis is inflammation and irritation of the stomach mucosal lining, often aggravated by irregular meals or excess acid.

6. How are water-soluble nutrients such as glucose and amino acids transported from the small intestine to the liver?

  1. A. Via lacteals into the thoracic duct
  2. B. Via blood capillaries into the hepatic portal vein
  3. C. Via lymphatic vessels into the subclavian vein
  4. D. Via pulmonary arteries directly to the heart
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Answer: B

Water-soluble nutrients absorb into capillaries of villi and travel directly to the liver through the hepatic portal vein.

7. Which hormone causes the liver to convert excess blood glucose into glycogen during assimilation?

  1. A. Glucagon
  2. B. Insulin
  3. C. Adrenaline
  4. D. Thyroxine
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Answer: B

Insulin secreted by the pancreas stimulates liver cells to convert glucose into stored glycogen.

8. What instrument is used in laboratory settings to measure the total energy content of a dried food sample?

  1. A. Potometer
  2. B. Bomb calorimeter
  3. C. Respirometer
  4. D. Sphygmomanometer
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Answer: B

A bomb calorimeter measures the heat energy released when a known mass of food is completely combusted in pure oxygen.

9. Why is dietary fiber (cellulose) an essential component of a balanced human diet, even though humans cannot digest it?

  1. A. It provides essential amino acids.
  2. B. It stimulates peristalsis and prevents constipation.
  3. C. It yields 38 ATP per gram.
  4. D. It dissolves fat-soluble vitamins.
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Answer: B

Dietary fiber adds bulk to intestinal contents, retaining water and facilitating smooth peristaltic movements to prevent constipation.

10. What is the primary function of the colon (large intestine) in human nutrition?

  1. A. Complete chemical digestion of lipids
  2. B. Reabsorption of water and mineral salts from undigested waste
  3. C. Secretion of trypsin and lipase
  4. D. Absorption of amino acids into lacteals
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Answer: B

The colon absorbs remaining water and dissolved minerals from indigestible remnants to form solid feces.

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