Hydrochloric acid in gastric juice is important because it
Correct answer: C. kills most swallowed bacteria and gives pepsin the acid pH it needs
- A. digests proteins directly into amino acids
- B. emulsifies the fat in the food
- C. kills most swallowed bacteria and gives pepsin the acid pH it needs
- D. neutralises the acid arriving from the mouth
Explanation
The acid brings the stomach contents to about pH 2, which is the optimum for pepsin and also converts inactive pepsinogen into pepsin, while destroying most of the microbes swallowed with the food. The acid itself is not an enzyme, so it does not hydrolyse protein, and emulsification is the work of bile in the duodenum. The stomach lining is protected from the acid by a thick layer of mucus.
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About Human Digestive System
The human digestive system breaks food into absorbable molecules through mechanical processing, enzyme action and chemical conditions along the alimentary canal. Questions cover the mouth, stomach, small and large intestines, liver, pancreas and associated secretions, including the digestion and absorption of carbohydrates, proteins, lipids, vitamins, minerals and water.
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