Question
Question: Enzyme pepsin in the gastric juice helps in the digestion of- A) Carbohydrates B) Fats C) Nucl...
Enzyme pepsin in the gastric juice helps in the digestion of-
A) Carbohydrates
B) Fats
C) Nucleic acids
D) Proteins
Solution
Digestion is the process by which organism’s break down complex food materials into a simpler absorbable form. Digestive juices and enzymes, secreted by various parts of the digestive tract, help in this breakdown of food substances.
Complete answer:
We know that mucosa, the inner lining of the stomach, has gastric glands which secrete the gastric juice.
Gastric juice is acidic in nature and is secreted by three main cells of gastric glands-
1. Mucous neck cells secrete mucus, which lubricates and protects the stomach wall from excoriation by highly acidic HCl.
2. Parietal or oxyntic cells secrete hydrochloric acid, which maintains the acidic pH of the stomach optimal for pepsins.
3. Peptic or chief cells secrete proenzyme pepsinogen, which is converted to its active form, pepsin, by exposure to HCl. Pepsin converts proteins into proteases and peptides (peptides).
Let us also look at various enzymes, their source and substrates.
| Enzyme | Source | Substrate |
|---|---|---|
| Proteases: - Pepsin,- Trypsin,- Peptidase. | - Stomach lining,- Pancreas,- Small intestine. | - Proteins,- Proteins,- Proteins. |
| Lipases | Pancreas | Fats |
| Amylases: - Salivary amylase,- Pancreatic amylase,- Maltase.- Lactase | - Salivary glands, - Pancreas, - Small intestine, - Small intestine | - Starch, - Polysaccharides,- Maltose, - Lactose |
| Nucleases: - Nuclease,- Nucleosidase. | - Pancreas, - Small intestine. | - Polynucleotide(DNA/ RNA), - Nucleotide |
We can say that pepsin in gastric juice helps in the digestion of proteins.
Hence, the correct answer is option D.
Note: Disorders of digestive system-
i) Vomiting- It is the expulsion of food through the mouth from the stomach. It can be caused due to food poisoning or gastroesophageal reflex action.
ii) Diarrhoea- It is a condition of abnormal bowel movement. Continuous discharge of fluid occurs from the anus.
iii) Indigestion- In this, a person is unable to digest food properly leading to a feeling of fullness.