Question

Gastric juice contains:
(a) Pepsin, Lipase, and Rennin
(b) Trypsin, Lipase, and Rennin
(c) Trypsin, pepsin, and Lipase
(d) Trypsin, Pepsin, and Rennin

Answer 1

Hint: The stomach is the first organ in the alimentary canal where food enters after chewing. The major process done here is the breakdown of proteins by proteolytic enzymes. Extremely low pH is the essential requirement for these enzymes to work properly.

Complete step by step answer:
The stomach is a J shaped muscular organ present in the abdominal cavity, in between the oesophagus and first part of the small intestine i.e. duodenum. Lining of the stomach contains gastric glands which are made of three main types of cells –
Neck cells: Secrete mucus protects the mucosa of the stomach from acidic environment.
Peptic of chief cells: Secrete proenzyme pepsinogen which when activated by hydrochloric acid, gets converted to active enzyme pepsin. It is a proteolytic enzyme that breaks down proteins into smaller molecules.
Oxyntic or parietal cells: Secrete hydrochloric acid which activates the pepsin enzyme. It is also essential for the absorption of vitamin B12.
Apart from pepsin, lipase and rennin are also two important enzymes secreted by gastric cells. Rennin is not found in adults but only found in the gastric juice of infants. It is mainly involved in the breakdown of milk proteins that enter in large concentrations in the infant body. Lipase is another enzyme secreted by gastric cells. It is a lipolytic enzyme that breaks down fats to smaller molecules i.e. monoglycerides and diglycerides.
So, the correct answer is ‘(b) Trypsin, Lipase, and Rennin’.

Note: A healthy adult human secretes around 1.5 liters of gastric juice in a day. Further, there are three stages in which gastric acid is released in the stomach. The second phase-out of this or gastric phase is the one in which the maximum amount of gastric juice is released.