Q. Which of the following enzymes is/are released in stomach for protein digestion ?
1. Chymotrypsin
2. Trypsin
3. Pepsin
Select the correct answer using the code given below :
a) Only 1 and 2
b) Only 3
c) Only 2 and 3
d) 1, 2 and 3
Correct Answer: b) Only 3
Question from UPPSC Prelims 2025
Explanation:
Only pepsin is released in the stomach for protein digestion. Chief cells of the gastric glands secrete pepsinogen, which is activated to pepsin by gastric HCl; pepsin works optimally in the acidic pH of the stomach. Trypsin and chymotrypsin are pancreatic proteases; they are secreted into the duodenum as trypsinogen and chymotrypsinogen and activated (by enteropeptidase and trypsin) in an alkaline environment. Hence they are not released in the stomach.
– Option 1 (Only 1 and 2): Incorrect—both chymotrypsin and trypsin are pancreatic, not gastric.
– Option 2 (Only 3): Correct—pepsin is the gastric protease.
– Option 3 (Only 2 and 3): Incorrect—includes trypsin, which is not released in the stomach.
– Option 4 (1, 2 and 3): Incorrect—adds pancreatic enzymes not secreted by the stomach.
