Question

Assertion (A): Gastric juice plays an important role in absorption of vitamin B12.
Reason (R): Gastric juice contains Castle’s intrinsic factor.
Identify the correct option from the following:

• (A) and (R) are true, (R) is correct explanation for (A).
• (A) and (R) are true, (R) is not correct explanation for (A).
• (A) is true, but (R) is false.
• (A) is false, but (R) is true.

Hint:

Intrinsic factor in gastric juice is essential for vitamin B12 absorption in the small intestine, preventing deficiencies like pernicious anemia.

Answer 1

The Correct Option is A

Let’s assess the assertion and reason by breaking down their biological basis.
First, consider Assertion (A): Gastric juice plays a role in vitamin B12 absorption.
This is true because gastric juice, produced in the stomach, facilitates the absorption of vitamin B12 in the small intestine.
Now, evaluate Reason (R): Gastric juice contains Castle’s intrinsic factor.
This is also true—intrinsic factor is a glycoprotein secreted by the stomach’s parietal cells, present in gastric juice.
Finally, does (R) explain (A)? Yes, intrinsic factor binds to vitamin B12, forming a complex that is absorbed in the ileum of the small intestine, directly explaining the role of gastric juice in B12 absorption.

Final Answer: Both (A) and (R) are true, and (R) correctly explains (A). Thus, the correct option is (1).