Q.41 Given below are two statements : One is labelled as Assertion (A) and the other is labelled as
Reason (R).

Assertion (A) :Gluconse homeostasis relies predominantly on the antagonistric effects of the
hormones, insulin and glucagon.

Reasons (R) :When the blood glucose level rises above the normal range, the Secretion of
insulin trigger the uptake of glucose from the blood into body cells, decreasing
the blood glucose concentration. When the blood glucose level drops below
the normal range, the secretion Of glucagon promotes the release Of glucose
into the blood from energy stores, such as liver glycogen, increasing the blood
glucose concentration.

In the light of the above statements, choose the most appropriate answer from the options given
below :
(1)Both (A) and (R) are correct and (R) is the correct explanation of (A)
(2)Both (A) and (R) are correct but (R) is NOT the correct explanation of (A)
(3)(A) is correct but (R) is not correct
(4)(A) is not correct but (R) is correct

Both Assertion (A) and Reason (R) are correct, and (R) is the correct explanation of (A).
Option (1) is right because insulin and glucagon’s antagonistic actions directly maintain glucose homeostasis, as detailed in (R).

Option Breakdown

• (1) Both (A) and (R) correct; (R) explains (A): Matches facts—insulin lowers glucose via uptake; glucagon raises it via glycogenolysis/gluconeogenesis.​

• (2) Both correct but (R) not explanation: Wrong, as (R) precisely describes the “antagonistic effects” in (A).​

• (3) (A) correct, (R) incorrect: No, (R) accurately states mechanisms (insulin triggers uptake; glucagon releases from liver stores).

• (4) (A) incorrect, (R) correct: False, as (A) is true—”predominantly” fits, despite minor roles of other hormones like cortisol.​

Glucose homeostasis insulin glucagon is a core concept in biochemistry for competitive exams like GATE Life Sciences and NEET. This assertion-reason question tests understanding of their antagonistic roles in blood sugar regulation.

Core Mechanisms

Insulin, from beta cells, rises post-meal to promote glucose uptake into muscle/adipose and inhibit hepatic output. Glucagon, from alpha cells, activates during fasting via cAMP/PKA, driving glycogenolysis and gluconeogenesis in liver.

Why Option (1)?

(R) directly explains (A)’s “antagonistic effects” with precise actions: insulin decreases blood glucose; glucagon increases it from stores like glycogen.​

Exam Tips

Focus on “predominantly” in (A)—ignores minor hormones. Practice similar questions on pancreatic islets for GATE BT. This keeps glucose at 4-6 mM for energy balance.