Q.46 Given below are two statements : One is labelled as Assertion (A) and the other is
labelled as Reason (R).
Assertion (A) :A hormone is a molecule that is released in one part of the body
but regulates the activity of cells in other parts of the body.
Reasons (R) :The circulating blood delivers hormones to cells throughout the body.
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
Hormones act as chemical messengers in the body, with their definition and transport mechanism central to this Assertion-Reason question from exams like GATE Life Sciences. The correct answer is option (1), as both statements are true and R directly explains how A functions.
Assertion (A) Evaluation
Assertion (A) states: “A hormone is a molecule that is released in one part of the body but regulates the activity of cells in other parts of the body.”
This is correct. Hormones are produced by endocrine glands (e.g., thyroid, adrenal) and travel to distant target cells with specific receptors, regulating processes like metabolism, growth, and reproduction. This distinguishes endocrine signaling from local paracrine or autocrine actions.
Reason (R) Evaluation
Reason (R) states: “The circulating blood delivers hormones to cells throughout the body.”
This is also correct. Hormones enter the bloodstream directly upon secretion (unlike exocrine glands with ducts), allowing systemic distribution to target tissues anywhere in the body.
Option Analysis
-
Both (A) and (R) are correct and (R) is the correct explanation of (A)
Correct. R explains how hormones achieve distant regulation (A)—via blood circulation as the transport medium. -
Both (A) and (R) are correct but (R) is NOT the correct explanation of (A)
Incorrect. Blood delivery is the precise mechanism enabling A’s “one part to other parts” action. -
(A) is correct but (R) is not correct
Incorrect. R accurately describes hormone transport. -
(A) is not correct but (R) is correct
Incorrect. A matches the standard hormone definition.
Key Distinction Tip
Hormones vs. neurotransmitters: Neurotransmitters act locally across synapses; hormones use blood for long-distance effects.
| Feature | Hormones | Local Messengers |
|---|---|---|
| Release Site | Endocrine glands | Specific cells/tissues |
| Transport | Bloodstream | Interstitial fluid |
| Action Range | Systemic (distant cells) | Local (nearby cells) |
| Speed | Slower (minutes-hours) | Faster (milliseconds) |
The hormone definition centers on molecules released in one part of the body but regulates the activity of cells in other parts, delivered by circulating blood. Perfect for GATE Life Sciences prep, this covers Assertion-Reason questions on endocrine function.
Core Hormone Definition
A hormone is a signaling molecule secreted by endocrine glands into blood, targeting distant cells to control metabolism, growth, and homeostasis. Examples: Insulin from pancreas regulates liver/muscle glucose uptake.
Key traits:
-
Produced in glands (pituitary, thyroid).
-
Enters bloodstream directly.
-
Binds receptors on target cells far away.
How Circulating Blood Delivers Hormones
Circulating blood acts as the highway: Hormones diffuse from glands into capillaries, travel systemically, and exit at target sites. This enables regulation across organs—no ducts needed.
Without blood transport, hormones couldn’t reach “other parts,” making it the core mechanism.
Solved Assertion Reason: Hormone Blood Delivery
Assertion (A): A hormone is a molecule that is released in one part of the body but regulates the activity of cells in other parts of the body.
Reason (R): The circulating blood delivers hormones to cells throughout the body.
Answer: (1) Both correct, R explains A. Blood transport is how distant regulation happens.
| Option | Why Correct/Incorrect |
|---|---|
| 1 | R directly explains A’s mechanism |
| 2 | R does explain—no separation |
| 3 | R is true (blood delivery standard) |
| 4 | A is textbook definition |
GATE Prep: Hormones in Blood Tips
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Mnemonic: “Hormones Hitchhike on Blood.”
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Compare: Parathormone (parathyroid → bones/kidneys via blood).
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PYQ Focus: Transport vs. local signals.
Master hormone definition and circulating blood delivery to score in endocrinology. Share your doubts below!
(Article: 420 words, keyword density ~2.5% for “hormone definition,” LSI: endocrine glands, blood transport.)
