Q.200 Zoology ⭐ 360° Option Elimination Active

NEET 2023 Zoology Question 200 Solution

Topic: Chemical Coordination and Integration · Official NTA Booklet Code G5

Question

Which of the following are NOT under the control of thyroid hormone? A. Maintenance of water and electrolyte balance B. Regulation of basal metabolic rate C. Normal rhythm of sleep-wake cycle D. Development of immune system E. Support the process of R.B.Cs formation Choose the correct answer from the options given below:

(1)D and E only
(2)A and D only
(3)B and C only
(4)C and D only

✓

Verified Against NTA Final Answer Key

Option (4) : C and D only

📚 Chemical Coordination and Integration Easy

📋 Given Parameters & Problem Setup

Endocrine Gland Thyroid gland (

T_3

and

T_4

)

Criterion Functions that are NOT under the control of thyroid hormone

⚡

The 30-Second Exam Hall Shortcut: ⚡ Pineal & Thymus Roles Filter: C & D Are NOT Thyroid Functions!

⏱️ Save ~25 seconds

Normal sleep-wake rhythm is regulated by MELATONIN from the Pineal gland (C). Immune system development is driven by THYMOSINS from the Thymus gland (D). Water balance (A), BMR (B), and erythropoiesis (E) are all controlled by thyroid hormones! Match Option (4) C and D only!

1 Sleep-wake cycle (circadian rhythm) -> Regulated by Melatonin (Pineal gland) -> C is NOT thyroid.

2 Development and differentiation of immune system -> Regulated by Thymosins (Thymus gland) -> D is NOT thyroid.

3 Thyroid hormone functions: Regulates BMR (B), supports RBC formation (E), maintains water and electrolyte balance (A).

4 Therefore, C and D are NOT under thyroid control.

5 Match Option (4) C and D only.

🛡️

Why You Can 100% Trust This Shortcut: Canonical NCERT Chemical Coordination and Integration thyroid physiological functions inventory.

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Canonical Functions of Thyroid Hormones (T3 and T4)

Thyroxine ( $T_4$ ) and triiodothyronine ( $T_3$ ) exert widespread metabolic actions across human tissues:

\text{\textbf{Thyroid Hormones}} \longrightarrow \begin{cases} \mathbf{\text{Regulation of basal metabolic rate (BMR) [B]}} \\[2pt] \mathbf{\text{Maintenance of water and electrolyte balance [A]}} \\[2pt] \mathbf{\text{Support of red blood cell formation (erythropoiesis) [E]}} \\[2pt] \text{Control of carbohydrate, protein, and lipid metabolism} \end{cases}

Step 2

Identification of Non-Thyroid Hormone Functions

Analyzing the specific endocrine control of functions C and D: - Function C (Sleep-wake cycle): Regulated by the hormone melatonin, secreted by the pineal gland to maintain 24-hour diurnal circadian rhythms. - Function D (Development of immune system): Regulated by peptide hormones called thymosins, secreted by the thymus gland to promote T-lymphocyte differentiation and humoral antibody production.

\begin{aligned} \text{\textbf{Function C (Sleep-wake rhythm):}} & \quad \mathbf{\text{Melatonin (Pineal Gland)}} \\[3pt] \text{\textbf{Function D (Immune system):}} & \quad \mathbf{\text{Thymosins (Thymus Gland)}} \end{aligned}

Step 3

Verbatim NCERT Reference

NCERT states under Thyroid Gland: "Thyroid hormones play an important role in the regulation of the basal metabolic rate. These hormones also support the process of red blood cell formation... Maintenance of water and electrolyte balance is also influenced by thyroid hormones." Melatonin regulates "24-hour (diurnal) rhythm... sleep-wake cycle". Thymosins play "a major role in the differentiation of T-lymphocytes... development of immune system".

⭐

360° Option Elimination Engine Key Feature

Diagnose every choice: Know exactly why the right option works and why distractors fail.

4-Option Deep Scan

1 1

✗ Incorrect

Verdict & Scientific Reason:

RBC formation (E) IS supported by thyroid hormones.

⚠️

Student Fallacy (Why candidates pick this trap): Thinking thyroid hormone has no role in erythropoiesis.

2 2

✗ Incorrect

Verdict & Scientific Reason:

Water and electrolyte balance (A) IS influenced by thyroid hormones.

⚠️

Student Fallacy (Why candidates pick this trap): Assuming water/electrolyte balance is regulated solely by aldosterone/ADH.

3 3

✗ Incorrect

Verdict & Scientific Reason:

BMR regulation (B) is the quintessential primary action of thyroid hormones.

⚠️

Student Fallacy (Why candidates pick this trap): Denying thyroid control of basal metabolic rate.

4 4

✓ 100% Correct

Verdict & Scientific Reason:

Both C (sleep-wake cycle controlled by melatonin) and D (immune system controlled by thymosins) are NOT under thyroid control.

💡

Why this is airtight: None; textbook verbatim match.

⚠️

NTA Trap Alert: Water Balance & RBC Formation Under Thyroid Hormones Trap

Students often associate water balance only with ADH/Aldosterone and RBC formation only with Erythropoietin, forgetting that NCERT explicitly lists both as physiological functions of thyroid hormones as well.

🛡️ How to avoid the -1 mark: Remember: Thyroid controls BMR, RBCs, and Water/Electrolytes. Pineal controls Sleep-wake. Thymus controls Immune system.

📖

Core NEET Syllabus Standard

NCERT Biology · Chemical Coordination and Integration Standard Benchmark

Core Scientific Principle Tested:

"Thyroid hormones regulate BMR, RBC formation, and water/electrolyte balance. Melatonin regulates sleep-wake cycle; Thymosins regulate immune system development."

Syllabus Focus: Thyroid Gland, Pineal Gland & Thymus Gland

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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NEET 2023 Zoology Question 200 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Pineal & Thymus Roles Filter: C & D Are NOT Thyroid Functions!

Step-by-Step Rigorous Workflow & Mathematical Proof

Canonical Functions of Thyroid Hormones (T3 and T4)

Identification of Non-Thyroid Hormone Functions

Verbatim NCERT Reference

360° Option Elimination Engine Key Feature

NTA Trap Alert: Water Balance & RBC Formation Under Thyroid Hormones Trap

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

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