NEET (UG) · Zoology, Class 11
Chemical Coordination and Integration: NEET PYQ, 2018–2026
Chemical Coordination and Integration (Zoology, Class 11) has been asked 16 times in the 7 NEET papers from 2018, 2020, 2021, 2023, 2024, 2025 and 2026: about 2.3 questions a paper, 6% of all Zoology questions. It is the 9th most-asked of 15 Zoology chapters. NEET 2026 had 3 from it. Last checked 28 October 2026.
Questions per paper
Year by year.
| Year | Questions |
|---|---|
| 2018 | 1 |
| 2020 | 2 |
| 2021 | 1 |
| 2023 | 2 |
| 2024 | 3 |
| 2025 | 4 |
| 2026 | 3 |
From 2021 to 2024 each paper had 200 questions (a Section B with a choice); the others had 180.
Inside the chapter
Topics asked most.
- Endocrine glands11
- Hormone mechanism3
- Hormonal disorders2
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10 Chemical Coordination and Integration questions to practise.
Our own questions, written in the NEET pattern and checked, each with an explanation. Pick an option to see the answer.
Q1 · Zoology · Chemical Coordination and Integration
The pituitary gland is lodged in a bony cavity called the:
Answer: (D)
The pituitary gland sits in a bony cavity, the sella turcica, and is attached to the hypothalamus by a stalk. Anatomically it is divided into an adenohypophysis and a neurohypophysis.
Q2 · Zoology · Chemical Coordination and Integration
A patient has bulging eyes, rapid heartbeat, weight loss and a diffusely enlarged thyroid. Blood tests show high thyroxine. Which statement correctly predicts the blood TSH level and explains it?
Answer: (A)
Thyroxine exerts negative feedback on the hypothalamus (TRH) and anterior pituitary (TSH). When thyroxine is high, TSH falls. The disorder described is Graves disease, in which antibodies stimulate the TSH receptor on the thyroid, so the gland overproduces thyroxine. The pituitary responds to the high thyroxine by reducing TSH, which is why blood TSH is low.
Q3 · Zoology · Chemical Coordination and Integration
Following accidental removal of the parathyroid glands during thyroid surgery, a patient develops intermittent muscle cramps and tetany. Which explanation best accounts for this?
Answer: (A)
Parathyroid hormone is the main regulator of blood calcium. It raises calcium by stimulating osteoclast-mediated bone resorption, increasing renal calcium reabsorption, and enhancing intestinal calcium absorption indirectly through vitamin D. Its loss causes hypocalcaemia, and the resulting excitability of nerves and muscles produces tetany. Calcitonin acts in the opposite direction to PTH and is not the hormone removed here.
Q4 · Zoology · Chemical Coordination and Integration
In old individuals the thymus degenerates. As a result:
Answer: (A)
The thymus secretes thymosins, which play a major role in the differentiation of T-lymphocytes and promote antibody production. It degenerates in old individuals, which decreases thymosin production, and as a result their immune responses become weak.
Q5 · Zoology · Chemical Coordination and Integration
Which hypothalamic substance acts as the prolactin-inhibiting factor, restraining the secretion of prolactin from the anterior pituitary?
Answer: (A)
Principle: the hypothalamus controls the anterior pituitary through releasing and inhibiting hormones carried in the hypophyseal portal circulation. Prolactin is unusual because its main control is inhibitory, and dopamine is the principal inhibitory factor. Identify the controlling chemical, its source (hypothalamus) and its target (anterior pituitary, prolactin), and do not confuse it with GnRH or oxytocin, which act on different hormones or different glands.
Q6 · Zoology · Chemical Coordination and Integration
Renin released by the kidney raises blood pressure by generating angiotensin II. Which adrenal hormone is stimulated by angiotensin II, and what does it do in the distal tubule of the nephron?
Answer: (A)
Principle: the renin-angiotensin system raises blood pressure. Renin converts angiotensinogen to angiotensin I, which becomes angiotensin II. Angiotensin II stimulates aldosterone secretion from the zona glomerulosa of the adrenal cortex. Aldosterone acts on the distal tubule to increase sodium reabsorption and potassium excretion, which increases blood volume. The hormone's source is the zona glomerulosa, and its target is the distal tubule.
Q7 · Zoology · Chemical Coordination and Integration
Which hormone, secreted by the zona glomerulosa of the adrenal cortex, acts on the kidney tubules to promote reabsorption of sodium ions and water?
Answer: (A)
Principle: the adrenal cortex has three zones. The outer zona glomerulosa secretes mineralocorticoids, mainly aldosterone, which regulate electrolyte and water balance. Application: the stem names the zona glomerulosa and the action on sodium and water reabsorption, which identifies aldosterone directly. Recall the zone-to-hormone link: glomerulosa gives mineralocorticoids, fasciculata gives glucocorticoids such as cortisol, and reticularis gives sex steroids.
Q8 · Zoology · Chemical Coordination and Integration
A child born in an iodine-deficient region has stunted growth, delayed mental development and a swollen neck. Which condition best describes this, and what is its primary cause?
Answer: (A)
Principle: thyroxine (T4) and triiodothyronine (T3) contain iodine, and the thyroid cannot make them without it. Low thyroxine raises TSH, which enlarges the thyroid into a goitre. Application: the developmental features (stunted growth, mental retardation) mean the deficiency occurred in childhood, when thyroxine is essential for normal growth and brain development. That makes the diagnosis cretinism, not adult myxoedema, and the cause is iodine-deficient thyroxine synthesis.
Q9 · Zoology · Chemical Coordination and Integration
A hormone activates a G-protein-coupled receptor that stimulates phospholipase C in a target cell. Which of the following correctly describes the roles of the two products of PIP2 hydrolysis?
Answer: (A)
Gq-coupled receptors activate phospholipase C, which cleaves membrane PIP2 into IP3 and DAG. IP3 diffuses to the ER and opens calcium release channels. DAG remains in the membrane, where it, together with Ca2+, activates protein kinase C. Remember the solubility of each product, because that determines where it works.
Q10 · Zoology · Chemical Coordination and Integration
Melatonin, the hormone of the pineal gland, plays a very important role in regulating:
Answer: (C)
Melatonin plays a very important role in the regulation of the 24-hour (diurnal) rhythm of our body, such as maintaining the normal rhythms of the sleep–wake cycle and body temperature. It also influences metabolism, pigmentation, the menstrual cycle and defence capability.
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All 16 real NEET questions from Chemical Coordination and Integration.
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About Chemical Coordination and Integration in NEET.
How many questions come from Chemical Coordination and Integration in NEET?
Chemical Coordination and Integration (Zoology, Class 11) has been asked 16 times in the 7 NEET papers from 2018, 2020, 2021, 2023, 2024, 2025 and 2026: about 2.3 questions a paper, 6% of all Zoology questions. It is the 9th most-asked of 15 Zoology chapters. NEET 2026 had 3 from it.
Which topics of Chemical Coordination and Integration are asked most in NEET?
Endocrine glands (11), Hormone mechanism (3), Hormonal disorders (2), counted over the papers from 2018–2026.
Is Chemical Coordination and Integration important for NEET 2027?
It is in the syllabus in force, so it can be asked. By past papers it ranks 9 of 15 in Zoology; use that to decide how much time it gets, not whether to study it.
Where can I solve Chemical Coordination and Integration NEET previous year questions?
On Nikaalle, free: sign up and practise every past NEET question from Chemical Coordination and Integration with an explanation for each, or sit the full papers timed. The ten questions on this page are our own, written in the same pattern.
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