Chemical coordination and integration — NEET Biology Questions 2026

Insulin deficiency leads to both hyperglycemia and ketone production.

- Increased thyroid hormone → increased metabolism → weight loss.

- GIP inhibits gastric secretion and motility, not enhances it.

Both statements are true from NCERT. The Assertion states neural coordination provides rapid responses, and the Reason explains this by stating “The neural coordination is fast but short-lived” - this directly explains WHY neural responses are rapid (because they are fast-acting). The Reason provides the mechanistic basis for the rapid response capability mentioned in the Assertion.

Hormones are categorized by their chemical nature, which dictates their mode of action, including how they regulate gene expression. Let's analyze each hormone: - A. Estradiol: It is a steroid hormone (2). Steroid hormones interact with intracellular receptors, and the hormone-receptor complex directly interacts with the genome to regulate gene expression. So, 'W' (Interacts directly with the genome via its receptor complex) or 'X' (Binds to intracellular receptors and alters gene transcription) would be correct for its gene regulation. Both W and X are largely synonymous in this context. - B. Oxytocin: It is a peptide hormone (1). Peptide hormones bind to membrane-bound receptors and generate second messengers to regulate cellular metabolism. So, 'Y' (Generates second messengers which regulate cellular metabolism) or 'Z' (Binds to membrane-bound receptors and activates protein kinases) are relevant. - C. Thyroxine: It is an iodothyronine (3). Like steroid hormones, iodothyronines interact with intracellular receptors to regulate gene expression. So, 'X' (Binds to intracellular receptors and alters gene transcription) or 'W' (Interacts directly with the genome via its receptor complex) would be correct. - D. Adrenaline: It is an amino-acid derivative (4). Adrenaline binds to membrane-bound receptors and generates second messengers. So, 'Y' (Generates second messengers which regulate cellular metabolism) or 'Z' (Binds to membrane-bound receptors and activates protein kinases) are relevant. Now let's check the options based on the NCERT text: - (A-2) Estradiol (Steroid) – (W) Interacts directly with the genome via its receptor complex. (Correct) - (B-1) Oxytocin (Peptide) – (Y) Generates second messengers which regulate cellular metabolism. (Correct) - (C-3) Thyroxine (Iodothyronine) – (X) Binds to intracellular receptors and alters gene transcription. (Correct) - (D-4) Adrenaline (Amino-acid derivative) – (Z) Binds to membrane-bound receptors and activates protein kinases. (Correct, as this is how second messengers are often generated or lead to effects) Option (d) correctly links all three columns based on NCERT information. Options (b), (c), and (a) have incorrect linkages. This question integrates knowledge about hormone classification, receptor location, and the ultimate effect on gene expression or cellular metabolism.