NEET Biology Chemical Coordination and Integration MCQs Set 05

Answer: (c) 51 amino acid

Explanation:
1. Insulin has 51 amino acids: chain A with 21 and chain B with 30.
2. The chains are joined by disulfide bridges.

Teacher's Note:
1. A + B = 21 + 30.
2. Sanger sequenced it.

Answer: (c) Pineal body

Explanation:
1. Brain sand (corpora arenacea) consists of calcium deposits in the pineal body.
2. It increases with age.

Teacher's Note:
1. Pineal calcification.
2. Visible on X-ray in adults.

Answer: (a) Fats are catabolised to form glucose

Explanation:
1. Without dietary carbohydrate, a diabetic patient still has glucose in urine because fats and proteins are converted to glucose.
2. Fat breakdown is the main source in the option set.

Teacher's Note:
1. Lack of insulin forces fat use.
2. Gluconeogenesis adds glucose.

Answer: (c) To release glucose from liver cells and glycogenolysis promotion

Explanation:
1. Glucagon stimulates glycogenolysis and gluconeogenesis in the liver, releasing glucose.
2. It does not increase glycogenesis.

Teacher's Note:
1. Glucagon raises blood sugar.
2. It acts mainly on liver cells.

Answer: (d) Silk moth

Explanation:
1. Bombykol is the sex pheromone of the female silk moth.
2. It attracts the male for mating.

Teacher's Note:
1. First pheromone identified.
2. It is volatile.

Answer: (d) Rate of formation of red blood cells

Explanation:
1. Erythropoietin from the kidney stimulates red blood cell formation in bone marrow.
2. It does not regulate blood pressure or glucose.

Teacher's Note:
1. Kidney senses low oxygen.
2. EPO raises RBC count.

Answer: (d) Erythropoetin

Explanation:
1. Gastrin, secretin and CCK are made in the GI tract.
2. Erythropoietin is made by the kidney.

Teacher's Note:
1. GI hormones: gastrin, secretin, CCK, GIP.
2. Kidney: erythropoietin.

Answer: (c) Atrial natriuretic factor

Explanation:
1. Atrial natriuretic factor from atrial walls dilates blood vessels and lowers blood pressure.
2. It increases sodium excretion.

Teacher's Note:
1. ANF opposes the renin-angiotensin system.
2. It is a peptide.

Answer: (c) Corpus luteum

Explanation:
1. The corpus luteum is a temporary endocrine gland formed after ovulation.
2. Corpus callosum is in the brain and corpus striatum is in the cerebrum.

Teacher's Note:
1. Corpus luteum: progesterone.
2. It degenerates unless pregnancy occurs.

Answer: (c) Pancreas

Explanation:
1. Secretin stimulates the pancreas to release bicarbonate-rich juice.
2. It also inhibits gastric secretion.

Teacher's Note:
1. Secretin acts on pancreatic duct cells.
2. CCK acts on gall bladder and pancreatic enzymes.

Answer: (a) Prostaglandins

Explanation:
1. Prostaglandins are local hormones that act near their site of production.
2. Cytokinins are plant hormones.

Teacher's Note:
1. Prostaglandins: lipid derived.
2. Work in paracrine fashion.

Answer: (a) Adrenalin

Explanation:
1. Adrenaline causes vasodilation in muscles, raises oxygen consumption and stimulates glucose formation.
2. Glucagon and ACTH do not cause vasodilation.

Teacher's Note:
1. Adrenaline is an emergency hormone.
2. It raises blood glucose.

Answer: (c) FSH

Explanation:
1. FSH regulates Sertoli cells of the testis, which nourish sperm.
2. LH acts on Leydig cells.

Teacher's Note:
1. FSH: Sertoli.
2. LH: Leydig.

Answer: (a) Sodium

Explanation:
1. cAMP, cGMP and calcium act as second messengers.
2. Sodium is not a second messenger.

Teacher's Note:
1. Second messengers amplify hormone signals.
2. Ca2+ works with calmodulin.

Answer: (a) administered antithyroid substance like thiourea.

Explanation:
1. Thiourea blocks thyroxine synthesis, so metamorphosis is delayed and tadpoles keep growing into giants.
2. Thyroxine in excess speeds metamorphosis.

Teacher's Note:
1. Thyroxine triggers metamorphosis.
2. Antithyroid drugs delay it.

Answer: (c) Parathyroid and Adrenal

Explanation:
1. The parathyroid and adrenal glands are purely endocrine.
2. Testes, ovary and pancreas are heterocrine and thymus has other functions too.

Teacher's Note:
1. Heterocrine: pancreas, gonads.
2. Pure endocrine: pituitary, thyroid, adrenal.

Answer: (b) Causes strong uterine contractions during parturition

Explanation:
1. Oxytocin causes strong uterine contractions at parturition.
2. It is released from the posterior pituitary.

Teacher's Note:
1. Positive feedback during labour.
2. Also milk ejection.

Answer: (b) Myxoedema

Explanation:
1. Deficiency of thyroxine in adults causes myxoedema with low BMR, weight gain and water retention.
2. Cretinism occurs in infants.

Teacher's Note:
1. Adult hypothyroidism = myxoedema.
2. Simple goitre needs iodine deficiency.

Answer: (a) Adrenaline

Explanation:
1. The adrenal medulla secretes adrenaline.
2. Cortisol, aldosterone and androgens come from the cortex and would be affected.

Teacher's Note:
1. Cortex: steroids.
2. Medulla: catecholamines.

Answer: (c) Glucagon – Beta cells (Source)

Explanation:
1. Glucagon is made by alpha cells, not beta cells.
2. Beta cells secrete insulin.

Teacher's Note:
1. Delta cells: somatostatin.
2. Corpus luteum: relaxin.

Answer: (c) Insulin

Explanation:
1. Human insulin is produced by recombinant DNA technology in bacteria.
2. Morphine, quinine and nicotine come from plants.

Teacher's Note:
1. Humulin was the first recombinant insulin.
2. Made in E. coli.

Answer: (a) Oxytocin from maternal pituitary

Explanation:
1. Parturition is induced by oxytocin from the maternal posterior pituitary.
2. Foetal signals stimulate its release.

Teacher's Note:
1. Oxytocin: uterine contraction.
2. Part of a positive feedback loop.