Reproductive System – NDA Biology PYQs

NDA 2026-I

Q. 1. In which one of the following groups of animals, oestrus cycle is not observed?

(a) Cows

(b) Monkeys

(c) Rats

(d) Tigers

Answer: (b) Monkeys

Explanation: Most non-human mammals have an oestrus cycle (also called the ‘heat’ cycle), during which the female is sexually receptive. This includes cows, rats, tigers, dogs, and most other mammals. Primates: including monkeys, apes, and humans: do not have an oestrus cycle. Instead, they have a menstrual cycle, which involves shedding of the uterine lining at the end of an unfertilised cycle. The oestrus cycle does not involve menstruation. Concept Tested: Primates (including monkeys) have menstrual cycles, not oestrus cycles; oestrus is found in most other mammals

★ JOVIK Exam Insight NDA tests the oestrus vs menstrual cycle distinction. Rule: primates (monkeys, apes, humans) → menstrual cycle. All other common mammals (cows, rats, dogs, cats, tigers) → oestrus cycle. The key difference: menstrual cycle involves bleeding (endometrial shedding); oestrus cycle does not.

Q. 2. In which cell does the first meiotic cell division take place during the process of spermatogenesis?

(a) Spermatogonium

(b) Primary spermatocyte

(c) Secondary spermatocyte

(d) Sertoli cell

Answer: (b) Primary spermatocyte

Explanation: Spermatogenesis is the process of sperm production in the testes. The sequence is: Spermatogonium (diploid, 2n) undergoes mitosis to produce primary spermatocytes. The primary spermatocyte then undergoes Meiosis I (the first meiotic division) to produce two secondary spermatocytes (haploid, n). Each secondary spermatocyte then undergoes Meiosis II to produce spermatids, which mature into spermatozoa. Sertoli cells are supporting nurse cells, not cells that divide to produce sperm. Concept Tested: Primary spermatocyte undergoes Meiosis I (first meiotic division) during spermatogenesis

NDA 2025-II

Q. 3. The menstrual cycle in females is controlled by hormones that are secreted by

(a) Ovary and lacrimal gland

(b) Ovary and sebaceous gland

(c) Ovary and pituitary gland

(d) Prostate and pituitary gland

Answer: (c) Ovary and pituitary gland

Explanation: The menstrual cycle is regulated by a coordinated interplay between the pituitary gland and the ovaries. The pituitary gland secretes FSH (follicle-stimulating hormone) and LH (luteinising hormone). FSH stimulates follicle development in the ovary; LH triggers ovulation. The ovaries, in turn, secrete oestrogen (during follicular phase) and progesterone (during luteal phase). These four hormones regulate the 28-day cycle. The lacrimal gland produces tears; the sebaceous gland produces sebum: neither is involved in menstrual regulation. Concept Tested: Menstrual cycle regulated by hormones from the ovary (oestrogen, progesterone) and pituitary gland (FSH, LH)

NDA 2022-I

Q. 4. Which one of the following is the mechanism of action of oral contraceptive pills?

(a) They kill the egg.

(b) They kill the sperm.

(c) They kill the zygote.

(d) They inhibit the release of egg.

Answer: (d) They inhibit the release of egg.

Explanation: Combined oral contraceptive pills contain synthetic oestrogen and progesterone. These hormones suppress the pituitary gland’s release of FSH and LH. Without the LH surge, ovulation does not occur: no egg is released. Since fertilisation requires an egg, pregnancy is prevented. The pills do not kill eggs, sperm, or zygotes; they work by preventing ovulation from occurring in the first place. Concept Tested: Oral contraceptive pills prevent pregnancy by inhibiting ovulation (suppressing FSH and LH from the pituitary)

NDA 2020

Q. 5. Which one of the following is NOT a component of human male reproductive system?

(a) Cervix

(b) Urethra

(c) Seminal vesicle

(d) Vas deferens

Answer: (a) Cervix

Explanation: The cervix is the lower narrow part of the uterus in females. It is a component of the female reproductive system, not the male. The male reproductive system includes: the testes (sperm production), epididymis (sperm maturation), vas deferens (sperm transport), seminal vesicles (seminal fluid), prostate gland, urethra (carries both semen and urine), and the penis. The cervix has no equivalent structure in males. Concept Tested: Cervix is a female reproductive structure; it is not part of the male reproductive system

★ JOVIK Exam Insight NDA tests which organs belong to which reproductive system. Cervix = female only. Urethra = present in both male and female (but used differently). Vas deferens, seminal vesicle, prostate = male only. Fallopian tube, ovary, uterus, vagina = female only.

NDA 2014-II

Q. 6. Which one of the following is not a part of female reproductive system?

(a) Fallopian tube

(b) Cervix

(c) Urethra

(d) Vagina

Answer: (c) Urethra

Explanation: The urethra is the tube that carries urine from the bladder to the outside of the body. In females, it is a urinary structure, not a reproductive one: it opens separately from the vagina. The female reproductive system includes the ovaries, fallopian tubes, uterus, cervix, and vagina. While the urethra is present in females, it belongs to the urinary system. Concept Tested: Urethra is a urinary structure in females, not part of the female reproductive system

NDA 2010-II

Q. 7. Statement I: Reproduction is the process by which living organisms produce young ones of their species. There are different forms of reproduction.

Statement II: Sex organs, male and female, are mandatory for reproduction.

(a) Both the statements are individually true and statement II is the correct explanation of statement I

(b) Both the statements are individually true but statement II is not the correct explanation of statement I

(c) Statement I is true but statement II is false

(d) Statement I is false but statement II is true

Answer: (c) Statement I is true but statement II is false

Explanation: Statement I is correct: reproduction is the process of producing new individuals of the same species, and it occurs in multiple forms: sexual and asexual. Statement II is false: sex organs are not mandatory for all forms of reproduction. Many organisms reproduce asexually: bacteria reproduce by binary fission, fungi by spores, many plants by vegetative propagation, and some animals by budding or parthenogenesis: none of which require sex organs. Concept Tested: Reproduction occurs in both sexual and asexual forms; sex organs are NOT mandatory for all types of reproduction

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