Understanding spermatogenesis is essential for B. Pharm students preparing for reproductive biology, pharmacology, and toxicology exams. These Spermatogenesis MCQs with answer focus on cellular stages, hormonal regulation, seminiferous tubule architecture, spermiogenesis, and clinical implications of impaired sperm production. Questions emphasize spermatogonial types, meiotic events, Sertoli and Leydig cell functions, the blood–testis barrier, and pharmacological modulators affecting fertility. Each MCQ is tailored to reinforce concepts relevant to drug action, endocrine interactions, and laboratory interpretation, helping you link basic science with therapeutic and toxicologic contexts. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. Which cell type is the immediate precursor to primary spermatocytes in human spermatogenesis?
- Type B spermatogonia
- Secondary spermatocyte
- Spermatid
- Sertoli cell
Correct Answer: Type B spermatogonia
Q2. Approximately how long does complete spermatogenesis take in adult human males?
- About 16 days
- About 35 days
- About 64 days
- About 120 days
Correct Answer: About 64 days
Q3. Which hormone directly stimulates Leydig cells to produce testosterone?
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Prolactin
- Inhibin
Correct Answer: Luteinizing hormone (LH)
Q4. Which cells form the blood–testis barrier through tight junctions?
- Leydig cells
- Sertoli cells
- Peritubular myoid cells
- Spermatogonia
Correct Answer: Sertoli cells
Q5. Which Sertoli cell secretion binds testosterone within the seminiferous tubule lumen?
- Inhibin
- Androgen-binding protein (ABP)
- Anti-Müllerian hormone (AMH)
- Prostaglandin E
Correct Answer: Androgen-binding protein (ABP)
Q6. During which substage of prophase I does homologous recombination (crossing over) primarily occur?
- Leptotene
- Zygotene
- Pachytene
- Diplotene
Correct Answer: Pachytene
Q7. How many functional sperm are normally produced from one primary spermatocyte?
- 1
- 2
- 4
- 8
Correct Answer: 4
Q8. Which protein replaces histones during chromatin condensation in spermiogenesis?
- Topoisomerase
- Protamines
- Actin
- Tubulin
Correct Answer: Protamines
Q9. The acrosome of the sperm is derived from which intracellular organelle during spermiogenesis?
- Endoplasmic reticulum
- Golgi apparatus
- Mitochondrion
- Lysosome
Correct Answer: Golgi apparatus
Q10. Which region of the sperm contains the mitochondrial sheath that supplies ATP for motility?
- Head
- Midpiece
- Principal piece
- End piece
Correct Answer: Midpiece
Q11. What is the structural arrangement of microtubules in the sperm flagellar axoneme?
- 9+0 arrangement
- 9+2 arrangement
- 7+2 arrangement
- 6+0 arrangement
Correct Answer: 9+2 arrangement
Q12. Which cell type secretes inhibin B that negatively regulates FSH secretion?
- Leydig cells
- Sertoli cells
- Spermatocytes
- Hypothalamic neurons
Correct Answer: Sertoli cells
Q13. Exogenous testosterone therapy typically suppresses spermatogenesis by which mechanism?
- Direct toxic effect on spermatogonia
- Stimulating ABP production
- Negative feedback on GnRH/LH/FSH secretion
- Enhancing Sertoli cell function
Correct Answer: Negative feedback on GnRH/LH/FSH secretion
Q14. Which stage of meiotic division reduces chromosome number from diploid to haploid in spermatogenesis?
- Between spermatogonium and primary spermatocyte
- Meiosis I (primary → secondary spermatocyte)
- Meiosis II (secondary spermatocyte → spermatid)
- Spermiogenesis (spermatid → spermatozoon)
Correct Answer: Meiosis I (primary → secondary spermatocyte)
Q15. The cycle length of the seminiferous epithelium in humans is approximately:
- 8 days
- 16 days
- 28 days
- 64 days
Correct Answer: 16 days
Q16. Which sperm maturation event primarily occurs in the epididymis?
- DNA condensation by protamines
- Acrosome formation
- Acquisition of motility and fertilization capacity
- Meiotic divisions
Correct Answer: Acquisition of motility and fertilization capacity
Q17. Which clinical condition of the testes is most likely to impair spermatogenesis due to increased testicular temperature?
- Varicocele
- Hydrocele
- Testicular torsion
- Orchitis
Correct Answer: Varicocele
Q18. Spermiation refers to which process in spermatogenesis?
- Initiation of meiosis
- Release of mature spermatozoa into the lumen
- Division of spermatogonia
- Formation of the blood–testis barrier
Correct Answer: Release of mature spermatozoa into the lumen
Q19. Which marker is commonly used clinically to evaluate Sertoli cell function and spermatogenic activity?
- Testosterone level
- Inhibin B level
- LH level
- Prolactin level
Correct Answer: Inhibin B level
Q20. Which cells are found in the interstitium between seminiferous tubules and produce testosterone?
- Sertoli cells
- Peritubular myoid cells
- Leydig cells
- Spermatogonia
Correct Answer: Leydig cells
Q21. Anti-sperm antibodies are most likely to form after which event?
- Administration of FSH
- Disruption of the blood–testis barrier or vasectomy
- Increased inhibin secretion
- Elevated ABP within seminiferous tubules
Correct Answer: Disruption of the blood–testis barrier or vasectomy
Q22. Which of the following best describes type Ad (dark) spermatogonia in humans?
- Committed precursors that immediately enter meiosis
- Transit-amplifying cells producing many daughter cells
- Stem cells that self-renew to maintain the germline
- Post-meiotic cells differentiating into sperm
Correct Answer: Stem cells that self-renew to maintain the germline
Q23. Which pharmacologic agent is most likely to reduce spermatogenesis by directly damaging DNA synthesis in germ cells?
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- Alkylating chemotherapy agents (e.g., cyclophosphamide)
- Selective serotonin reuptake inhibitors
- Beta-blockers
Correct Answer: Alkylating chemotherapy agents (e.g., cyclophosphamide)
Q24. The principal piece of the sperm tail is characterized by which sheath?
- Mitochondrial sheath
- Fibrous sheath
- Axonemal sheath
- Microvillus sheath
Correct Answer: Fibrous sheath
Q25. Which event triggers the acrosome reaction during fertilization?
- Contact with cumulus cells only
- Binding to zona pellucida glycoproteins
- Exposure to epididymal secretions
- Passage through the vas deferens
Correct Answer: Binding to zona pellucida glycoproteins
Q26. Which of the following best describes spermatogonial proliferation in adult testes?
- All spermatogonia immediately enter meiosis
- Spermatogonial stem cells balance self-renewal and differentiation
- Spermatogonia are post-mitotic and do not divide
- Spermatogonial numbers decline steadily with each cycle
Correct Answer: Spermatogonial stem cells balance self-renewal and differentiation
Q27. Which hormone is secreted by the hypothalamus to regulate testicular function via the pituitary?
- Gonadotropin-releasing hormone (GnRH)
- Thyrotropin-releasing hormone (TRH)
- Corticotropin-releasing hormone (CRH)
- Growth hormone-releasing hormone (GHRH)
Correct Answer: Gonadotropin-releasing hormone (GnRH)
Q28. Which of the following is a common functional consequence of cryptorchidism on spermatogenesis?
- Enhanced spermatogenesis due to warmer environment
- Reduced spermatogenesis due to elevated testicular temperature
- No effect on spermatogenesis
- Increased Leydig cell testosterone production
Correct Answer: Reduced spermatogenesis due to elevated testicular temperature
Q29. Which process in spermiogenesis forms the flagellum from centrioles?
- Acrosome formation
- Axoneme assembly
- Chromatin condensation
- Mitochondrial translocation
Correct Answer: Axoneme assembly
Q30. Which statement about FSH action in the testis is correct?
- FSH acts primarily on Leydig cells to increase testosterone
- FSH acts on Sertoli cells to support spermatogenesis
- FSH directly induces meiosis in spermatogonia
- FSH inhibits androgen-binding protein production
Correct Answer: FSH acts on Sertoli cells to support spermatogenesis
Q31. Which of the following best characterizes Sertoli cell “nurse” functions?
- They produce sperm and release them into blood
- They provide structural support, nutrients, and phagocytose residual bodies
- They secrete testosterone for systemic circulation
- They form the acrosome of sperm
Correct Answer: They provide structural support, nutrients, and phagocytose residual bodies
Q32. What is the typical WHO lower reference limit for normal sperm concentration in semen?
- 5 million/mL
- 15 million/mL
- 50 million/mL
- 100 million/mL
Correct Answer: 15 million/mL
Q33. Which pathway correctly traces sperm from site of production to ejaculation?
- Seminiferous tubules → rete testis → efferent ductules → epididymis → vas deferens
- Seminiferous tubules → epididymis → rete testis → vas deferens → ejaculatory duct
- Rete testis → seminiferous tubules → vas deferens → epididymis
- Efferent ductules → seminiferous tubules → epididymis → urethra
Correct Answer: Seminiferous tubules → rete testis → efferent ductules → epididymis → vas deferens
Q34. Which cellular change is characteristic of spermiogenesis (final differentiation of spermatids)?
- DNA replication
- Chromatin condensation and acrosome/flagellum formation
- Production of estrogen
- Cell fusion into syncytium
Correct Answer: Chromatin condensation and acrosome/flagellum formation
Q35. What is the primary role of the blood–testis barrier?
- Facilitate transport of immune cells into tubules
- Protect developing germ cells from toxicants only
- Maintain a specialized microenvironment and prevent immune reactions to germ cell antigens
- Secrete androgen-binding protein into lumen
Correct Answer: Maintain a specialized microenvironment and prevent immune reactions to germ cell antigens
Q36. Which event occurs during meiosis II in spermatogenesis?
- DNA replication
- Separation of sister chromatids producing haploid spermatids
- Synapsis of homologous chromosomes
- Formation of the acrosomal vesicle
Correct Answer: Separation of sister chromatids producing haploid spermatids
Q37. Which of the following best describes the effect of FSH on Sertoli cells at the molecular level?
- FSH decreases cAMP signaling in Sertoli cells
- FSH binds receptors and increases cAMP, promoting Sertoli support functions
- FSH directly stimulates Leydig cell androgen production
- FSH induces apoptosis of spermatogonia
Correct Answer: FSH binds receptors and increases cAMP, promoting Sertoli support functions
Q38. What structural modification allows sperm to penetrate the zona pellucida?
- Elongation of the midpiece
- Acrosome reaction releasing hydrolytic enzymes
- Condensation of mitochondrial DNA
- Fusion with Sertoli cells
Correct Answer: Acrosome reaction releasing hydrolytic enzymes
Q39. Which diagnostic test directly assesses spermatogenic output from the testes?
- Serum LH measurement
- Testicular biopsy/histology
- Scrotal ultrasound
- Vasography
Correct Answer: Testicular biopsy/histology
Q40. Sertoli cell-only syndrome is characterized by which finding?
- Normal spermatogenesis with low testosterone
- Absence of germ cells with only Sertoli cells lining tubules
- Excessive Leydig cell proliferation
- Hyperactive spermatogonial stem cells
Correct Answer: Absence of germ cells with only Sertoli cells lining tubules
Q41. Which factor is most important for maintaining testicular temperature below core body temperature?
- Inguinal canal vasculature
- Cremaster and dartos muscle function and pampiniform plexus heat exchange
- Presence of epididymis
- Testosterone secretion
Correct Answer: Cremaster and dartos muscle function and pampiniform plexus heat exchange
Q42. What is the primary consequence of obstructive azoospermia at the level of the epididymis or vas deferens?
- Absence of sperm production by testes
- Normal spermatogenesis with failure of sperm delivery into ejaculate
- Increased sperm motility
- Elevated inhibin B levels due to obstruction
Correct Answer: Normal spermatogenesis with failure of sperm delivery into ejaculate
Q43. Which of the following is TRUE about spermatogenic cell junctions?
- Tight junctions remain static throughout spermatogenesis
- Tight junctions between Sertoli cells reorganize to allow germ cell movement toward lumen
- Gap junctions form the blood–testis barrier
- Desmosomes are the only junctions present in seminiferous epithelium
Correct Answer: Tight junctions between Sertoli cells reorganize to allow germ cell movement toward lumen
Q44. Which molecular change in sperm chromatin enhances paternal DNA compaction?
- Increased histone acetylation
- Replacement of histones by protamines
- Dephosphorylation of DNA polymerase
- Increase in nucleosome number
Correct Answer: Replacement of histones by protamines
Q45. Which zone of the epididymis primarily stores mature sperm ready for ejaculation?
- Caput (head)
- Corpus (body)
- Cauda (tail)
- Rete epididymis
Correct Answer: Cauda (tail)
Q46. Pulsatile release of which hypothalamic hormone is necessary to initiate puberty and maintain spermatogenesis?
- Somatostatin
- Gonadotropin-releasing hormone (GnRH)
- Insulin
- Cortisol
Correct Answer: Gonadotropin-releasing hormone (GnRH)
Q47. Which testicular cell expresses steroidogenic enzymes such as 17β-HSD necessary for testosterone synthesis?
- Sertoli cells
- Leydig cells
- Spermatids
- Epithelial cells of epididymis
Correct Answer: Leydig cells
Q48. Which change is expected in the semen analysis of a man exposed to high-dose radiation that damages dividing germ cells?
- Increased sperm concentration
- Azoospermia or oligospermia due to germ cell loss
- Elevated motility with normal count
- Increased inhibin B levels
Correct Answer: Azoospermia or oligospermia due to germ cell loss
Q49. Which statement best describes capacitation of sperm?
- Occurs entirely within the testis before ejaculation
- Biochemical changes in the female reproductive tract that enable acrosome reaction and fertilization
- Formation of the acrosome in the epididymis
- Replacement of histones by protamines
Correct Answer: Biochemical changes in the female reproductive tract that enable acrosome reaction and fertilization
Q50. Which function is NOT a role of Sertoli cells in supporting spermatogenesis?
- Phagocytosis of residual cytoplasm during spermiogenesis
- Secretion of androgen-binding protein
- Production of testosterone for systemic androgenic effects
- Formation of the blood–testis barrier
Correct Answer: Production of testosterone for systemic androgenic effects
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