Class 12/Question Bank/Competency Based
Created by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
BioNotesBioNotesCreated by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
Competency Based Questions on Human Reproduction
1. Analyze the hormonal graph: A woman visits a doctor with concerns about irregular cycles. Blood tests reveal that her LH levels remain consistently low throughout her cycle, with no mid-cycle surge. Which of the following consequences is inevitable in this cycle? a) Menstruation will not occur. b) The endometrium will not proliferate. c) Ovulation will not occur. d) The corpus luteum will persist indefinitely.
2. Assertion (A): The second meiotic division in the human secondary oocyte is unequal. Reason (R): It ensures the retention of bulk cytoplasm in the ovum to support early embryonic development. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) A is false but R is true.
3. Predict the Outcome: If the vasa efferentia in the male reproductive system are blocked, the gametes will not be transported from: a) Epididymis to Vas deferens. b) Testes to Epididymis. c) Rete testis to Epididymis. d) Vas deferens to Ejaculatory duct.
4. Clinical Application: A patient is diagnosed with oligospermia (low sperm count). The doctor suggests checking the temperature of his scrotum. What is the biological basis? a) High scrotal temperature kills Leydig cells. b) High scrotal temperature impairs spermatogenesis in seminiferous tubules. c) Low scrotal temperature causes thickening of semen. d) Temperature does not affect sperm count.
5. Calculate: How many secondary spermatocytes and secondary oocytes are required to form 100 spermatozoa and 100 ova respectively? a) 50 Secondary Spermatocytes, 100 Secondary Oocytes. b) 100 Secondary Spermatocytes, 100 Secondary Oocytes. c) 25 Secondary Spermatocytes, 100 Secondary Oocytes. d) 50 Secondary Spermatocytes, 50 Secondary Oocytes.
6. Assertion (A): The placenta is considered a hemochorial type in humans. Reason (R): Fetal blood mixes freely with maternal blood to ensure maximum nutrient transfer. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) A is true, but R is false.
7. Immunology link: Why is breastfeeding recommended for the first few months of an infant's life? a) It contains higher fat content. b) It contains IgA antibodies that provide passive immunity. c) It contains IgG antibodies. d) It contains oxytocin.
8. Analyze the sequence: Sequence of layers a sperm must penetrate to fertilize the ovum? a) Plasma membrane -> Zona Pellucida -> Corona Radiata b) Corona Radiata -> Zona Pellucida -> Perivitelline space -> Plasma membrane c) Zona Pellucida -> Corona Radiata -> Plasma membrane d) Perivitelline space -> Corona Radiata -> Zona Pellucida
9. Case Analysis: A woman has strictly blocked fallopian tubes. Which ART method is strictly contra-indicated? a) IVF b) ICSI c) GIFT d) Surrogacy
10. Reasoning: Why does the corpus luteum degenerate if fertilization does not occur? a) Due to drop in FSH. b) Due to absence of hCG signal from the trophoblast. c) Due to high Prolactin. d) Due to Oxytocin.
11. Identify the missing link: Hypothalamus -> GnRH -> Anterior Pituitary -> ____ -> Sertoli Cells -> Spermiogenesis. a) LH b) FSH c) Testosterone d) Inhibin
12. Assertion (A): Removal of ovaries in the first trimester of pregnancy leads to abortion. Reason (R): The placenta is not yet fully developed to take over progesterone secretion. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) A is false but R is true.
13. Comparative Analysis: Unlike spermatogenesis, oogenesis in humans: a) Is continuous. b) Involves equal cytokinesis. c) Is initiated during the embryonic development stage. d) Produces 4 functional gametes.
14. Physiology: What triggers the "fetal ejection reflex"? a) Release of oxytocin from the fetal pituitary. b) Fully developed fetus and placenta. c) High Prolactin. d) Rupture of the sac.
15. Critical Thinking: If the acrosome of a sperm is damaged but the sperm is still motile, what will be the result? a) The sperm will swim faster. b) It can fertilize but fusion will be delayed. c) The sperm will be unable to penetrate the zona pellucida. d) The sperm will die.
A 28-year-old athlete, Sarah, has amenorrhea. Her body fat is very low. LH/FSH are low.
16. Diagnose: Primary disruption likely occurring?
17. Connect: Link between low body fat and cessation of cycle?
18. Evaluate: Sarah is at high risk for bone fractures. Why?
Researchers add sperm to oocytes in a calcium-free medium. Multiple sperm enter (polyspermy).
19. Analyze: Which event requires calcium to trigger the "slow block"?
20. Explain: Mechanism of the Cortical Reaction?
A woman took a teratogen drug during the 5th week of pregnancy.
21. Reason: Why is the first trimester the most critical window?
22. Creating a Flowchart: Parturition feedback.
23. Formulating a Hypothesis: Declining sperm count.
24. Visualizing Development: Hormones during pregnancy.
25. Scenario Analysis (Infertility): Sperm die in cervical mucus.
26. Argumentation: "Placenta as multiple organs."
27. Designing a Public Health Plan: Rural Menstrual Hygiene.