Practice questions › Class 12 › Biology › Human Reproduction Male reproductive system and sperm transport Question 1 Which statement best explains the origin of seminal plasma?
(a) Testes alone produce the fluid as well as every sperm (b) It is urine sent through the vas deferens (c) Secretions of seminal vesicles, prostate, and bulbourethral glands contribute to it (d) The epididymis is the only secretory gland Show answer (c) Secretions of seminal vesicles, prostate, and bulbourethral glands contribute to it
Accessory-gland secretions form much of seminal plasma and support sperm transport and function.
Question 2 Sperm are present, but secretions from all male accessory glands are absent. Which component is most directly reduced?
(a) The chromosome number of sperm (b) Formation of seminiferous tubules (c) Seminal plasma (d) Sperm production, because testes and accessory glands are identical Show answer (c) Seminal plasma
Accessory glands contribute fluid rather than generating sperm chromosomes or seminiferous tissue.
Female reproductive system and mammary glands Question 3 At which region does human fertilisation most commonly occur?
(a) Ampullary–isthmic junction of the oviduct (b) Ovary, because fimbriae project from it (c) Cervix (d) Uterine endometrium Show answer (a) Ampullary–isthmic junction of the oviduct
The ovulated secondary oocyte and sperm usually meet near the ampullary–isthmic junction.
Question 4 A fringed funnel sweeps the released cell toward the oviduct. What is this region?
(a) Infundibulum with fimbriae (b) An ovarian fringe that remains part of the ovary (c) The upper part of the vagina (d) Uterus, the usual site of fertilisation Show answer (a) Infundibulum with fimbriae
Fimbriae are projections of the oviductal infundibulum and help collect the ovulated cell.
Spermatogenesis and sperm structure Question 5 Which sperm region contains mitochondria that support motility?
(a) Tail tip only (b) Acrosome (c) Head, because the nucleus supplies swimming energy (d) Middle piece Show answer (d) Middle piece
The middle piece contains numerous mitochondria that provide energy for movement.
Question 6 Enzymes needed to penetrate egg envelopes are concentrated in which structure?
(a) Middle piece, because it contains the nucleus (b) Acrosome (c) Neck centriole alone (d) Tail Show answer (b) Acrosome
The cap-like acrosome overlies the sperm nucleus and contains hydrolytic enzymes.
Menstrual cycle and hormonal coordination Question 7 A cycle graph shows a narrow, high pituitary peak just before day 14. Which hormone is represented?
(a) hCG in a non-pregnant cycle (b) LH (c) Progesterone, which peaks before ovulation (d) FSH alone, because its surge directly causes ovulation Show answer (b) LH
The mid-cycle LH surge is the immediate endocrine trigger for ovulation.
Question 8 A broad ovarian-hormone peak appears after ovulation and declines near the cycle's end. Which hormone is it?
(a) GnRH stored by the corpus luteum (b) Progesterone (c) Estrogen only, because progesterone peaks before ovulation (d) FSH, because the pituitary peak persists through the luteal phase Show answer (b) Progesterone
The corpus luteum secretes progesterone, producing a broad luteal-phase rise.
Oogenesis, follicular growth, and ovulation Question 9 What does the ruptured Graafian follicle become after ovulation?
(a) Zona pellucida (b) Primary oocyte (c) Corpus luteum before ovulation (d) Corpus luteum Show answer (d) Corpus luteum
After releasing the secondary oocyte, follicular tissue transforms into the corpus luteum.
Question 10 Which sequence correctly orders ovarian events?
(a) Graafian follicle → corpus luteum → ovulation (b) Ovulation → primordial follicle → oogonium (c) Growing follicles → Graafian follicle → ovulation → corpus luteum (d) Corpus luteum → ovulation → Graafian follicle Show answer (c) Growing follicles → Graafian follicle → ovulation → corpus luteum
The mature follicle ruptures at ovulation and its remnant luteinises afterward.
Cleavage, blastocyst formation, and implantation Question 11 Which blastocyst component gives rise chiefly to the embryo proper?
(a) Blastocoel fluid (b) Trophoblast alone forms the entire embryo (c) Morula, which implants without becoming a blastocyst (d) Inner cell mass Show answer (d) Inner cell mass
The inner cell mass forms the embryo, while trophoblast has major implantation and extraembryonic roles.
Fertilisation and prevention of polyspermy Question 12 Which event enables a sperm to penetrate the egg envelopes?
(a) Regression of the zona pellucida before contact (b) Acrosomal reaction and release of hydrolytic enzymes (c) Entry of many sperm at once (d) Mitochondria in the acrosome provide all motility Show answer (b) Acrosomal reaction and release of hydrolytic enzymes
Zona contact stimulates the acrosomal reaction, releasing enzymes needed for penetration.
Pregnancy, placenta, and embryonic development Question 13 Which statement best describes development after implantation?
(a) All organs form only after birth (b) No major changes occur until labour (c) Organ differentiation and fetal maturation proceed progressively through gestation (d) The embryo is already fully formed at implantation Show answer (c) Organ differentiation and fetal maturation proceed progressively through gestation
Implantation establishes pregnancy, but development continues through ordered embryonic and fetal stages.
Parturition and neuroendocrine control Question 14 Why is the oxytocin loop during labour called positive feedback?
(a) Stronger contractions increase cervical stretch, which promotes still more oxytocin and contraction (b) The loop maintains an unchanging contraction strength (c) Each contraction reduces the next contraction until labour stops (d) Oxytocin weakens the uterine response Show answer (a) Stronger contractions increase cervical stretch, which promotes still more oxytocin and contraction
The response amplifies the original stimulus until delivery terminates the loop.
Lactation and colostrum Question 15 Why is colostrum especially valuable to a newborn?
(a) It makes the infant actively produce the transferred maternal antibodies (b) It contains no proteins (c) It should be discarded because it has no immune value (d) It supplies maternal antibodies that provide passive protection Show answer (d) It supplies maternal antibodies that provide passive protection
Colostrum is rich in antibodies, including IgA, transferred ready-made from mother to infant.
Where does fertilisation usually happen? Wrong
Fertilisation usually occurs in the uterus because that is where the baby develops.
Why it feels right. I picture every stage happening in the same place.
Right
Fertilisation usually occurs in a uterine tube. The early embryo later implants in the uterus.
Worked example
Sequence
Egg enters uterine tube → Fertilisation usually in tube → Embryo travels → Implantation in uterus
Fertilisation and implantation occur at different locations. Trace an ovulated egg into the uterine tube. After fertilisation the early embryo travels towards the uterus, where implantation can occur. Previous chapter Sexual Reproduction in Flowering Plants Next chapter Reproductive Health 
