Every Book Back multiple-choice question from Human Reproduction (12th Standard Zoology, Samacheer Kalvi) — each with the correct option highlighted and a clear, worked explanation. Free to read in English and Tamil.
Q1
The mature sperms are stored in the
- A. Seminiferous tubules
- B. Vas deferens
- C. EpididymisCorrect
- D. Seminal vesicle
Explanation. Mature spermatozoa are temporarily stored in the epididymis, a coiled tube where they undergo functional maturation and gain motility before ejaculation.
Q2
The male sex hormone testosterone is secreted from
- A. Sertoli cells
- B. Leydig cellsCorrect
- C. Epididymis
- D. Prostate gland
Explanation. Testosterone, the primary male sex hormone, is synthesized and secreted by the interstitial cells of Leydig, which are located in the connective tissue surrounding the seminiferous tubules.
Q3
The glandular accessory organ which produces the largest proportion of semen is
- A. Seminal vesicleCorrect
- B. Bulbourethral gland
- C. Prostate gland
- D. Mucous gland
Explanation. The seminal vesicles secrete an alkaline fluid that constitutes about sixty percent of the total volume of semen, making it the largest contributor among accessory glands.
Q4
The male homologue of the female clitoris is
- A. Scrotum
- B. PenisCorrect
- C. Urethra
- D. Testis
Explanation. The clitoris in females and the penis in males are homologous organs, as they both develop from the same embryonic structures and function as sensitive erectile organs.
Q5
The site of embryo implantation is the
- A. UterusCorrect
- B. Peritoneal cavity
- C. Vagina
- D. Fallopian tube
Explanation. Following fertilization in the fallopian tube, the developing blastocyst travels to the uterus and embeds itself in the thick endometrium layer during implantation.
Q6
The foetal membrane that forms the basis of the umbilical cord is
- A. AllantoisCorrect
- B. Amnion
- C. Chorion
- D. Yolk sac
Explanation. The allantois is an extra-embryonic membrane that extends from the caudal end of the yolk sac, serving as the structural base for the development of the umbilical cord.
Q7
The most important hormone in initiating and maintaining lactation after birth is
- A. Oestrogen
- B. FSH
- C. ProlactinCorrect
- D. Oxytocin
Explanation. Prolactin, secreted by the anterior pituitary gland, is the key hormone responsible for initiating milk production and maintaining lactation after childbirth.
Q8
Mammalian egg is
- A. Mesolecithal and non-cleidoic
- B. Microlecithal and non-cleidoic
- C. Alecithal and non-cleidoicCorrect
- D. Alecithal and cleidoic
Explanation. Human and other mammalian eggs are alecithal because they lack yolk, and non-cleidoic because they are not enclosed in a protective hard shell.
Q9
The process which the sperm undergoes before penetrating the ovum is
- A. Spermiation
- B. Cortical reaction
- C. Spermiogenesis
- D. CapacitationCorrect
Explanation. Capacitation is the final physiological conditioning process that sperm cells must undergo inside the female reproductive tract to gain the ability to fertilize the egg.
Q10
The milk secreted by the mammary glands soon after child birth is called
- A. Mucous
- B. ColostrumCorrect
- C. Lactose
- D. Sucrose
Explanation. Colostrum is a yellowish, nutrient-rich fluid secreted by the mammary glands during the first few days after parturition, providing crucial antibodies for the newborn.
Q11
Colostrum is rich in
- A. IgE
- B. IgACorrect
- C. IgD
- D. IgM
Explanation. Colostrum contains high concentrations of immunoglobulin A antibodies, which protect the newborn's digestive tract from pathogens and help build passive immunity.
Q12
The Androgen Binding Protein (ABP) is produced by
- A. Leydig cells
- B. Hypothalamus
- C. Sertoli cellsCorrect
- D. Pituitary gland
Explanation. Sertoli cells, also known as nurse cells, produce androgen-binding protein to concentrate testosterone within the seminiferous tubules, which is essential for stimulating spermatogenesis.
Q13
Find the wrongly matched pair
- A. Bleeding phase - fall in oestrogen and progesterone
- B. Follicular phase - rise in oestrogen
- C. Luteal phase - rise in FSH levelCorrect
- D. Ovulatory phase - LH surge
Explanation. During the luteal phase of the menstrual cycle, progesterone and estrogen levels rise, which exerts negative feedback on the anterior pituitary, keeping FSH levels low.
Q14
Assertion (A): In human male, testes are extra abdominal and lie in scrotal sacs.
Reason (R): Scrotum acts as thermoregulator and keeps temperature lower by 2°C for normal sperm production.
- A. A and R are true, R is the correct explanation of ACorrect
- B. A and R are true, R is not the correct explanation of A
- C. A is true, R is false
- D. Both A and R are false
Explanation. The scrotum keeps the testes outside the pelvic cavity, maintaining a temperature lower than internal body temperature, which is essential for viable sperm production.
Q15
Assertion (A): Ovulation is the release of ovum from the Graafian follicle.
Reason (R): It occurs during the follicular phase of the menstrual cycle.
- A. A and R are true, R is the correct explanation of A
- B. A and R are true, R is not the correct explanation of A
- C. A is true, R is falseCorrect
- D. Both A and R are false
Explanation. Ovulation is the release of a secondary oocyte from a mature Graafian follicle. However, it occurs at the end of the follicular phase, triggered by an LH surge, rather than during it.
Q16
Assertion (A): Head of the sperm consists of acrosome and mitochondria.
Reason (R): Acrosome contains spiral rows of mitochondria.
- A. A and R are true, R is the correct explanation of A
- B. A and R are true, R is not the correct explanation of A
- C. A is true, R is false
- D. Both A and R are falseCorrect
Explanation. The head of a human sperm contains the acrosome and nucleus, while mitochondria are located in the middle piece to generate motility energy. Therefore, both the assertion and reason are incorrect.
Q17
Painful menstruation is termed as
- A. DysmenorrhoeaCorrect
- B. Menorrhagia
- C. Amenorrhoea
- D. Oligomenorrhoea
Explanation. Dysmenorrhoea is the biological term for painful menstruation. In comparison, menorrhagia is excessive bleeding, amenorrhoea is the absence of menstruation, and oligomenorrhoea is infrequent menstruation.
Q18
Which one of the following menstrual irregularities is correctly matched?
- A. Menorrhagia - excessive menstruation
- B. Amenorrhoea - absence of menstruationCorrect
- C. Dysmenorrhoea - irregularity of menstruation
- D. Oligomenorrhoea - painful menstruation
Explanation. Amenorrhoea is correctly defined in the text as the absence of menstruation. Menorrhagia describes heavy/prolonged bleeding, dysmenorrhoea refers to painful periods, and oligomenorrhoea represents infrequent cycles.
