Question 1: Which of the following correctly lists ALL major reproductive events in humans in the right order? (a) Gametogenesis → Insemination → Fertilisation → Implantation → Gestation → Parturition (b) Insemination → Gametogenesis → Fertilisation → Implantation → Parturition → Gestation (c) Gametogenesis → Fertilisation → Insemination → Implantation → Gestation → Parturition (d) Gametogenesis → Implantation → Insemination → Fertilisation → Gestation → Parturition
Solution:
Answer: (a) Solution:The correct order is: Gametogenesis (formation of gametes) → Insemination (transfer of sperms into female genital tract) → Fertilisation (fusion of gametes to form zygote) → Implantation (attachment of blastocyst to uterine wall) → Gestation (embryonic development) → Parturition (delivery of baby). This sequence is explicitly mentioned in the introductory paragraph of Chapter 2.
Question 2: Assertion (A): Humans are viviparous and sexually reproducing organisms. Reason (R): In humans, the young ones are born after developing inside the mother's body, and reproduction involves fusion of male and female gametes. (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
Solution:
Answer: (a) Solution:Humans are sexually reproducing (fusion of gametes occurs) and viviparous (young ones develop inside the mother and are born alive - not hatched from eggs). R correctly explains A by describing both the sexual reproduction aspect (gamete fusion) and viviparous nature (development inside mother's body).
Question 3: Which of the following statements is CORRECT regarding differences between male and female reproductive events in humans? (a) Ovum formation continues in old women just like sperm formation in old men (b) Sperm formation begins at birth whereas ovum formation begins at puberty (c) Sperm formation continues even in old men but ovum formation ceases in women around fifty years of age (d) Both sperm and ovum formation cease after the age of fifty in their respective sexes
Solution:
Answer: (c) Solution: As stated in NCERT's introductory paragraph: 'sperm formation continues even in old men, but formation of ovum ceases in women around the age of fifty years.' This cessation of ovum formation is associated with menopause. This is a fundamental biological difference between male and female reproductive biology.
Question 4: The process of transfer of sperms into the female genital tract is called: (a) Fertilisation (b) Insemination (c) Gametogenesis (d) Implantation
Solution:
Answer: (b) Solution: Insemination refers specifically to the transfer of sperms into the female genital tract. Fertilisation is the fusion of male and female gametes. Gametogenesis is the formation of gametes. Implantation is the attachment of blastocyst to the uterine wall.
Question 5: Which of the following is the correct definition of 'gestation'? (a) Fusion of male and female gametes to form a zygote (b) Attachment of blastocyst to the uterine wall (c) Embryonic development inside the mother's body (d) Delivery of the baby from the mother's body
Solution:
Answer: (c) Solution: Gestation refers to embryonic development (development of the foetus inside the mother's uterus). Fertilisation = fusion of gametes to form zygote. Implantation = attachment of blastocyst to uterine wall. Parturition = delivery of the baby.
Page No. 26-28 (Male Reproductive System)
Question 6: The testes are situated outside the abdominal cavity within a pouch called scrotum because: (a) The scrotum protects testes from physical injury (b) The scrotum maintains a temperature 2-2.5°C lower than normal internal body temperature, essential for spermatogenesis (c) The scrotum provides hormonal support for androgen secretion (d) The scrotum helps in transportation of sperms to the epididymis
Solution:
Answer: (b) Solution: The scrotum helps in maintaining the low temperature of the testes (2-2.5°C lower than normal internal body temperature), which is necessary for spermatogenesis. Cryptorchidism (undescended testes) results in infertility because spermatogenesis cannot occur at normal body temperature.
Question 7: What is the approximate shape, length and width of an adult testis? (a) Spherical; 2-3 cm long; 4-5 cm wide (b) Oval; 4-5 cm long; 2-3 cm wide (c) Elongated; 6-8 cm long; 1-2 cm wide (d) Oval; 2-3 cm long; 4-5 cm wide
Solution:
Answer: (b) Solution: As per NCERT: In adults, each testis is oval in shape, with a length of about 4 to 5 cm and a width of about 2 to 3 cm. The testis is covered by a dense covering. Each testis has about 250 compartments called testicular lobules.
Question 8: Each testis has approximately how many compartments called testicular lobules, and how many seminiferous tubules does each lobule contain? (a) 200 lobules; 2-4 seminiferous tubules each (b) 300 lobules; 1-2 seminiferous tubules each (c) 250 lobules; 1-3 seminiferous tubules each (d) 250 lobules; 3-5 seminiferous tubules each
Solution:
Answer: (c) Solution: As per NCERT: Each testis has about 250 compartments called testicular lobules. Each lobule contains one to three highly coiled seminiferous tubules in which sperms are produced.
Question 9: Assertion (A): Sertoli cells are found inside the seminiferous tubules. Reason (R): Sertoli cells provide nutrition to the developing germ cells and support spermiogenesis. (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
Solution:
Answer: (b) Solution:Sertoli cells are indeed found inside (lining the inside of) seminiferous tubules - so A is true. Sertoli cells do provide nutrition to the germ cells and support spermiogenesis - R is also true. However, R does not explain WHY Sertoli cells are inside the tubules. They are inside because they need to be in direct contact with the germ cells. Hence R is not the correct explanation.
Question 10: Leydig cells (interstitial cells) are located in which region of the testis and what is their primary function? (a) Inside seminiferous tubules; produce sperms (b) Interstitial spaces outside seminiferous tubules; synthesise and secrete androgens (c) Interstitial spaces outside seminiferous tubules; provide nutrition to germ cells (d) Rete testis; facilitate sperm transport
Solution:
Answer: (b) Solution:The regions outside the seminiferous tubules, called interstitial spaces, contain small blood vessels and interstitial cells or Leydig cells. Leydig cells synthesise and secrete testicular hormones called androgens. They are distinct from Sertoli cells, which provide nutrition to germ cells from inside the seminiferous tubules.
Question 11: Arrange the following male accessory ducts in the correct order of sperm transport from testis to exterior: (P) Epididymis (Q) Rete testis (R) Vas deferens (S) Vasa efferentia (T) Urethra (U) Ejaculatory duct (a) Q → S → P → R → U → T (b) P → Q → S → R → U → T (c) Q → P → S → R → U → T (d) S → Q → P → R → U → T
Solution:
Answer: (a) Solution:The correct transport path as per NCERT: Seminiferous tubules open into rete testis (Q) → vasa efferentia (S) leave the testis → epididymis (P) → vas deferens (R) ascends to abdomen, loops over urinary bladder → receives duct from seminal vesicle → ejaculatory duct (U) → opens into urethra (T) → urethral meatus.
Question 12: The urethra in males originates from which structure and opens externally as which structure? (a) Urinary bladder; penile opening (b) Ejaculatory duct; glans penis (c) Urinary bladder; urethral meatus (d) Vas deferens; urethral meatus
Solution:
Answer: (c) Solution: As stated in NCERT: 'The urethra originates from the urinary bladder and extends through the penis to its external opening called urethral meatus.' The urethra serves as a common passage for both urine (from urinary bladder) and semen (via ejaculatory duct).
Answer: (a) Solution:Seminiferous tubules are highly coiled structures in which sperms are produced (b). Leydig cells synthesise and secrete androgens (a). Sertoli cells provide nutrition to the germ cells inside seminiferous tubules (c). Spermatogonia are the immature male germ cells (spermatogonia) present on the inside wall of seminiferous tubules (d).
Question 14: Which of the following is the correct set of male accessory glands? (a) Paired seminal vesicles, a prostate and paired bulbourethral glands (b) A seminal vesicle, paired prostates and a bulbourethral gland (c) Paired seminal vesicles, paired prostates and a bulbourethral gland (d) A seminal vesicle, a prostate and paired bulbourethral glands
Solution:
Answer: (a) Solution:The male accessory glands as per NCERT include: paired seminal vesicles, a prostate (single), and paired bulbourethral glands. Their secretions constitute the seminal plasma which is rich in fructose, calcium and certain enzymes.
Question 15: Which of the following is NOT a component of seminal plasma? (a) Fructose (b) Calcium (c) Certain enzymes (d) Glucose
Solution:
Answer: (d) Solution:Seminal plasma is rich in fructose, calcium, and certain enzymes - as stated in NCERT. Glucose is NOT mentioned as a component. The secretions of the seminal vesicles, prostate, and bulbourethral glands together constitute the seminal plasma.
Page No. 28-31 (The Female Reproductive System)
Question 16: Consider the following statements about the female reproductive system: (I) The female reproductive system consists of a pair of ovaries. (II) Ovaries produce the female gamete and several steroid hormones. (III) Each ovary is about 2-4 cm in length. (IV) Ovaries are connected to the uterus by fallopian tubes only (not to pelvic wall). Select the INCORRECT statement: (a) IV only (b) III only (c) I and II (d) II and IV
Solution:
Answer: (a) Solution: Statements I, II and III are correct. Statement IV is incorrect because each ovary is connected to BOTH the pelvic wall AND the uterus by ligaments. The ovary is not connected to the uterus by fallopian tubes - the fallopian tube extends from the periphery of each ovary to the uterus but is not the connecting ligament.
Question 17: The ovarian stroma is divided into two zones. Which of the following correctly identifies them? (a) An inner cortex and an outer medulla (b) A peripheral cortex and an inner medulla (c) An outer medulla and an inner cortex (d) A peripheral medulla and an inner cortex
Solution:
Answer: (b) Solution:Each ovary is covered by a thin epithelium which encloses the ovarian stroma. The stroma is divided into two zones - a peripheral cortex and an inner medulla. The peripheral cortex contains the ovarian follicles in various stages of development.
Question 18: Assertion (A): Mammary glands are structurally and functionally integrated with the female reproductive system. Reason (R): Mammary glands support the processes of ovulation, fertilisation, and pregnancy. (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
Solution:
Answer: (c) Solution:A is true - mammary glands ARE structurally and functionally integrated with the female reproductive system. However, R is FALSE - mammary glands support lactation (breastfeeding/child care) after birth, NOT ovulation or fertilisation. NCERT states they support processes of ovulation, fertilisation, pregnancy, birth and child care - but mammary glands specifically support the child care/lactation part.
Question 19: The fallopian tubes (oviducts) are approximately how long and what is the name of the funnel-shaped part near the ovary? (a) 8-10 cm; ampulla (b) 10-12 cm; infundibulum (c) 12-15 cm; isthmus (d) 10-12 cm; fimbriae
Solution:
Answer: (b) Solution:Each fallopian tube is about 10-12 cm long and extends from the periphery of each ovary to the uterus. The part closer to the ovary is the funnel-shaped infundibulum. The edges of the infundibulum possess finger-like projections called fimbriae, which help in collection of the ovum after ovulation.
Question 20: Match the parts of the fallopian tube with their correct descriptions:
Answer: (a) Solution: Fimbriae are finger-like projections at the edges of infundibulum that help collect ovum after ovulation (d). Infundibulum is the funnel-shaped part closer to the ovary (c). Ampulla is the wider part of the oviduct where fertilisation typically occurs (b). Isthmus has a narrow lumen and joins the uterus (a).
Question 21: The cavity of the cervix is called the cervical canal, and it along with the vagina forms which structure? (a) The fallopian canal (b) The endometrial canal (c) The birth canal (d) The uterine canal
Solution:
Answer: (c) Solution: The cavity of the cervix is called cervical canal. The cervical canal along with the vagina forms the birth canal through which the baby passes during delivery (parturition).
Question 22: Which of the following is the correct sequence of the three layers of the uterine wall from outermost to innermost? (a) Endometrium → Myometrium → Perimetrium (b) Myometrium → Endometrium → Perimetrium (c) Perimetrium → Endometrium → Myometrium (d) Perimetrium → Myometrium → Endometrium
Solution:
Answer: (d) Solution: The wall of the uterus has three layers: the external thin membranous perimetrium (outermost), middle thick layer of smooth muscle - myometrium (middle), and inner glandular layer called endometrium (innermost) that lines the uterine cavity. Endometrium undergoes cyclical changes during menstrual cycle; myometrium contracts strongly during delivery.
Question 23: Assertion (A): The shape of the uterus is like an inverted pear. Reason (R): The uterus is supported by ligaments attached to the pelvic wall and opens into the vagina through a narrow cervix. (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
Solution:
Answer: (b) Solution:A is true - the uterus is described as having an inverted pear shape. R is also true - the uterus is supported by ligaments attached to the pelvic wall and opens into the vagina through a narrow cervix. However, R does not explain WHY the uterus is shaped like an inverted pear. Hence both are true but R is not the correct explanation.
Question 24: Which of the following correctly states the functional difference between myometrium and endometrium? (a) Myometrium undergoes cyclical changes during menstrual cycle; endometrium contracts during delivery (b) Endometrium undergoes cyclical changes during menstrual cycle; myometrium exhibits strong contraction during delivery (c) Both myometrium and endometrium undergo cyclical changes during the menstrual cycle (d) Endometrium synthesises hormones; myometrium responds to those hormones
Solution:
Answer: (b) Solution:The endometrium is the inner glandular layer that undergoes cyclical changes during the menstrual cycle (proliferation and shedding). The myometrium is the middle thick layer of smooth muscle that exhibits strong contraction during delivery of the baby. This functional distinction is frequently tested.
Question 25: Which of the following is NOT part of the female external genitalia? (a) Mons pubis (b) Labia majora (c) Cervix (d) Clitoris
Solution:
Answer: (c) Solution:The female external genitalia include mons pubis, labia majora, labia minora, hymen, and clitoris. The cervix is an INTERNAL structure - the narrow lower part of the uterus that opens into the vagina. It is not part of the external genitalia.
Question 26: Consider the following statements about the hymen: (I) The hymen is a membrane that often partially covers the vaginal opening. (II) Hymen is always torn during the first coitus. (III) Hymen can be broken by sudden fall, jolt, or insertion of a vaginal tampon. (IV) In some women the hymen persists even after coitus. (V) Presence or absence of hymen is a reliable indicator of virginity. How many of these statements are CORRECT? (a) Two (I and III only) (b) Three (I, III and IV) (c) Four (I, II, III and IV) (d) Two (I and IV only)
Solution:
Answer: (b) Solution:Statements I, III and IV are correct. Statement II is incorrect - hymen is OFTEN torn during first coitus but not always. Statement V is incorrect - the NCERT explicitly states 'the presence or absence of hymen is not a reliable indicator of virginity or sexual experience.' Hence 3 statements (I, III, IV) are correct.
Question 27: The mons pubis in the female external genitalia is best described as: (a) Fleshy folds of tissue that surround the vaginal opening (b) Paired folds of tissue under the labia majora (c) A cushion of fatty tissue covered by skin and pubic hair (d) A tiny finger-like structure at the junction of the labia minora
Solution:
Answer: (c) Solution: Mons pubis is described in NCERT as 'a cushion of fatty tissue covered by skin and pubic hair.' The labia majora are fleshy folds of tissue extending from mons pubis surrounding the vaginal opening. The labia minora are paired folds under the labia majora. The clitoris is a tiny finger-like structure at the junction of the two labia minora.
Question 28: The glandular tissue of each breast is divided into how many mammary lobes, and what do the cells of alveoli secrete? (a) 10-12 lobes; hormones (b) 15-20 lobes; milk (c) 20-25 lobes; colostrum (d) 15-20 lobes; enzymes
Solution:
Answer: (b) Solution:The glandular tissue of each breast is divided into 15-20 mammary lobes containing clusters of cells called alveoli. The cells of alveoli secrete milk, which is stored in the cavities (lumens) of alveoli. The alveoli open into mammary tubules, which join to form mammary ducts.
Question 29: Match the structural components of the mammary gland:
Column I
Column II
(i) Alveoli
(a) Connected to lactiferous duct, opens at nipple
(ii) Mammary duct
(b) Cells secrete milk
(iii) Mammary ampulla
(c) Tubules of each lobe join together
(iv) Lactiferous duct
(d) Wider structure formed by several mammary ducts
Answer: (a) Solution:Alveoli cells secrete milk (b). Several tubules of each lobe join to form a mammary duct (c). Several mammary ducts join to form a wider mammary ampulla (d). The mammary ampulla is connected to the lactiferous duct which opens at the nipple from where milk is expressed during breastfeeding (a).
Question 30: Which of the following statements about mammary glands is INCORRECT? (a) Mammary glands are characteristic of all female mammals (b) They contain glandular tissue and variable amount of fat (c) The lactiferous duct opens at the areola (d) Mammary glands are one of the female secondary sexual characteristics
Solution:
Answer: (c) Solution:The lactiferous duct opens at the NIPPLE, not the areola. The areola is the pigmented area surrounding the nipple. The lactiferous duct is the final duct that carries milk from the mammary ampulla to the exterior at the nipple. All other statements are correct as per NCERT.
Page No. 31-33 (Gametogenesis)
Question 31: Spermatogenesis starts at the age of puberty due to a significant increase in the secretion of which hormone? (a) LH (Luteinising Hormone) (b) FSH (Follicle Stimulating Hormone) (c) GnRH (Gonadotropin Releasing Hormone) (d) Testosterone
Solution:
Answer: (c) Solution:Spermatogenesis starts at the age of puberty due to significant increase in the secretion of GnRH (gonadotropin releasing hormone), a hypothalamic hormone. GnRH then acts at the anterior pituitary gland and stimulates secretion of two gonadotropins - LH and FSH - which in turn regulate spermatogenesis.
Question 32: FSH acts on which cells and stimulates secretion of what factors? (a) Leydig cells; androgens (b) Sertoli cells; factors that help in spermiogenesis (c) Spermatogonia; GnRH (d) Primary spermatocytes; LH
Solution:
Answer: (b) Solution:FSH acts on the Sertoli cells and stimulates secretion of some factors which help in the process of spermiogenesis (transformation of spermatids into spermatozoa). LH acts at the Leydig cells and stimulates synthesis and secretion of androgens. Androgens in turn stimulate the process of spermatogenesis.
Question 33: A primary spermatocyte completes the first meiotic division to form two secondary spermatocytes. How many chromosomes does each secondary spermatocyte contain? (a) 46 chromosomes (b) 92 chromosomes (c) 23 chromosomes (d) 44 chromosomes
Solution:
Answer: (c) Solution: Each spermatogonium is diploid and contains 46 chromosomes. Some spermatogonia become primary spermatocytes which undergo the first meiotic division (reduction division), forming two equal, haploid secondary spermatocytes with only 23 chromosomes each.
Question 34: The process of transformation of spermatids into spermatozoa is called: (a) Spermatogenesis (b) Spermiation (c) Spermiogenesis (d) Capacitation
Solution:
Answer: (c) Solution: Spermiogenesis is the process by which spermatids are transformed into spermatozoa (sperms). After spermiogenesis, sperm heads become embedded in the Sertoli cells. Spermiation is the process by which mature spermatozoa are released from the seminiferous tubules. Spermatogenesis is the overall process of sperm formation.
Question 35: Which of the following correctly describes the sperm structure? (I) A plasma membrane envelops the whole body of sperm. (II) The sperm head contains an elongated haploid nucleus with acrosome at the anterior portion. (III) The middle piece possesses mitochondria that produce energy for flagellar movement. (IV) The acrosome is filled with enzymes that help fertilisation of the ovum. (a) I, II and III only (b) II, III and IV only (c) I, III and IV only (d) I, II, III and IV
Solution:
Answer: (d) Solution:All four statements are correct. The plasma membrane envelops the whole sperm (I). The sperm head contains an elongated haploid nucleus; the anterior portion is covered by acrosome (II). The middle piece has numerous mitochondria producing energy for tail movement (III). The acrosome contains enzymes essential for fertilisation (IV).
Question 36: For normal fertility, what is the minimum percentage of sperms with normal shape/size and minimum percentage showing vigorous motility in a human male ejaculate? (a) At least 40% normal shape; at least 60% vigorous motility (b) At least 60% normal shape; at least 40% vigorous motility (c) At least 50% normal shape; at least 50% vigorous motility (d) At least 70% normal shape; at least 30% vigorous motility
Solution:
Answer: (b) Solution: As per NCERT: The human male ejaculates about 200 to 300 million sperms during a coitus. For normal fertility, at least 60 per cent sperms must have normal shape and size and at least 40 per cent of them must show vigorous motility. These are clinically important values used in semen analysis.
Question 37: Assertion (A): The process by which sperm heads become embedded in Sertoli cells is called spermiation. Reason (R): Mature spermatozoa are finally released from the seminiferous tubules by the process called spermiation. (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
Solution:
Answer: (d) Solution:A is FALSE. The embedding of sperm heads in Sertoli cells occurs during spermiogenesis (transformation of spermatids to spermatozoa), not during spermiation. R is TRUE. Spermiation is specifically the process by which mature spermatozoa are released from the seminiferous tubules. Hence A is false but R is true.
Question 38: Oogenesis is initiated during which developmental stage? (a) At puberty (b) After birth during childhood (c) During embryonic development (d) At the time of first menstruation (menarche)
Solution:
Answer: (c) Solution: The process of formation of a mature female gamete is called oogenesis. Oogenesis is initiated during the embryonic development stage itself - when a couple of million gamete mother cells (oogonia) are formed within each fetal ovary. No more oogonia are formed and added after birth.
Question 39: Primary oocytes are arrested at which stage of meiosis until they are stimulated to resume meiosis? (a) Metaphase-I (b) Anaphase-I (c) Prophase-I (d) Telophase-I
Solution:
Answer: (c) Solution: Oogonia cells start division and enter into prophase-I of the meiotic division and get temporarily arrested at that stage. These arrested cells are called primary oocytes. They remain in this arrested state from fetal life until puberty, when they are stimulated to resume meiosis during each menstrual cycle.
Question 40: The secondary follicle is characterised by the primary oocyte getting surrounded by more layers of granulosa cells along with which new structure? (a) A new zona pellucida (b) A new theca (c) An antrum (d) Corpus luteum
Solution:
Answer: (b) Solution:The primary follicles get surrounded by more layers of granulosa cells and a new theca, and are called secondary follicles. The secondary follicle soon transforms into a tertiary follicle which is characterised by a fluid-filled cavity called antrum. A new zona pellucida is formed by the secondary oocyte later.
Question 41: Which of the following correctly describes what happens at the tertiary follicle stage? (a) The primary oocyte completes second meiotic division and forms secondary oocyte (b) The primary oocyte completes first meiotic division forming secondary oocyte and first polar body (c) The secondary oocyte completes second meiotic division forming ovum and second polar body (d) The oogonia undergo mitotic division to form primary oocytes
Solution:
Answer: (b) Solution: At the tertiary follicle stage, the primary oocyte within the follicle grows in size and completes its first meiotic division. It is an unequal division resulting in the formation of a large haploid secondary oocyte and a tiny first polar body. The secondary oocyte retains bulk of the nutrient-rich cytoplasm.
Question 42: Match the following follicle stages with their characteristics:
Column I
Column II
(i) Primary follicle
(a) Fluid-filled cavity (antrum) present
(ii) Secondary follicle
(b) Primary oocyte surrounded by single layer of granulosa cells
(iii) Tertiary follicle
(c) Mature follicle; ruptures during ovulation
(iv) Graafian follicle
(d) Primary oocyte with multiple granulosa layers and new theca
Answer: (a) Solution:Primary follicle: primary oocyte surrounded by a layer of granulosa cells (b). Secondary follicle: primary oocyte surrounded by more granulosa layers and a new theca (d). Tertiary follicle: characterised by fluid-filled antrum (a). Graafian follicle: mature follicle that ruptures to release secondary oocyte during ovulation (c).
Question 43: During ovulation, which structure ruptures and what is released? (a) Primary follicle ruptures; primary oocyte is released (b) Tertiary follicle ruptures; secondary oocyte is released (c) Graafian follicle ruptures; secondary oocyte (ovum) is released (d) Secondary follicle ruptures; mature ovum is released
Solution:
Answer: (c) Solution: The Graafian follicle (mature follicle) now ruptures to release the secondary oocyte (ovum) from the ovary by the process called ovulation. Note: The released cell is technically a secondary oocyte (not a fully mature ovum), as it completes meiosis II only after fertilisation.
Page No. 33-35 (Menstrual Cycle)
Question 44: In which group of animals does the menstrual cycle occur, and what is it called in other female mammals? (a) Menstrual cycle occurs in all female mammals; it is called oestrous cycle in some (b) Menstrual cycle occurs in female primates (monkeys, apes, humans); other mammals show oestrous cycle (c) Menstrual cycle occurs only in humans; all other animals show oestrous cycle (d) Menstrual cycle occurs in all placental mammals
Solution:
Answer: (b) Solution:The reproductive cycle in female primates (e.g., monkeys, apes, and human beings) is called menstrual cycle. Other non-primate female mammals have a different cycle called the oestrous cycle. The menstrual cycle begins at puberty (menarche) and repeats approximately every 28/29 days.
Question 45: Which of the following is the INCORRECT statement about the menstrual flow? (a) Menstrual flow results due to breakdown of endometrial lining of the uterus and its blood vessels (b) Menstrual flow lasts for 3-5 days (c) Menstrual flow forms a liquid that comes out through the vagina (d) Menstruation only occurs if the released ovum is fertilised
Solution:
Answer: (d) Solution:Statement D is INCORRECT - Menstruation only occurs if the released ovum is NOT fertilised (if fertilisation does NOT occur). If the ovum is fertilised, the menstrual cycle stops and pregnancy begins. Statements A, B, and C are all correct as per NCERT.
Question 46: During the follicular phase of the menstrual cycle, which TWO events occur simultaneously? (a) Primary follicles develop into Graafian follicle AND endometrium degenerates (b) Primary follicles develop into mature Graafian follicle AND endometrium regenerates through proliferation (c) Ovulation occurs AND corpus luteum forms (d) Corpus luteum secretes progesterone AND endometrium proliferates
Solution:
Answer: (b) Solution:During the follicular phase, the primary follicles in the ovary grow to become a fully mature Graafian follicle (follicular development) and simultaneously the endometrium of uterus regenerates through proliferation. These changes in the ovary and uterus are induced by changes in levels of pituitary and ovarian hormones.
Question 47: Assertion (A): Cyclic menstruation is an indicator of normal reproductive phase in women. Reason (R): Menstrual cycles extend between menarche and menopause, with menopause occurring around 50 years of age. (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
Solution:
Answer: (b) Solution: A is true - cyclic menstruation is indeed an indicator of normal reproductive phase. R is also true - menstrual cycles extend between menarche (first menstruation at puberty) and menopause (around 50 years of age). However, R merely defines the period of cyclic menstruation and does not explain WHY it is an indicator of normal reproductive phase. Hence both are true but R is not the correct explanation.
Question 48: Both LH and FSH attain a peak level on approximately which day of the menstrual cycle, and what specific event is triggered by the LH surge? (a) 7th day; follicular maturation (b) 14th day (mid-cycle); ovulation (c) 21st day; corpus luteum formation (d) 28th day; menstruation
Solution:
Answer: (b) Solution: Both LH and FSH attain a peak level in the middle of the cycle (about 14th day). The rapid secretion of LH leading to its maximum level during the mid-cycle is called LH surge. The LH surge induces rupture of the Graafian follicle and thereby the release of the ovum - this is ovulation.
Question 49: Which of the following correctly describes the corpus luteum and its primary secretion? (a) Corpus luteum is formed from remnants of Graafian follicle after ovulation and secretes large amounts of progesterone (b) Corpus luteum is formed from the primary follicle and secretes estrogen (c) Corpus luteum is formed from endometrial tissue and secretes LH (d) Corpus luteum is formed from the secondary follicle and secretes FSH
Solution:
Answer: (a) Solution: After ovulation, the remaining parts of the Graafian follicle transform as the corpus luteum. The corpus luteum secretes large amounts of progesterone, which is essential for maintenance of the endometrium. Such an endometrium is necessary for implantation of the fertilised ovum and maintenance of pregnancy.
Question 50: What happens to the corpus luteum in the absence of fertilisation? (a) It continues to grow and secretes more progesterone (b) It degenerates, causing disintegration of endometrium and onset of menstruation (c) It transforms into a primary follicle for the next cycle (d) It secretes HCG to maintain the menstrual cycle
Solution:
Answer: (b) Solution: In the absence of fertilisation, the corpus luteum degenerates. This causes disintegration of the endometrium, leading to menstruation, which marks a new cycle. If fertilisation occurs, the corpus luteum is maintained (by hCG from the embryo) and all menstrual events stop during pregnancy.
Page No. 35-37 (Fertilisation & Early Development)
Question 51: During copulation, sperms are released into the vagina and swim to reach which region where fertilisation takes place? (a) The isthmus of the fallopian tube (b) The uterine cavity (c) The ampullary region of the fallopian tube (d) The cervical canal
Solution:
Answer: (c) Solution: During copulation (coitus), semen is released by the penis into the vagina (insemination). The motile sperms swim rapidly, pass through the cervix, enter the uterus, and finally reach the ampullary region of the fallopian tube. The ovum released by the ovary is also transported to the ampullary region where fertilisation takes place.
Question 52: Which of the following statements about fertilisation is CORRECT? (a) Fertilisation can occur anywhere in the fallopian tube (b) Fertilisation occurs in the isthmus of the fallopian tube (c) Fertilisation can only occur if the ovum and sperms are transported simultaneously to the ampullary region (d) Fertilisation occurs in the uterine cavity before implantation
Solution:
Answer: (c) Solution:Fertilisation can only occur if the ovum and sperms are transported simultaneously to the ampullary region. This is why not all copulations lead to fertilisation and pregnancy. The ovum has a limited lifespan after ovulation, and sperms must reach the ampullary region at the right time.
Question 53: The acrosome reaction during fertilisation specifically helps in which process? (a) Activating the sperm's motility in the female reproductive tract (b) Helping the sperm enter into the cytoplasm of the ovum through the zona pellucida and plasma membrane (c) Blocking the entry of additional sperms after one sperm has entered (d) Completing the second meiotic division of the secondary oocyte
Solution:
Answer: (b) Solution: The secretions of the acrosome help the sperm enter into the cytoplasm of the ovum through the zona pellucida and the plasma membrane. The zona pellucida contact induces changes in the membrane that block the entry of additional sperms (preventing polyspermy), but this is a separate membrane change - not the acrosome reaction itself.
Question 54: After fusion of sperm and ovum, the secondary oocyte completes its second meiotic division. This second meiotic division is unequal and results in: (a) Two equal secondary oocytes (b) Formation of a second polar body and a haploid ovum (ootid) (c) Formation of two first polar bodies (d) Formation of a diploid zygote directly
Solution:
Answer: (b) Solution: The second meiotic division is also unequal and results in the formation of a second polar body and a haploid ovum (ootid). Soon after, the haploid nucleus of the sperm and that of the ovum fuse together to form a diploid zygote. This zygote contains 46 chromosomes (23 from sperm + 23 from ovum).
Question 55: The sex of the baby depends on which of the following? (I) Whether X or Y chromosome-bearing sperm fertilises the ovum (II) The chromosome constitution of the mother (III) The chromosome constitution of the father (IV) The type of ovum produced by the mother (a) I and III only (b) I, II and III (c) I only (d) II and IV only
Solution:
Answer: (a) Solution: All ova produced by females carry X chromosome (since females are XX). In males (XY), 50% sperms carry X chromosome and 50% carry Y. The sex of the baby depends on whether X or Y chromosome-bearing sperm fertilises the ovum (I). Since father is XY, the sperm determines sex - hence father's chromosome constitution (III) is relevant. The mother's chromosomes and type of ovum don't determine sex.
Question 56: As the zygote moves from the isthmus of oviduct towards the uterus, it undergoes mitotic divisions called cleavage. What are the daughter cells produced called? (a) Blastocysts (b) Morula (c) Blastomeres (d) Trophoblasts
Solution:
Answer: (c) Solution: The mitotic division starts as the zygote moves through the isthmus of the oviduct towards the uterus and forms daughter cells called blastomeres. The embryo with 8-16 blastomeres is called a morula. The morula continues to divide and transforms into a blastocyst as it moves further into the uterus.
Answer: (b) Solution:The correct sequence: Zygote → cleavage produces blastomeres → when 8-16 blastomeres are present = morula → morula continues dividing and transforms into blastocyst as it moves into the uterus → trophoblast of blastocyst attaches to endometrium → implantation occurs. This sequence is explicitly described in NCERT.
Question 58: In the blastocyst, which layer gets attached to the endometrium and which group of cells eventually forms the embryo? (a) Inner cell mass attaches to endometrium; trophoblast forms the embryo (b) Trophoblast attaches to endometrium; inner cell mass forms the embryo (c) Both trophoblast and inner cell mass attach to endometrium equally (d) Trophoblast attaches to endometrium; trophoblast also forms the embryo
Solution:
Answer: (b) Solution:In the blastocyst, blastomeres are arranged into an outer layer called trophoblast and an inner group of cells called the inner cell mass. The trophoblast layer gets attached to the endometrium. The inner cell mass gets differentiated as the embryo. After attachment, the uterine cells divide rapidly and cover the blastocyst - embedding it in the endometrium (implantation).
Question 59: Implantation is defined as: (a) The process of fertilisation of the ovum by the sperm (b) The attachment of trophoblast to the endometrium leading to embedding of blastocyst in the endometrium (c) The release of the ovum from the Graafian follicle (d) The formation of the placenta after the embryo is established
Solution:
Answer: (b) Solution: After the trophoblast layer attaches to the endometrium and the inner cell mass gets differentiated as the embryo, the uterine cells divide rapidly and cover the blastocyst. As a result, the blastocyst becomes embedded in the endometrium of the uterus. This is called implantation and it leads to pregnancy.
Question 60: What are chorionic villi and which structural unit do they help form? (a) Finger-like projections on trophoblast that along with uterine tissue form the placenta (b) Blood vessels in the endometrium that nourish the embryo (c) Projections of the inner cell mass that form the three germ layers (d) Structures of the amnion that protect the foetus
Solution:
Answer: (a) Solution: After implantation, finger-like projections appear on the trophoblast called chorionic villi, which are surrounded by the uterine tissue and maternal blood. The chorionic villi and uterine tissue become interdigitated with each other and jointly form a structural and functional unit between the developing embryo (foetus) and the maternal body called placenta.
Question 61: Which of the following hormones are produced EXCLUSIVELY during pregnancy (not in non-pregnant state)? (a) Estrogens, progesterone and cortisol (b) Human chorionic gonadotropin (hCG), human placental lactogen (hPL) and relaxin (c) FSH, LH and prolactin (d) Oxytocin, thyroxine and cortisol
Solution:
Answer: (b) Solution: As explicitly stated in NCERT: 'hCG, hPL and relaxin are produced in women only during pregnancy.' Estrogens, progesterone, cortisol, prolactin, and thyroxine are present in non-pregnant women too (though their levels increase several-fold during pregnancy).
Question 62: Which of the following correctly describes the role of the placenta? (I) Facilitates supply of oxygen and nutrients to the embryo (II) Removes carbon dioxide and excretory waste from the embryo (III) Acts as an endocrine tissue and produces hormones (IV) Directly connects maternal blood vessels to foetal blood vessels (a) I, II and III only (b) I and II only (c) I, II, III and IV (d) III and IV only
Solution:
Answer: (a) Solution:Statements I, II and III are correct. The placenta facilitates supply of O2 and nutrients (I) and removal of CO2 and waste (II). It also acts as an endocrine tissue and produces hCG, hPL, estrogens, progestogens, relaxin etc. (III). Statement IV is incorrect - the placenta does NOT directly connect maternal and foetal blood vessels; there is an interdigitation (barrier) that allows exchange without direct mixing of maternal and foetal blood.
Question 63: What are the three primary germ layers formed from the inner cell mass immediately after implantation? (a) Ectoderm, mesoderm and endoderm (b) Trophoblast, ectoderm and endoderm (c) Ectoderm, myoderm and endoderm (d) Epiderm, mesoderm and hypoderm
Solution:
Answer: (a) Solution:Immediately after implantation, the inner cell mass (embryo) differentiates into an outer layer called ectoderm and an inner layer called endoderm. A mesoderm soon appears between the ectoderm and the endoderm. These three layers - ectoderm, mesoderm and endoderm - give rise to all tissues (organs) in adults.
Question 64: By what week (trimester) of pregnancy are most major organ systems formed, including well-developed limbs and external genital organs? (a) By end of 4 weeks (end of first month) (b) By end of 8 weeks (end of second month) (c) By end of 12 weeks (first trimester) (d) By end of 24 weeks (second trimester)
Solution:
Answer: (c) Solution:By the end of 12 weeks (first trimester), most of the major organ systems are formed. For example, the limbs and external genital organs are well-developed. The heart is formed by one month, limbs and digits by two months. The first movements of the foetus and hair on head appear during the fifth month.
Question 65: Arrange the following foetal developmental milestones in the correct order: (P) First movements of foetus and appearance of hair on head (Q) Heart is formed (R) Foetus fully developed, ready for delivery (S) Limbs and digits develop (T) Body covered with fine hair, eyelids separate (a) Q → S → P → T → R (b) S → Q → P → T → R (c) Q → P → S → T → R (d) P → Q → S → T → R
Solution:
Answer: (a) Solution: Correct chronological order: After one month - heart formed (Q); end of second month - limbs and digits develop (S); fifth month - first foetal movements and hair on head (P); end of 24 weeks (second trimester) - body covered with fine hair, eyelids separate, eyelashes formed (T); end of nine months - foetus fully developed, ready for delivery (R).
Page No. 38 (Parturition & Lactation)
Question 66: The average duration of human pregnancy is about 9 months. This duration is called: (a) Parturition period (b) Gestation period (c) Lactation period (d) Neonatal period
Solution:
Answer: (b) Solution:The average duration of human pregnancy is about 9 months, which is called the gestation period. At the end of the gestation period, vigorous contraction of the uterus causes expulsion/delivery of the foetus. This process of delivery of the foetus (childbirth) is called parturition.
Question 67: Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from: (a) The maternal pituitary gland alone (b) The hypothalamus of the mother (c) The fully developed foetus and the placenta (d) The corpus luteum during late pregnancy
Solution:
Answer: (c) Solution: Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from the fully developed foetus and the placenta, which induce mild uterine contractions called foetal ejection reflex. This triggers release of oxytocin from the maternal pituitary.
Question 68: What type of feedback mechanism operates between uterine contractions and oxytocin secretion during parturition? (a) Negative feedback - stronger contractions inhibit further oxytocin release (b) Positive feedback - stronger contractions stimulate further oxytocin secretion leading to even stronger contractions (c) No feedback - oxytocin is released at a constant rate throughout parturition (d) Negative feedback - oxytocin inhibits uterine contractions to prevent premature delivery
Solution:
Answer: (b) Solution:This is a classic positive feedback mechanism. Oxytocin acts on the uterine muscle and causes stronger uterine contractions, which in turn stimulate further secretion of oxytocin. The stimulatory reflex between the uterine contraction and oxytocin secretion continues, resulting in stronger and stronger contractions leading to expulsion of the baby.
Question 69: Assertion (A): The milk produced during the initial few days of lactation is called colostrum. Reason (R): Colostrum is rich in antibodies (especially IgA) absolutely essential for developing resistance in new-born babies. (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
Solution:
Answer: (a) Solution:Both A and R are true. Colostrum is the milk produced in the initial few days of lactation (A). It contains several antibodies absolutely essential to develop resistance (passive immunity) for the new-born babies (R). R correctly explains why colostrum is especially important for new-borns. Breast-feeding during initial infant growth is recommended by doctors for bringing up a healthy baby.
Question 70: Consider the following statements about parturition and lactation: (I) Vigorous contraction of the uterus at end of pregnancy is caused by oxytocin. (II) Oxytocin is released from the foetal pituitary. (III) The mammary glands start producing milk towards the end of pregnancy. (IV) Colostrum is produced only after the first month of lactation. (V) Breast-feeding during the initial period of infant growth is recommended by doctors. How many of these statements are CORRECT? (a) Two (I and V) (b) Three (I, III and V) (c) Four (I, II, III and V) (d) Two (III and V)
Solution:
Answer: (b) Solution: Statements I, III and V are correct. Statement II is INCORRECT - oxytocin is released from the MATERNAL pituitary, not the foetal pituitary. Statement IV is INCORRECT - colostrum is produced during the INITIAL FEW DAYS of lactation, not after the first month. Hence three statements (I, III, V) are correct.
Question 71: Which of the following is the correct sequence of events during parturition? (a) Oxytocin release → Foetal ejection reflex → Stronger contractions → Baby expelled → Placenta expelled (b) Foetal ejection reflex → Oxytocin release from maternal pituitary → Stronger uterine contractions (positive feedback) → Baby expelled through birth canal → Placenta expelled (c) Progesterone surge → Foetal ejection reflex → Oxytocin release → Baby expelled → Placenta expelled (d) Corpus luteum degeneration → Oxytocin release → Foetal ejection reflex → Baby expelled
Solution:
Answer: (b) Solution: Correct sequence: Signals from developed foetus and placenta → mild uterine contractions (foetal ejection reflex) → triggers oxytocin release from maternal pituitary → oxytocin causes stronger contractions → stronger contractions stimulate more oxytocin (positive feedback) → stronger and stronger contractions → baby expelled through birth canal (parturition) → placenta also expelled soon after.
Question 72: The process by which mammary glands produce milk after childbirth is called: (a) Colostrum synthesis (b) Galactopoiesis (c) Lactation (d) Mammogenesis
Solution:
Answer: (c) Solution: The mammary glands of the female undergo differentiation during pregnancy and start producing milk towards the end of pregnancy by the process called lactation. This helps the mother in feeding the new-born. The milk produced during the initial few days of lactation is called colostrum which contains several antibodies essential to develop resistance for the new-born babies.
Question 73: Assertion (A): After parturition, the placenta is also expelled out of the uterus. Reason (R): The placenta is a temporary organ that functions only during pregnancy to provide nutrients and oxygen to the developing foetus. (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
Solution:
Answer: (a) Solution:Both A and R are true. As per NCERT: 'Soon after the infant is delivered, the placenta is also expelled out of the uterus' (A is true). The reason correctly explains A - the placenta is a temporary organ that exists only during pregnancy to facilitate exchange of nutrients, oxygen, waste between foetus and mother. Once the baby is born, the placenta has served its purpose and is expelled.
Question 74: Which of the following about the inner cell mass (embryoblast) is CORRECT? (I) It contains certain cells called stem cells. (II) Stem cells have the potency to give rise to all the tissues and organs. (III) The inner cell mass differentiates into ectoderm and endoderm, with mesoderm appearing later. (IV) Inner cell mass forms the trophoblast layer. (a) I, II and III only (b) I and II only (c) II, III and IV only (d) I, II, III and IV
Solution:
Answer: (a) Solution:Statements I, II and III are correct. The inner cell mass contains stem cells that have the potency to give rise to all tissues and organs (I and II). It differentiates into ectoderm (outer layer) and endoderm (inner layer), with mesoderm appearing between them later (III). Statement IV is INCORRECT - the inner cell mass forms the embryo, NOT the trophoblast. The trophoblast is the outer layer of the blastocyst.
Question 75: A comprehensive question - Select the CORRECT match of terms and their definitions:
(i) Menarche
(a) Cessation of menstrual cycles around 50 years
(ii) Menopause
(b) First menstruation at puberty
(iii) Spermiation
(c) Release of mature spermatozoa from seminiferous tubules
Answer: (a) Solution:Menarche = first menstruation beginning at puberty (b). Menopause = cessation of menstrual cycles around 50 years of age (a). Spermiation = process by which sperms are released from the seminiferous tubules (c). Spermiogenesis = process of transformation of spermatids into spermatozoa/sperms (d). These four terms are all defined clearly in NCERT Chapter 2.
1. What are the main components of the male reproductive system?
Ans. The male reproductive system primarily consists of the testes, seminal vesicles, prostate gland, bulbourethral glands, and the penis. The testes are responsible for producing sperm and hormones like testosterone. The accessory glands contribute to the formation of semen, which nourishes and transports sperm during ejaculation.
2. How does sperm structure contribute to its function?
Ans. The structure of sperm is highly specialised for its function of fertilisation. It consists of a head containing genetic material, an acrosome that helps penetrate the egg, a midpiece packed with mitochondria for energy, and a tail (flagellum) that provides motility. This design allows sperm to effectively reach and fertilise the ovum.
3. What is oogenesis and how does it differ from spermatogenesis?
Ans. Oogenesis is the process of egg (ovum) formation in females, which occurs in the ovaries. Unlike spermatogenesis, which produces millions of sperm continuously, oogenesis results in the formation of a limited number of ova (typically one per menstrual cycle). Oogenesis also involves distinct stages such as the primary oocyte, secondary oocyte, and polar bodies, reflecting its complex regulation and hormonal control.
4. What role do the oviducts and uterus play in female reproduction?
Ans. The oviducts (fallopian tubes) and uterus are crucial components of the female reproductive system. The oviducts transport the ovum from the ovary to the uterus and are the site of fertilisation. The uterus provides a suitable environment for the implantation and development of a fertilised egg, supporting the early stages of pregnancy.
5. What is the significance of the endometrium and mammary glands in female reproductive health?
Ans. The endometrium is the inner lining of the uterus, which thickens during the menstrual cycle to prepare for potential implantation of a fertilised egg. If fertilisation does not occur, the endometrium sheds during menstruation. Mammary glands are essential for lactation, providing nourishment to infants after birth. Both structures play vital roles in female reproductive health and overall reproductive success.
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