1. Two statements are given below – one labelled Assertion (A) and the other labelled Reason (R).
Which of the following is correct?
A. Both A and R are true, and R is a correct explanation of A.
B. Both A and R are true, but R is not a correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
Ans: A. Both A and R are true, and R is a correct explanation of A.
2. Organisms possessing identical sex chromosomes are referred to as the homogametic sex. Organisms with different sex chromosomes are known as the heterogametic sex.
Which of the following is CORRECT about humans?
A. Both males and females are homogametic.
B. Both males and females are heterogametic.
C. Males are homogametic while females are heterogametic.
D. Males are heterogametic, while females are homogametic.
Ans: D. Males are heterogametic while females are homogametic.
3. Which of these cells of the human male reproductive system is haploid?
A. Spermatid
B. Sertoli cell
C. Leydig cell
D. Spermatogonium
Ans: A. spermatid
4. Globozoospermia is a condition where sperm have a characteristic round head lacking the acrosome. Which of the following functions will a sperm NOT be able to do because of the above condition?
A. Enter the cervix
B. Penetrate the ovum
C. Leave the ejaculatory duct
D. Swim to the Fallopian tube
Ans: B. penetrate the ovum
5. Which of these statements about the female reproductive system is FALSE?
A. Menarche marks the initiation of oogenesis.
B. The germ layers start forming after implantation.
C. The oocyte completes meiosis after the entry of sperm.
D. Ovulation and menstruation stop permanently after menopause.
Ans: A. Menarche marks the initiation of oogenesis.
6. Which of these hormones would be detected in both a pregnant female and a female who is not pregnant?
A. Relaxin
B. Prolactin
C. Progesterone
D. Human chorionic gonadotropin
Ans: C. progesterone
7. Which of the following statements describes the difference between the placenta and the umbilical cord?
A. The placenta secretes hormones, whereas the umbilical cord does not.
B. The placenta persists after pregnancy, while the umbilical cord is expelled.
C. The placenta is lined with veins and arteries, while the umbilical cord is not.
D. The placenta interlocks with foetal tissues, whereas the umbilical cord interlocks with the uterine tissue.
Ans: A. The placenta secretes hormones, whereas the umbilical cord does not.
8. Some events of pregnancy in humans are written below in a sequence.
(i) complete development of foetus
(ii) uterine contraction
(iii) dilation of cervix
(iv) delivery of the baby
(v) lactation
Between which of the following events does the shedding of the placenta happen?
A. (i) and (ii)
B. (ii) and (iii)
C. (iii) and (iv)
D. (iv) and (v)
Ans: D. (iv) and (v)
9. (a) Hormones play a crucial role in maintaining balance in living systems through feedback loops. This means that the release of a hormone regulates (increases/decreases) its further release in the body. One such example is oxytocin in the female reproductive system. Explain the feedback loop for oxytocin by answering the following questions.
(i) From where is oxytocin released?
(ii) At what stage of pregnancy do oxytocin levels peak?
(b) Is the feedback mechanism for oxytocin positive or negative in nature? Justify.
Ans:
10. Spermatozoa are the mature male gametes in many sexually reproducing organisms. Thus, spermatogenesis is the male version of gametogenesis, of which the female equivalent is oogenesis. The cells in the germline that undergo meiosis, primary spermatocytes or primary oocytes, are derived from the zygote by a long series of mitoses before the onset of meiosis. Male and female gametes have different histories, marked by different patterns of gene expression that reflect their developmental origin as XY or XX embryos.
Source: https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/gametogenesis
The spermatozoa fuse with the egg cell to create a viable embryo. The ovum is released by the action of gonadotropins in the female body.
(a) Does ovulation happen during the period of pregnancy? Give a reason for your answer.
(b) Why are contraceptive pills able to inhibit ovulation?
Ans:
11. In the diagram of a human sperm given below:
(a) What is the ploidy of the nucleus?
(b) Why does the middle piece have a lot of mitochondria?
(c) What is the role of the acrosome?
(d) Only one sperm is able to fertilise the egg. How is this ensured?
Ans:
(a) Haploid
(b) To provide energy to the sperm to swim
(c) Contains enzymes that help in the process of fertilization
(d) The first sperm induces changes in the ovum membrane to block the entry of other sperms.
12. A period tracking app is a mobile application that maintains information such as the date of onset of menstruation, ovulation, duration of menstrual cycle, etc. A female who got her period on January 22 is using the period tracking app. Based on your understanding of the menstrual cycle, what will be the tentative date of ovulation estimated by the app? Provide a reason.
Ans: Tentative date: between February 4 and February 6. Reason: Ovulation happens between the 14th and 16th day from the onset of the latest or previous menstruation/period.
13. Polyspermy is an extremely rare condition in which an ovum is fertilised by more than one sperm.
(a) How many chromosomes will a zygote contain if 2 sperms fertilise an ovum?
(b) How is polyspermy prevented in humans?
Ans:
(a) 69 chromosomes
(b) Contact between a sperm and an ovum causes changes in the zona pellucida that block the entry of other sperms.
14. Answer the following questions:
(i) For a human male, out of the two sex chromosomes, we can tell which sex chromosome is from which parent. Can we assume the same for a human female? Give a reason for your answer.
(ii) What is the probability of fertilisation between an ovum and a sperm containing the Y chromosome? Give a reason.
Ans:
15. Answer the following questions about the human female reproductive system.
(a) Name the part where the secondary oocyte completes meiosis.
(b) Complete this statement. The completion of the second meiotic division of secondary oocyte is triggered by the ________________. (rupture of the Graafian follicle in the ovary, penetration of zona pellucida by the sperm)
(c) The ploidy of the secondary oocyte before reaching (a) is ___ and after (b) is ___.
Ans:
16. Read the two statements below and answer the questions that follow:
Statement I: Female P has been a surrogate mother once.
Statement II: Female Q is a national-level swimmer.
(a) Is it correct to say that the hymen is DEFINITELY broken in both females P and Q?
(b) Give a reason to support your answers to (a).
Ans:
17. The table below outlines some milestones of pregnancy.
| Day 1 | Fertilisation |
| Day 2 | The morula is formed |
| Day 5 | The inner cell mass is formed |
| Day 7 | Implantation |
Pregnancy tests detect the presence of the human chorionic gonadotropin (hCG) in blood or urine to confirm pregnancy.
(a) A pregnancy test done after which day is likely to yield a positive result?
(b) Give reasons for your answer to (a).
Ans:
(a) After day 7 OR after implantation
(b) The placenta is formed after implantation, and it secretes hCG.
18. Meiotic arrest is a phenomenon noticed during oogenesis in human females, where oocytes are arrested in the primary oocyte stage.
(a) What is the chromosomal count of these primary oocytes?
(b) How are these primary oocytes converted to ovum?
Ans:
19. Study each of the diagrams below and answer the questions that follow them.
(a) The image shows a normal pregnancy and the condition of placenta previa.
(i) Which part of the reproductive tract is the placenta obstructing?
(ii) Which part does (i) open into?
(b) The image shows a normal pregnancy and three conditions related to placenta (accreta, increta, and percreta).
Name the layer of the uterus being penetrated in the following conditions. State the function of the layer during pregnancy.
(i) placenta accreta
(ii) placenta increta
Ans:
20. Read the two statements below and answer the questions that follow.
Statement I: Pregnancy is characterised by the lack of menstruation.
Statement II: Lack of menstruation definitely indicates pregnancy.
(a) Mark each of the statements as true or false.
(b) Give reasons to support your answer in (a).
Ans:
21. Read the information below and answer the questions that follow.
A scientist harvested an embryo from the womb of a sheep just after implantation for the purpose of cloning. (Note: Assume that the female reproductive system and development stages of sheep are the same as humans.)
Draw the stage of the embryo at which the scientist harvested it and label the part which:
(a) attaches to the endometrium
(b) is capable of giving rise to a clone
Ans:
22. (a) Highlight one aspect by which meiosis during oogenesis differs from regular meiosis.
(b) Name two hormones that are common to spermatogenesis and oogenesis.
(c) State the function of hormone identified in (b) in both human male and female.
Ans:
23. For each of the following parameters, compare the processes of oogenesis and spermatogenesis and comment if they are similar or different. Enter your answer in the format as shown:
| Parameter | Oogenesis | Spermatogenesis | Similar/Different |
| Number of gametesproduced from one oocyte or primaryspermatocyte | |||
| Onset |
Ans:
| Parameter | Oogenesis | Spermatogenesis | Number of gametesproduced from one oocyte or primary spermatocyte |
| Number of gametes produced from one oocyte or primary spermatocyte | 1 | 4 | Different |
| Onset | Fetal development | Puberty | Different |
24. (a) Cryptorchidism is a condition in which one or both of the testes fail to descend from the abdomen.
(i) If cryptorchidism of both testes is left untreated, would it lead to infertility? Give reasons.
(ii) Can a male with cryptorchidism of only one testis produce sperm? Give reasons.
(b) Orchidopexy is a surgical procedure for treating cryptorchidism.
(i) Name the part to which the testes are moved outside the abdomen.
(ii) Write the exact temperature range of the testes after orchidopexy.
Ans:
25. Mark the following statements as true or false and provide a reason for each.
(a) The Graafian follicle persists in the absence of fertilisation.
(b) The corpus luteum is detected only in pregnant women.
(c) The urethra serves as the common opening for the elimination of urine, unfertilised eggs, and menstrual blood.
Ans:
OR
26. The image below shows the levels of various hormones measured in a human female throughout the course of her pregnancy.
Based on the image, answer the following questions.
Ans:
27. Refer to the diagram below.
The first circle (P) includes parts of the human female reproductive system that support conception, and the second circle (R) includes parts that support pregnancy.
(a) Name two parts each that belong to
(i) P
(ii) R
(b) Name two parts that support both contraception and pregnancy.
(c) Name two parts that function as endocrine glands and indicate whether they belong to P or R.
(d) Which part of (c) is temporary?
Ans:
28. Observe the diagram of the human male reproductive system shown below with some of its parts marked P, Q, R, S, and T.
(a) For each of the following statements pertaining to male infertility, identify and name the parts between which sperm transfer is obstructed.
(i) The obstruction of the vas deferens leads to low sperm count.
(ii) Epididymitis is the inflammation of the epididymis.
(b) Fill in the blank using one of the options enclosed in the brackets.
Retrograde ejaculation occurs when the semen enters the urinary bladder. This is possible because of the existing anatomy of the human male reproductive system, i.e., the __________ (vas deferens merges with ureter, urinary bladder opens into the vas deferens, urethra emerges from the urinary bladder).
Ans:
29. Mark the following statements as true or false and provide an explanation for each.
(a) The umbilical cord contains blood vessels that connect the foetus to the mother’s heart.
(b) The mitotic differentiation of immature male and female germ cells begins at puberty.
(c) The meiotic divisions in oogenesis are unequal.
(d) Sexual intercourse between a healthy male and female might not always lead to fertilisation.
(e) The sex of the child depends on the sex chromosome contributed by the ovum.
Ans:
30. Answer the following questions about the human female reproductive system:
(a) The consumption of alcohol during pregnancy causes birth defects in the foetus. What is the function of placenta due to which alcohol should be avoided during pregnancy?
(b) Indu gave birth to a pair of female twins. How many egg/s were released at the start of her pregnancy?
(c) C-section is a surgical procedure performed when there are complications during the delivery. The baby is safely delivered through an incision in the abdominal wall and uterus. Which two parts of the female reproductive tract does the baby NOT pass through?
(d) To delay menstruation, a synthetic form of progesterone called progestin is commonly prescribed. This is administered by a medical professional for managing heavy or painful periods or preventing menstrual symptoms during important events or vacations. What could be the possible role of progesterone here?
(e) Infants suffer from the risk of infection if they are not breastfed within few hours of birth. What could be the reason?
Ans:
OR
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