Human Reproduction | Class 12 Zoology | Previous Years Questions and Answers (2018 to 2020)

 1. HUMAN REPRODUCTION

2020 SAY

1.   The embryo with 8 to 16 blastomeres is called a ............ (1)

(a)    Gastrula                           (b)  Morula

(c)    Blastula                            (d)  Trophoblast

ü Answer:

(b) Morula

2.   Observe the diagrammatic view of male reproductive system given below and name parts labelled a, b, c & d. (2)

ü Answer:

a. Vas deferens

b. Epididymis

c. Urethra

d. Testis

3.   Rearrange the following human reproductive events in the correct order of their occurrence: (2)

Lactation → Formation of Zygote → Insemination → Implantation → Fertilisation → Gametogenesis → Gestation → Parturition

ü Answer:

Gametogenesis → Insemination → Fertilisation → Formation of Zygote → Implantation → Gestation → Parturition → Lactation

2020 MARCH

1.  "All copulations lead to fertilization and pregnancy". Do you agree with this statement? Justify your answer. (2)

ü Answer:

No. Fertilization happens only if ovum & sperms are transported simultaneously. So all copulations do not lead to fertilization & pregnancy.

2.   The graph given below shows the level of ovarian hormones in a normally menstruating woman during follicular phase. (3)

a.      Name 'A' and 'B'.

b.     Reconstruct the graph showing the level of hormones in luteal phase.

c.      Name the hormone secreted by Corpus Luteum and mention its function.

ü Answer:

(a) A= Progesterone, B= Estrogen.

(b)

(c) Hormone: Progesterone.

Function: Maintains endometrium/ pregnancy.

2019 SAY June

1.   Find out the correct sequence: (1)

a.      Fertilisation → Zygote → Blastula → Morula → Cleavage → Implantation.

b.     Fertilisation → Zygote → Cleavage → Morula → Implantation → Blastula.

c.      Fertilisation → Zygote → Morula → Cleavage → Implantation → Blastula.

d.     Fertilisation → Zygote → Cleavage → Morula → Blastula → Implantation.

ü Answer:

(d) Fertilisation → Zygote → Cleavage → Morula → Blastula → Implantation.

2.   'LH Surge' induces the rupture of Graafian follicle. (2)

a.      Which gland produces LH and in which day LH Surge happens?

b.     Write the role of LH in males.

ü Answer:

(a) Pituitary gland. 14^th day of the Menstrual cycle.

(b) LH acts on the Leydig cells and stimulates secretion of androgens.

2019 MARCH

1.   The milk produced during the initial few days of lactation is called ....................... (1)

ü Answer:

Colostrum.

2.   "The sex of the baby is determined by the father and not by the mother." Do you agree with this statement? Substantiate your answer. (2)

ü Answer:

Yes. Because male can produce two types of gametes (sperms) – one with X chromosome and other with Y chromosome. Y chromosome is responsible for the male sex of the baby. Female can produce only gametes (Egg) containing X chromosome. X chromosome is responsible for female sex of the baby.

3.   Observe the diagram given below showing the sectional view of the female reproductive system and name the parts labelled 'A', 'B', 'C' & 'D'. (2)

ü Answer:

A= Endometrium / Uterus

B= Ovary

C= Isthmus of fallopian tube

D= Ampulla of fallopian tube

2018 SAY

1.   Number of spermatids produced from 25 primary spermatocytes are (1)

(a)  25                  (b) 50

(c) 100                (d) 250

ü Answer:

(c) 100.

2.   Match the columns B & C with column A. (3)

A	B	C
Ovulation	Endometrium	LH
Implantation	Uterus	Progesterone
Gestation	Graafian follicle	hCG

ü Answer:

A	B	C
Ovulation	Graafian follicle	LH
Implantation	Endometrium	Progesterone
Gestation	Uterus	hCG

2018 MARCH

1.   Name the cells in testes which synthesize and secrete the androgens. (1)

ü Answer:

Leydig cells (Interstitial cells).

2.   ln a classroom discussion, a student said that the sex of the baby is determined by father. Analyse the statement and give reason for it. (2)

ü Answer:

This statement is true. Because male can produce two types of gametes (sperms) – one with X chromosome and other with Y chromosome. Y chromosome is responsible for the male sex of the baby. Female can produce only gametes (Egg) containing X chromosome. X chromosome is responsible for female sex of the baby.

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