Human Reproduction — Page 3 | NEET Biology

Q21

The estrous cycle is a characteristic of

A human males only

B human females only

C mammalian males other than primates

D mammalian females other than primates

Correct Answer

Option D

Solution

(d) Estrous cycle is characteristic of mammalian females other than primates.

Q22

Match the following columns and select the correct option. Placenta - hCG, Zona pellucida - primary egg membrane, Bulbourethral glands - lubrication, Leydig cells - androgens

A i iv ii iii

B iii ii iv i

C ii iii iv i

D iv iii i ii

Correct Answer

Option C

Solution

(c) Placenta - hCG; Zona pellucida - primary egg membrane; Bulbourethral glands - lubrication; Leydig cells - androgens.

Q23

Capacitation occurs in:

A Epididymis

B Vas deferens

C Female reproductive tract

D Rete testic

Correct Answer

Option C

Solution

(c) Capacitation is increase in fertilising capacity of sperms which occurs in female reproductive tract.

It is required to render sperm to fertilize an oocyte.

Q24

The shared terminal duct of the reproductive and urinary system in the human male is:

A Urethra

B Ureter

C Vas deferens

D Vasa efferentia

Correct Answer

Option A

Solution

(a) Urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids from the body.

The urethra travels through the penis, and carries semen as well as urine.

Q25

Which one of the following statements about human sperm is correct?

A Acrosome has a conical pointed structure used for piercing and penetrating the egg

B The sperm lysins in the acrosome dissolve the egg envelope facilitating fertilisation

C Acrosome serves as a sensory structure leading the sperm towards the ovum

D Acrosome serves no particular function

Correct Answer

Option B

Solution

(b) Acrosome contains hydrolytic enzymes that dissolve the zona pellucida, facilitating fertilization.

Q26

Capacitation refers to changes in the:

A Ovum before fertilization

B Ovum after fertilization

C Sperm after fertilization

D Sperm before fertilization

Correct Answer

Option D

Solution

(d) Capacitation and acrosomal reaction occur before fertilization.

The process of capacitation happens when sperms enter vagina.

During this period, cholesterol vesicles are removed from the acrosome.

Q27

Extrusion of second polar body from egg nucleus occurs:

A after entry of sperm but before fertilisation

B after fertilisation

C before entry of sperm into ovum

D simultaneously with first cleavage

Correct Answer

Option A

Solution

(a) Extrusion of second polar body from egg nucleus occurs after entry of sperm into the secondary oocyte but before fertilisation.

The entry of sperm into the ovum induces completion of the meiotic division of the secondary oocyte.

Entry of sperm causes breakdown of metaphase promoting factor (MPF) and turns on anaphase promoting complex (APC).

During gametogenesis, one cell becomes the secondary oocyte the other cell forms the first polar body.

The secondary oocyte then commences meiosis 2 which arrests at metaphase and will not continue without fertilization.

At fertilization meiosis 2 completes, forming a second polar body.

Q28

Capacitation occurs in:

A Epididymis

B Vas deferens

C Female reproductive tract

D Rete testis

Correct Answer

Option C

Solution

(c) Capacitation (increase in fertilizing capacity of sperms) occurs in the female reproductive tract.

Q29

Grey crescent is the area

A at the point of entry of sperm into ovum

B just opposite to the site of entry of sperm into ovum

C at the animal pole

D at the vegetal pole

Correct Answer

Option B

Solution

(b) On the surface of the egg opposite to the point of sperm entry, the peripheral area of the egg becomes lighter in colour and assumes a grey appearance.

This area is crescentric in shape and is known as the grey crescent.

Q30

Which one of the following statements is false in respect of viability of mammalian sperm?

A Sperm is viable for only up to 24 hours.

B Survival of sperm depends on the

pH

of the medium and is more active in alkaline medium.

C Viability of sperm is determined by its motility.

D Sperms must be concentrated in a thick suspension.

Correct Answer

Option A

Solution

(a) Sperm is viable for 2-3 days.