Railway Science (Biology-Reproduction in Animals) (Part-III)

Total Questions: 50

11. ______ is the age during which the reproductive organs of human males and females become functional, the gonads begin producing gametes and sex hormones and humans become sexually mature. [RRB Group D 12/10/2018 (Morning)]

Correct Answer: (d) adolescence
Solution:

The period of life, when the body undergoes changes, leading to reproductive maturity, is called adolescence. It begins around the age of 11 and lasts upto 18 or 19 years of age. In girls, adolescence may begin a year or two earlier than in boys.

12. The number of chromosomes in a human female germ cell is ________. [RRB Group D 12/10/2018 (Evening)]

Correct Answer: (c) 23
Solution:

Meiosis is a way cells very carefully count and divide their chromosomes so that each gamete, each egg or sperm, has exactly 23 chromosomes. Then, when an egg with its 23 chromosomes is fertilized by a sperm with its 23 chromosomes, the resulting fertilized egg has exactly 46 chromosomes.

13. How many testicles does a man have? [RRB Group D 15/10/2018 (Morning)]

Correct Answer: (a) two
Solution:

Testicles are the male reproductive organs responsible for producing sperm and the male sex hormone testosterone. The testes are situated outside the abdominal cavity within a pouch called scrotum.

14. The female germ-cells or eggs are made in the: [RRB Group D 15/10/2018 (Afternoon)]

Correct Answer: (a) Ovaries
Solution:

Ovaries - The primary female sex organs that produce the female gamete (ovum) and several steroid hormones such as estrogen and progesterone. The ovaries are located on each side of the lower abdomen.
Vagina - Canal in female mammals that receives the male reproductive cells, or sperm, and also functions as an excretory canal during the period of menstruation.
Cervix - It attaches the uterus to the vagina and provides a passage between the vaginal cavity and the uterine cavity. Uterus is responsible for gestation (pregnancy), menstruation, and labor and delivery.

15. As the reproductive tissues begin to mature, the body's normal growth begins to slow down. This state of adolescence is called _________. [RRB Group D 15/10/2018 (Evening)]

Correct Answer: (c) youth
Solution:

The menstrual flow results due to breakdown of the endometrial lining of the uterus and its blood vessels which forms liquid that comes out through vagina. Menstruation only occurs if the released ovum is not fertilized. Lack of menstruation may be indicative of pregnancy.

16. In humans, fertilization occurs in ______. [RRB Group D 15/10/2018 (Evening)]

Correct Answer: (a) Fallopian tube
Solution:

The Fallopian tubes are two thin tubes connecting the ovaries to the uterus. They provide a pathway for eggs to travel from the ovaries to the uterus and are the site where sperm and egg typically meet and fertilization occurs. Each fallopian tube is about 10-12 cm long and extends from the periphery of each ovary to the uterus.

17. A male gamete in humans carries which of the following chromosomes ? [RRB Group D 22/10/2018 (Morning)]

Correct Answer: (c) Either X or Y chromosome
Solution:

This is because a male gamete, also known as a sperm cell, is a haploid cell that contains only one sex chromosome. The sex chromosome can be either X or Y, depending on which one was inherited from the father during meiosis.
A sperm cell with an X chromosome will produce a female offspring (XX) when it fertilizes an egg cell, while a sperm cell with a Y chromosome will produce a male offspring (XY) when it fertilizes an egg cell.

18. In which part of the male reproductive system is the main genetic material found? [RRB Group D 22/10/2018 (Evening)]

Correct Answer: (b) Sperm
Solution:

Ureter: Each kidney has a narrow tube called a ureter, which carries urine from the kidney to the bladder. Prostate gland: It is located just below the bladder in men and surrounds the top portion of the tube.
The prostate's primary function is to produce the fluid that nourishes and transports sperm (seminal fluid). Scrotum: The testes are situated outside the abdominal cavity within a pouch.
It helps in maintaining the low temperature of the testes (2 - 2.5 oC lower than the normal internal body temperature) necessary for spermatogenesis.

19. Name the duct that originates from the male testicle and carries sperm upward in the body. [RRB Group D 23/10/2018 (Evening)]

Correct Answer: (b) Sperm duct
Solution:

It carries the sperms from the testes to the urethra. It is made of fibrous tissue and muscle tissue. Other parts of male reproductive system - External Organs (Penis, scrotum, Testicles), Internal Organs (Prostate, Urethra, Vas deferens).

20. A basic event in reproduction is the creation of a/an_____. [RRB Group D 23/10/2018 (Evening)]

Correct Answer: (a) DNA copy
Solution:

The DNA (Deoxyribonucleic acid) in the nucleus of a cell, is the information source for making protein. In the reproduction process, cellular apparatus is created around the DNA copy. RNA - Ribonucleic acid.