Question 2.
Fill in the blanks.
a. In humans, sperm production occurs in the organ ----------------.
b. In humans, ------ chromosome is responsible for maleness.
c. In male and female reproductive system of human, ------------- gland is same.
d. Implantation of the embryo occurs in ------
e. ---------- type of reproduction occurs without fusion of gametes.
f. The body breaks up into several fragments and each fragment starts to live as a new individual. This is -- -- -- -- -- -- -- type of reproduction.
g. Pollen grains are formed by -- ----- -- -- -- division in locules of anthers.
Answer:
a. Testes,
Explanation: Testes are situated in the scrotum, outside the abdominal cavity. Testes contain numerous seminiferous tubules which consists of germinal epithelium it divides by meiosis to produce sperms.
b. Y chromosome.
Explanation: Men have XY sex chromosomes
and women have XX sex-chromosomes. A reproductive system with specific organs develops in the body of men and women due to these sex-chromosomes only. X-chromosome is present in both whereas Y-chromosome is present in men
only.
c. Pituitary gland.
Explanation: Follicle stimulating hormone(FSH), Luteinizing hormone(LH) are the hormones found in male and females. FSH stimulates testicular growth in male’s LH is also called interstitial cell-stimulating hormone (ICSH), it stimulates Leydig cell production of testosterone. It acts synergistically with FSH. In females, an acute rise of LH ("LH surge") triggers ovulation and development of the corpus luteum.
This hormone stimulates the growth of ovarian follicles in the ovary before the release of an egg from one follicle at ovulation.
d. Oviduct.
Explanation: Formation of a zygote by the union of sperm and ovum is called as fertilization. It is internal in humans. Semen is ejaculated in the vagina during copulation. This semen consists numbers of few millions start their journey by the route of vagina – uterus – oviduct. One of those few million sperms fertilizes the only ovum present in the oviduct.
e. Asexual.
Explanation: The process of formation of a new organism by an organism of same species without the involvement of gametes is called as asexual reproduction. This reproduction does not involve the union of two different gametes, therefore, the new organism has exact genetic similarity with the reproducing organism.
f. Fragmentation.
Explanation: This type of asexual reproduction occurs in multicellular organisms; the body of parent organism breaks up into many fragments and each fragment starts to live as an independent new organism. This type of reproduction occurs in algae like Spirogyra, and sponges.
g. meiosis
Explanation: Meiosis takes place in locules of anther which forms haploid pollen grains.
