This set of Biology Multiple Choice Questions & Answers (MCQs) focuses on “Human Reproduction – Spermatogenesis”.
1. The onset of spermatogenesis starts at _________
Explanation: Spermatogenesis is the process of the production of sperms from spermatogonia in the testis. Puberty is the time of onset of this process.
2. What is the process of conversion of spermatids to sperms called?
Explanation: Spermatids are produced as a result of meiosis of spermatogonia and thus are haploid. These spermatogonia mature and differentiate further to produce sperms by the process of spermiogenesis.
3. What is the process of release of sperms from Sertoli cells called?
Explanation: Spermiation refers to the release of sperms from Sertoli cells. Spermatogenesis is the process of the production of sperms from spermatogonia. Spermiogenesis is the process of conversion of spermatids to mature sperms.
4. A person with tetraploidy will have _______ set of chromosomes in their Spermatids.
Explanation: Spermatogenesis produces haploid spermatids from diploid spermatogonia. A tetraploid person will have tetraploid spermatogonia which upon undergoing meiosis will result in diploid spermatids. The person would be infertile.
5. If a male is born with 3 million spermatogonia in each testis, the maximum number of sperms that he can produce in his lifetime is 24 million.
Explanation: One spermatogonium upon undergoing a process of spermatogenesis produces 4 haploid sperms. Thus 3 million spermatogonia in each testis which is a total of 6 million spermatogonia should indeed produce 24 million sperms if undergone meiosis. However, spermatogonia also undergo mitosis giving rise to many more spermatogonia by the age of puberty and even after that.
6. Which hypothalamic hormone is responsible for the onset of Spermatogenesis at puberty?
a) Gonadotrophin Releasing Hormone (GnRH)
b) Follicle Stimulating Hormone (FSH)
c) Luteinising Hormone (LH)
Explanation: GnRH is the hormone released by the Hypothalamus which acts on the anterior pituitary gland to release LH and FSH which in turn leads to the onset of Spermatogenesis.
7. Testosterone belongs to a class of hormones called _________
Explanation: Androgens are a class of hormones that are lipid in nature. In males, testosterone is the primary androgen while in females it is estrogen.
8. Which cells are responsible for the nourishment of spermatids while they mature to produce sperms?
b) Mother cells
c) Sertoli cells
d) Leydig cells
Explanation: The primary spermatocytes undergo meiosis to produce haploid spermatids. These spermatids attach to Sertoli cells (also called as nurse cells) to get nourishment while they mature to produce functional sperms which are released via the process of spermiation.
9. Identify the correct pair of hormone and its target cells in the context of spermatogenesis.
a) Gonadotrophin: Leydig cells
b) Luteinising Hormone: Sertoli cells
c) Testosterone: Pituitary gland
d) Follicle Stimulating Hormone: Sertoli cells
Explanation: Gonadotrophic Hormone is released by Hypothalamus and acts on Anterior Pituitary. Anterior pituitary releases Luteinising Hormone which acts on Leydig cells. Leydig cells release Androgens which act on a variety of targets to initiate Spermatogenesis. Anterior Pituitary also releases Follicle Stimulating hormone which acts on Sertoli cells to release various factors that promotes spermatogenesis.
10. Which of the following is not a Gonadotrophin?
Explanation: GnRH released by the hypothalamus and FH and LSH released by the anterior pituitary are gonadotrophins. Testosterone, on the other hand, belongs to the class of hormones called androgens.
11. What part of sperm is attached to Sertoli cells prior to spermiation?
Explanation: Spermatids are produced by meiosis from primary spermatocytes. These spermatids then transform into sperms which attach to Sertoli cells for nourishment and further development via their heads. They are then released by the process of spermiation.
Sanfoundry Global Education & Learning Series – Biology – Class 12.
To practice all areas of Biology, here is complete set of 1000+ Multiple Choice Questions and Answers.
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