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Human Reproduction — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYHuman Reproduction4 Marks
Question
What is spermatogenesis? Briefly describe the process of spermatogenesis.###Explain the process of spermatogenesis. (Diagram is not required)###According to spermatogenesis (i) Development of sperm from primary spermatocytes. Explain it. (ii) Role of hormones which secreting from pituitary gland (iii) Structure of sperm (Diagram is not necessary)
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Answer

→ Ans. Spermatogenesis is a process by which mature sperm cells are produced from immature male germ cells (spermatogonia) in testes. It begins at puberty.
→ The spermatogonia (sing. spermatogonium) are present on the inside wall of seminiferous tubules.
→ They multiply by mitotic division and increase in numbers.
→ Each spermatogonium is diploid and contains 46 chromosomes.
→ Some of the spermatogonia called primary spermatocytes, periodically undergo meiosis.
→ A primary spermatocyte completes the first meiotic division (reduction division) leading to formation of two equal, haploid cells called secondary spermatocytes, which have only 23 chromosomes each.
→ The secondary spermatocytes undergo the second meiotic division to produce four equal, haploid spermatids. The number of chromosome in each spermatid is 23.
→ The spermatids are transformed into spermatozoa (sperms) by the process called spermiogenesis.
→ After spermiogenesis, sperm heads become embedded in the sertoli cells, and are finally released from the seminiferous tubules by the process called spermiation.
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