Reproduction in Organisms Test 2

• We are very well aware with the male reproductive system where testes are the primary sex organs and located in an extra abdominal pouch of skin called scrotum.
• Each testes possess nearly 250 testicular lobules and each lobule has at least one to three seminiferous tubules where the spermatogenesis process takes place.
• As we know that spermatogenesis as the name suggests is the process of generation of sperms.
• Spermatogonia or the immature germ cells are present within the seminiferous tubules and these cells divide by mitosis and some of them enter Meiosis I to become primary spermatocytes and then they complete Meiosis I to become secondary spermatocytes.
• Secondary spermatocytes now Meiosis II to become spermatids which will differentiate into spermatozoa or sperms and will be released into the lumen of tubules.
• In these tubules are present two types of cells one is Sertoli’s cells which will provide nutrition to the growing sperms and the Leydig cells which secretes Testosterone which helps in maintaining the reproductive tract.
• Oestrogen and progesterone are the female hormones and oxytocin hormone helps in contraction of uterus and milk production in lactating females.

Therefore, from the above explanation we can say that spermatogenesis is promoted by Testosterone.

Hence, the correct answer is (C).

Spermatogenesis​:

• The process of formation of a mature female gamete is called oogenesis.
• Unlike sperm formation that starts at puberty, egg formation begins before birth.
• Primordial germ cells complete the proliferative stage or oogenesis in the early embryonic stage when million of gamete mother cells (oogonia) are formed within each fetal ovary, no more oogonia are formed and added after birth. 

• The ovum is enclosed by the inner thin, transparent, non-cellular coat zona pellucida and outer thick coat corona radiata.
• During fertilization sperm first comes in contact with the corona radiata and zona pellucida to reach the plasma membrane of the egg(ovum).
• The figure represents Ovum.
  

• Menopause marks the end of a woman's fertility and the cease of the menstrual cycle.
• The ovaries stop producing hormones and in humans, the menstrual cycle ceases at around 50 years of age. 

1. Zygote is also diploid and fertilized ovum formed by fusion of male and female gametes.

2. Spermatogonia are the cells on the inside wall of seminiferous tubules and consist of 46 chromosomes.

3. Secondary oocyte has 23 chromosomes and is formed by meiosis-I of primary oocyte.

4. Oogonia are also diploid and are formed in the fetal ovary.​

Given below is the figure of follicle: