What is oogenesis , Biology

Assignment Help:

What is Oogenesis ?

The female sex cells, or eggs, are formed in the ovaries, the primary sex organs of the female. The precursor of the egg cells, or oogonia, are formed during the prenatal development of the ovaries in the female embryo. However, the oogonia do not increase in number until after the third month of fetal development.

Oogonia divide by mitosis to form primary oocytes. These cells gradually die off, but about 200,000 are left in each ovary at puberty (about 11 to 14 years of age). Over the course of a woman's reproductive life, only about 450 oocytes will mature completely into eggs.

The primary oocyte begins meiosis, undergoing a very unequal division in which the larger cell becomes a secondary oocyte, and the other forms the first polar body, which eventually dies off. The second meiotic division, also unequal, forms a haploid ootid and a second polar body that also dies off. What is left is a single haploid egg cell or ovum (plural ova) that is 75,000 times larger than a sperm cell. The ovum contains contains proteins, lipids, and other raw materials for development. It is thought that the reason 3 of the 4 cells that result from meiosis die off is to provide the one surviving egg with sufficient resources for development.

 


Related Discussions:- What is oogenesis

Polarity do water-soluble and fat-soluble substances, Q. Which type of pola...

Q. Which type of polarity do water-soluble and fat-soluble substances respectively have? Water-soluble substances are polar molecules that are they have electrically charged ar

Quantitative characters - population density, Quantitative Characters - Pop...

Quantitative Characters - Population Density Density denotes the average number of individuals of a particular species in a unit area. In other words, it represents the numeri

Explain the communication process, Q. Explain the communication process? ...

Q. Explain the communication process? Communication is a process by which information is exchanged between individuals through a common system of symbols, signs, or behavior. C

Obtaining blood cultures, • Blood cultures are critical in the diagnosis an...

• Blood cultures are critical in the diagnosis and management of IE. • Obtain blood cultures before starting antimicrobial therapy whenever possible. • Intravascular infection l

Slromal swelling pressure for corneal hydration, How is the responsible slr...

How is the responsible slromal swelling pressure for corneal hydration? Slromal Swelling Pressure Stromal Swelling Pressure (SSP) is the pressure exerted by GAG (Glycosa

Antibodies, Antibodies Antibodies are important.tools for detecting and...

Antibodies Antibodies are important.tools for detecting and localising specific molecules in the cells due to their high specificity. The first requirement for this is to produ

Cells, What physical and metaboloic constraints limit cell size?

What physical and metaboloic constraints limit cell size?

Explain the procedures involved in blood doping, Describe the procedures in...

Describe the procedures involved in blood doping. What are the physiological mechanisms behind blood doping that attempt to achieve the desired outcome(s).

Determine the applications of biotin, Applications of Biotin Biotin is...

Applications of Biotin Biotin is mainly used in the preparation of injection, and also in the manufacture of vitamin B complex and multi-vitamin preparations. It is used in

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd