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

What are the chemical requirements of implant materials, What are the Chemi...

What are the Chemical requirements of implant materials It must withstand corrosion by body fluids It should not have any direct or indirect negative effects on the surround

Determine the importance of behavioural observations, Determine the importa...

Determine the importance of Behavioural observations Behavioural observations are often noteworthy to the extent that they involve alterations in the examiner's usual response

Explain about osseointegration, Explain about Osseointegration Osseoint...

Explain about Osseointegration Osseointegration is regarded as the process of direct bone apposition on implant surfaces where the bone in contact with the implant later underg

Describe genetic recombination , Describe Genetic Recombination ? Genet...

Describe Genetic Recombination ? Genetic recombination, which provides the variation necessary for evolution, can occur through a variety of processes during cell reproduction:

Understanding behaviour of diabetic patients, Q. Understanding Behaviour of...

Q. Understanding Behaviour of diabetic patients? Beliefs  Each of us has a set of beliefs that were learned by us when we were young. These include religious beliefs and

How many hours will the bag last, Mr. Jones I.V. was hung at noon. It is a ...

Mr. Jones I.V. was hung at noon. It is a liter bag and is infusing at 65 ml/hr. How many hours will this bag last?

Photosynthesis, why is a potted plant destarched before starting the experi...

why is a potted plant destarched before starting the experiment to investigate the factors necessary for photosynthesis

Consists of the production of atp, Select all that are true/correct: Cellul...

Select all that are true/correct: Cellular respiration consists of the production of ATP in several steps using enzymes. Photosynthesis produces carbohydrates using carbon dioxide

Define starch retrogradation, Starch Retrogradation The starch paste or...

Starch Retrogradation The starch paste or solution obtained after the gelatinisation is not stable and generally produces a viscoelastic, firm  and rigid gel. Structural transf

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