Fusion of egg and sperm pro-nuclei, Biology

Assignment Help:

Fusion of Egg and Sperm Pro-Nuclei

The fusion of the sperm and egg which is the beginning of the fertilization process is completed with the fusion of the male and female pronuclei to from the zygote nucleus called synkaryon. Usually the nuclear fusion occurs between 10 to 20 minutes after attachment of the sperms to the egg. In sea urchins the completion of second meiotic division occurs after the entry of the sperm and the resulting haploid egg nucleus is known as female pronucleus. The sperm nucleus after its entry into the ovum is known as male pronucleus. After its entry in the ovum there is a breakdown in the sperm nuclear envelop, decondensation of chromatin and the formation of the pronuclear envelope.

In sea urchins at the completion of meiosis the female pronucleus is located in the central region of the egg and the male nucleus is located initially in the cortical region of the egg at the site of its entry. Before the fusion of the pronuclei, the sperm pronucleus has to migrate a considerable distance through the egg cytoplasm. In sea urchins a structure called sperm aster mediates this movement of the pronucleus. The sperm aster is a complex of long microtubules that radiate from the paired sperm centrioles. The centrioles which enter into the egg along with the sperm nucleus form the microtubule organising centre for the sperm aster. The microtubules of the sperm aster push the male pronucleus towards the centre of the egg. The astral microtubules also contact female pronucleus and pull it abruptly towards the male pronucleus. This activity continues until the two pronuclei are displaced to the centre of the egg where they fuse to form the synkaryon.


Related Discussions:- Fusion of egg and sperm pro-nuclei

Function of centrioles, FUNCTION In animal cells centrioles play import...

FUNCTION In animal cells centrioles play important role in initiation of cell division by arranging spindle fibres between two poles of cell.Thus they play a role in division o

Explain the micronutrients requirements during sepsis, Explain the Micronut...

Explain the Micronutrients Requirements during Sepsis Micronutrients: The requirement of almost all vitamins and certain mineral increases due to infection and inflammation. In

Enumerate different implant materials, Q. Enumerate different implant mater...

Q. Enumerate different implant materials? Biomaterials fall into four categories: metal and metal alloys, ceramics (carbon included in this group) synthetic polymers, and natur

Explain trifluridine, Explain Trifluridine  (Viroptic)  Trifluridine is...

Explain Trifluridine  (Viroptic)  Trifluridine is a nucleoside analog active against herpes viruses, including acyclovir-resistant strains. Marketed in an ophthalmic preparatio

Mycoplasmosis, Mycoplasmosis Mycoplasmas are the aetiological agents o...

Mycoplasmosis Mycoplasmas are the aetiological agents of bovine pleuropneumonia in cattle caused by Mycoplasma mycoides subsp. mycoides, caprine pleuropneumonia in goats cause

Explain the determination and application of vitamin e, Explain the Determi...

Explain the Determination of Vitamin E DL-α-Tocopherol is oxidized with ferric chloride and the ferrous ions formed are measured colorimetrially with the aid of α,α'-dipyridyl

Define national programmes targeting children and adolescent, Define Nation...

Define National Programmes Targeting Children and Adolescents? Two programmes specially target children and adolescents as a vulnerable group. These are: a) Mid Day Meal Pro

Explain huntington disease gene, Research methods used in studying a geneti...

Research methods used in studying a genetic disease change with technological advances. These changes can be seen in Reading 22.1: Discovering the Huntington Disease Gene, which de

What is telophase, What is telophase? Telophase is the cell divides apa...

What is telophase? Telophase is the cell divides apart and screws itself.

What are benefits of increasing the growth of bifidobacteria, What are the ...

What are the benefits of increasing the growth of bifidobacteria? Bifidobacteria displaces potential pathogens selectively, showing an antibiotic like effect, which is unrelate

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