Fusion of egg and sperm pro-nuclei, Biology

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.

Posted Date: 1/25/2013 12:18:28 AM | Location : United States







Related Discussions:- Fusion of egg and sperm pro-nuclei, Assignment Help, Ask Question on Fusion of egg and sperm pro-nuclei, Get Answer, Expert's Help, Fusion of egg and sperm pro-nuclei Discussions

Write discussion on Fusion of egg and sperm pro-nuclei
Your posts are moderated
Related Questions
Q. Control of Aflatoxin? Control: Because aflatoxins are potentially widespread in occurrence and have an insidious combination of acute and chronic toxicity, it is prudent to

define glycolysis.describe the various steps of glycolysis

Explain the Bunsen Burner? It is a type of gas burner that gives very hot flame by allowing air to enter at the base and mix with the gas. It is used - (a) For sterilizing i

Explain what is Correction of Hypovolemia ? Intravenous fluids should be given to correct hypovolemia and optimize preload to the heart. This is particularly important in sept

List the types of Gellan gum.   The three types of gellan gums are: High acetyl gellan (partially deacetylated) Low acetyl gellan (highly deacetylated) High cl

M a l i g nant catarrhal fever (MCF) Malignant catarrhal fever is invariably fatal generalized lymphoproliferative disease of cattle and sometimes of wild ruminants. It is

C h oice of transgenic animal First and foremost is the selection of animal species in which gene of interest is to be transferred. Whatever is the goal of production of tran

What Physical fitness tests examine? Physical fitness tests examine the components of physical fitness such as endurance, speed, strength, flexibility and body composition. The

Explain the Skeletal System? Skeletal System: The support framework, or skeleton, in the human body is composed of mostly hard mineral substances. Unlike crustaceans or insec

MYCOPLASMOSIS Mycoplasma organisms are the smallest free living, lack of cell-wall and bounded by a triple layer of plasma membrane. The organisms are pleuomorphic in shape, viz.