Events after sperm and egg fusion, Biology

Events after Sperm and Egg Fusion

The entry of the sperm into the egg activates the egg. The activation of egg results in two types of responses.

(1) The early responses and

(2) The late responses.

The early response for the entry of the sperm into the egg is the prevention of polyspermy i.e. the entry of or fusion of more than one sperm into the egg. Polyspermy may result in several abnormalities such as polyploidy, abnormal mechanism of chromosomal separation during cell division and ultimate death of the embryo. Organisms have evolved different types of mechanisms for prevention of entry of more than one sperm into egg. Generally any one of the three different strategies may be involved in the prevention of polyspermy. For instance in fishes the sperm can enter into the egg only through the narrow opening the micropyle, the rest of the egg being covered by the impermeable chorion. In sea urchins and mammals there is a restriction on the number of sperm that are able to penetrate the extracellular coats and fuse with the egg. In mammals the sperm have to migrate the long female reproductive tract to reach the egg and further, the structural changes in zona pellucida block polyspermy. Certain animals such as salamanders do permit the entry several sperm into the egg but only the nucleus of one of the sperm can fuse with the egg to form the zygote nucleus; other sperm nuclei degenerate.

Posted Date: 1/25/2013 12:18:00 AM | Location : United States







Related Discussions:- Events after sperm and egg fusion, Assignment Help, Ask Question on Events after sperm and egg fusion, Get Answer, Expert's Help, Events after sperm and egg fusion Discussions

Write discussion on Events after sperm and egg fusion
Your posts are moderated
Related Questions
Sterile Technique Every effort should be made to conduct implant surgery under sterile operating conditions. Chlorhexidine 0.2% is used as a pre-operative mouthwash and skin pr

Q. Chronic complications of diabetes? These occur gradually when the diabetics do not monitor the blood sugar and they are careless about eating, exercise and the medications a

Q. Show the Valuation of Biodiversity? Serious research in this field has only been recently initiated and the methodologies for valuation are still evolving. Important valuat

Gametogenesis - Human Development Gametogenesis as you are responsive is the process of formation and development of specialized reproductive cells, ova in females and sperms

What is a pipette and how is it used? There are lots of types of pipettes (or pipette), but most are basically a fancier version of a medicine dropper or eye dropper. They are

why their is different amount of yolk is present in eggs.

Q. Discuss the advantages of implant supported maxillo-facial prosthesis. Maxillofacial Prosthodontics involves the prosthetic rehabilitation of patients with congenital or acq

Q. How Time affecting taste quality? Time- Time is another factor which affects sensation. Salt on tongue is sensed in a fraction of a second; whereas, bitter things may requir

PARATHYRIOD GLANDS - They develop from the endoderm of the embryo. The parathyroid glands consist of four separate glands located on the posterior surface of the lobes of

Q. What are the major purposes of the organic molecules for living beings? Ans. Organic molecules, like, lipids, carbohydrates and proteins perform several functions for