Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Primary Egg Envelopes
These are the egg envelopes which develop in the ovary between oocyte and follicle cells in the space occupied by the interdigitating microvilli. Such envelopes have been named variously in different animals.
a) It is named as vitelline envelope or vitelline membrane in insects, molluscs, amphibians and birds.
b) In tunicates and fishes, it is known as chorion. In many sharks and bony fishes the primary envelope has striated appearance and is referred to as zona radiata representing the degraded microvilli of the growing oocyte. The perforation in the zona radiata becomes the micropyle through which the spermatozoa can enter the egg.
c) In mammals, the unstriated and modified zona pellucida is formed as a result of joint efforts of egg and follicle cells. While escaping the Graafian follicle mammalian oocyte carries on the surface of zona pellucida a layer of follicle cells known as corona radiata. The primary envelopes usually stick closely to the egg surface. These later on participate in the formation of fertilization membrane.
What are the main causes of the loss of biological diversity nowadays? The biggest dangers to biological diversity today are the action of humans. The most of them is the destr
Explain Food lipids It is either consumed in the form of "visible" fats, which have been separated from the original plant or animal sources, such as vegetable oil and butter,
N a ture of viruses Viruses vary in their size ranging from 20 nm (200 Ao) to 350 nm (3,500 Ao) and in shapes from spherical to bullet, rod, brick or filamentous forms. Some
What are Proteins and Why they are important for us? We just read that proteins are essential for maintaining and sustaining life. What are proteins or what constitutes protein
Crustose Lichen Stage - Xerarch On bare rocks, conditions are inhospitable for life, as there is extreme deficiency of water and nutrients, great exposure to sun, and extremes
Give the results of DistaE Dissection ? Results : For acute dissection of different parts of aorta, the mortality is reported as 9 to 33 per cent. In the International Regis
What is Interspecific Competition in ecology explain? Populations in nature usually share their surrounding environment in time and space with populations of other species. If
Each of the properties that follow is characteristic of the carbon atom. In each case, indicate how the property contributes to the role of the carbon atom as the most important at
Nuclease is an enzyme which degrades the nucleic acids. A nuclease can be DNA-specific (a DNase), RNA-specific (RNase) or non-specific. It might act only on single stranded nuclei
Explain the Glass Test Tubes - Food Microbiology Sterile glass tubes are used for culturing microorganisms in liquid or solid media. Sterility in tubes is maintained by using c
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd