Primary egg envelopes, Biology

Assignment Help:

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.


Related Discussions:- Primary egg envelopes

In which condition number of white blood cell decreases, The condition in w...

The condition in which there is a DECREASE in the number of white blood cells in humans is termed as: a) Leukocytosis (pron: lew-kO-sigh-toe-sis) b) Leukopenia (pron: lew-kO

Define mechanisms for antinutritional effect on human, Define mechanisms fo...

Define mechanisms for antinutritional effect on Human? There are several possibilities: reduced availability of amino acids to cancer cells by reversing the carcinogen-induced

Diagnosis and treatment of myocarditis, Diagnosis X-ray chest show...

Diagnosis X-ray chest shows cardiomegaly.  ECG shows conduction defect, low voltage QRS, atrial and ventricular disrhythrnias.  Echocardiogram - decreased LV cont

How big of a container would you need to hold it, Assume you were given a m...

Assume you were given a mixture consisting of one molecule each of all possible sequences of a smallish protein of molecular weight 4800 daltons. If the average molecular weight of

Ecology lab assignment, i need to complete a model on loop analysis Java an...

i need to complete a model on loop analysis Java and answer questions on my assignment sheet....any experts to help me do my lab homework?

Final atp count in both prokaryotes and eukaryotes, Degrade a monoglyceride...

Degrade a monoglyceride that has an 18-carbon fatty acid attached to it by Ester bonds. You will have to degrade the glycerol component followed by the fatty acid in presence of O2

What is interpretation of stress echocardiography, Q. What is Interpretatio...

Q. What is Interpretation of Stress Echocardiography? The standard approach to interpretation is qualitative. The attendant need for training and problems posed for reproducibi

Describe ps with vsd in tetralogy of fallot''s, Describe PS with VSD in Tet...

Describe PS with VSD in Tetralogy of Fallot's ? This group is also known as Tetralogy of Fallot's physiology. The classic example is Fallot's tetralogy characterized by: (1) Se

How is reproduction done in beings of the class reptilia, How is reproducti...

How is reproduction done in beings of the class Reptilia? These beings reproduce sexually by internal fecundation by means of copulation among male and female individuals. They

Sample titration - estimation of vitamin c in a solution, Define Sample Tit...

Define Sample Titration - estimation of vitamin c in a solution? Take the given unknown solution provided to you in a 100 ml volumetric flask. Dilute the sample ascorbic acid s

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