Meroblastic or partial cleavage, Biology

Assignment Help:

Meroblastic or partial cleavage

The egg does not divide totally because divisions are restricted to only a part of the egg where as the rest of the egg remains completely uncleaved. It is of two types:

A. Discoidal meroblastic cleavage: It occurs in the heavily yoked macrolecithal and highly telolecithal eggs, as for instance in cephalopod molluscs, reptiles, birds and monotremes (egg laying mammals). The cleavage is restricted to the cytoplasmic germinal disc located at the animal pole. Even the germinal disc divides incompletely where as the entire yolk mass remains undivided.

B. Superficial meroblastic cleavage: This takes place in the centrolecithal eggs of insects. Cell divisions are restricted to the peripheral cytoplasmic layer whereas the centrally located yolky is left undivided.


Related Discussions:- Meroblastic or partial cleavage

Describe about aorto pulmonary window, Describe about Aorto Pulmonary Windo...

Describe about Aorto Pulmonary Window ? This uncommon malformation consists of communication usually non-restrictive between the adjacent walls of the ascending aorta and pulmo

Explain antigens, Explain Antigens ? A blood type, or group, is based ...

Explain Antigens ? A blood type, or group, is based upon the presence or absence of certain substances called antigens on the surface of the red blood cells. Antigens are subs

What is Implant Failure, What is Implant Failure Implant Failure : Th...

What is Implant Failure Implant Failure : The total failure of implant to fulfil its purpose which are49 Surgical Complications, Long Term Implant Failures and Ma

Lungs - respiratory organs, Lungs - Respiratory Organs In arachnid art...

Lungs - Respiratory Organs In arachnid arthropods such as scorpion and spider, respiration takes place by means of book lungs. There are four pairs of these structures in the

Autochory - dispersal of seeds, Autochory - Dispersal of Seeds This m...

Autochory - Dispersal of Seeds This mechanism of self-dispersal is based on forceful expulsion of the seed from the fruit because of desiccation or turgidity of the cells of

What is the structure of the adult fern, What is the structure of the adult...

What is the structure of the adult fern within which cells undergoing meiosis can be found? In these plants meiosis takes place within structures known as sorus (plural, sori),

Basic properties to proteins, Define Basic Properties To Proteins, To Be a ...

Define Basic Properties To Proteins, To Be a Good Foaming Agent? A protein must: a) Be able to rapidly absorb at the air-water interface during whipping, b) Undergo rapid

Define iron status of the individual, Define Iron Status of the Individual ...

Define Iron Status of the Individual Lastly, iron status of the individual is a floury determinant of how much iron is absorbed. On a mixed diet with some haem iron, the overal

Parthenocarpy, Parthenocarpy It is generally observed that the fruit d...

Parthenocarpy It is generally observed that the fruit develops after fertilization and it has fertile seeds inside it. However, this is not always so. Fruits of certain variet

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