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

Accidents and losses, Accidents and Losses Accident can be considered ...

Accidents and Losses Accident can be considered as an incident occurring without intention and results in injury, loss of body part or even death of a human being or a few per

What are extraembryonic membranes, Q. What are extraembryonic membranes? ...

Q. What are extraembryonic membranes? Extraembryonic membranes are membranous structures that appear in parallel with the embryo and play vital roles in the embryonic developme

Define disadvantages of using the plate counts method, Define Disadvantages...

Define Disadvantages of Using the Plate Counts Method? 1. It takes time, usually 24 hours or more is required to obtain visible colonies. 2. Microbial count obtained depends

What are the main components of the cytoskeleton, The cytoskeleton is a net...

The cytoskeleton is a network of very little tubules and filaments spread throughout the cytoplasm of eukaryotic cells. It is made of microtubules, microfilaments and intermediate

Physiological regeneration, Physiological Regeneration This type of r...

Physiological Regeneration This type of regeneration is a regular physiological function including the continuous replacements of cells and tissues, and thus is indispensible

Gills - respiration, Gills - Respiration Gills are highly vascularise...

Gills - Respiration Gills are highly vascularised extensions of gas exchange membranes. The simple type may be extension of the body surface as in sea-slugs, sea stars and ma

Synovial fluid and amniotic fluid collection, Synovial fluid Collection: ...

Synovial fluid Collection: The technique of obtaining synovial fluid is called arthrocentesis. It is used to characterize type of arthritis and to differentiate inflammatory

What are lichens, What are lichens? How do fungi participate in this ecolog...

What are lichens? How do fungi participate in this ecological interaction? Lichens are produced by mutualist ecological interaction among fungi and algae or among fungi and cya

What is the acrosome of the sperm cell, Q. What is the acrosome of the sper...

Q. What is the acrosome of the sperm cell? How is it formed? The acrosome is a structure that contains a great number of digestive enzymes it is formed by the union of Golgi ap

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