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

How is hiv transmitted, Q. How is HIV transmitted? What is the disease caus...

Q. How is HIV transmitted? What is the disease caused by this virus? The HIV (human immunodeficiency virus) is supposed to be transmitted through blood, semen, vaginal secretio

Define the role of riboflavin in respiratory chain, Define the Role of Ribo...

Define the Role of Riboflavin in Respiratory Chain? Riboflavin catalyzes numerous oxidation-reduction reactions. Conversion of riboflavin to flavin mononucleotide (FMN) and the

Soil mixing, Soil Mixing The larger soil organisms are responsible for ...

Soil Mixing The larger soil organisms are responsible for considerable mechanical mixing and weathering of soil. The wedge-like action of roots and other underground plant orga

What are the chronic complications of diabetes, Q. What are the Chronic com...

Q. What are the Chronic complications of diabetes? • Atherosclerosis: Degeneration of walls of the arteries due to fatty plaques - deposition on arterial walls. Diabetics ar

Genetics, name a disorder of human blood that is caused by mutation

name a disorder of human blood that is caused by mutation

Explain about atrial septal defect, Explain about Atrial Septal Defect (ASD...

Explain about Atrial Septal Defect (ASD) ? ASD occurs as an isolated anomaly in 5- 10 per cent of all CHDs. These communications occur in four sites i.e. in the central portion

Explain eicosanoids, Explain Eicosanoids Eicosanoids are the  local h...

Explain Eicosanoids Eicosanoids are the  local hormones formed  by  body  tissues during self-healing responses  to  stimuli.  Eicosanoids are  a family  of  compounds  deriv

Why is the occurrence of eyelids in amphibians, Q. Why is the occurrence of...

Q. Why is the occurrence of eyelids in amphibians in comparison to their absence in fishes an adaptation to terrestrial life? Eyelids associated to lacrimal glands protect and

What is pollen, What is pollen? Pollen grains are the male gametophytes...

What is pollen? Pollen grains are the male gametophytes of the phanerogamic (flowering) plants. Thus within the pollen grains the male gametes of these plants are produced by m

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