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

Lateral roots - root apex, Lateral Roots - Root Apex Lateral roots no...

Lateral Roots - Root Apex Lateral roots normally arise at a definite distance behind the tip from areas close to or opposite the points of xylem star. So, a triarch root can

Chromolipid, CHROMOLIPID Formed by lipid & pigment, eg. carotene, xanth...

CHROMOLIPID Formed by lipid & pigment, eg. carotene, xanthophylls. Lycopene present in tomato & red chilli. Carrot is rich in b-carotene, converted into vitamin A.

Define primary motor cortex corticospinal interneuron a, Define Primary mot...

Define Primary motor cortex corticospinal interneuron A Primary motor cortex (M1) corticospinal interneuron A that produces action potentials during movements of the big toe of

Is there vaccine against tuberculosis, Is there vaccine against tuberculosi...

Is there vaccine against tuberculosis? The vaccine against tuberculosis is known as BCG (bacillus Calmette-Guérin). BCG is not used in some countries where tuberculosis is not

Disorders of upper respiratory tract, DISORDERS OF UPPER RESPIRATORY TRACT:...

DISORDERS OF UPPER RESPIRATORY TRACT: Common Cold: It is most frequent and most common infection in infants  and children. Common cold corresponds  to  acute nasopharyn

Explain the dispersed phase of colloidal system, Explain the dispersed phas...

Explain the dispersed phase of colloidal system Colloidal systems are not restricted to the dispersion of a solid in liquid.  Each of the three states of matter - gaseous, soli

Define erythropoietin, Erythropoietin (EPO) A. acts by increasing the p...

Erythropoietin (EPO) A. acts by increasing the production of red blood cells by cells in the bone marrow. B. is secreted by peritubular interstitial cells of the kidney cort

Explain risk factors and their role in cad, Explain risk factors and their ...

Explain risk factors and their role in cad ? The concept of risk factors constitutes a major advance for developing strategies to prevent CVD. The Framingham Heat Study played

Where in the process does this chemical element take part, Until the Krebs ...

Until the Krebs cycle, aerobic respiration can be explained without mentioning oxygen, the chemical element after which the reaction gets its name. Where in the process does this c

Respiration, Cutaneous respiration in frogs and toads

Cutaneous respiration in frogs and toads

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