Patters of cleavage, Biology

Patters of Cleavage

In most of the animal groups with spherical or almost spherical egg and little or moderate amount of yolk (micro-or mesolecithal eggs), the first and second divisions result in four blastomeres of almost equal size. Because of greater concentration of yolk platelets in the vegetal hemisphere, the third cleavage divides the 4 blastomeres in latitudinal plane giving rise to 8 cells arranged in two tiers of 4 blastomeres each including one tier of 4 small blastomeres (micromeres) in the animal hemisphere and the second tier of 4 large blastomeres (macromeres) in the vegetal hemisphere. The arrangement of blastomeres in these two tiers is very distinct and on this basis, the cleavage may be of:

  • Radial Type
  • Spiral Type
Posted Date: 1/25/2013 1:01:51 AM | Location : United States







Related Discussions:- Patters of cleavage, Assignment Help, Ask Question on Patters of cleavage, Get Answer, Expert's Help, Patters of cleavage Discussions

Write discussion on Patters of cleavage
Your posts are moderated
Related Questions
There may also be non-use existence values for components of biological diversity due to the value placed on biodiversity purely based on its continued existence, irrespective of w

Q. Is there any situation in which the DNA is made based on the RNA template? What is the enzyme involved? The process in which the DNA is synthesized having as template a RNA

MID BRAIN - Optics lobes 4 in number ( Corpora Quadrizemmini ) in frog corpora bizemmini . Solid, optocoel is absent. 2 superior coculi and 2 inferior coculi are present.

In the prokaryotes,  RNA transcribed  from protein-coding  genes or messenger  RNA, mRNA,  need  little  or  no  changes  prior  to  translation.  In reality, several mRNA   molecu

Posterior Leaflet: In the posterior leaflet a quadrangular excision of the sector involved in the prolapse is done. This may be up to 15-20 per cent of the leaflet. The remaining

Describe TS Murmur and their characterstic ? Characteristic: It is a rumbling, and diastolic murmur heard at left lower sterna border that increases with inspiration. An OS may

Causes of Cancer We know earlier that a malignant tumor is a large aggregation of cancer cells, all of them descended from a single founder cell that was once a normal cell wi

General characteristics of phylum

Explain the Pseudomonas - Characteristics of Bacteria? Pseudomonas are aerobic, gram negative, straight or slightly curved rods that are motile by polar flagella. Many species

Describe the monomer unit of a protein and how monomer units are assembled into peptides.