Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Spiral Cleavage - Metazoa
In Spiral Cleavage, however, the third and fourth cleavage planes are oblique to the polar axis and the resulting blastomeres do not lie on top of one another but above the furrows between the cells. The spindles during the third cleavage are arranged in the form of a spiral, therefore, the name spiral cleavage. This type of cleavage is seen in all invertebrate except the echinoderms (i.e. in annelids, molluscs, arthropods nemertenes and polyclad planarians).
Figure: Spiral cleavage showing transition from 4 to 8 to 16 cell stage
Spirally cleaving embryos are said to have mosaic or determinate form of development. This means that the organ forming regions of the egg are strictly localised in the egg from the very beginning and the fate of the blastomeres is determined early. If the blastomeres are separated, each will continue to develop up to a certain time as though it was a part of the whole and give rise to defective, partial embryos. In the early embryos an unidentified cytoplasmic factor is segregated into one of the blastomeres, the mesentoblast (this is also called the '4 d' cell) which gives rise to the future mesoderm.
Disadvantages of Protozoa
separation of nucleic acid
Q. Merits and Demerits of system classification? Merits The merits of this system\are as under: • Careful observation and original description of the genera from living
Metabolic Process Location Within the study of biochemistry, what tends to obtain lost amidst the numerous pathways and enzymes is the fact which metabolism concerns the overal
Q. What is the difference between mussels and octopuses regarding their circulatory systems? How does that difference influence the mobility of these animals? Cephalopod mollus
Explain the term Trans fatty acids? Plant derived fats and oils contain cis-fatty acids. You may recall reading about the cis and trans isomers in the Nutritional Biochemistry
Explain the Solid-Liquid Equilibria? A freezing-point curve (freezing point as a function of liquid composition) and a solubility curve (composition of a solution in equilibriu
In the time of Darwin the results of Mendel's research on biological inheritance had not been published, Genetics was not yet developed, neither DNA nor the concept of genetic muta
Q. Do protozoans have a cellular nucleus? All protozoans, as eukaryotes have nucleus, some species like the paramecium have two nuclei the micronucleus and the macronucleus.
How Lysosomal enzymes involved in the scavenging of aged Lysosomal enzymes are also involved in the scavenging of aged and damaged cells. In several diseased states and also by
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd