Totipotency and pluripotency, Biology

Assignment Help:

Totipotency and Pluripotency

In the starting we said that the fertilized egg cell (zygote) has the capacity or potentiality to give rise to all kinds of cell types, like a blood cell or a bone cell or a muscle cell etc. In embryological terminology such a cell is said to be totipotent. The zygote cleaves and makes a large number of blastomeres. The blastomeres may as well remain totipotent up to a certain stage and have the capacity to form every cell type of the organism. Though, as development proceeds the various blastomeres lose totipotency but may still be pluripotent. By pluripotent it is meant that they are able to make several but not all of the various cell types or tissues. Ultimately, with further development, even the pluripotency is lost and different groups of cells of the embryo are now capable of forming only one particular cell type or tissue.

For instance, up to a certain stage of embryonic development prospective ectodermal cells can make either epidermis or neural tissue, i.e. they are pluripotent. But at a later stage cells of one region of ectoderm can make only epidermal tissue and those of another region can distinguish only into neural tissue. What may be the cause of progressive restriction of potency in diverse embryonic cells although they are all descendents of the same single cell, zygote? Each one of these embryonic cells contains a nucleus which is also the descendent of similar zygotic nucleus. Does the restriction in potency in several embryonic cells result from differential distribution of specific cytoplasmic substances between different blastomeres during cleavage of zygote and subsequent divisions? We may ask a identical question with regards to the nucleus which contains the genes that direct the differentiation into specific tissues and cells types.


Related Discussions:- Totipotency and pluripotency

What is continuous full thickness incision, Q. What is continuous full thic...

Q. What is continuous full thickness incision? 2. Continuous full - thickness incisions are indicated for a variety of situations outlined below. This type of incision may be u

Results-ross operation--surgical techniques, Results: The risk of isolate...

Results: The risk of isolated aortic valve replacement is 3-4 per cent. The long term survival for 5, 10 and 15years is 75 per cent, 60 per cent and 40 per cent respectively. The

What is single cross between two mountain rabbits, In mountain rabbits, the...

In mountain rabbits, the EL-1 gene is located on chromosome 3. Seven alleles of this gene have been identified in the population. With respect to EL-1, what is the maximum number o

What are the maintenance sequences of implant, Maintenance sequences of imp...

Maintenance sequences of implant Achieving a successful result with the treatment is only half the battle won. The main challenge is maintain that result over a long period of

Xerophytes, Xerophytes Xerophytes are sometimes loosely defineri as 'pl...

Xerophytes Xerophytes are sometimes loosely defineri as 'plants of dry habitats'. But others have defined xerophytes as 'plants which grow on the substratum that usually beco

What is the auditory tube and its function, Q. What is the auditory tube an...

Q. What is the auditory tube and its function? Auditory tube (Eustachian tube) connects each middle ear to the throat. This tube conducts air between tympanic cavity and outsid

Define atherosclerosis, Q. Explain Atherosclerosis? Atherosclerosis is ...

Q. Explain Atherosclerosis? Atherosclerosis is one of the most important causes of morbidity and mortality in developed as well as in developing countries. Atherogenesis occurs

How can the presence, Q. How can the presence, function of muscular tissue ...

Q. How can the presence, function of muscular tissue and localization in beings of the phylum Annelida is explained? In these beings there are a longitudinal muscular layer und

Define meiosis, Give two examples in each case of organs or tissues in whic...

Give two examples in each case of organs or tissues in which you would expect  (a) meiosis,  (b) mitosis to be taking place   a) Meiosis is likely to

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