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 are the respective functions of phospholipids, Q. What are the respect...

Q. What are the respective functions of phospholipids, carbohydrates and proteins of the cell membrane? Membrane phospholipids have a structural function they form the bilipid

Types of embryogeny, Types of Embryogeny On the basis of the plane of...

Types of Embryogeny On the basis of the plane of division of the zygote and of the cells of the 2-celled proembryo, and also taking into account the relative contributions of

Are gametes always made by meiosis, Q. Are gametes always made by meiosis? ...

Q. Are gametes always made by meiosis? In the haplontic haplobiontic life cycle and in the plant life cycle (diplobiontic life cycle) gametes are made by mitosis and not by mei

How many carbon dioxide molecules liberated in krebs cycle, Q. How many car...

Q. How many carbon dioxide (CO 2 ) molecules are liberated after each cycle of the Krebs cycle? For a single glucose how many carbon dioxide molecules were already liberated by the

What are alternative medicines, Question 1: Differentiate between Tradi...

Question 1: Differentiate between Traditional, complementary and alternative medicines. Cite examples for each type. Definition of Traditional, alternative medicines and

Why do protease-supplying cells of the stomach, Why do protease-supplying c...

Why do protease-supplying cells of the stomach and of the pancreas make only precursors of the active proteolytic enzymes? The stomach and the pancreas make zymogens of the pro

Explain acute infections fever, Explain Acute Infections Fever Acute In...

Explain Acute Infections Fever Acute Infections Fever:  Acute fevers are of short duration with acute symptoms, the body temperature may rise to above 104°F. Examples of such i

Define some detrimental effects of fungi, Define some Detrimental Effects o...

Define some Detrimental Effects of Fungi? These cause diseases of animals and humans. These either cause superficial mycoses (infection of skin, hair and nails) or systemic

What is lymphatic network, What is Lymphatic Network? The lymphatic net...

What is Lymphatic Network? The lymphatic network consists of the lymphatic vessels, which circulate lymph throughout the body. Lymph is a liquid which carries out exchange of g

Why different types of seizures may occur, Why Different types of seizures ...

Why Different types of seizures may occur? Different types of seizures may occur: 1) Generalized or tonic-clonic seizures, where the entire brain curtex is involved and post

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