Problem of polarity, Biology

Assignment Help:

Problem of Polarity

The control of polarity in regenerating coelentrates like hydra has received much attention for many years. You are already aware that while a hydra is cut in half, the half with the basal disc will form a hew hypostome and the half consisting of the hypostome will generate a new basal disc. Furthermore, if a hydra is cut into various segments perpendicular to the body axis, then each middle segment will regenerate both of the a basal disc and a hypostome. So every region of the hydra can give rise to a new organism.

Yet hypostomes, as well foot does not make anywhere or at all levels along the longitudinal axis of the animal; they form just only at the distal end. This indicates that a series of gradients arise from the two poles in Hydra that is rigidly polarized along the distal proximal axis. Grafting experiments have given further evidence for the existence of gradients in the hydra. When the hypostome tissue was added to the middle region of other hydra it formed a new bud with hypostome extending outward. When the basal disc cells were likewise grafted the new bud extended to form a new pedal disc and foot. In addition if grafts of both basal disc and hypostome cells were grafted together to the gastric region no supernumerary parts made. This observation suggests which signals from opposite ends of the hydra tend to counteract each other, causing the hydra to lose its polarity. Other experiments have as well shown which normal regeneration of the hypostome can be inhibited when an intact hypostome is grafted into the body of the hydra.


Related Discussions:- Problem of polarity

Pollution - environmental pollution, Pollution - Environmental Pollution ...

Pollution - Environmental Pollution Pollution refers to any undesirable change in the physical, chemical or biological characteristics of our environment, i.e. air, water and

Loss of biological diversity nowadays, Q. What are the main causes of the l...

Q. What are the main causes of the loss of biological diversity nowadays? The largest dangers to the biological diversity today are the action of humans. The major of them is t

Explain about ia muscle-spindle, Which of the following occur in response t...

Which of the following occur in response to an increase in the length of the right knee extensors in response to a quick tap applied to the right patellar tendon?  An increase in t

Botulism, B o tu l i s m It is a toxicity in chickens, turkeys, d...

B o tu l i s m It is a toxicity in chickens, turkeys, ducks and other aquatic birds caused by a bacterial toxin produced by anaerobic bacteria Clostridium botulinum mai

Light and dark reactions, Evidence for Existence of Light and Dark Reaction...

Evidence for Existence of Light and Dark Reactions The process of photosynthesis was known in its bare outline already at the beginning of this century. But the phenomenon wa

Energy storage, Energy Storage As we said above, food intake and ener...

Energy Storage As we said above, food intake and energy expenditure for animals is approximately equal. If energy expenditure exceeds food intake, then the excess energy is t

Cell Coat, What role would a cell coat play if it was a part of a city?

What role would a cell coat play if it was a part of a city?

Explain amylase, Amylase The presence of pancreatic amylase brings abou...

Amylase The presence of pancreatic amylase brings about  the breakdown  of starch  and glycogen and  its action is similar to salivary amylase. The hydrolysis of  starch and gl

Liver, how the gall bladder develops in a trnsplanted liver tissue ?

how the gall bladder develops in a trnsplanted liver tissue ?

Is cell division happening during the entire cell cycle, Is cell division h...

Is cell division happening during the entire cell cycle? What is interphase? Cell division properly happens during the mitotic phase of the cell cycle. During interphase proces

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