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

Explain adverse effects of famciclovir, Adverse Effects of Famciclovir ...

Adverse Effects of Famciclovir Famciclovir has been generally well tolerated. Headache, nausea and diarrhea have been reported. Like acyclovir, famciclovir has been associated

Metabolic process location, Metabolic Process Location Within the study...

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

Indicator organism, a) What are the needsfor an organism to be an indicator...

a) What are the needsfor an organism to be an indicator organism? b)  In Australia, National Parks and coastal beaches attract various visitors during holiday periods.  EPA is

Explain the physiological effects of ingestion of fibres, Explain the Physi...

Explain the Physiological effects of ingestion of fibres? Physiological effects of ingestion of fibres with adsorption properties are: 1. Diminished absorption of lipids. Wi

Germ layers - metazoa, Germ Layers - Metazoa The infolding of the blas...

Germ Layers - Metazoa The infolding of the blastoderm of the blastula forms a gastrula with two or more layers. The outer layer is the ectoderm' and the endoderm lines the inn

Explain glycophorin, Since erythrocytes  red blood cells do not hold any su...

Since erythrocytes  red blood cells do not hold any sub cellular  organelles they are essentially  a membranous  sac for carrying  haemoglobin their plasma membrane  is a convenien

What is the typical vegetation of the grasslands, What is the typical veget...

What is the typical vegetation of the grasslands? The Grasslands are mainly formed of herbaceous (nonwoody) vegetation: grass, small trees and bushes.

Explain about monocot plants and dicot plants, What are the major morpholog...

What are the major morphological differences between monocot plants and dicot plants? The main differentiation criteria among monocots and dicots are: number of cotyledons (see

State the study of linked genes, Why is drosophila a convenient animal for ...

Why is drosophila a convenient animal for the study of linked genes? The fruit fly drosophila is suitable for the study of Genetics because it shows many distinct traits but on

Merits of micro propagation, Merits of Micro Propagation The special m...

Merits of Micro Propagation The special merits of micro propagation are: 1. It considerably increases the rate of multiplication 2. High rate of multiplication can be ma

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