activity regulation

Genes do not operate to produce enzymes all the time. Each gene is normally more or less repressed (inactive); but, when a particular enzyme is needed, the relevant gene becomes active to bring about the production of that enzyme. A totally active gene can produce a very l..

Nervous Regulation - The heart is regulated to a large extent through the central nervous system. The heart nerve branches from the vagus nerve from the medulla oblongata and the sympathetic nerve fibres from the spinal cord. The vagus nerves are cardiac inhibitory nerves. When ..

.g., nocturnal activity of some desert animals, long trips migration by many birds. E.g., Arctic terns, Siberian crane, American golden plover, Bison and caribou. vi) Homeothermy This is achieved through evaporation of sweat in the mammals from their bodies during summer and through insul..

Hormones are informational molecules. They are secreted in response to changes in the environment inside or outside the body. These are released into the extracellular fluid, where they are diffused into the blood stream. The latter carries them from the site of production to the site of action. Th..

Introduction - Genes do not operate to produce enzymes all the time. Each gene is normally more or less repressed (inactive); but, when a particular enzyme is needed, the relevant gene becomes active to bring about the production of that enzyme. A totally active gene can produce..

Vitamins are a complex group of organic compounds that are required in small quantities for regulation of various body activities. Though they are needed in small quantities, they are essential for our well being. Since most of them cannot be synthesized in the body, they must f..

Vitamins are a complex group of organic compounds that are required in small quantities for regulation of various body activities. Though they are needed in small quantities, they are essential for our well being. Since most of them cannot be synthesized in the body, they ..

This is a prominent, spherical or oval structure found at the centre of the cell. It is the controlling centre of all cell activities and has been described as the brain of the cell. It regulates all metabolic and hereditary activities of the cell. The nucleus is comp..

The hypothalamus is a part of the brain, situated at the base of the fore brain. It consists of several masses of the grey matter called hypothalamic nuclei, scattered in the white matter. It is connected to the anterior lobe of the pituitary gland by hypophysal portal blood vessels and with ..

>The repressor protein binds with the operate gene, RNA polymerase cannot be allowed and hence structural genes get switched off. The repressor protein is kept in an active state by the inducer which is usually the substrate molecule. The repressible operon has the same components as in i..