regulation

Pollution of the environment is a major global problem of today. It is heartening to note that in the last 25 years or so, scientists and environmentalists have created a great deal of awareness on environment pollution. Several national and international laws and charters and institutions no..

Structure and function in living systems Reproduction and heredity Regulation and behavior Populations and ecosystems Diversity and adaptations of organism..

Structure and function in living systems Reproduction and heredity Regulation and behavior Populations and ecosystems Diversity and adaptations of organism..

There are small storage tanks which intercept and store the overflow of smaller catchment areas. Small dams are built below the higher elevation of the catchment area. Outflow from the tank is regulated according to the availability of water. This ensures uniform distribution of wate..

The pressure built up inside the cells as a result of the entry of water is called osmotic pressure. The entry of water into the cells is regulated by the solutes in the cell. Less concentration of solutes means more concentration of water. Positive osmotic pressure means more water insid..

Repressible Operon - Another type of operon system is the repressible operon which is regulated by a chemical substance called co-repressor. It is almost always the end product of a metabolic reaction. The operon is switched off when the co-repressor, is present. Tryptophan operon of E. c..

Physiological Action - (i) Nitrogen is non-poisonous. But animals placed in an atmosphere of nitrogen die due to asphyxiation (lack of oxygen). (ii) Nitrogen dilutes the oxygen of the air and helps in regulating the rate of respiration and combustion. Breathing in pure oxygen enhances the..

Protein synthesis is a controlled process in which a given protein is synthesised in the cell only when it is necessary. When a particular protein is to be synthesised the specific gene has to express and initiate transcription. The mechanism that stimulates the expression of certain genes ..

. These chemicals are called the growth regulators as they either promote or inhibit the growth of the plants. Flowering and seed germination are regulated by the duration of light. This is known as photoperiodism. Plants respond to photoperiodism by a specialised pigment called..

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 large amount of enzyme. If ..