Biology

  Microbes - The Micro-World Microbes are the major components of biological systems on this earth. Microbes are present everywhere – in soil, water, air, inside our bodies and that of other animals and plants. Microbes are diverse– protozoa, bacteria, fungi and microscopic animal and plant viruses, viroids and also prions that are proteinacious infectious agents. Microbes like bacteria and many fungi can be grown on nutritive media to form colonies, that can be seen with the naked eyes. Such cultures are useful in studies on micro-organisms. Microbes are harmful and useful to man in diverse ways. Microbes in Household Products Production of curd from milk Micro-organisms such as Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and convert it to curd. During growth, the LAB produce acids that coagulate and partially digest the milk proteins. A small amount of curd added to the fresh milk as inoculum or st...

  Health Health is defined as a state of complete physical, mental and social well-being. Factors Affecting Health Health is affected by – Genetic disorders – deficiencies with which a child is born and deficiencies/defects which the child inherits from parents from birth; Infections Life style including food and water we take, rest and exercise we give to our bodies, habits that we have or lack etc. Disease When the functioning of one or more organs or systems of the body is adversely affected, this state is called disease. Types of disease - Infectious Non-infectious Pathogens A wide range of organisms belonging to bacteria, viruses, fungi, protozoans, helminths, etc., causing diseases in human are called pathogens . Sometimes, pathogens are carried on/in other's organisms body, these pathogens transmitting agents/organisms are called vectors . Common Disease in Humans Typhoid Salmonella typhi is a pa...

  Evolutionary Biology is the biology in which we study about history of life forms on earth. Various theory has been proposed about origin of life forms. Theories about origin of life forms Various theories has been given in support how first life appear on earth. They are as below - Some scientists believe that it came from outside. Early Greek thinkers thought units of life called spores were transferred to different planets including earth. ‘Panspermia’ is still a favourite idea for some astronomers. For a long time it was also believed that life came out of decaying and rotting matter like straw, mud, etc. This was the theory of spontaneous generation . Louis Pasteur by careful experimentation demonstrated that life comes only from pre-existing life. He showed that in pre-sterilised flasks, life did not come from killed yeast while in another flask open to air, new living organisms arose from ‘killed yeast’. Oparin of Russia and Haldane of England pro...