BIOLOGY NOTES FOR NEET PDF DOWNLOAD-BIOTECHNOLOGY
“Biotechnology may be defined as use of micro-organism, or plant cells or their products to generate different products at industrial scale and services useful to human beings.
” A powerful industry based on microbes has been developed in recent time. A careful selection of microbial strains, improved method of extraction and purification of the product, have resultant in enormous yields.
The use of living organisms in systems or process for the manufacture of useful products. It may involve algae, bacteria, fungi, yeast, cells of Higher plants & animals or subsystems of any of these or isolated components from living matter.
Old biotechnology is based on the natural capabilities of micro organisms.
e.g. formation of citric acid, production of penicillin by penicillum Notatum.
New biotechnology is based on Recombinant DNA technology.
e.g. Human gene production insulin. It has been transferred and expressed in bacteria like E.coli. In, modern biotechnology, different types of valuable products are produced with help of microbiology, biochemistry, tissue culture, chemical engineering and Genetic engineering, molecular biology and immunology.
MICROBES IN HOUSEHOLD PRODUCTS:
A common example is the production of curd from milk. Micro-organisms such as Lactobacillus and other 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 starter contain millions of LAB, which at suitable temperatures multiply, thus converting milk to curd, which also improves its nutritional quantity by increasing vitamin B12. In our stomach too, the LAB play very beneficial role in checking disease causing microbes.
The dough, which is used for making foods such as dosa and idli is also fermented by bacteria. The puffed up appearance of dough is due to the production of CO2 gas. Similarly the dough, which is used for making bread, is fermented using baker’s yeast (Saccharomyces cerevisiae.) A number of traditional drinks (e.g. “Todi’ prepared from sap of palms) and foods are also made by fermentation by the microbes. Microbes are also used to ferment fish, soyabean and bamboo shoots to make foods. Cheese, is one of the oldest food items in which microbes were used. Different varieties of cheese are known by their characteristic texture flavour and taste, the specificity coming from the microbes used. For example, the large holes in Swiss cheese’ are due to production of a large amount of CO2 by a bacterium named propionibacterium sharmanii. The ‘Roquefort cheese’ are ripened by growing a specific fungi on them, which gives them a particular flavour.
Louis Pasteur showed in the middle of nineteenth century that beer and butter milk are product of fermentation brought about by “yeast”. It is a microscopic single celled organism – Saccharomyces cerevisiae. Presently however yeast product for human and animals consumption are produced on commercial scale.
“Alcohol was the first product of ancient biotechnology”
There are basically two types of yeasts (i) Baker’s yeast (ii) Alcohol yeast or Brewer’s yeast Baker‘s yeast generally utilize during the preparation of food materials to increase the taste of food, flavour in food and nutrients in food. It is also utilized as “Leavening agent.”
By the incomplete degradation of complex organic compounds (sucrose) by yeast fermentation, alcohol is formed.