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Environmental Issues

 c 16 Pollution is the undesirable change brought about by chemical, particulate matter, or biological materials to air, water, or soil. Air Pollution ● Air is a complex, dynamic natural entity, which is essential for supporting life on earth. ● Air pollutant is a substance that causes harm to the humans and other living organisms. ● Some of the common pollutants of air: ○ Nitrogen dioxide ○ Sulphur dioxide ○ Carbon monoxide and carbon dioxide ○ Volatile organic compounds ○ Particulate matter Control of Air Pollution ● Air pollution causes severe respiratory disorders in humans and other animals and also affects plants. It can be controlled by the following ways: ○ Fitting smokestacks and smelters, with filters to separate pollutants from the harmless gases ○ Particulate matter can be removed by using an electrostatic precipitator . It contains electrode wires maintained at several thousand volts, which produce electrons. These electrons cling on to dust particles and give them a ...
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Ecosystem

 c 14 ● Ecosystem is the interaction of living things among themselves and with their surrounding environment. ● There are two basic ecosystems − terrestrial and aquatic. Structure of Ecosystem ● The interactions between the various biotic and abiotic factors of an ecosystem lead to the maintenance of the ecosystem. ● Stratification is the vertical distribution of the different species occupying the different levels. For example, trees occur at a higher level then shrubs. ● The various aspects taken into consideration to study the functioning of ecosystem are: ○ Productivity ○ Decomposition ○ Energy flow ○ Nutrient cycling Productivity ● A constant supply of sunlight is required for the proper functioning of any ecosystem. ● The amount of biomass produced per unit area over a time period by plants during photosynthesis is defined as the primary productivity . ● It is expressed as weight (g−2) or energy (Kcal m−2). ● Productivity can be mainly divided into gross primary productivity...
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Organisms and Environment

 c 13 ● Ecology deals with interactions among different organisms and their environment. ● Organisms get adapted to their environment for their survival and reproduction. ● The rotation of the earth about its axis brings about changes in the environment, leading to different seasons. This leads to the formation of various biomes such as desert, grassland, etc. ● Life not only exists in favourable habitats, but also in harsh and extreme conditions. ● The environment of an organism can be divided into: ○ Abiotic factors ○ Biotic factors Abiotic Factors ● Some of the major abiotic factors that interact with the organisms are: ○ Temperature − It is the most relevant abiotic factor since all organisms require an optimum temperature for their metabolism and other body functions. Depending upon their ability to tolerate temperature range, organisms are of two types- stenothermal (restricted to a narrow range of temperature) and eurythermal (can tolerate a wide range of temperature). ○ Wa...
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Biotechnology: Principles and processes

 c 11 What is biotechnology? ● Biotechnology refers to the technology using biology, which has applications in agriculture, food processing industry, medicine diagnostics, bioremediation, waste treatment, and energy production. ● The European Federation of Biotechnology (EFB) defines biotechnology as “the integration of natural science and organisms, cells, parts thereof and molecular analogues for products and services”. Basis of Modern Biotechnology ● Genetic engineering − Introduction of foreign genetic material (DNA/RNA) into the host’s genome and altering its phenotype ● Aseptic techniques − Involves maintenance of contamination-free ambience in chemical engineering processes for manufacture of products such as antibiotics, vaccines, etc.This is done so as to enable the growth of only desired microbes responsible for a bioprocess. Genetic Engineering ● Asexual reproduction preserves the genetic information while sexual reproduction preserves variations. ● Plant and animal hy...
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Biodiversity and Conservation

 c 15 ● Biodiversity occurs not only in the species level, but also in the macromolecular levels. ● Biodiversity as described by Edward Wilson is the combined diversity at all levels of biological organisation. ● The most important forms of biodiversity are: ○ Genetic diversity (diversity at the genetic level) ○ Species diversity (diversity at the species level) ○ Ecological diversity (diversity at the ecosystem level) ● There are close to 1.5 million plants and animals that have to be discovered and described. More species have been discovered in temperate regions as compared to tropics. ● According to an estimate made by Robert May, global species biodiversity is about 7 million. ● Of the total species discovered so far, 70% are animals and 22% are plants. Of the animals, 70% are insects. ● India has 2.4% of the world’s land and 8.1% of the total species diversity. According to May’s estimate, 78% of the biodiversity is still to be discovered. ● Applying this to India’s biodiver...
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Biotechnology and its Applications

 c 12 Genetically Engineered Crops ● Genetically engineered crops have desirable genes (as of insect/pest resistance, giving better yield) incorporated in them. ● Genetically modified crops have ○ more tolerance to abiotic stresses such as cold, drought, salinity, heat, etc. ○ insect/pest resistance ○ reduced post-harvest losses ○ efficient mineral usage by plants ○ enhanced nutritional value (e.g., Vitamin A rich rice) Bt Cotton ● Bacillus thuringiensis is a bacterium that produces proteins to kill certain insects such as lepidopterans (armyworm), coleopterans (beetles), and dipterans (flies/ mosquitoes). B. thuringiensis produces a protein crystal containing a toxic protein (inactivated state). ● Inactivated toxin Activated in the presence of Alkaline PH activated toxin (gut of insect) ● Activated toxin binds to the epithelial cells in the midgut of insect and creates pores that cause lyses and swelling and eventually death of insect. ● This toxin is encoded by a gene called Cry ...
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Microbes in human welfare

 c 10 Microbes - Household and Industrial applications Household Applications ● Lactic acid bacteria (LAB) ○ Milk is converted into Curd in the presence of Lactobacillus Bacteria. ○ LAB produces acids that coagulate and partially digest milk proteins. ○ Small amount of curd that is added to the milk for curdling acts as an inoculum containing thousands of LABS, which further multiply. ○ LAB enhances the nutritional value of milk by increasing Vitamin B12. ○ LAB present in stomach prevents infections. ● Fermentation ○ Dosaand idli dough is fermented by bacteria, which produces CO2gas and gives it a puffed-up appearance. ○ Dough used for making breads is fermented by baker’s yeast (Saccharomyces cerevisiae). ● ‘Toddy’ (a traditional drink from South India made by fermenting sap from palm trees) ● Cheese making ○ The bacterium Propionibacterium sharmanii is used in ‘Swiss cheese’ to give it its characteristic holes by producing large amount of carbon dioxide. ○ ‘Roquefort cheese’ is ...
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