Effects of air pollution on living organisms

Our respiratory system has a number of mechanisms that help in protecting us from air pollution. The hair in our nose filters out large particles. The sticky mucus in the lining of the upper respiratory tract captures smaller particles and dissolves some gaseous pollutants. When the upper respiratory system is irritated by pollutants sneezing and …

Pollutants in the atmosphere

Once pollutants enter the troposphere they are transported downwind, diluted by the large volume of air, transformed through either physical or chemical changes or are removed from the atmosphere by rain during which they are attached to water vapour that subsequently forms rain or snow that falls to the earth’s surface. The atmosphere normally disperses …

Types and sources of Air Pollution

Air pollution occurs due to the presence of undesirable solid or gaseous particles in the air in quantities that are harmful to human health and the environment. Air may get polluted by natural causes such as volcanoes, which release ash, dust, sulphur and other gases, or by forest fires that are occasionally naturally caused by …

Structure of the atmosphere

The atmosphere is normally composed of 79 percent nitrogen, 20 percent oxygen and one percent as a mixture of carbon dioxide, water vapour and trace amounts of several other gases such as neon, helium, methane, krypton, hydrogen and xenon. The general structure of the atmosphere has several important features that have relevance to environmental problems. …

History of air pollution

The origin of air pollution on the earth can be traced from the times when man started using firewood as a means of cooking and heating. Hippocrates has men tioned air pollution in 400 BC. With the discov ery and increasing use of coal, air pollution became more pronounced especially in urban areas. It was …

Pollution

‘We spray our elms, and the following spring,  trees are silent of robin song, not because  we sprayed the robins directly but because  the poison traveled step by step through the  now familiar elm-earthworm-robin cycle’ – Rachael Carson This quotation appeared in Rachael Carson’s  book entitled Silent Spring. In the years following the publication of …

Production of Micro & Macro molecules

“Biotechnology” emerged as a result of integration of biological science wit technology. It is the application of scientific and engineering principles to the processing of materials by biological agents to provide goods and services. Processes such as baking, brewing and cheese making have been in use for many years and were developed long before man …

Laws of Heredity

  Law of segregation or Law of Purity of gametes: The factors are separated during gamete formation, each gamete having only one factor and which is not influenced by the other factor though both had remained together (Now, this is called the first law).  Law of independent assortment: Factors for different characters behave independently. No …

Mendelian Principles

Johann Gregory Mendel was an Australian monk, who conducted several experiments with pea plants in the garden. He found several contrasting characteristics in pea plants such as tall and dwarf plants, yellow & green cotyledons, and round and wrinkled seeds etc. These characters occurred repeatedly generation after generation because pea plants are self pollinated. In …

Citric Acid

Almost all of the world’s output of citric acid, an intermediate in tricarboxylic acid cycle, is produced microbiologically. Citric acid cycle is a food preservative and flavoring agent of fruit juices, candy, ice cream, marmalade and other products. It is also used in pharmaceuticals as an iron chelator (binder), as a preservative for store blood, …