Regulation of metabolism by the mediation of enzyme

A good coordination of anabolic and catabolic processes is required for the growth and maintenance of a cell. The working of metabolic machinery is dependent on enzyme catalyzed reactions. Thus a fine control of enzyme catalyzed reactions is essential in the regulation of metabolism. For the study of these reactions, we can make use of both prokaryotic and eukaryotic organisms. There exist four major steps in metabolic regulation. They are compartmentation of enzymes, differentiating pathways for catabolism and anabolism of a key substrate, interaction of substrates with change in kinetic factors and control of enzyme activity and enzyme concentration. The factors which control the actual functioning concentration of the enzymes in a cell are the rates of enzyme synthesis and degradation. A prokaryotic cell is a cell with a plasma membrane. The plasma membrane acts as a substrate for organic enzymes. In a eukaryotic cell, compartmentation of metabolic machineries occurs for very specific purposes. A plasma membrane is associated with this cell too which serves the purpose of selective transportation of important cations, anions and neutral compounds. Metabolic reactions are always reversible which makes use of two types of enzymes. One enzyme is used for forward reaction and the other one for backward reaction. These reactions are called opposing unidirectional reactions or substrate cycles.

Irrigation

Irrigation is defined as the artificial application of water to land for agricultural purposes. Irrigation is required when there is a deficiency in rainfall, non-uniform rainfall and augmentation of crop yields. It is also required in cash crops cultivation, orchards and gardens. Irrigation increases the food output, prevents damage through drought and floods and lowers production risks. Irrigation also increases the employment, value of land property, ground water storage etc. In a direct irrigation project, water is directly diverted from the river into the canal. Water is stored in a reservoir with the construction of a dam across the river in an indirect irrigation project. In the initial days, single purpose irrigation projects were announced and implemented by the various governments which were meant for a particular purpose. Now multipurpose irrigation projects are running which serves purposes like irrigation, navigation, power generation, flood control, domestic water supply, industrial water supply and tourism. Based on the financial return, irrigation projects are classified into three. They are productive, unproductive and protective. Irrigation potential is the aggregate area that can be irrigated in a year by the amount of water available at the field. India’s irrigation potential was only 19.5 M ha in 1947 which now crossed 120 M ha. The various systems of irrigation are gravity irrigation, lift irrigation, infiltrating irrigation, sewage irrigation and supplemental irrigation.

Designing dams

Dam is a water reservoir which is constructed across a river. It can be used for irrigation and power production. Water can be stored during the days of excess rainfall and can be released during other days to achieve continuous hydro power generation and irrigation. Dams are also effective in the protection from flood. Dams also serve some other purposes like navigation, fishing and recreation. Dams are also effective in improving climatic conditions and lowering river pollution. But dams can also harm in many ways. It may lead to the submergence of fertile lands, migration of population and disturbance in wildlife. The different requirements while choosing the dam site are there should be good runoff from the catchment area with minimum percolation losses, soil should be free from harmful soluble salts and minerals, runoff should be free from excessive slit load, there should be high and steep side hills, rock and soil erosion should be minimum, rock formation should have dip in the upstream direction, submergence of forest and cultivated lands should be minimum, site should be away from seismic zone and there should not be any vegetation and marshy land.