Role of Autotrophs and Heterotrophs

Role of Autotrophs and HeterotrophsB moulderia ar unicellular micro-organisms that ar constitute everywhere on earth. They be classified under prokaryotes. Prokaryotes are organisms which do not have a membrane bound nucleus unlike eukaryotes which possess a come up formed nucleus. though the bacterium do not possess the nucleus, they have genetic material in their DNA. The bacteriuml DNA is give in their cytoplasm.Though bacteria whoremaster cause diseases, only a small percentage of bacteria do so. The rest of the bacteria are harmless. The pathogenic bacteria are called parasitic bacteria and they thrive on the nutrition of other living matter for their survival. On the other hand, the saprophytic bacteria lead a dependent social intercourseship with other living matter and do not cause any harm.Bacteria can be classified under various categories. They can be classified according to shape, nutritional and oxygen requirements, staining characteristics, motility, presence of cell wall and spore formation. Based on the nutritional requirements, they are classified in toHeterotrophsAutotrophsheterotrophic bacteriaHeterotrophic bacteria grow on organic substances formed by animals and plants. They break down complex organic substances from these openings and derive carbon. Heterotrophic bacteria are divided in to Photosynthetic heterotrophs- These enforce the strength of lightChemotrophic heterotrophs These obtain energy from oxidation reduction reactions.The heterotrophic bacteria cover enzymes which act on the complex organic substances and derive energy. Most of the heterotrophic bacteria are aerobic organisms and they need oxygen for their survival. Based on their relation with the energy sources they are again divided in to Saprotrophic bacteria- These bacteria derive nutrition from dead tissues. These are the common types of heterotrophsSaprophytic bacteria These bacteria depart in close association with another species like plants and bot h of them get benefited. Most of the saprophytic bacteria live in association with the roots of the plants. The bacteria convert the atmospheric normality in to nitrates which is utilized by the plants which in turn supply carbohydrates to the bacteria for their survival.Parasitic bacteria These bacteria live in close association with another species like plants and animals and derive their energy in expense of them.Heterotrophs exhibit two basic strategies for deriving energy from the organic substrates agitation In this service, the organic substrate acts as both electron acceptor and electron donor. There is no requirement of oxygen or other electron acceptor. fermentation yields lesser energy (58 kcal/mole)Respiration This process requires external electron acceptor. The or so common electron acceptor is molecular oxygen. When oxygen is used, the process is called aerobic respiration. If nitrates and sulphates are used, the process is called anaerobic respiration. Respira tion yields more energy (686 Kcal/ mole). Most of the carbon in the atmosphere is derived by the process of respiration. 40%-80% of the respiration occurs under the soil.AutotrophsAutotrophic bacteria are organisms whose sole source of nutrition is carbon dioxide. They need only weewee, inorganic salts and carbon dioxide for growth. They are divided in to Photosynthetic autotrophs These bacteria utilize energy from light and are anaerobic organisms. This common among the two types and are quite diverse. These include cyanobacteria, green sulfur bacteria, purple sulfur bacteria, and purple non-sulfur bacteria. Suphur bacteria utilize hydrogen sulphide whereas others utilize water for nutritional process.Chemosynthetic autotrophs These derive energy from oxidation of inorganic materials like iron, due south, ammonia and nitrite. These organisms are anaerobic. These are unremarkably make up deep under the water and they are responsible for the food chain under the water. They deri ve the inorganic substrates from the volcanic vents.Soil biologyPlants are terrestrial organisms and they obtain most of their nutrients from the soil. Animals derive energy indirectly from plants and other animals. This requires utilization of many elements such as inorganic compounds from the environment which are converted in to organic substances before they can be used as energy. The cycling of these elements is catalyzed by the bacteria present in the soil.Soil is the upper most layer of earth which varies in depth from a few inches to over twenty feet. The type of the soil depends on the four factors including the parent rock, the climate, the age and the biologic factors like plants, bacteria and organic substances. Most of the biological activity occurs at the surface. Most of the organic substances are found in the upper layer or the upper horizon. Majority of the bacteria are found in the upper six to twelve inches of soil. Both autotrophic and heterotrophic bacteria are found in the soil. Among the two heterotrophic bacteria are more commonly found in the soil. The heterotrophic bacteria in soil belong to the inn Eubacteriales and Actinomycetales. The Actinomycetales are represented by the genera Streptomyces, Nocardia and Micromonospora. These bacteria have an earthy odour.Maximum bacterial growth and activity in the soil are found around the roots of the plants. This region is called rhizosphere. Almost all the ecological interactions occur in this region. These interactions could be favorable, unfavorable, indispensable and sometimes lethal. The most important plump of the soil microorganisms is to decompose various kinds of organic matter.As said earlier, cycling of elements is done by bacteria. This is done to make the elements available for reuse. The elements are usually found in the reduced state inside the cell. When they are mineralized, they are in an oxidized state. They serve three functions They form the basic components of the cel lThey provide energyThey act as electron acceptors during oxidation reactionsBacteria are involved in three types of racks in the cycling of the elements necessary for energy Carbon cycleNitrogen cycleSulphur cycleCarbon cycleAbout 50% of the dry weight of all living organisms is composed of carbon. The ultimate source of this organic carbon is the atmospheric carbon dioxide.Role of heterotrophsReduce carbon dioxide by photosynthesisFix carbon dioxide from preformed organic compoundsDecompose the dead tissues of animals and plants and release the elements to be used againRole of autotrophsReduce carbon dioxide by photosynthesisUtilize carbon dioxide from dissolution of carbonates and bicarbonatesNitrogen CycleNitrogen is the most important geomorphological element of all living organisms. Though it is abundant in nature, it cannot be utilized by the plants and animals. The newton cycle is concerned with incorporation of atmospheric nitrogen and organic nitrogen of dead plants and animals on to forms that are usable by higher organisms. Bacteria, both heterotrophs and autotrophs are involved in this cycle.There are flipper processes of nitrogen cycleAmmonification The dead animals and plants are decomposed by the heterotrophs which release protein and other nitrogenous substances. These substances are broken down in to amino acids which are shatter to release ammonia. This release of ammonia from organic nitrogenous substance is called ammonificationNitrification The oxidation of ammonia in to nitrates is called nitrification. This takes place by two steps. The first step called nitrosification results in the formation of nitrites which are toxic to plants. The second step is oxidation in which the toxic nitrite is converted in to the non-toxic nitrates.Nitrate reduction The reversal process of nitrification is called nitrate reduction. The nitrate is converted in to nitrate which in turn is converted in to ammonia. Many organisms can assimilate cellula r nitrogen from this ammonia.Denitrification -Certain microorganisms are clear of reducing nitrates in to nitrites and subsequently to gaseous nitrogen. This process is called denitrification.Nitrogen steriliseation Nitrogen fixation is a process by which the bacteria both autotrophs and heterotrophs fix atmospheric nitrogen. It is symbiotic of it is done by the bacteria living in the plant roots and non-symbiotic if it is done by bacteria independently.Role of heterotrophs in nitrogen cyclePrimarily responsible for ammonification get under ones skin nitrate reduction convolute in denitrificationInvolved in symbiotic nitrogen fixationRole of autotrophsInvolved in ammonification under anaerobic conditions. The amine that is formed is oxidized to release ammoniaExclusively involved in nitrification. The family of autotrophs called Nitrobactericeaa is involved in this reactionCause nitrate reductionInvolved in denitrificationInvolved in non -symbiotic nitrogen fixationSulphur cycleS ulphur is essential for all living organisms as sulphur containing amino acids are present in all proteins. It occurs in both organic and inorganic combinations. Cycling of sulphur is similar to nitrogen cycle. diversity between organic and elemental states and between oxidized and reduced state are carried out by bacteria.Role of heterotrophsHeterotrophs in the soil degrade the proteins in the soil and liberate sulphur.Role of autotrophsAutotrophs oxidize various forms sulphur like hydrogen sulphide. The phototrophic autotrophs oxidize hydrogen sulphide in to elemental sulphur. The chemosynthetic autotrophs oxidize sulphur in to sulphates. Sulphate is the most suitable source of sulphur for plants. This sulphate is assimilated and converted in to proteins.Fresh water biologyFresh water is define as water containing less than 1% of salt. The different fresh water zones include ponds and lakes and streams and rivers.Ponds and lakesPonds and lakes consists of three zonesUppermost l ittoral zone- This zone absorbs direct sunlight and contains algae, snails, insects, crustaceans and fishes. oculus limnetic zone This contains planktonsLower profundal zone- This zone contains heterotrophic bacteria. Very little enter this zone and therefore it is very ideal for growth of the heterotrophs decompose the dead organisms by using oxygen through the process of respiration.Streams and riversThese are water bodies which move in one direction. The characters of these water bodies change during their course. There are three separate of these water bodies source, mid stream and mouth. The place where they reach and join another water source including ocean is called the mouth. The source of these water bodies contains high oxygen levels and hence the heterotrophs thrive here very well. Near the mouth, the light penetration and the oxygen content are very less and autotrophic bacteria are found in this region.Both heterotrophs and autotrophs exist and survive in the fresh water bodies. The processes are very similar to those that occur in the soil. In the fresh water bodies, these bacteria take care of the inorganic requirements of the algae which is similar to the plants on the soil. These organisms get in to these water bodies from air, soil, sewage, organic wastes, dead plants and animals. Climatic, geographical and biological conditions communicate about great variation in the bacterial population. Rivers and stream show their highest count during rainy season. Dust blowing in to the rivers and streams also contributes to many bacteria. Animals contribute to the bacterial population by bathing and dropping their excreta.Among the various cycling of elements, the nitrogen cycle is most common one occurring in the water bodies.Role of heterotrophsThey act on the dead animals and plants and other organic wastes and liberate nitrogenThey can cause nitrate reduction resulting in the release of ammoniaRole of autotrophsThe genus Nitrosomonas and nitro bacter species cause nitrification processInvolved in ammonification under anaerobic conditions. The amine that is formed is oxidized to release ammonia