Scientifically the species which are the exact copies of their parents are termed as clones and the process is called as cloning. Clones are formed by asexual reproduction without any genetic alterations ( as occurs in sexual reproduction ). The species produced via this type of technique have limited life spans and low chances of survival.
According to the theory of evolution, the species which fits themselves best in environment have better chances of survival and every species have some sort of variations as compared to their parents which makes them suitable for the changing environment. Its amazing that the Prokaryotes produces via asexual reproduction in which are exact copy of their parents, still most of them survives in harsh environmental conditions.
Post Reproduction Adaptations
It is seen in species that after the reproduction they might adapt some changes at genetic level both Eukaryotes and Prokaryotes. This mostly seen in Prokaryotes because they need lot of changes to survive.
Single Cell species which reproduce through asexual reproduction have greater abilities to adapt the environmental changes at their genetic level so that their next progenies will already have and not facing problems. But this adaptation is very quick and limited only few species are able to adapt rest of them are dead. This maintains their population because sigle cell species are disease causing agents for Eukaryotes, if their population increase drastically others may face problems.
Why they produce via Asexual mode?
The Prokaryotes are harmful for Eukaryotes as they are disease causing agents. However they contribute a lot in the ecosystem.( discussed in next section). Here are the major reasons:
- Their population is controlled because they replicate themselves as very high frequency if all of them able to survive than whole ecosystem will unbalanced soon.
- Being a single cell they have best mode of regulation of their next generation, however some species are able to produce via sexual mode of reproduction during extreme conditions e.g: Aspergillus
Application in Biotechnology
Their rapid growth and multiplication attracted scientists and researchers to use them as natural bioreactors. Along with their life cycle they produce some metabolic chemicals which are benifitable sometime and sometime harmful.
- Production of antibiotics by bacteria and fungi. Streptomycin,tetracycline and erythromycin are some of the commonly known antibiotics which are made from fungi and bacteria.
- Production of Chemicals, Enzymes and other Bioactive Molecules
- Examples of acid producers are
- Aspergillus niger (a fungus) of citric acid
- Acetobacter aceti (a bacterium) of acetic acid
- Clostridium butylicum (a bacterium) of butyric acid
- Lactobacillus (a bacterium) of lactic acid.
- Yeast (Saccharomyces cerevisiae) is used for commercial production of ethanol.
- Lipases are used in detergent formulations and are helpful in removing oily stains from the laundry.
- The bottled juices are clarified by the use of pectinases and proteases.
- Streptokinase produced by the bacterium Streptococcus and modified by genetic engineering is used as a ‘clot buster’ for removing clots from the blood vessels of patients who have undergone myocardial infraction leading to heart attack.
- Another bioactive molecule, cyclosporin A, that is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus Tnchoderma polysporum.
- Statins produced by the yeast Monascus purpureus have been commercialized as blood-cholesterol lowering agents. It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.
- Conversion of Milk into Curd by Lactobacillus.
- Fermentation of milk in industries.
- Sewage treatment.
- Production of Biogas.
- Microbes as biocontrol agents : Biocontrol refers to the use of biological methods for controlling plant diseases and pests. Biological agents are a better alternative to weedicides and pesticides.
- Microbes as Biofertilisers.
NCERT text books from 6 to 12.
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BIOTECHNOLOGY