Q.No. 14
Write a note on gene cloning.
Answer:
GENE CLONING:
Cloning is a technology for achieving eugenic aims.
Clone:
A clone is defined as a cell or individual and all its asexually produced off springs. All members of a clone are genetically identical except when a mutation occurs. Generally no normal animal reproduces naturally by cloning. Several insects and many plants do, in some circumstance whereas few do so regularly.
Cloning of Mammals:
In 1997, scientists in Scotland succeeded in cloning a sheep. Other mammalian species (mice and cows) have since been cloned.
Method of Cloning:
In this procedure the nucleus from a fertilized egg is removed and a nucleus from a cell of a fully developed individual is inserted in its place. The altered Zygote is then implanted in a suitable womb and brought to term. The new individual formed in this way is a genetically identical clone of the individual whose nucleus was used. Thus cloning could make multiple copies of a desired genotype.
Embryo Twining:
Another type of cloning is the division of a single egg or early embryo into one or more separate embryos, as in the case of identical twins. Offspring from this type of cloning are genetically identical but carry chromosomes from each of the two parents. This type of cloning has already been used to produce genetically identical cattle and other farm animals. Man is likely to one cloning techniques for production of valuable animals of known pedigree such as horses etc.
Human Cloning:
At some places scientists are making attempt to clone human embryo, which they believe can serve as transplant donor. There is a lot of controversy public as to whether human cloning should be attempted or not.
Types of cloning:
There are three common types of cloning: 1. Gene cloning
2. Organism cloning
3.Gene cloning Cell cloning/tissue culture
1.Gene Cloning:
It is the manipulation (treatment or use) of genes. In this process, desired a carrier genes or pieces of DNA are introduced into a host (usually bacteria) by means of a carriers (called vector, usually plasmid of bacterium) system.The foreign DNA becomes permanent feature of the host. It is replicated and passed on to daughter cells along with host DNA. Thus a number of clones of desired genes are formed. The foreign DNA could come from another organism or might be an artificially synthesized gene.
2. Cell cloning / Tissue culture:
Multiplication or asexual production of a line of cells genetically identical to the original is called cell cloning or tissue culture. It is now common in plants however not yet possible in animals. Bacteria and yeast naturally exercise this technique. In plants, cells from leaves, roots or other tissues are isolated and cultured in special medium. A small tumour like mass of cells called callus is formed. All the cells of callus are genetically identical. When supplied with growth hormones, callus may develop into small plantlets. The plantlets may produce mature plants when planted in soil.
3. Organism cloning:
Organisms with desired characters (transgenic organisms) may be produced in large numbers by asexual process without the involvement of meiosis and fertilization. Such production of organisms is called organism cloning.
Q.no. 15
What is the role of biology in the protection and conservation of our environment?
Answer:
CAUSES OF ENVIRONMENTAL DETERIORATION:
Industrial Pollution:
Industrialization has helped mankind to raise the standard of living. It has at the same time destroyed our environment. Tons of industrial waste, and effluents in solid, liquid or gas form are being injected into the environment by the industries. These effluents frequently contain sizable amount of certain very toxic even carcinogenic material.
Air Pollution:
Heavy metals like lead from automobiles, chromium from tanneries, are playing havoc to human health. Environmental pollution has reached alarming level in some countries. Pollution in Pakistan: The environmental pollution is a national problem in Pakistan.
Pollution in Pakistan: The environmental pollution is a national problem in Pakistan.
Water Pollution:
Our rivers, canals are highly polluted with city sewage and industrial waste, which are dropped into these bodies. The life in fresh water of Pakistan has nearly docked. The fish population has been most adversely affected.
Atmospheric Pollution:
In cities particular, the exhaust from automobile is enormously adding lead into the atmosphere. There is then a need for lead free supplies of petrol your vehicles to reduce this population. We need to take protective measures as early as possible.
Groundwater pollution:
As mentioned above, agriculture may be a key source of pollution , especially for groundwater. Fertilisers and pesticides applied to crops can seep into the ground and contaminate underwater rivers and waterbeds, thus compromising the quality of wells, boreholes and other places from which groundwater is extracted for human use.
Microbiological pollution:
Unlike most others on this list, microbiological pollution may be a present sort of water contamination. Microorganisms such as bacteria, protozoa and viruses can infiltrate water supplies, causing diseases such as bilharzia and cholera. Humans are most vulnerable to this type of pollution in situ s where adequate water treatment systems aren't yet in place.
Nutrient pollution:
While they’re vital for underwater flora and fauna to flourish, an excess of nutrients can upset the delicate imbalance of water-based ecosystems. Fertilisers contain a high concentration of nutrients which, if they contaminate rivers, lakes and coastal areas, can cause algal blooming which will block out sunlight and inhibit the expansion of other organisms.
Oxygen-depletion pollution:
Another consequence of algal blooms is their consumption of oxygen supplies. This means that those species which depend on oxygen to survive are killed off, while anaerobic ones thrive. Some anaerobic microorganisms are capable of manufacturing ammonia, sulphides and other harmful toxins, which may make the water even more dangerous to animals (and humans, too).
Surface water pollution:
Referring to all water sources above ground, such as rivers, lakes, seas and oceans, surface water pollution can occur both naturally, accidentally and intentionally. For example, monitoring has an all-important role in natural flood management, which may cause poor water quality, while accidental oil spills and negligent industries emptying waste into water bodies are also key contributors.
CONSEQUENCES:
These problems, therefore, need to be addressed or else they would soon be out of control, in which case the biocomponents of the world ecosystem would suffer irreparable loss and this environment would no longer support life on this planet.
PROTECTION & CONSERVATION OF ENVIRONMENT:
Biology helped mankind in attracting attention to this problem and the biologists are striving to find the solution to set this environment right wherever it has deteriorated.
Industrial Waste's Treatment:
Biologists have already asked for the treatment of industrial effluent to be made obligating.
Biological Control:
Several ways of bioremediation are also under investigation. For example algae have been found to reduce pollution of heavy metal by bio-absorption.
Conservation of Wildlife:
The biologists have worked out the list of endangered species of various animals and stressed the needs for their protection, which if not protected would soon be extinct.
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