Rabu, 16 November 2011

Global Warming

Global warming is the increasing temperature of earth surface, it had happened since the mid-20th century and it is still continuing until now. Global warming is a bad thing for the earth and the life on it.
Many things cause global warming. Earth naturally insulted by a delicate balance of heat-trapping (greenhouse) gases in the atmosphere. These gases protect the earth, when the sun shines on the earth, these gases absorb some the heat of the sunlight to keep the earth warm enough to support the life. However, human activities since the industrial revolution have released more and more carbon dioxide so it has increased the concentration of greenhouse gases. The other gases that become greenhouse gases in the atmosphere are methane, tropospheric ozone, CFCs, and nitrous oxide. The increasing of these gases in the atmosphere makes more and more heat that is trapped in the atmosphere, so it makes temperature increase too. That is the most important thing that causes global warming. There are still many things that cause global warming and they are still caused by human activities, for example deforestation.
Global warming brings damaging effects for the earth and the life on it, for example:

Rising sea levels, leading to more coastal erosion, flooding during storms, and permanent inundation.
Increase drought and increase incident of wildfires.
Impact on human health because mosquitoes and other disease-carrying insects and rodents spread diseases over larger geographical regions.
Disruption of agriculture.
Climate changes.
Global warming is the worst thing that may happen in the earth, but it doesn’t mean that global warming progress cannot be hampered. We can solve this global warming problem to avoid the worst effect of global warming. These are some ways that we can do to solve global warming:
Do not cut down the tree. We must plant the trees and keep them well.
Minimize the used of electricity.
Save the water.
Reduce the used of car and motorcycle because every time we drive a car, we release carbon dioxide and other heat-trapping gases into the air.
Minimize the used of AC.
Every little thing that we do now will determine the kind of world in the future, so keep saving the earth.


Source : http://verayaniarif.wordpress.com/2010/10/05/explanation-text-about-green-house/

What is gene splicing?

Gene splicing is the removal of introns (intervening sequences) from the primary trascript of a discontinuous gene during the process of Transcription.
Gene splicing is the process of chemically cutting DNA in order to add bases to the DNA strand. The DNA is cut using special chemicals called restriction enzymes, which there are thousands of, and each one has its own, unique and specific code of DNA that it can cut.

 

Why does gene splicing work?

Gene splicing is one of the important step in central dogma of eukaryotic cells
Gene splicing is a post-transcriptional modification in which a single gene can code for multiple proteins. Gene Splicing is done in eukaryotes, prior to mRNA translation, by the differential inclusion or exclusion of regions of pre-mRNA. Gene splicing is an important source of protein diversity. During a typical gene splicing event, the pre-mRNA transcribed from one gene can lead to different mature mRNA molecules that generate multiple functional proteins. Thus, gene splicing enables a single gene to increase its coding capacity, allowing the synthesis of protein isoforms that are structurally and functionally distinct. Gene splicing is observed in high proportion of genes. In human cells, about 40-60% of the genes are known to exhibit alternative splicing.
Why was gene splicing done?
In natural conditin in a eukaryotic cell it is done so as to remove the gene part which does not code for any protein and are called exons and to join the rest parts which are known as introns so as to make gene more specific and meaningfull In laboratory condition it is done to insert a new type of gene in other organism by means of plasmid or other method
What is the benefit of gene therapy?
It has the potential to cure genetic diseases. Curing a disease is more economical that treating it for long period of time.

What are the advantages of gene splicing?
Gene splicing involves removing a specific gene from one plant to putting it into the DNA of another, transferring the characteristic of one plant to the other. This technology has been a lot less controversial than eugenics and cloning, because so far it has only been attempted with plants. The benefits of this scientific advance are clearly documented in the developing world.
What are the disadvantages of gene splicing?
Some disadvantages of Gene Splicing, is that we spend about 40 million every year on it, when we could be spending it in schools. Teachers are being laid off by the dozens, because of the economic downfall, while, that much money is being spent on Gene splicing.
How is gene-splicing accomplished?
Gene Splicing Mechanism In natural condition in eukaryotic cells:
There are several types of common gene splicing events. These are the events that can simultaneously occur in the genes after the mRNA is formed from the transcription step of the central dogma of molecular biology.
Exon Skipping: This is the most common known gene splicing mechanism in which exon(s) are included or excluded from the final gene transcript leading to extended or shortened mRNA variants. The exons are the coding regions of a gene and are responsible for producing proteins that are utilized in various cell types for a number of functions.

Intron Retention: An event in which an intron is retained in the final transcript. In humans 2-5 % of the genes have been reported to retain introns. The gene splicing mechanism retains the non-coding (junk) portions of the gene and leads to a demornity in the protein structure and functionality.
Alternative 3' splice site and 5' splice site: Alternative gene splicing includes joining of different 5' and 3' splice site. In this kind of gene splicing, two or more alternative 5' splice site compete for joining to two or more alternate 3' splice site
Gene therapy replaces the faulty gene with what?
They diactivate a virous that attacks genes and plant a healthy gene it the virous then in plant the virous in the child or adult they ither use a needle and put it strait in the body or cover it in fat an then you have to injest it.

What is the goal of gene therapy?
to be able to replace or supplement the defective gene with a normal allele


 Source : http://wiki.answers.com/Q/What_is_gene_splicing