1 Describe the genetic code in your own words and the three

1) Describe the genetic code in your own words, and the three coding systems in which DNA affects phenotype.Describe each process separetly .

2) Describe, in your own words, evolution and how it produces and redistributes variation? explian each of the four merchanisms of evolution separately.

3) Explain (from an evoluionary point of view) why tuberculosis was not eradicated after the discovery of antibiotics. What is the current status of tuberculosis treatment? and why are there increasing problems with treating tuberculosis in different regions of the worldd?

Solution

1.Like every operating things have there specific sequences,our DNA too has a specific sequence which are called as \'code\'.It is said as \'genetic code\' because it contains all the infoormation of our genes(characterstics) of our ancestors.These genetic codes are further translated into proteins by living cells in our body.

Three coding systems in which DNA affects phenotype are:

(i)Mutation-The mutations are called mismatches beacause they are positions ehere the nucleotide that is inserted into the daughter polynucleotide doesnot match,by base pairing the nucleotide at corresponding position in the template DNA.If in case the mismatch is obtained inside the daughter double helix then one of its granddaughter molecules produced during the next round of DNAreplication will carry a permanent double stranded version of the mutation.

(ii)DNA repair-Every day the genomes face a lot of damages and that doubles when the errors that occur when the genome replicates.These damages need efficient repair systems.The repair systems will help the genome to maintain its essentiality of the cellular functions.

(iii)Recombination-The genomes will undergo very slight changes,if the recombination wont occur.The several accumulation of mutations over a span of time will result in small scale alteration in the nucleotide sequence of the genome.But the role of recombination is to restructing the genome.

2.A period or process by which a living organism goes through different variations since ages is called as evolution.

Production is something that is produced to come in use of human.The nature starts producing its raw material into an useful way so that humans can sustain in the present environment.

Redistribution occurs in evolution to achieve greater social equality.This particular thing helps in distributing all types of genes in order to sustain in the environment.

THe four mechanisms are:

(i)Natural selection-Natural selection is the idea that only the strong can survive.This means that each generation must pass on anew trait.For example giraff having longer neck. This makes it easier to reach to the leaves on the top of the tree.But before,the ancestors of giraff were not having longer necks.

(ii)Geographical isolation-ex-storm,The isolation of the species may led to adapting to different environments due to geographical isolation.

(iii)Mutation-In whicch a particular phenotype is favoured by the environment over another.

(iv)Ecological niche-when an organism in in need of food and shelter it tries to live in that environment and it starts adjusting itself there.It sometimes has to undergo so many body changes.

ex-The bark of the trees were previously white but due to the pollution now the bark of the trees are dark.

3.In the history ,Tuberculosis was one of the dangerous disease and people thought it came from the pig.Later on,by the scientists the pathogen was diagnosed .Paul Ehrilch discovered a chemical that could kill the microorganism taht caused Syphillis which could destroy disease causing microorganisms.

The new era has develpoed three effective agents isiniazid,pyraziamide,rifampicin which have been very effective.These agents almost kill the bacilli.

Tb have been associated with the spread of HIV infection.