Question

Genetic Code

The genetic code is what allows the string of nucleotides in our DNA to code for the sequence of amino acids that make up proteins.

1. Briefly explain what this genetic code is in general and how it works.
2. What is meant by the universality of the genetic code?
3. Explain briefly what the advantages and disadvantages of this type of genetic code are to humans.

ANSWER MUST BE ORIGINAL AND NO PLAGIARISM

Answer 1

Genome or genetic material of an organism is a sequence of nucleotides or DNA in an organism. This DNA contains mainly of the junk DNA which does not code for protein and very less amount is that of the coding DNA.

The non coding region of DNA does not code for any proteins. This region includes the promoter, operator, terminator, enhancer etc.

The coding region of DNA, genetic code, contains the genetic message. It codes for proteins which are the most important players in the activity of a cell and therefore, an organism. Genetic code is read in triplet, each triplet is called codon and codes for one amino acid. This is called specificity of genetic code. One amino acid may have more than one codons, called as degeneracy of genetic code. There are 64 codons for 21 amino acids.There is one start codon (AUG) which codes for methione and three stop codons (UAA, UAG, UGA) which do not code for any amino acid. When a stop codon is encountered translation is terminated. In almost all organisms, every codon codes for the same amino acid. Due to this reason genetic code is said to be universal in nature.

A coding sequence of DNA which is in 5' to 3' direction codes for its complementary template strand which is in direction 3' to 5'. The template strand undergoes transcription and forms mRNA which is complementary to it and is in direction 5' to 3'. This mRNA undergoes translation and codes for amino acids. This is how genetic code works and codes for proteins.

Advantages of genetic code -

Degeneracy - mutation of nucleotide prevents mutation of amino acid so protein gets saved

Wobble hypothesis - one codon is recognized by more than one tRNA so, less energy will be spent in synthesizing tRNA.

Disadvantages of genetic code -

We wont be able to detect silent mutation due to degeneracy.

Insertion and deletion mutation may shift the frame of gene.

Non sense mutation will cause the formation of a stop codon which will lead to premature termination of translation.

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