Lesson Genetic Code For 1000 Sc Botony

                                Genetic Code

Genetic code is a combination of 3 nucleotides, which specify a perticular Amino-acid.

Explanation:

 

deoxyribonucleic acid is the basic genetic together with hereditory material.It caries data inwards the shape of genetic code.There are 3 nucleotides inwards a codon.There are next reasons of forming triplet:

Two Nucleotides:

Two nucleotide codon does non shape plenty combinations to code for unlike xx amino-acids.

Four Nucleotides:

Four nucleotides forms exclusively 42 or sixteen unlike combinations of nucleotides which was likewise non satisfactory.

Three Nucleotides:

Three nucleotides tin dismiss shape 64 unlike combinations.It is to a greater extent than than plenty to code for the xx amino-acids.

Discovery:

Genetic code was tested & discovered past times Cricks, Nirenberg, Leader & Khorana.They made artificial mRNAs for synthesizing poly peptide Aminoacyl-tRNA complexes alongside the assistance of artificial mRNA.They tested all 64 codons for specifying unlike amino-acids.

Characteristics:

 

Genetic code direct keep next major characteristics:

Triplet Code:

Each genetic code consists of a triplet of nucleotides or nitrogen bases, inwards a perticular sequence, which tin dismiss specify a perticular amino-acid.

Initiating Codon:

Out of 64 codons AUG is e'er acquaint at the start of mRNA that codes for Methionine together with it acts equally a Initiating codon.

Stop Codon:

Three codons UAA, UAG, UGA job non code for whatever amino-acid together with they human activeness equally Stop Codon.They are acquaint at the halt of mRNA, then called equally halt codon.

Code is Ambiguous:

The genetic code is ambiguous, that is, same codon may specifies to a greater extent than than i amino-acid, e.g., UUU codon usually code for Phenylalanine precisely inwards presence of Streptomycin, likewise code for Serin.

Code is Degenerative:

Genetic code is degenerative, which agency that to a greater extent than than i codon (means many codons) tin dismiss specify the same amino-acid, e.g., CCU, CCC, CCA & CCG specify the same amino-acid Prolin.One interesting affair is observed inwards these codons is that the root ii bases of the triplet are constant, whereas the tertiary base of operations tin dismiss vary, e.g., all codon starting alongside CC specify Prolin.

None-overlapping:

The genetic code shows non-overlapping, pregnant that no unmarried base of operations tin dismiss accept part inwards the formation of to a greater extent than than i codon at a time.

Commaless:

The genetic code is commaless, which agency that at that topographic point is no punctuation betwixt 3 nucleotide units.

Universal:

Genetic code is universal.It agency that they are same inwards around all the organisms, e.g., AGA specifies Arginine inwards Bacteria, Human & all other organisms.Thus the genes tin dismiss hold upward transformed from i organism to around other due to their universality.They tin dismiss hold upward successfully transcribed together with translated inwards their novel Host.The report of genetic code of Mitochondrial deoxyribonucleic acid showed that Genetic codes are non then universal, e.g., UGA codon is unremarkably a halt codon precisely inwards Mitochondria it codes for Tryptophan.Thus it appears that Genetic codes are non quite universal.

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