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Molecular Basis of Inheritance

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12

Whose experiments cracked the DNA  and discovered unequivocally that is genetic code is a triplet?

• Nirenberg and Mathaei

• Hershey and Chase

• Morgan and Sturtevant

A.

Nirenberg and Mathaei

The existence of a triplet code was simply an assumption till 1961 when Nirenberg and Methaei proved its existence by experiment. They were able to synthesise artificial mRNA, which contained only one nitrogenous base, ie, uracil. This synthetic poly-U sequence was then placed in a cell-free system containing protein synthesizing enzymes (extracted from bacterium E. coil) and 20 amino acids together with necessary ATP. During the process, a small polypeptide molecule was produced, which was formed by the linking of phenylalanine. This issuggested that UUU is code for phenylalanine. Nirenberg got Nobel Prize for his contributions.

The existence of a triplet code was simply an assumption till 1961 when Nirenberg and Methaei proved its existence by experiment. They were able to synthesise artificial mRNA, which contained only one nitrogenous base, ie, uracil. This synthetic poly-U sequence was then placed in a cell-free system containing protein synthesizing enzymes (extracted from bacterium E. coil) and 20 amino acids together with necessary ATP. During the process, a small polypeptide molecule was produced, which was formed by the linking of phenylalanine. This issuggested that UUU is code for phenylalanine. Nirenberg got Nobel Prize for his contributions.

337 Views

Name the genetic material for majority of organisms.

DNA (Deoxyribose nucleic acid)
965 Views

List the function of RNA.

Functions of RNA
RNA acts as genetic material in viruses
It also functions as an adapter and messenger
It also acts as a catalytic molecule and catalyses various biochemical reactions.
721 Views

List the number of base pairs in :

(i) lambda bacteriophage

(ii) E.coli and

(iii) haploid content of human DNA.

(i) 48502 bp
(ii) 4.6 x 106 bp and
(iii) 3.3 x 109 bp.
757 Views

How many nucleotides are present in a bacteriophage $\mathrm{\varphi }$ x 174.

5386
805 Views

Comment two chains of DNA have antiparallel polarity.

The Two chain of DNA are antiparallel that is
if one chain has 5’ x 3’ polarity the other chain has 3’ x 5’ polarity.
658 Views