Multiple Choice Questions

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Out of A-T, G-C pairing, bases of DNA may exist in alternate valency state owing to arrangement called

  • tautomerisational mutation

  • analogue substitution

  • point mutation

  • frameshift mutation


A.

tautomerisational mutation

In the early 1950s, guanine and thymine were generally portrayed in the enol form, although there was little data to support the predominance of one form over the other. James Watson and Francis Crick discovered that by using the keto forms instead of the enol forms, they could "form" two base pairs, an adenine thymine pair and a guanine-cytosine pair, that had the same overall size and shape. These base pairs formed the basis for Watson and Crick's model of DNA.

The process of changing keto form in to enol form of a given organic compound is known as tautomerisational mutation.


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What will be the codons in mRNA if the DNA codes are ATG - CAG?

  • TAC - GTC

  • UAC - GUC

  • UCA - TUA

  • TCA - GTC


Which one of the following triplet codon is a chain termination codon?

  • UGU

  • AAU

  • UUG

  • UAG


A-DNA is

  • left-handed helix with 12 nucleotide pairs per turn

  • right-handed helix with 11 nucleotide pairs per turn

  • right handed helix with 12 nucleotide pairs per turn

  • left-handed helix with 11 nucleotide pairs per tum


Which one of the following triplet codon is known as initiation codon?

  • UUU

  • UAA

  • AUG

  • UGA


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Short Answer Type

What is ribozyme?


Multiple Choice Questions

DNA sequences that code for protein are known as

  • introns

  • exons

  • control regions

  • intervening sequences


Structural element of chromatin is

  • histone

  • acid protein and DNA

  • nuclear matrix

  • nucleosomes


Melting of DNA at an elevated temperature (70°C) is primarily due to the breakdown of

  • phosphodiester bonds

  • glycosidic bonds

  • disulphide bonds

  • hydrogen bonds


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The chemical nature of chromatin is as follows

  • nucleic acids

  • nucleic acid and histone proteins

  • nucleic acids, histone and non-histone proteins

  • nucleic acids and non-histone proteins


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