Molecular Basis - 23-08-23

The Hershey-Chase experiment determined that

• (a) protein and DNA are the hereditory materials of viruses

• (b) protein, not DNA, is the hereditary material of viruses

• (c) viruses do not contain hereditary material

• (d) DNA, not protein, is the hereditary material of viruses.

Information used by Watson and Crick to determine the structure of DNA included

• (a) electron micrographs of individual DNA molecules

• (b) light micrographs of bacteriophage particles

• (c) nuclear magnetic resonance analysis of DNA

• (d) X-ray crystallography of double-stranded DNA

Double-stranded DNA looks a little like a ladder that has been twisted into a helix or spiral. The side supports of the ladder are

• (a) individual nitrogenous bases

• (b) alternating bases and sugars

• (c) alternating bases and phosphate groups

• (d) alternating sugars and phosphates

The steps of the ladder are

• (a) individual nitrogenous bases

• (b) pairs of bases

• (c) alternating bases and phosphate groups

• (d) alternating sugars and bases

Experiments by Avery, Macleod, and McCarty supported DNA as the genetic material by showing that

• (a) both protein and DNA samples provided the transforming factor

• (b) DNA was not complex enough to be the genetic material

• (c) only samples with DNA provided transforming activity

• (d) even though DNA was molecularly simple, it provided adequate variation to act as the genetic material

Hershey and Chase used radioactive ³⁵S and ³²P in experiments to provide evidence that DNA was the genetic material. These experiments pointed to DNA because

• (a) progeny viruses retained ³²P but not ³⁵S

• (b) retention of ³²P in progeny viruses indicated that DNA was passed on

• (c) loss of ³⁵S in progeny viruses indicated that proteins were not passed on

• (d) All of the above

Arrange them on the basis of increasing size:

• (a) Nucleotide, chromosome, gene, genome

• (b) Genome, chromosome, Nucleotide gene

• (c) Nucleotide, genome, gene, chromosome

• (d) Nucleotide, gene, chromosome, genome

In the process of transcription in Eukaryotes, the RNA polymerase I transcribes

• (a) Precursor of mRNA, hnRNA

• (b) mRNA with additional processing, capping and tailing

• (c) tRNA, 5 srRNA and snRNAs

• (d) rRNAs – 28 S, 18 S and 5.8 S

The nucleosome structure of eukaryotic chromatin is due to all of the following histones, except

• (a) H1

• (b) H2A

• (c) H2B

• (d) H3

A : Nitrogen base is linked to pentose sugar through

N-glycosidic linkage.

B : Phosphate group is linked to 5’ - OH of a nucleoside

through phosphoester linkage.

• (1) If both statements are correct

• (2) If both statements are incorrect

• (3) If only statement A is correct

• (4) If only statement B is correct