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 Multiple Choice QuestionsMultiple Choice Questions

171.

In the lactose operon of Escherichia coli what is the function of promoter

  • Binding of Gyrase enzyme

  • Binding of RNA polymerase

  • Codes for RNA polymerase

  • Processing of messenger RNA


172.

Sex factor in bacteria is

  • F-replicon

  • chromosomal replicon

  • RNA

  • sex pillies


173.

Most simple amino acid is

  • lysine

  • glycine

  • aspartic acid 

  • nucleic acid


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174.

Which of the following be named for DNA produced from RNA?

  • A- DNA

  • B- DNA

  • C- DNA

  • Z- DNA


C.

C- DNA

The DNA synthesized on template of RNA by the enzyme reverse transcriptase is called complementary DNA (C-DNA).

A-DNA is a right-handed double helix fairly similar to the more common B-DNA form, but with a shorter, more compact helical structure whose base pairs are not perpendicular to the helix-axis as in B-DNA.

 In B-DNA, the most common double helical structure found in nature, the double helix is right-handed with about 10–10.5 base pairs per turn. The double helix structure of DNA contains a major groove and minor groove.

Z- DNA is the double helix that has a left- handed rather than the usual right handed twist and the suagr- phosphate backbone followsa zig-zag course.


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175.

The length of DNA having 23 base pair is

  • 78 Ao 

  • 78.4 Ao.

  • 74.8 Ao 

  • 78.2Ao


176.

Number of nitrogenous bases in a codon is

  • 2

  • 5


177.

Chromosomes can be stained with one of the following chemicals

  • acetocarmine 

  • safranine

  • light green

  • eosin


178.

In a DNA molecule, distance between two bases is

  • 2 nm/ 20 Å

  • 0.2 nm/ 2 Å

  • 3.4 nm/ 34 Å

  • 0.34 nm/ 3.4 Å


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179.

Balbiani rings are the sites of

  • DNA replication

  • RNA and protein synthesis

  • synthesis of lipids

  • synthesis of polysaccharides


180.

Which of the following is structural subunit of DNA?

  • Protein

  • Carbohydrate

  • RNA

  • Nucleotide


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