Restriction enzymes:

• are endonucleases which cleave DNA at specific sites

• make DNA complementary to an existing DNA or RNA

• cut or join DNA fragments

• are required in vectorless direct gene transfer.

Restriction enzymes are used to cut

• single stranded RNA

• double stranded DNA

• single stranded DNA

• double stranded RNA

Which one among the following is just a cloning plasmid not an expression plasmid?

• pBAD-18-Cam

• pBCSK

• pUC18

• pET

What is the first step in the Southern Blot technique

• Denaturation of DNA on the gel for hybridization with specific probe

• Production of a group of genetically identical cells

• Digestion of DNA by restriction enzyme

• Isolation of DNA from a nucleated cell such as the one from the scene of crime

Polymerase chain reaction is most useful in

• DNA synthesis

• DNA amplification

• protein synthesis

• amino acid synthesis

Shorter generation time of E. coli compared to eukaryotes may be explained on the basis of

• shape

• large surface : volume ratio

• presence of cell wall

• absence of organelles

Which of the following enzymes is used to join bits of DNA?

• Ligase

• Primase

• Endonuclease

• DNA polymerase

Assertion : In recombinant DNA technology, human genes are often transferred into bacteria (prokaryotes) or yeast (eukaryote).

Reason : Both bacteria and yeast multiply very fast to form huge populations which express the desired gene.

• If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

• If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

• If Assertion is true but Reason is false.

• If both Assertion and Reason are false

Molecular scissors, which cut DNA at specific site is

• pectinase

• polymerase

• restriction endonuclease

• ligase

cDNA probes are copied from the messenger RNA molecules with the help of

• restriction enzymes

• reverse transcriptase

• DNA polymerase

• adenosine deaminase