Biology : Biotechnology : Principles and Processes

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

• pBAD-18-Cam

• pBCSK

• pUC18

• pET

Restriction enzymes are used to cut

• single stranded RNA

• double stranded DNA

• single stranded DNA

• double stranded RNA

Molecular scissors, which cut DNA at specific site is

• pectinase

• polymerase

• restriction endonuclease

• ligase

The usual source of restriction endonucleases used in gene cloning is from

• fungi

• bacteria

• plants

• viruses

DNA fragments generated by the restriction endonucleases in a chemical reaction can be separated by

• centrifugation

• polymerase chain reaction

• electrophoresis

• restriction mapping

The colonies of recombinant bacteria appear white in contrast to blue colonies of non-recombinant bacteria because of

• Non-recombinant bacteria containing $\mathrm{\beta }$-galactosidase

• lnsertional inactivation of $\mathrm{\alpha }$-galactosidase in non-recombinant bacteria

• lnsertional inactivation of $\mathrm{\alpha }$-galactosidase in recombinant bacteria

• Inactivation of glycosidase enzyme in recombinant bacteria

During gene cloning, the enzyme used to join the insert DNA with the plasmid vector is

• DNA ligase

• restriction endonuclease

• alkaline phosphatase

• exonuclease

The structure of E. coli chromosomal DNA is

• double- stranded, right handed and circular

• single- stranded, right handed and circular

• double- stranded, left handed and linea

• double- stranded, left handed and circular

Passage cells help in

• transport of water towards pericycle

• transport of water towards epiblema

• absorption of water from soil

• passage of CO₂ towards stomata