Science (English Medium) Class 12 - CBSE Important Questions for Biology

Distinguish between exonuclease and endonuclease.

How does restriction endonuclease function?

State the importance of using a bioreactor.

Why is the coding sequence of an enzyme β-galactosidase a preferred selectable marker in comparison to the ones named above?

One of the major contributions of biotechnology is to develop pest-resistant varieties of cotton plants. Explain how it has been made possible.

Prepare a flow chart in formation of recombinant DNA by the action of restriction endonuclease enzyme EcoRI.

What is ‘Ori’ ? State its importance during cloning of a vector.

Explain the importance of ‘Selectable marker’, with the help of a suitable example.

Why should a bacterium be made ‘competent’ ?

Explain the role of ‘microinjection’ and ‘gene gun’ in biotechnology

Answer the following question.
β galactosidase enzyme is considered a better selectable marker. Justify the statement.

Answer the following question.
Expand ‘YAC’ and mention what it was used for.

Answer the following question.
Explain the significance of palindromic nucleotide sequence in the formation of recombinant DNA.

Answer the following question.
Write the use of restriction endonuclease in the formation of recombinant DNA.

What is the cell that receives a recombinant gene called?

Give a reason why :
Proteases are added during the isolation of DNA for genetic engineering.

Give a reason why :
Single cloning site is preferred in a vector.

How does the β-galactosidase coding sequence act as a selectable marker? Why is it a preferred selectable marker to antibiotic resistance genes? Explain.

In a pathological lab, a series of steps were undertaken for finding the gene of interest. Describe the steps, or make a flow chart showing the process of amplification of this gene of interest.

The figure below shows the structure of a plasmid.

A foreign DNA was ligated at BamH1. The transformants were then grown in a medium containing antibiotics tetracycline and ampicillin.

Choose the correct observation for the growth of bacterial colonies from the given table.