Science (English Medium) Class 12 - CBSE Question Bank Solutions for Biology

Which of the given statements is correct in the context of visualizing DNA molecules separated by agarose gel electrophoresis?

'Restriction' in Restriction enzyme refers to ______.

In agarose gel electrophoresis, DNA molecules are separated on the basis of their ______.

While isolating DNA from bacteria, which of the following enzymes is not required?

The role of DNA ligase in the construction of a recombinant DNA molecule is ______.

Which of the following bacteria is not a source of restriction endonuclease?

Which of the following statements does not hold true for restriction enzyme?

Would you choose an exonuclease while producing a recombinant DNA molecule?

What does H in’ ‘d’ and ‘III’ refer to in the enzyme Hind III?

Restriction enzymes should not have more than one site of action in the cloning site of a vector. Comment.

Restriction enzymes that are used in the construction of recombinant DNA are endonucleases which cut the DNA at ‘specific-recognition sequence’. What would be the disadvantage if they do not cut the DNA at specific-recognition sequence?

A plasmid DNA and a linear DNA (both are of the same size) have one site for a restriction endonuclease. When cut and separated on agarose gel electrophoresis, plasmid shows one DNA band while linear DNA shows two fragments. Explain.

How does one visualise DNA on an agarose gel?

A mixture of fragmented DNA was electrophoresed in an agarose gel. After staining the gel with ethidium bromide, no DNA bands were observed. What could be the reason?

What parameters are used for tiger census in our country’s national parks and sanctuaries?

Which of the following would necessarily decrease the density of a population in a given habitat?

Which one of the following organisms reproduces sexually only once in its lifetime?

The density of a population in a habitat per unit area is measured in different units. Write the unit of measurement against the following:

Bacteria

The density of a population in a habitat per unit area is measured in different units. Write the unit of measurement against the following:

Banyan

The density of a population in a habitat per unit area is measured in different units. Write the unit of measurement against the following:

Deer