Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions for Biology

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?

Which of the following countries has the highest biodiversity?

Which one of the following is not a major characteristic feature of biodiversity hot spots?

Amongst the animal groups given below, which one appears to be more vulnerable to extinction?

What does the term ‘Frugivorous’ mean?

A species-area curve is drawn by plotting the number of species against the area. How is it that when a very large area is considered the slope is steeper than that for smaller areas?

Is it possible that productivity and diversity of a natural community remain constant over a time period of, say one hundred years?

There is greater biodiversity in tropical /subtropical regions than in temperate region. Explain.

Is it true that there is more solar energy available in the tropics? Explain briefly.

Species diversity decreases as we move away from the equator towards the poles. What could be the possible reasons?