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

Mention the evolutionary significance of the Homo habilis

Mention the evolutionary significance of the Homo erectus

What is an age-pyramid?

How does restriction endonuclease function?

Although a prokaryotic cell has no defined nucleus, yet DNA is not scattered throughout the cell. Explain.

Explain the roles of the following with the help of an example each in recombinant DNA technology :

Restriction Enzymes

Explain divergent evolution with two examples. 

Explain the role of histones in forming a nucleosome.

Answer the following question.
What is "population" according to you as a biology student? 

Answer the following question.
"The size of a population for any species is not a static parameter." Justify the statement with specific reference to fluctuations in the population density of a region in a given period of time.

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.

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

State the medicinal value and the bioactive molecules produced by Penicillium notatum.

State the medicinal value and the bioactive molecules produced by Monascus purpureus.

State the medicinal value and the bioactive molecules produced by Trichoderma polysporum.

Answer the following question based on Meselson and Stahl's experiment on E. coli :

Write the name of the chemical substance used as the only source of nitrogen in the experiment.

Study the flow chart given below and complete the equation that follows by identifying 1, 2, 3 and 4.

N_{t + 1} = N_t + {(1+ 2) − (3 + 4)}

Mention the different ways by which the population density of different species can be measured.

Name the microbes that help the production of the following product commercially:
Statin