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

If a population growing exponentially double in size in 3 years, what is the intrinsic rate of increase (r) of the population?

Give three hypotheses for explaining why tropics show greatest levels of species richness.

What is the significance of the slope of regression in a species-area relationship?

What initiatives were taken for reducing vehicular air pollution in Delhi? Has air quality improved in Delhi?

Describe the structure of a nucleosome.

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 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)}