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

1. Give an example of a genus of fungi that forms mycorhizal association with plants. 
2. How does the plant derive benefits from this association?

The biomass of a standing crop of phytoplankton is 4 kg/m², which supports a large standing crop of zooplankton having a biomass of 11 kg/m². This is consumed by small fishes having a biomass of 25 kg/m², which are then consumed by large fishes with a biomass of 37 kg/m².

Draw an ecological pyramid indicating the biomass at each stage and also name the trophic levels. Mention whether it is an upright or inverted pyramid.

With the help of a flow chart, illustrate how an infected animal cell can survive while viruses are being replicated or released.

The following is well-known abbreviation, which have been used in this chapter. Expand to its full form:

AIDS

The following is well-known abbreviation, which have been used in this chapter. Expand to its full form:

NACO

The following is well-known abbreviation, which have been used in this chapter. Expand to its full form:

HIV

Explain enzyme – replacement therapy to treat adenosine deaminase deficiency. Mention two disadvantages of this procedure.

A large number of married couples the world over are childless. It is shocking to know that in India the female partner is often blamed for the couple being childless.

1. Why in your opinion the female partner is often blamed for such situations in India? Mention any two values that you as a biology student can promote to check this social evil.
2. State any two reasons responsible for the cause of infertility.
3. Suggest a technique that can help the couple to have a child where the problem is with male partner.

Why do children cured by enzyme-replacement therapy adenosine deaminase deficiency need periodic treatment?

What does the following equation represent? Explain:

p² + 2pq + q² = 1.

How did an American Company, Eli Lilly use the knowledge of r-DNA technology to produce human insulin?

Write the function of adenosine deaminase enzyme.

Expand the Given and mention one application of each:

PCR

It is established that RNA is the first genetic material. Explain giving three reasons.

Suggest any two possible treatments that can be given to a patient exhibiting adenosine deaminase deficiency.

List the criteria a molecule that can act as genetic material must fulfill. Which one of the criteria are best fulfilled by DNA or by RNA thus making one of them a better genetic material than the other? Explain.

After a brief medical examination a healthy couple came to know that both of them are unable to produce functional gametes and should look for an ‘ART’ (Assisted Reproductive Technique). Name the ‘ART’ and the procedure involved that you can suggest to them to help them bear a child.

Recombination DNA−technology is of great importance in the field of medicine. With the help of a flow chart, show how this technology has been used in preparing genetically engineered human insulins.

An infertile couple is advised to adopt test-tube baby programme. Describe two principle procedures adopted for such technologies.

State the role of C-peptide in human insulin.