Biology Delhi Set 2 2015-2016 Commerce (English Medium) Class 12 Question Paper Solution

Suggest a technique to a researcher who needs to separate fragments of DNA.

State a difference between a gene and an allele.

Give an example of a human disorder that is caused due to a single gene mutation.

Suggest the breeding method most suitable for animals that are below average in milk productivity.

Excessive nutrients in a fresh water body cause fish mortality. Give two reasons.

Name the causative organism of the disease amoebiasis. List three symptoms of the disease.

Identify 'A', 'B', 'C' and 'D' in the given table.
 

Discuss the role the enzyme DNA ligase plays during DNA replication.

Explain the importance of syngamy and meiosis in a sexual life cycle of an organism.

List the events that lead to biogas production from waste water whose BOD has been reduced significantly.

Why the plants that inhabit a desert are not found in a mangrove? Give reasons.

Describe the experiment that helped Louis Pasteur to dismiss the theory of spontaneous generation of life.

Differentiate between somaclones and somatic hybrids. Give one example of each.

Why is breast-feeding recommended during the initial period of an infant's growth? Give reasons.

Suggest and describe a technique to obtain multiple copies of a gene of interest in vitro.

What is a GMO?

List any five possible advantages of a GMO to a farmer.

Given below is a list of six micro-organisms. State their usefulness to humans.

1. Nucleopolyhedrovirus
2. Saccharomyces cerevisiae
3. Monascus purpureus
4. Trichoderma polysporum
5. Penicillium notatum
6. Propionibacterium sharmanii

A couple with normal vision bear a colour blind child. Work out a cross to show how it is possible and mention the sex of the affected child.

Prior to a sports event blood & urine samples of sports persons are collected for drug tests.

1. Why is there a need to conduct such tests?
2. Name the drugs the authorities usually look for.
3. Write the generic names of two plants from which these drugs are obtained.

In certain seasons we sweat profusely while in some other season we shiver. Explain.

"In a food-chain, a trophic level represents a functional level, not a species." Explain.

Name any two places where it is essential to install electrostatic precipitators. Why is it required to do so?

Mention one limitation of the electrostatic precipitator.

How has RNAi technique helped to prevent the infestation of roots in tobacco plants by a nematode Meloidegyne incognitia?

Give an example of an autosomal recessive trait in humans. Explain its pattern of inheritance with the help of a cross.

Reproductive and Child Healthcare (RCH) programmes are currently in operation. One of the major tasks of these programmes is to create awareness amongst people about the wide range of reproduction related aspects. As this is important and essential for building a reproductively healthy society.

1. “Providing sex education in schools in one of the ways to meet this goal.” Give four points in support of your opinion regarding this statement.
2. List any two ‘indicators’ that indicate a reproductively healthy society.

Why should we conserve biodiversity ? How can we do it?

Explain the importance of biodiversity hot-spots and sacred groves.

Represent diagrammatically three kinds of age-pyramids for human populations.

How does an age pyramid for human population at given point of time helps the policy-makers in planning for future.

Explain the post-pollination events leading to seed production in angiosperms.

List the different types of pollination depending upon the source of pollen gain.

Briefly explain the events of fertilisation and implantation in an adult human female.

Comment on the role of placenta as an endocrine gland.

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.

Differentiate between analogy and homology giving one example each of plant and animal respectively.

How analogy and homology considered as an evidence in support of evolution ?