Biology All India Set 2 2013-2014 Commerce (English Medium) Class 12 Question Paper Solution

Why is Gambusia introduced into drains and ponds?

State Gause’s Competitive Exclusion Principle.

Name the enzymes that are used for the isolation of DNA from bacterial and fungal cells for recombinant DNA technology.

State the role of C peptide in human insulin.

Why is it not possible for an alien DNA to become part of a chromosome anywhere along its length and replicate normally?

Why is secondary immune response more intense than the primary immune response in humans?

Why are analogous structures a result of convergent evolution?

Name the vegetative propagules in the following :

Agave

Name the vegetative propagules in the following

Bryophyllum

List the symptoms of Ascariasis. How does a healthy person acquire this infection?

Write the scientific name of the fruit-fly. Why did Morgan prefer to work with fruit-flies for his experiments? State any three reasons.

Linkage and crossing-over of genes are alternatives of each other. Justify with the help of an example.

State the difference between the structural genes in a Transcription Unit of Prokaryotes and Eukaryotes.

In Snapdragon, a cross between true-breeding red flowered (RR) plants and truebreeding white flowered (rr) plants showed a progeny of plants with all pink flowers.

The appearance of pink flowers is not known as blending. Why?

In Snapdragon, a cross between true-breeding red flowered (RR) plants and truebreeding white flowered (rr) plants showed a progeny of plants with all pink flowers.

What is this phenomenon known as?

Write the location and function of the Sertoli cells in humans.

Write the location and functions of the following in human testes :

Leydig cells

Construct an age pyramid which reflects an expanding growth status of human population.

Describe the mutual relationship between fig tree and wasp and comment on the phenomenon that operates in their relationship.

How have transgenic animals proved to be beneficial in: Production of biological products

How have transgenic animals proved to be beneficial in: Chemical safety testing

How does a restriction nuclease function? Explain

Explain the significant role of the genus Nucleopolyhedrovirus in an ecological sensitive area.

Identify 'a', 'b', 'c',’d’, 'e' and 'f' in the table given below:

Why is pedigree analysis done in the study of human genetics? State the conclusions that can be drawn from it.

A woman has certain queries as listed below, before starting with contraceptive pills. Answer them

What do contraceptive pills contain and how do they act as contraceptives?

A woman has certain queries as listed below, before starting with contraceptive pills. Answer them.

What schedule should be followed for taking these pills?

Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination.

Why angiosperm anthers are called dithecous?

Describe the structure of its microsporangium.

Since the origin of life on Earth, there were five episodes of mass extinction of species.

How is the ‘Sixth Extinction’, presently in progress, different from the previous episodes?

Since the origin of life on Earth, there were five episodes of mass extinction of species.

Who is mainly responsible for the 'Sixth Extinction’?

Since the origin of life on Earth, there were five episodes of mass extinction of species List any four points that can help to overcome this disaster.

Two types of aquatic organisms in a lake show specific growth patterns as shown below, in a brief period of time. The lake is adjacent to an agricultural land extensively supplied with fertilisers.

Answer the questions based on the facts given above:

(i) Name the organisms depicting the patterns A and B.

(ii) State the reason for the growth pattern seen in A.

(iii) Write the effects of the growth patterns seen above.

Name and describe the technique that helps in separating the DNA fragments formed by the use of restriction endonuclease

Explain, giving three reasons, why tropics show greatest levels of species diversity.

Community Service department of your school plans a visit to a slum area near the school with an objective to educate the slum dwellers with respect to health and hygiene.

(a) Why is there a need to organize such visits?

(b) Write the steps you will highlight, as a member of this department, in your interaction with them to enable them to lead a healthy life.

Describe the Hershey and Chase experiment. Write the conclusion drawn by the scientists after their experiment.

Work out a typical Mendelian dihybrid cross and state the law that he derived from it.

With advancements in genetics, molecular biology and tissue culture, new traits have been incorporated into crop plants. Explain the main steps in breeding a new genetic variety of a crop

State the objective of animal breeding.

List the importance of inbreeding.

State the disadvantage of inbreeding among cattle. How it can be overcome?

Give an example of a new breed each of cattle and poultry.

Where does fertilization occur in humans? Explain the events that occur during this process.

A couple where both husband and wife are producing functional gametes, but the wife is still unable to conceive, is seeking medical aid. Describe any one method that you can suggest to this couple to become happy parents

Explain the different ways apomictic seeds can develop, Give an example of each.

Mention one advantage of apomictic seeds to farmers.

Draw a labelled mature stage of a dicotyledonous embryo.