Biology All India Set 3 2013-2014 Commerce (English Medium) Class 12 Question Paper Solution

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

Name the stage of cell division where segregation of an independent pair of chromosomes occurs.

Write an alternate source of protein for animal and human nutrition.

Give an example of a plant which came into India as a contaminant and is a cause of pollen allergy.

Name the type of association that the genus Glomus exhibits with higher plants.

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.

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.

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

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

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 two factors responsible for conferring stability to double helix structure of DNA.

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 effect of the high concentration of L.H. on a mature Graafian follicle

State the function of a reservoir in a nutrient cycle

Explain the carbon cycle with the help of a simplified model.

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

The following graph shows the species - area relationship. Answer the following questions as directed.

(a) Name the naturalist who studied the kind of relationship shown in the graph. Write the observations made by him.

(b) Write the situations as discovered by the ecologists when the value of 'Z'
(Slope of the line) lies between.

(i) 0.1 and 0.2

(ii) 0.6 and 1.2

What does 'Z' stand for?

(c) When would the slope of the line 'b' become steeper?

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.

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

Explain adaptive radiation with the help of a suitable example.

Cite an example where more than one adaptive radiations have occurred in an isolated geographical area. Name the type of evolution your example depicts and state why it is so named.

Name any two copper releasing IUDs.

Explain how they act as effective contraceptives in human females.

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.

State how the constant internal environment is beneficial to organisms.

Explain any two alternatives by which organisms can overcome stressful external conditions.

Explain the process of sewage water treatment before it can be discharged into natural water bodies.

Explain the process of replication of a retrovirus after it gains entry into the human body.

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.

Describe the various steps of Griffith’s experiment that led to the conclusion of the 'Transforming Principle'.

How did the chemical nature of the ‘Transforming Principle' get established?

Describe how the lac operon operates, both in the presence and absence of an inducer in E.coli.