Question Paper - Biology 2013 - 2014-CBSE 12th-Class 12 CBSE (Central Board of Secondary Education) (CBSE)



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Year2013 - 2014 (March)

Alternate Sets


Marks: 70
Q: 1[1]

Name the part of the flower which the tassels of the corn- cob represent.

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Q: 2[1]

Mention any two contrasting traits with respect to seeds in pea plant that were studied by Mendel.

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Q: 3[1]

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

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Q: 4[1]

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

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Q: 5[1]

State the role of C peptide in human insulin.

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Q: 6[1]

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

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Q: 7[1]

State Gause’s Competitive Exclusion Principle.

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Q: 8[1]

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

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Q: 9[2]

Why are the human testes located outside the abdominal cavity? Name the pouch in which they are present.

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Q: 10[2]

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?

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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?

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Q: 11[2]

With the help of one example, explain the phenomena of co-dominance and multiple allelism in human population.

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Q: 12 | Attempt Any One[2]
Q: 12.1[2]

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

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Q: 12.2[2]

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

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Q: 13[2]

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

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Q: 14[2]

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

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Q: 15[2]

How does a restriction nuclease function? Explain

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Q: 16[2]

How have transgenic animals proved to be beneficial in:

Production of biological products

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How have transgenic animals proved to be beneficial in:

Chemical safety testing

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Q: 17[2]

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

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Q: 18[2]

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

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Q: 19 | Attempt Any One[3]
Q: 19.1[3]

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

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Q: 19.2[3]

Why angiosperm anthers are called dithecous? Describe the structure of its microsporangium.

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Q: 20[3]

If implementation of better techniques and new strategies are required to provide more efficient care and assistance to people, then why is there a statutory ban on amniocentesis? Write the use of this technique and give reason to justify the ban.

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Q: 21[3]

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

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Q: 22[3]

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

No.SyndromeCauseCharacteristics of  affected individualsSex
1.Down'sTrisomy of 21'a' (i)
2.'c'XXYOverall masculine
3.Turner's45 with XO'e' (i)
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Q: 23[3]

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.

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Q: 24[3]

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?

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Q: 25[3]

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

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Q: 26[3]

State the function of a reservoir in a nutrient cycle

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

Explain the simplified model of carbon cycle in nature.

G~ve schematic representation of carbon cycle.

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Q: 27[3]

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?


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

Who is mainly responsible for the 'Sixth Extinction’?

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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.


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Q: 28 | Attempt Any One[5]
Q: 28.1[5]

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

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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

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Q: 28.2[5]

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

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Mention one advantage of apomictic seeds to farmers.

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Draw a labelled mature stage of a dicotyledonous embryo.

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Q: 29 | Attempt Any One[5]
Q: 29.1[5]

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

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

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Q: 29.2[5]

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

In the medium where E. coli was growing, lactose was added, which induced the lac operon. Then, why does lac operon shut down some time after addition of lactose in the medium?

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Q: 30 | Attempt Any One[5]
Q: 30.1[5]

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

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Q: 30.2[5]

State the objective of animal breeding.

What are the objectives of animal breeding?

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

List the limitations of inbreeding. How can the limitations be overcome?

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List the importance of inbreeding.

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

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Other Solutions

Ncert Chemistry Textbook for Class 12 Part 1
Ncert Chemistry Textbook for Class 12 Part 2
Ncert Mathematics Textbook for Class 12 Part 1
Ncert Physics Textbook for Class 12 Part 1
Ncert Physics Textbook for Class 12 Part 2
R.D. Sharma Mathematics Vol. 1 & 2 Class - 12