Subject

Biology

Class

CBSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.
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 Multiple Choice QuestionsShort Answer Type

1.

How do cytokine barriers provide innate immunity in humans?


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2.

Write the dual purpose served by Deoxyribonucleoside triphosphates in the polymerisation.


Deoxyribonucleoside triphosphates (DTPs) purpose:

(i) DTPs serves as substrates i.e. nucleotides during replication.

(ii) DTPs supply energy for polymerisation reaction by breaking of high energy terminal phosphates bond.


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3.

Write the names of the following :
(a) A 15 mya primate that was ape-like
(b) A 2 mya primate that lives in East African grasslands


4.

Mention the chemical change that proinsulin undergoes, to be able to act as mature insulin.


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5.

Name two diseases whose spread can be controlled by the eradication of Aedes mosquitoes.


6.

How did a citizen group called Friends of Arcata Marsh, Arcata, California, USA, help to improve water quality of the marshland using Integrated Waste Water Treatment ? Explain in four steps.


7.

Your advice is sought to improve the nitrogen content of the soil to use for cultivation of a non-leguminous terrestrial crop.

(a) Recommend two microbes that can enrich the soil with nitrogen.

(b) Why do leguminous crops not require such enrichment of the soil?


8.

You have obtained a high yielding variety of tomato. Name and explain the procedure that ensures retention of the desired characteristics repeatedly in large populations of future generations of the tomato crop.


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9.

Name the source plants of heroin drug. How is it obtained from the plants?


10.

Write the effects of heroin on the human body.


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