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

11.

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

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12.

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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13.

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

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14.

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

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15.

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

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16.

How does a restriction nuclease function? Explain.


Each restriction endonuclease functions by ‘inspecting’ the length of a DNA sequence. Once it finds its specific recognition sequence, it binds to the DNA and cuts each of the two strands of the double helix at specific points in their sugar -phosphate backbones. Each restriction endonuclease recognizes a specific palindromic nucleotide sequences in the DNA.

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17.

How have transgenic animals proved to be beneficial in:
(a) Production of biological products
(b)Chemical safety testing.

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18.

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

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19.

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

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20.

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

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