CBSE Class 12 Biology Sample Paper 2013 Set I

SECTION - A

Q.1 Which of the following is a recessive trait of the garden pea plant

a) Full pod shape b) Yellow seed colour c) Terminal flower d) Garden pod colour

Q.2 i) In the absence of predator, which curve (a) or (b) would appropriately depict the prey population?

ii) Give the function of molecular scissors of Biotechnology.

Q.3 The human male and female bird are heterogametic while the human female and male bird are homogametic. Why are they called so?

Q.4 Explain why pyramid of energy is always upright.

Q.5 What is heterochromatin ?

Q.6 Which Mendel’s Law of inheritance is universally acceptable without any exception? State the law.

Q.7 What is the difference between conformers and regulators? Give example.

Q.8 What is the norm set by Euro II for petrol and diesel vehicles?

SECTION – B

Q.9 Name the genes that constitute an operon. How does Lac operon get switched on in presence of lactose?

Q.10 What is a trophic level? Give example.

Q.11 How two adaptive radiation makes one convergent evolution? Give example.

Q.12 What are the hotspots of biodiversity?

Q.13 Define and design a test cross.

Q.14 Explain phenotypic adaptation with an example.

Q.15 a) If the double stranded DNA has 20% cytosine, calculate the percentage of adenine in DNA.

b) What is Bt cotton?

Q.16 Distinguish between the following :

a) Grazing food chain and detritus food chain.

b) Detritus and Litter

Q.17 a) Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?

b) Give two ways by which we can make a host cell accept the negatively charged DNA.

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