CBSE Class 12 Biology Sample Paper 2018 Set D

SECTION – A

Q.1 What is heterogamety? Give an example of an organism showing it.

Q.2 What are the characteristic feature of a true breeding line.

Q.3 State what happens when an alien gene is ligated at Sal I site of PBR 322 plasmid?

Q.4 What is the host called that produces a foreign gene product? What is this product called?

Q.5 Name the Green house gases.

SECTION – B

Q.6 Write the function of adenosine deaminase enzyme. State the cause of ADA deficiency in humans. Mention a possible permanent cure for an ADA deficiency patient.

Q.7 a) While carrying out a PCR, denaturation step was missed. What will be its effect on the process?

b) What is Gel electrophoresis?

Q.8 a) Name the major Biomes of India.

b) Why are small animals rarely found in polar region.

Q.9 a) List 2 ways of measuring the standing crop of a trophic level.

b) Construct an ideal pyramid of energy, where 10,00,000 joules of sunlight is available. Label all its trophic level.

Q.10 What are ‘a’ and ‘b’ in the transcription unit represented below.

OR

How does palaeontological evidences support evolution of organism on earth? 

SECTION – C

Q.11 a) A, B, D are 3 independently assorting genes with their recessive alleles a, b, d respectively. A cross made between individual of AabbDD genotype with aabbdd. Find out the types of genotypes of the offspring produced.

b) Differentiate between multiple allelism and pleiotropy, with the help of an example each.

Q.12 Differentiate between dominance, co-dominance and incomplete dominance with example.

Q.13 a) Mention the contribution of genetic maps in human genome project.

b) How does HIV differ from bacteriophage?

c) Why hnRNA is required to undergo splicing?

Q.14 Explain the process of Replication in short.

Q.15 a) State the significance of biochemical similarities amongst diverse organisms in evolution.

b) List 2 main propositions of Oparin and Haldane.

c) Identify the examples of convergent evolution from the following.

i) Flippers of penguin and dolphins.

ii) Eye of octopus and mammals

iii) Vertebrate brains.

Q.16 Draw a labelled diagram to explain S.L. Miller experiment.

Q.17 a) State the effect of UV-B on human eyes.

b) How does Jhum cultivation promote deforestation?

c) Explain the relationship between BOD and DO with a graph.

Q.18 a) What is E1 NiNo effect? Explain how it accounts for biodiversity loss.

b) Differentiate between bad and good ozone.

c) What is biological magnification?

Q.19 a) Why is India said to have greater ecosystem diversity than Norway?

b) Write about David Tillman’s experiment.

c) Draw species area relationship graph.

Q.20 Name the different types of insitu and exsitu conservation.

Q.21 a) Why are oceans less productive?

b) Name the type of food chains responsible for the flow of large fraction of energy in aquatic and terrestrial ecosystem.

c) Give the difference between gaseous and sedimentary cycle.

Q.22 a) How does an alien DNA gain entry into a plant cell by biolistic method.

b) Name two commonly used bio-reactors.

c) What is Bt in Bt cotton?

OR

Give the adaptations in Desert plants.

SECTION – D

Q.23 Biotechnology is the use of living organism or substance obtained from living organism in industrial processes. It has developed in recent times. Today, the term biotechnology is used in a restricted sense to refer to processes which employ genetically modified organism.

a) Name any four substances produced by methods of old biotechnology.

b) Give two examples of products formed using modern biotechnology.

c) What value is learnt from this?

SECTION – E

Q.24 a) Differentiate between Turner’s and Klinefelter’s syndrome.

b) Explain the sex determination in birds.

c) Draw labelled diagram of Harshey Chase experiment.

OR

Explain the process of Translation with labelled diagram.

Q.25 a) Who first constructed rDNA and from where did they isolate the gene?

b) Describe the features of cloning vectors.

OR

a) How was Humulin produced?

b) Describe in short RNAi.

c) Give the full form of ELISA.

Q.26 Name the interaction in each of the following :

a) i) Cuckoo lays her eggs in the crow’s nest.

ii) Orchid grows on a mango tree.

iii) Ticks live on the skin of dogs.

iv) Sea anemone found on the shell of hermit crab.

b) How does our body adopt to low O₂ at high altitude?

c) When an organism is called a conformer? Explain with example.

d) How do desert lizard cope with temperature variations in their environment.

OR

a) What is meant by 10% law?

b) Give two examples of man made ecosystems.

c) Why are mosses and ferns so few? Give reason.

d) What is green house effect?

e) Draw a diagram of electrostatic precipitator.

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