KENDRIYA VIDYALAYA SANGATHAN, ERNAKULAM REGION

PRE BOARD EXAMINATION

SUB : BIOLOGY (044)

CLASS XII (2016-2017)

TIME; 3 HRS MAX.MARKS:70

General Instructions

1. All questions are compulsory

2. The question paper consist of four sections A, B, C , D and E Section A consist of 5

questions of one mark each. Section B is of 5 questions of two marks each. Section C is of

12 questions of three marks each. Section D is of 1question of 4 marks and Section E of 3

questions of five marks each.

3. There is no overall choice. However, an internal choice has been provided in one

question of 2 marks, one question of 3 marks and three questions of 5 marks weightage. A

student has to answer only one of the alternatives in such questions

4. Wherever necessary, the diagrams drawn should be neat and properly labelled

Section A

1. The body size of crow and parrot are not very different, yet their life span shows wide difference. Give the life span.

2. In a monohybrid cross the F2 generation shows identical phenotypic and genotypic ratios. What does it tell us about the nature of alleles involved?

3. In which technique do we use Taq polymerase enzyme 4. Why is the introduction of genetically engineered lymphocytes into an ADA

deficient patient not a permanent cure?5. When and why do some animals like snails go into aestivation?

Section B6. Name the contraceptive developed by CDRI Lucknow.What are its

Special features as compared to other contraceptive7. What is polygenic inheritance? Give two examples

ORWho proposed embryological evidence for organic evolution?State the Biogenetic law

8. Identify A, B, C and D in the table given below

Microbes Product Biological activity Medical ailment/procedure

A Streptokinase Clot Buster DTrichoderma polysporum

B C Transplant surgery

9.. Giving two reasons explain why there is more species diversity in tropical latitudes than in temperate ones

10.

Identify the type of the given ecological pyramid and give example each of pyramid of number and pyramid of biomass in such cases

Section C

11. Describe in sequence the events that lead to the development of a pollen mother cell into a three celled pollen grain.

12. Draw a labelled diagram of a microscopic structure of mammalian sperm

OR

Draw a diagrammatic section view of Human Ovary showing the various stages of follicle growing in it

13. A.Write the formula to calculate allele frequency in future generation according to Hardy-Weinberg equilibrium

b. What do you interpret when there is a disturbance in Hardy-Weinberg Equilibrium?

c. What are the factors that affect the Hardy-Weinberg Equilibrium?

14. Name and describe the technique that will help in solving a case of paternity dispute over the custody of a child by two different families

15. a Why did Hershey and Chase use 35S and 32 P for labelling in their experiment.

b. Why is DNA considered as a stable genetic material than RNA

16.Prevention is better than cure “Suggest some measures that can be adopted by students of your age group to prevent and control alcohol and drug abuse among adolescents

17. Transgenic Tobacco plant protects itself from the attack of Nematode.

a. Name the Nematode.

b. Explain RNA interference

18.

a.Name the organism in which the vector is inserted to get the copies of the desired gene

b. Mention the area labelled in the vector responsible for controlling the copy number of the inserted gene.

C. Name and explain the role of a selectable marker in the vector shown

19. You have developed a GM organism. Which government organisation will you approach to obtain clearance for its mass production? Why is such a body necessary? Give two reasons

20. How does production of Polyblend reduce the plastic wastes? Explain the case study of Mr. Ahmed Khan of Bangalore

21.Create an aquatic food chain in a water body into which effluents flow from a pesticide factory Diagrammatically Representation Bio magnification in the food chain

22. Mention any four methods by which the vehicular air pollution can be controlled

Section D

23.The film show arranged by the school health club members on the causes , harmful

effects and preventive measures against Vector born diseases had a greater impact on

Asok .In the evening his mother objects him emptying the fish tank in the living room. She

says no harmful mosquito survives in fresh water. It was not an easy task for Asok into

convince her mother

a. What would you say to convince her if you were in Asoks place?

b. Suggest three effective methods to prevent and control the spread of vector born

diseases?

24. Give reason why

a. Most zygotes in Angiosperms divide only after certain amount of Endosperm is formed

b. Ground nut seeds are nonalbuminous and castor seeds are albuminous

c. Micropyle remain as a small pore in the seed coat of a seed

d.Integument of the ovule harden and the water content is highly reduced as the seed mature

e. Apple and Cashew are not called true fruits

OR

a. Trace the development of Zygote up to its implantation in the Uterus

b. Name and draw a labelled sectional view of the embryonic stage that gets implanted

25. What is semi conservative DNA replication? How was it experimentally proved and by whom?

OR

A homozygous tall pea plant with green seeds is crossed with a dwarf pea plant with yellow seeds

a. What would be the phenotype and genotype of F1?b. Work out the phenotypic ratio of F2 generation with the help of a Punnet Square

26. A person has been diagnosed with HIV positive

a. Name the test which the person has undergone

b. Write the full name of the pathogen involved and the disease

c. Which particular cells of this person are likely to be destroyed?

d. Expand NACO

OR

a. Name the infective stage of Plasmodium which Anopheles mosquito takes in along with the blood meal of an infected person

b. Why does the infection cause fever in Humans?

c. Give a flow chart of the part of the life cycle of this parasite passed in the insect