KENDRIYA VIDYALAYA SANGATHAN, REGIONAL OFFICE, RAIPURdsUæh; fo|ky; laxBu] {ks=h; dk;kZy;] jk;iqj

2 st Pre Board Examination दूसरा izh&cksMZ ijh{kk Session l= :- 2014-2015 Class d{kk :- XII th

ckjgohaSUBJECT-Biology (044) Theory

Time: 3 hrs. Maximum Marks: 70General Instructions: i) All questions are compulsory. ii) This question paper consists of five sections A, B, C, D & E. Section A contains 5 questions of one mark each, section B contains 5 questions of two marks each, section C contains 12 questions of three marks each, section D contains 1 question of four marks and section E contain 3 questions of five marks each. iii) There is no overall choice. However, an internal choice has been provided in one question of two marks, one question of three marks and all three questions of five marks weightage. A student has to attempt only one of the alternatives in such questions. iv) Wherever necessary, the diagrams drawn should be properly labelled.

Section-A

1. If acrosome of a sperm becomes nonfunctional, which reproductive event will not be observed and why?

2. What is C-peptide?

3. Write action of restriction endonucleases during DNA technology.

4. Which type of inter-specific relationship is present between cuckoo and crow? Define it.

5. In what way UV-B influences our retina and DNA?

Section-B

6. What is placenta? Name any two specific enzymes secreted by it.

7. Why is the DNA better suited genetic material over RNA?

8. Can a child have blood group O, if his parents have blood group ‘A’ and ‘B’. Explain.

OR

When a cross is made between tall plant with yellow seeds (TtYy) and tall plant with green seeds (Ttyy), What proportion of phenotype in the offspring could be expected to be: (a) tall and green (b) dwarf and green.

9. How would you like to educate your careless friend to remain unaffected by HIV?

10. Why do toxic substances concentrations continuously increase in successive trophic level? What is the phenomenon called?

Section-C

11. In most higher plants cross pollination is preferred naturally in order to avoid inbreeding depression. Explain any three methods adopted by plants in this regard.

12. What is parturition? If you are asked to attempt an emergency delivery case then which hormones you would like to use and why for safe delivery?

13. You are a forensic inspector. You collected three samples from crime spot and taken it to the forensic lab. What main steps must to be performed by you to find out the real victim?

14. (a) What is genetic code?

(b) Who propounded triplet concept of genetic code?

(c) Write any three salient features of genetic code.

15. What is mean by divergent evolution? Explain it by giving example of evolution of Darwinian finches at Galapagos Island.

16. Each person receives different kind of non specific defense mechanism from their parents. Name any three types of such defense and explain in brief.

17. Complete the given table:-

Sl.No. Source organism Product Effect/usei Papaver sominiferum ----- -----ii ----- Lactic acid -----iii ----- ----- Immunosuppressive drug

18.(a) What are selectable marker?

(b) Write any two examples of selectable markers useful for E.coli.

(c) How would you confirm the success of insertion/recombination during the creation of r-DNA?

OR

What are plasmids? Who had isolated antibiotic resistance gene from them? Name the source organism from where that was isolated? Write the importance of plasmids in r-DNA technology. .

19. Design an experimental set-up for obtaining millions copies of desired DNA in vitro. Write the role of Taq polymerase during the process.

20. What are Bt-crops? How are these crops benefited from different categories of insect pests? Give suitable example in support of it.

21. Define population density. What are four basic processes that fluctuate population density in a given area during a given period? If N is population density at time t, then find out the population density at time t+1.

22. Interspecific interactions of two species of any population may be beneficial, detrimental or neutral. Explain each of them with the help of a suitable example.

Section-D (VBQ)

23. 19. During an excursion to a botanical garden, the teacher shows an old tree which was on the verge of extinction. As soon as the teacher advanced with the students, some enthusiastic students climbed up the tree and started cutting the branches, collecting its leaves as precious collection. Rajesh instead took photographs of the tree from various angles. The boys mocked at Rajesh while the teacher appreciated him.a) What values did Rajesh possess?b) Why should we conserve biodiversity?c) How can be biodiversity be conserved?

Section-E

24. (a) Draw and label any four parts in mature ovule of an angiosperm plant.

(b) Which cells of the embryo sac are involved in double fertilization? Define double fertilization.

(c) Write the significance of triple fusion.

(d) In what way zygote is different from PEN?

OR

(a) Compare spermatogenesis and oogenesis on to the following bases:- (i) site of process (ii) initiating period (iii) name of the product cell & its Quantity.

(b) What is LH surge?

(c) After rupture of mature graffian follicle, which structure forms from it. Write its significance.

25. (a) Define Hardey Weinberg principle. If in a diploid, allele frequency is “p” and “q” for the allele “A” and “a”, Give the binominal expression of the allelic frequency at equilibrium level.

(b) Explain any three factors which affect the above principle.

OR

What is an operon? How lac operon works when lactose concentration changes (presence/absence) in the E.coli Culture plate?

26. you are an active member of antimaleria campaign programme. Name the causative agents of disease malaria and illustrate how does the pathogen completes its life cycle? Suggest any three ways to prevent malarial infection.

OR

(a) How would you develop virus free plant of a rare plant species infected by retrovirus?

(b) What main steps one would like to practice for production of a hybrid/improved breed?

(c) Define germ plasm.