KENDRIYA VIAYALAYA NO.1, ICHHANATH, SURAT
First Pre-Board Examination 2012-13
Class –XII Subject –Biology
Time—3hours M.M.-70
Instructions-----
Note-i) All questions are compulsory.
ii) Questions 1—8 of section A are VSA type and carry one mark each.
iii) Questions 9---18 of section B are SA type and carry two marks each.
iv) Questions 19---27 of section C carry three marks each.
v) Questions 28—30 of section D are LA type and carry5marks each.
(Section-A)
Q.1 A bilobed dithecous anther has 100 microspore mother cells per microsporangium. How many male gametophytes this anther can produce?
Q.2 Mention two functions of codon---AUG.
Q.3 Name the scientist who disproved theory of spontaneous generation of life.
Q.4 What is it that prevents a child from a disease he /she is vaccinated against? Give one reason.
Q.5 Why is enzyme cellulase is used to isolate genetic material from a plant cell but not from an animal cell?
Q.6 Name a molecular diagnostic technique to detect the presence of a pathogen in its early stage of infection.
Q.7. If 8 individuals in a laboratory population of 80 fruit-flies died in a week, then what would Be the death rate for population for the said period?
Q.8 Mention one positive and one negative application of amniocentesis.
(Section –B)
Q.9 Mention the ploidy of the zygote and PEN in an Angiosperm. Also write the
Cause of the difference in them.
Q.10 A moss plant produces a large number of antherozoides but relatively only a
Few egg cells. Why?
Q.11 Write the working of an electrostatic precipitator.
Q.12 Name the type of food chain for the flow of larger fraction of energy in an aquatic and a terrestrial ecosystem respectively. Mention one difference between the two food chains.
Q.13 How does a test-cross help in identifying the genotypes of the organism? Explain.
Q.14 Name the host and site where the following occur in the life-cycle of malarial parasite
(a) formation of gametocytes (b) fusion of gametocytes
Q15 Honey collection improves when behives are kept in crop-fields during flowering season. Explain.
OR
How does addition of small amount of curd to fresh milk help formation of curd?
Mention a nutritional quality that gets added to the curd.
Q16 Why is the introduction of genetically engineered lymphocytes in to a ADA deficiency patient not a permanent cure? Suggest a permanent cure.
Q.17 How does the floral pattern of Mediterranean orchid Ophrys guarantee cross pollination?
Q.18 Mention any two reasons for high biodiversity in tropical rain forests.
(Section-C)
Q.19 Draw neat diagram of 7celled angiospermic ovule and label filiform apparatus,
Chalazal end , antipodals and secondary nucleus.
Q.20 During his studies on genes in Drosophila that were sex-linked,T.H.Morgan
Found F2phenotypic ratios deviated from expected 9:3:3:1. Explain the conclusion he
arrived at.
OR
Who proposed chromosomal theory of inheritance ?Write any two similarities in
Behaviour of chromosomes and genes during inheritance.
Q.21 Describe lac operon in the presence of an inducer with the help of diagram only.
Q.22 Name the type of human cell which is being attached by HIV in he human body.
Explain the events that occur in the cell which further lead to cause AIDS.
Q23. Explain the efforts which must be put in to improve health, hygiene and milk yield of
Cattle in a dairy farm.
Q24. Identiy a,b,c,d,e and f in the table given below______
Organism / Bioactive molecule / UseMonascus pepureus / a / b
c / d / antibiotic
e / Cyclosporin A / f
Q.25 How does RNA interference help in developing resistance in tobacco plant against
Nematode infection?
Q.26 Write the popular term used for recombinant DNA technology. Name the enzymes and
Vectors used in this technique.
Q.27 (a) Name the primates that lived about 15million years ago.List their characterstic
Features.
(b) Write the order in which Neanderthals, Homo habilis and Homo erectus appeared
On the earth.
© When did modern Homo sapiens appear on this planet .
(Section-D)
Q.28 (i) Make a labeled sketch of the experiment set up used by Stanley Miller. 3
(ii) What was the purpose of the experiment? 1
(iii) Name the compounds synthesized in this experiment. 1
OR
(i) Why is the human Genome Project called a mega project? 3
(ii) State any two applications of DNA fingerprinting. 1
(iii) AUG GAC CUG AUA UUU UGA is the base sequence in a strand of Mrna:
(a) Write the base sequence of the DNA strand from which it has been transcribed. 1/2
(b) Upon translation, how many amino acids will the resulting peptide have1/2
Q.29 When and where are primary Oocytes formed in a human female? Trace the development of these oocytes till ovulation. How do gonadotropins influence this process?5
OR
Describe briefly the development of a dicot embryo and explain its structure along
With diagram.
Q.30 (i) Name any three limitations of ecological pyramids 3
(ii) Differentiate primary succession from secondary one. 2
(iii)What is common between hydrarch and xerarch successions? 1
OR
A school going child of a reputed family of your locality become addicted to drug
Abuse recently .Write various warning signs which are to be seen in him by his
parents in coming few days .(write any ten only). 1/2 x10
Best Of Luck