CBSE Biology Past year paper Delhi (Set - 1) - 2010, Class 12 | Additional Study Material for NEET PDF Download

 Page 1


  
 
CBSE XII  |  Biology 
Board Paper 2010 – Delhi – Set 1 
 
     
CBSE 
 Class XII Biology (Theory) 
Board Paper 2010 - Delhi (Set 1) 
Time: 3 hrs Total Marks: 70 
 
General Instruction: 
1. All questions are compulsory. 
2. This question paper consists of four Sections A, B C and D. Section A contains 8  
questions of one mark each, Section B is of 10 questions of two marks each, Section C is 
of 9 questions of three marks each, and Section D is 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 all the three questions of 5 marks 
weight age. A student has to attempt only one of the alternatives in such questions. 
4. Wherever necessary, the diagrams drawn should be neat and properly labelled. 
 
SECTION A 
1. A bilobed, dithcous anther has 100 microspore mother cells per microsporangium how 
many male gametophytes this anther can produce? [1] 
 
2. Mention two functions of the codon AUG. [1] 
 
3. Name the scientist who disproved spontaneous generation theory. [1] 
 
4. What is it that prevents a child to suffer from a disease he/she is vaccinated against? 
Give one reason. [1] 
 
5. Why is the enzyme cellulase used for isolating genetic material from plant cells but not 
for animal cells? [1] 
 
6. Name a molecular diagnostic technique to detect the presence of a pathogen in its early 
stage of infection. [1] 
 
7. If 8 individuals in a laboratory population of 80 fruitflies died in a week then what 
would be the death rate of population for the said period? [1] 
 
8. Why is reproduction essential for organism? [1] 
 
Page 2


  
 
CBSE XII  |  Biology 
Board Paper 2010 – Delhi – Set 1 
 
     
CBSE 
 Class XII Biology (Theory) 
Board Paper 2010 - Delhi (Set 1) 
Time: 3 hrs Total Marks: 70 
 
General Instruction: 
1. All questions are compulsory. 
2. This question paper consists of four Sections A, B C and D. Section A contains 8  
questions of one mark each, Section B is of 10 questions of two marks each, Section C is 
of 9 questions of three marks each, and Section D is 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 all the three questions of 5 marks 
weight age. A student has to attempt only one of the alternatives in such questions. 
4. Wherever necessary, the diagrams drawn should be neat and properly labelled. 
 
SECTION A 
1. A bilobed, dithcous anther has 100 microspore mother cells per microsporangium how 
many male gametophytes this anther can produce? [1] 
 
2. Mention two functions of the codon AUG. [1] 
 
3. Name the scientist who disproved spontaneous generation theory. [1] 
 
4. What is it that prevents a child to suffer from a disease he/she is vaccinated against? 
Give one reason. [1] 
 
5. Why is the enzyme cellulase used for isolating genetic material from plant cells but not 
for animal cells? [1] 
 
6. Name a molecular diagnostic technique to detect the presence of a pathogen in its early 
stage of infection. [1] 
 
7. If 8 individuals in a laboratory population of 80 fruitflies died in a week then what 
would be the death rate of population for the said period? [1] 
 
8. Why is reproduction essential for organism? [1] 
 
  
 
CBSE XII  |  Biology 
Board Paper 2010 – Delhi – Set 1 
 
     
SECTION B 
 
9. A moss plant produces a large number of antherozoids but relatively only few egg cells. 
Why? [2] 
 
10. Mention the reasons for difference in ploidy of zygote and primary endosperm nucleus 
in an angiosperm. [2] 
 
11. How does an electrostatic precipitator work to remove particulate pollutants released 
from the thermal power plants? [2] 
 
12. Name the type of food chains responsible for the flow of larger fraction of energy in an 
aquatic and a terrestrial ecosystem respectively. Mention one difference between the 
two food chains. [2] 
 
13. How does a test-cross help in identifying the genotype of the organism? Explain. [2] 
 
14. Name the host and the site where the following occur in the life-cycle of a malarial 
parasite. [2] 
(a) Formation of gametocytes 
(b) Fusion of gametocytes 
 
15. Honey collection improves when beehives are kept in crop-fields during flowering 
season. Explain. [2] 
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. 
 
16. Why is the introduction of genetically engineered lymphocytes into a ADA deficiency 
patient not a permanent cure? Suggest a possible permanent cure. [2] 
 
17. How does the floral pattern on Mediterranean orchid Ophrys guarantee cross 
pollination? [2] 
 
18. In the biosphere immense biological diversity exists at all levels of biological 
organization. Explain any two levels of biodiversity. [2] 
 
 
 
 
 
 
 
Page 3


  
 
CBSE XII  |  Biology 
Board Paper 2010 – Delhi – Set 1 
 
     
CBSE 
 Class XII Biology (Theory) 
Board Paper 2010 - Delhi (Set 1) 
Time: 3 hrs Total Marks: 70 
 
General Instruction: 
1. All questions are compulsory. 
2. This question paper consists of four Sections A, B C and D. Section A contains 8  
questions of one mark each, Section B is of 10 questions of two marks each, Section C is 
of 9 questions of three marks each, and Section D is 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 all the three questions of 5 marks 
weight age. A student has to attempt only one of the alternatives in such questions. 
4. Wherever necessary, the diagrams drawn should be neat and properly labelled. 
 
SECTION A 
1. A bilobed, dithcous anther has 100 microspore mother cells per microsporangium how 
many male gametophytes this anther can produce? [1] 
 
2. Mention two functions of the codon AUG. [1] 
 
3. Name the scientist who disproved spontaneous generation theory. [1] 
 
4. What is it that prevents a child to suffer from a disease he/she is vaccinated against? 
Give one reason. [1] 
 
5. Why is the enzyme cellulase used for isolating genetic material from plant cells but not 
for animal cells? [1] 
 
6. Name a molecular diagnostic technique to detect the presence of a pathogen in its early 
stage of infection. [1] 
 
7. If 8 individuals in a laboratory population of 80 fruitflies died in a week then what 
would be the death rate of population for the said period? [1] 
 
8. Why is reproduction essential for organism? [1] 
 
  
 
CBSE XII  |  Biology 
Board Paper 2010 – Delhi – Set 1 
 
     
SECTION B 
 
9. A moss plant produces a large number of antherozoids but relatively only few egg cells. 
Why? [2] 
 
10. Mention the reasons for difference in ploidy of zygote and primary endosperm nucleus 
in an angiosperm. [2] 
 
11. How does an electrostatic precipitator work to remove particulate pollutants released 
from the thermal power plants? [2] 
 
12. Name the type of food chains responsible for the flow of larger fraction of energy in an 
aquatic and a terrestrial ecosystem respectively. Mention one difference between the 
two food chains. [2] 
 
13. How does a test-cross help in identifying the genotype of the organism? Explain. [2] 
 
14. Name the host and the site where the following occur in the life-cycle of a malarial 
parasite. [2] 
(a) Formation of gametocytes 
(b) Fusion of gametocytes 
 
15. Honey collection improves when beehives are kept in crop-fields during flowering 
season. Explain. [2] 
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. 
 
16. Why is the introduction of genetically engineered lymphocytes into a ADA deficiency 
patient not a permanent cure? Suggest a possible permanent cure. [2] 
 
17. How does the floral pattern on Mediterranean orchid Ophrys guarantee cross 
pollination? [2] 
 
18. In the biosphere immense biological diversity exists at all levels of biological 
organization. Explain any two levels of biodiversity. [2] 
 
 
 
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper 2010 – Delhi – Set 1 
 
     
SECTION C 
 
19. Draw a longitudinal section of a post-pollinated pistil showing entry of pollen tube into 
mature embryo-sac. Label filiform apparatus, chalazal end, Hilum antipodals, male 
gametes and secondary nucleus. 
OR 
Draw a labelled sectional view of seminiferous tubule of a human male. [3] 
 
20. During the studies on genes in Drosophila that were sex-linked T.H. Morgan found F 2 – 
population phenotypic ratios deviated from expected 9:3:3:1. Explain the conclusion he 
arrived at. [3] 
 
21. Describe the intiation process of transcription in Bacteria.  [3] 
 
22. Explain convergent and divergent evolution with the help of one example of each. [3] 
 
23. Name the type of human cell HIV attacks on its entry into the body. Explain the events 
that occur in the cell which further lead to cause immunodeficiency syndrome. [3] 
 
24. Explain the efforts which must be put in to improve health, hygiene and milk yield of 
cattle in a diary farm. [3] 
  
25. Identify a, b, c, d, e and f in the table given below. [3] 
 
Organism Bioactive molecule Use 
1. Monascus perpures 
(Yeast) 
a b 
2.               c d antibiotic 
3.               e Cycloporin A f 
 
 
26. Eco RI is used to cut a segment of foreign DNA and that of a vector DNA to form a 
recombinant DNA. Show with the help of schematic diagrams. [3] 
(i) The set of palindromic nucleotide sequence of bases pairs the Eco RI will recognize  
in both the DNA segments. Mark the site at which ECO RI will act and cut both the 
segments. 
(ii) Sticky ends are formed on both the segments where the two DNA segments will join 
later to form a recombinant DNA. 
 
27. How does RNA interface help in developing resistance in tobacco plant against 
nematode in infection? [3] 
 
Page 4


  
 
CBSE XII  |  Biology 
Board Paper 2010 – Delhi – Set 1 
 
     
CBSE 
 Class XII Biology (Theory) 
Board Paper 2010 - Delhi (Set 1) 
Time: 3 hrs Total Marks: 70 
 
General Instruction: 
1. All questions are compulsory. 
2. This question paper consists of four Sections A, B C and D. Section A contains 8  
questions of one mark each, Section B is of 10 questions of two marks each, Section C is 
of 9 questions of three marks each, and Section D is 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 all the three questions of 5 marks 
weight age. A student has to attempt only one of the alternatives in such questions. 
4. Wherever necessary, the diagrams drawn should be neat and properly labelled. 
 
SECTION A 
1. A bilobed, dithcous anther has 100 microspore mother cells per microsporangium how 
many male gametophytes this anther can produce? [1] 
 
2. Mention two functions of the codon AUG. [1] 
 
3. Name the scientist who disproved spontaneous generation theory. [1] 
 
4. What is it that prevents a child to suffer from a disease he/she is vaccinated against? 
Give one reason. [1] 
 
5. Why is the enzyme cellulase used for isolating genetic material from plant cells but not 
for animal cells? [1] 
 
6. Name a molecular diagnostic technique to detect the presence of a pathogen in its early 
stage of infection. [1] 
 
7. If 8 individuals in a laboratory population of 80 fruitflies died in a week then what 
would be the death rate of population for the said period? [1] 
 
8. Why is reproduction essential for organism? [1] 
 
  
 
CBSE XII  |  Biology 
Board Paper 2010 – Delhi – Set 1 
 
     
SECTION B 
 
9. A moss plant produces a large number of antherozoids but relatively only few egg cells. 
Why? [2] 
 
10. Mention the reasons for difference in ploidy of zygote and primary endosperm nucleus 
in an angiosperm. [2] 
 
11. How does an electrostatic precipitator work to remove particulate pollutants released 
from the thermal power plants? [2] 
 
12. Name the type of food chains responsible for the flow of larger fraction of energy in an 
aquatic and a terrestrial ecosystem respectively. Mention one difference between the 
two food chains. [2] 
 
13. How does a test-cross help in identifying the genotype of the organism? Explain. [2] 
 
14. Name the host and the site where the following occur in the life-cycle of a malarial 
parasite. [2] 
(a) Formation of gametocytes 
(b) Fusion of gametocytes 
 
15. Honey collection improves when beehives are kept in crop-fields during flowering 
season. Explain. [2] 
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. 
 
16. Why is the introduction of genetically engineered lymphocytes into a ADA deficiency 
patient not a permanent cure? Suggest a possible permanent cure. [2] 
 
17. How does the floral pattern on Mediterranean orchid Ophrys guarantee cross 
pollination? [2] 
 
18. In the biosphere immense biological diversity exists at all levels of biological 
organization. Explain any two levels of biodiversity. [2] 
 
 
 
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper 2010 – Delhi – Set 1 
 
     
SECTION C 
 
19. Draw a longitudinal section of a post-pollinated pistil showing entry of pollen tube into 
mature embryo-sac. Label filiform apparatus, chalazal end, Hilum antipodals, male 
gametes and secondary nucleus. 
OR 
Draw a labelled sectional view of seminiferous tubule of a human male. [3] 
 
20. During the studies on genes in Drosophila that were sex-linked T.H. Morgan found F 2 – 
population phenotypic ratios deviated from expected 9:3:3:1. Explain the conclusion he 
arrived at. [3] 
 
21. Describe the intiation process of transcription in Bacteria.  [3] 
 
22. Explain convergent and divergent evolution with the help of one example of each. [3] 
 
23. Name the type of human cell HIV attacks on its entry into the body. Explain the events 
that occur in the cell which further lead to cause immunodeficiency syndrome. [3] 
 
24. Explain the efforts which must be put in to improve health, hygiene and milk yield of 
cattle in a diary farm. [3] 
  
25. Identify a, b, c, d, e and f in the table given below. [3] 
 
Organism Bioactive molecule Use 
1. Monascus perpures 
(Yeast) 
a b 
2.               c d antibiotic 
3.               e Cycloporin A f 
 
 
26. Eco RI is used to cut a segment of foreign DNA and that of a vector DNA to form a 
recombinant DNA. Show with the help of schematic diagrams. [3] 
(i) The set of palindromic nucleotide sequence of bases pairs the Eco RI will recognize  
in both the DNA segments. Mark the site at which ECO RI will act and cut both the 
segments. 
(ii) Sticky ends are formed on both the segments where the two DNA segments will join 
later to form a recombinant DNA. 
 
27. How does RNA interface help in developing resistance in tobacco plant against 
nematode in infection? [3] 
 
  
 
CBSE XII  |  Biology 
Board Paper 2010 – Delhi – Set 1 
 
     
SECTION D 
28.  [5] 
(a) How does a chromosomal disorder differ from a Mendelian disorder? 
(b) Name any two chromosomal aberration associated disorders. 
(c) List the characteristics of the disorders mentioned above that help in their diagnosis. 
OR 
Fitness is the end result of the ability to adapt and get selected by nature. Explain with 
suitable example. 
 
29. When and where are primary oocytes formed in a human female? Trace the 
development of these occytes till ovulation (in menstrual cycle). How do gonadotropins 
influence this development process? [5] 
OR 
(a) Explain the events taking place at the time of fertilization of an ovum in a human female. 
(b) Trace the development of the zygote up to the implantation in the uterus. 
(c) Name and draw a labelled sectional view of the embryonic stage that gets implanted. 
 
30. Draw and explain a logistic curve for a population of density (N) at time (t) whose 
intrinsic rate of natural increase is (r) and carrying capacity is (k). [5] 
OR 
Describe the process of decomposition of detritus under the following heads: 
Fragmentational leaching; catabolism; humification and minerlization.