CBSE Biology Past year paper Delhi (Set - 3) - 2010, Class 12 | Additional Study Material for NEET PDF Download

 Page 1


  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
CBSE  
 Class XII Biology (Theory) 
Board Paper 2010 – Delhi (Set 3) 
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. Mention one positive and one negative application of amniocentesis. [1] 
 
2. How do animals like fish and snails avoid summer related unfavourable conditions? [1] 
 
3. In a pond there were 200 frogs. 40 more were born in a year. Calculate the birth rate of 
the population. [1] 
 
4. Mention two functions of the codon AUG. [1] 
 
5. Name a molecular diagnostic technique to detect the presence of a pathogen in its early 
stage of infection. [1] 
 
6. Name the scientist who disproved spontaneous generation theory. [1] 
 
7. What is it that prevents a child to suffer from a disease he/she is vaccinated against? 
Give one reason. [1] 
 
8. Why is the enzyme cellulose used for isolating genetic material from plant cells but not 
for animal cells? [1] 
 
 
 
 
 
 
 
Page 2


  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
CBSE  
 Class XII Biology (Theory) 
Board Paper 2010 – Delhi (Set 3) 
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. Mention one positive and one negative application of amniocentesis. [1] 
 
2. How do animals like fish and snails avoid summer related unfavourable conditions? [1] 
 
3. In a pond there were 200 frogs. 40 more were born in a year. Calculate the birth rate of 
the population. [1] 
 
4. Mention two functions of the codon AUG. [1] 
 
5. Name a molecular diagnostic technique to detect the presence of a pathogen in its early 
stage of infection. [1] 
 
6. Name the scientist who disproved spontaneous generation theory. [1] 
 
7. What is it that prevents a child to suffer from a disease he/she is vaccinated against? 
Give one reason. [1] 
 
8. Why is the enzyme cellulose used for isolating genetic material from plant cells but not 
for animal cells? [1] 
 
 
 
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
 
SECTION B 
9. Where does triple fusion take place in a flowering plant? Why is it so called? Mention its 
significance. [2] 
 
10.  Why certain regions have been declared as biodiversity “hot spots” by 
environmentalists of the world? Name any two “hot spot” regions of India. [2] 
 
11.  A moss plant produces a large number of antherozoids but relatively only a few egg 
cells. Why? [2] 
 
12. Why is the introduction of genetically engineered lymphocytes into a ADA deficiency 
patient not a permanent cure? Suggest a possible permanent cure. [2] 
 
13. Study the given food chain and answer the questions that follow: [2] 
 
(a) Give reasons why there is a continuous increase in the DDT content in different 
trophic levels of the chain. 
(b) Name the phenomenon responsible for the increase in DDT content. 
 
14. Honey collection improves when beehives are kept in crop-fields during flowering 
season. Explain. [2] 
OR 
How does addition of a small amount of curd to fresh milk help formation of curd?   
Mention a nutritional quality that gets added to the curd.  
 
 
 
 
Page 3


  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
CBSE  
 Class XII Biology (Theory) 
Board Paper 2010 – Delhi (Set 3) 
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. Mention one positive and one negative application of amniocentesis. [1] 
 
2. How do animals like fish and snails avoid summer related unfavourable conditions? [1] 
 
3. In a pond there were 200 frogs. 40 more were born in a year. Calculate the birth rate of 
the population. [1] 
 
4. Mention two functions of the codon AUG. [1] 
 
5. Name a molecular diagnostic technique to detect the presence of a pathogen in its early 
stage of infection. [1] 
 
6. Name the scientist who disproved spontaneous generation theory. [1] 
 
7. What is it that prevents a child to suffer from a disease he/she is vaccinated against? 
Give one reason. [1] 
 
8. Why is the enzyme cellulose used for isolating genetic material from plant cells but not 
for animal cells? [1] 
 
 
 
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
 
SECTION B 
9. Where does triple fusion take place in a flowering plant? Why is it so called? Mention its 
significance. [2] 
 
10.  Why certain regions have been declared as biodiversity “hot spots” by 
environmentalists of the world? Name any two “hot spot” regions of India. [2] 
 
11.  A moss plant produces a large number of antherozoids but relatively only a few egg 
cells. Why? [2] 
 
12. Why is the introduction of genetically engineered lymphocytes into a ADA deficiency 
patient not a permanent cure? Suggest a possible permanent cure. [2] 
 
13. Study the given food chain and answer the questions that follow: [2] 
 
(a) Give reasons why there is a continuous increase in the DDT content in different 
trophic levels of the chain. 
(b) Name the phenomenon responsible for the increase in DDT content. 
 
14. Honey collection improves when beehives are kept in crop-fields during flowering 
season. Explain. [2] 
OR 
How does addition of a small amount of curd to fresh milk help formation of curd?   
Mention a nutritional quality that gets added to the curd.  
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
15. 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] 
 
16. 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 
 
17. Why are F 2 phenotypic and genotypic ratios same in a cross between red-flowered 
snapdragon and white-flowered snapdragon plants.  
Explain with the help of a cross. [2] 
 
18. How does the floral pattern of Mediterranean orchid Ophrys guarantee cross 
pollination? [2] 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Page 4


  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
CBSE  
 Class XII Biology (Theory) 
Board Paper 2010 – Delhi (Set 3) 
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. Mention one positive and one negative application of amniocentesis. [1] 
 
2. How do animals like fish and snails avoid summer related unfavourable conditions? [1] 
 
3. In a pond there were 200 frogs. 40 more were born in a year. Calculate the birth rate of 
the population. [1] 
 
4. Mention two functions of the codon AUG. [1] 
 
5. Name a molecular diagnostic technique to detect the presence of a pathogen in its early 
stage of infection. [1] 
 
6. Name the scientist who disproved spontaneous generation theory. [1] 
 
7. What is it that prevents a child to suffer from a disease he/she is vaccinated against? 
Give one reason. [1] 
 
8. Why is the enzyme cellulose used for isolating genetic material from plant cells but not 
for animal cells? [1] 
 
 
 
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
 
SECTION B 
9. Where does triple fusion take place in a flowering plant? Why is it so called? Mention its 
significance. [2] 
 
10.  Why certain regions have been declared as biodiversity “hot spots” by 
environmentalists of the world? Name any two “hot spot” regions of India. [2] 
 
11.  A moss plant produces a large number of antherozoids but relatively only a few egg 
cells. Why? [2] 
 
12. Why is the introduction of genetically engineered lymphocytes into a ADA deficiency 
patient not a permanent cure? Suggest a possible permanent cure. [2] 
 
13. Study the given food chain and answer the questions that follow: [2] 
 
(a) Give reasons why there is a continuous increase in the DDT content in different 
trophic levels of the chain. 
(b) Name the phenomenon responsible for the increase in DDT content. 
 
14. Honey collection improves when beehives are kept in crop-fields during flowering 
season. Explain. [2] 
OR 
How does addition of a small amount of curd to fresh milk help formation of curd?   
Mention a nutritional quality that gets added to the curd.  
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
15. 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] 
 
16. 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 
 
17. Why are F 2 phenotypic and genotypic ratios same in a cross between red-flowered 
snapdragon and white-flowered snapdragon plants.  
Explain with the help of a cross. [2] 
 
18. How does the floral pattern of Mediterranean orchid Ophrys guarantee cross 
pollination? [2] 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
SECTION C 
19. During his 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] 
 
20. Describe the termination process of transcription in bacteria. [3] 
 
21. How does RNA interference help in developing resistance in tobacco plant against  
nematode infection? [3] 
 
22. Draw a longitudinal section of a post - pollinated Pistil showing entry of pollen tube 
into a mature embryo-sac. Label filiform apparatus, chalazal end, Hilum, antipodals, 
male gametes and secondary nucleus. [3] 
OR 
Draw a labelled sectional view of seminiferous tubule of a human male. 
 
23. Explain the efforts which must be put in to improve health, hygiene and milk yield of 
cattle in a dairy farm. [3] 
 
24. Explain convergent and divergent evolution with the help of one example of each. [3] 
 
25.  Eco RI is used 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 base pairs the Eco RI will recognise in 
both the DNA segments. Mark the site at which Eco RI will act and cut both the 
segments. 
(ii) Sticky ends formed on both the segments where the two DNA segments will join 
later to form a recombinant DNA. 
 
26.  An antibody molecule is represented as H 2L 2. Explain. [3] 
 
27.  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 
 
 
 
 
Page 5


  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
CBSE  
 Class XII Biology (Theory) 
Board Paper 2010 – Delhi (Set 3) 
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. Mention one positive and one negative application of amniocentesis. [1] 
 
2. How do animals like fish and snails avoid summer related unfavourable conditions? [1] 
 
3. In a pond there were 200 frogs. 40 more were born in a year. Calculate the birth rate of 
the population. [1] 
 
4. Mention two functions of the codon AUG. [1] 
 
5. Name a molecular diagnostic technique to detect the presence of a pathogen in its early 
stage of infection. [1] 
 
6. Name the scientist who disproved spontaneous generation theory. [1] 
 
7. What is it that prevents a child to suffer from a disease he/she is vaccinated against? 
Give one reason. [1] 
 
8. Why is the enzyme cellulose used for isolating genetic material from plant cells but not 
for animal cells? [1] 
 
 
 
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
 
SECTION B 
9. Where does triple fusion take place in a flowering plant? Why is it so called? Mention its 
significance. [2] 
 
10.  Why certain regions have been declared as biodiversity “hot spots” by 
environmentalists of the world? Name any two “hot spot” regions of India. [2] 
 
11.  A moss plant produces a large number of antherozoids but relatively only a few egg 
cells. Why? [2] 
 
12. Why is the introduction of genetically engineered lymphocytes into a ADA deficiency 
patient not a permanent cure? Suggest a possible permanent cure. [2] 
 
13. Study the given food chain and answer the questions that follow: [2] 
 
(a) Give reasons why there is a continuous increase in the DDT content in different 
trophic levels of the chain. 
(b) Name the phenomenon responsible for the increase in DDT content. 
 
14. Honey collection improves when beehives are kept in crop-fields during flowering 
season. Explain. [2] 
OR 
How does addition of a small amount of curd to fresh milk help formation of curd?   
Mention a nutritional quality that gets added to the curd.  
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
15. 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] 
 
16. 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 
 
17. Why are F 2 phenotypic and genotypic ratios same in a cross between red-flowered 
snapdragon and white-flowered snapdragon plants.  
Explain with the help of a cross. [2] 
 
18. How does the floral pattern of Mediterranean orchid Ophrys guarantee cross 
pollination? [2] 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
SECTION C 
19. During his 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] 
 
20. Describe the termination process of transcription in bacteria. [3] 
 
21. How does RNA interference help in developing resistance in tobacco plant against  
nematode infection? [3] 
 
22. Draw a longitudinal section of a post - pollinated Pistil showing entry of pollen tube 
into a mature embryo-sac. Label filiform apparatus, chalazal end, Hilum, antipodals, 
male gametes and secondary nucleus. [3] 
OR 
Draw a labelled sectional view of seminiferous tubule of a human male. 
 
23. Explain the efforts which must be put in to improve health, hygiene and milk yield of 
cattle in a dairy farm. [3] 
 
24. Explain convergent and divergent evolution with the help of one example of each. [3] 
 
25.  Eco RI is used 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 base pairs the Eco RI will recognise in 
both the DNA segments. Mark the site at which Eco RI will act and cut both the 
segments. 
(ii) Sticky ends formed on both the segments where the two DNA segments will join 
later to form a recombinant DNA. 
 
26.  An antibody molecule is represented as H 2L 2. Explain. [3] 
 
27.  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 
 
 
 
 
  
 
CBSE XII  |  Biology 
Board Paper – 2010 – Delhi – Set 3 
 
     
28. When and where are primary oocytes formed in a human female? Trace the 
development of these oocytes till ovulation (in menstrual cycle). How do gonadotropins 
influence this developmental 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 zygote up to its implantation in the uterus. 
(c) Name and draw a labelled sectional view of the embryonic stage that gets implanted. 
  
29. 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: 
Fragmentation; leaching; catabolism; humification and mineralization. 
 
30. Write the symptoms of haemophilia and sickle-cell anaemia in humans. 
Explain how the inheritance pattern of the two diseases differs from each other. [5] 
OR 
(a) Write Hardy-Weinberg principle. 
(b) Explain the three different ways that natural selection can affect the frequency of a 
heritable trait in a population shown in the graph given below.