CBSE Biology Past year paper Delhi (Set - 2) - 2012, Class 12 | Additional Study Material for NEET PDF Download

 Page 1


  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
CBSE  
Class XII Biology (Theory) 
Board Paper 2012 – Delhi (Set 2) 
Time: 3 hour    Total Marks: 70              Total Marks: 70 
 
General Instructions: 
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 
weightage. 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. Cucurbits and papaya plants bear staminate and pistillate flowers. Mention the 
categories they are put under separately on the basis of the type of flowers they 
bear. [1] 
 
2. A garden pea plant (A) produced inflated yellow pod, and another plant (B) of the same 
species produced constricted green pods. Identify the dominant traits.         [1] 
 
3. Write what do phytophagous insects feed on.              [1] 
 
4. What is the interaction called between Cuscuta and shoe flower bush?         [1] 
 
5. When do the oogenesis and the spermatogenesis initiate in human females and males 
respectively?                 [1] 
 
6. How does smoking tobacco in human lead to oxygen deficiency in their body?        [1] 
 
7. State the significance of the study of fossils in evolution.           [1] 
 
8. Name the following:                 [1] 
(a) The semi-dwarf variety of wheat is high-yielding and disease-resistant. 
(b) Anyone inter-specific hybrid mammal. 
 
 
 
Page 2


  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
CBSE  
Class XII Biology (Theory) 
Board Paper 2012 – Delhi (Set 2) 
Time: 3 hour    Total Marks: 70              Total Marks: 70 
 
General Instructions: 
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 
weightage. 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. Cucurbits and papaya plants bear staminate and pistillate flowers. Mention the 
categories they are put under separately on the basis of the type of flowers they 
bear. [1] 
 
2. A garden pea plant (A) produced inflated yellow pod, and another plant (B) of the same 
species produced constricted green pods. Identify the dominant traits.         [1] 
 
3. Write what do phytophagous insects feed on.              [1] 
 
4. What is the interaction called between Cuscuta and shoe flower bush?         [1] 
 
5. When do the oogenesis and the spermatogenesis initiate in human females and males 
respectively?                 [1] 
 
6. How does smoking tobacco in human lead to oxygen deficiency in their body?        [1] 
 
7. State the significance of the study of fossils in evolution.           [1] 
 
8. Name the following:                 [1] 
(a) The semi-dwarf variety of wheat is high-yielding and disease-resistant. 
(b) Anyone inter-specific hybrid mammal. 
 
 
 
  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
 
SECTION B 
9. [2] 
(a) Highlight the role of thymus as a lymphoid organ. 
(b) Name the cells that are released from the above mentioned gland. Mention how they 
help in immunity. 
 
10. Why do clown fish and sea anemone pair up? What is this relationship called?        [2] 
 
11. Some organisms suspend their metabolic activities to survive in unfavourable 
conditions. Explain with the help of any four examples.           [2] 
 
12.                    [2] 
(a) State the role of DNA ligase in biotechnology. 
(b) What happens when Meloidegyne incognitia consumes cells with RNAi gene? 
 
13. Draw a schematic diagram of a part of double stranded dinucleotide DNA chain having 
all the four nitrogenous bases and showing the correct polarity.                 [2] 
 
14. Name of parasite that causes filariasis in humans. Mention its two diagnostic symptoms. 
How is this transmitted to others?                                    [2] 
 
15. Name the source of streptokinase. How does this bioreactor molecule function in our 
body?                  [2] 
OR 
How do Mycorrhizae act as biofertilizers? Explain. Name a genus of fungi that forms a  
mycorrhizal association with plants. 
 
16.                    [2] 
(a) State the difference between meiocyte and gamete with respect to chromosome 
number. 
(b) Why is a whiptail lizard referred to as parthenogenetic? 
 
17. Explain the work carried out by Cohen and Boyer that contributed immensely in 
biotechnology.                 [2] 
 
18. Where is sporopollenin present in plants? State its significance with reference to its 
chemical nature.                             [2] 
  
 
 
 
 
Page 3


  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
CBSE  
Class XII Biology (Theory) 
Board Paper 2012 – Delhi (Set 2) 
Time: 3 hour    Total Marks: 70              Total Marks: 70 
 
General Instructions: 
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 
weightage. 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. Cucurbits and papaya plants bear staminate and pistillate flowers. Mention the 
categories they are put under separately on the basis of the type of flowers they 
bear. [1] 
 
2. A garden pea plant (A) produced inflated yellow pod, and another plant (B) of the same 
species produced constricted green pods. Identify the dominant traits.         [1] 
 
3. Write what do phytophagous insects feed on.              [1] 
 
4. What is the interaction called between Cuscuta and shoe flower bush?         [1] 
 
5. When do the oogenesis and the spermatogenesis initiate in human females and males 
respectively?                 [1] 
 
6. How does smoking tobacco in human lead to oxygen deficiency in their body?        [1] 
 
7. State the significance of the study of fossils in evolution.           [1] 
 
8. Name the following:                 [1] 
(a) The semi-dwarf variety of wheat is high-yielding and disease-resistant. 
(b) Anyone inter-specific hybrid mammal. 
 
 
 
  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
 
SECTION B 
9. [2] 
(a) Highlight the role of thymus as a lymphoid organ. 
(b) Name the cells that are released from the above mentioned gland. Mention how they 
help in immunity. 
 
10. Why do clown fish and sea anemone pair up? What is this relationship called?        [2] 
 
11. Some organisms suspend their metabolic activities to survive in unfavourable 
conditions. Explain with the help of any four examples.           [2] 
 
12.                    [2] 
(a) State the role of DNA ligase in biotechnology. 
(b) What happens when Meloidegyne incognitia consumes cells with RNAi gene? 
 
13. Draw a schematic diagram of a part of double stranded dinucleotide DNA chain having 
all the four nitrogenous bases and showing the correct polarity.                 [2] 
 
14. Name of parasite that causes filariasis in humans. Mention its two diagnostic symptoms. 
How is this transmitted to others?                                    [2] 
 
15. Name the source of streptokinase. How does this bioreactor molecule function in our 
body?                  [2] 
OR 
How do Mycorrhizae act as biofertilizers? Explain. Name a genus of fungi that forms a  
mycorrhizal association with plants. 
 
16.                    [2] 
(a) State the difference between meiocyte and gamete with respect to chromosome 
number. 
(b) Why is a whiptail lizard referred to as parthenogenetic? 
 
17. Explain the work carried out by Cohen and Boyer that contributed immensely in 
biotechnology.                 [2] 
 
18. Where is sporopollenin present in plants? State its significance with reference to its 
chemical nature.                             [2] 
  
 
 
 
 
  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
 
SECTION C 
 
19. Write the function of each of the following:                          [3] 
(a) Middle piece in human sperm. 
(b) Tapetum in anthers. 
(c) Luteinizing hormone in human males. 
 
20. Given below is the representation of amino acid composition of the relevant translated 
portion of ß - chain of haemoglobin, related to the shape of human red blood cells.    [3] 
                                   
 
(a) Is this representation indicating a normal human or a sufferer from certain related 
genetic disease? Give reason in support of your answer. 
(b) What difference would be noticed in the phenotype of the normal and the sufferer 
related to this gene? 
(c) Who are likely to suffer more from the defect related to the gene represented the 
males, the females or both males and females equally? And why? 
 
21. Draw a schematic sketch of pBR 322 plasmid and label the following in it:                     [3] 
(a) Any two restriction sites. 
(b) Ori and rop genes. 
(c) An antibiotic resistant gene. 
 
22. It is established that RNA is the first genetic material. Explain giving three reasons.     [3] 
OR 
(a) Name the enzyme responsible for the transcription of tRNA and the amino acid the 
initiator tRNA gets linked with. 
(b) Explain the role of initiator tRNA in initiation of protein synthesis. 
Page 4


  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
CBSE  
Class XII Biology (Theory) 
Board Paper 2012 – Delhi (Set 2) 
Time: 3 hour    Total Marks: 70              Total Marks: 70 
 
General Instructions: 
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 
weightage. 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. Cucurbits and papaya plants bear staminate and pistillate flowers. Mention the 
categories they are put under separately on the basis of the type of flowers they 
bear. [1] 
 
2. A garden pea plant (A) produced inflated yellow pod, and another plant (B) of the same 
species produced constricted green pods. Identify the dominant traits.         [1] 
 
3. Write what do phytophagous insects feed on.              [1] 
 
4. What is the interaction called between Cuscuta and shoe flower bush?         [1] 
 
5. When do the oogenesis and the spermatogenesis initiate in human females and males 
respectively?                 [1] 
 
6. How does smoking tobacco in human lead to oxygen deficiency in their body?        [1] 
 
7. State the significance of the study of fossils in evolution.           [1] 
 
8. Name the following:                 [1] 
(a) The semi-dwarf variety of wheat is high-yielding and disease-resistant. 
(b) Anyone inter-specific hybrid mammal. 
 
 
 
  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
 
SECTION B 
9. [2] 
(a) Highlight the role of thymus as a lymphoid organ. 
(b) Name the cells that are released from the above mentioned gland. Mention how they 
help in immunity. 
 
10. Why do clown fish and sea anemone pair up? What is this relationship called?        [2] 
 
11. Some organisms suspend their metabolic activities to survive in unfavourable 
conditions. Explain with the help of any four examples.           [2] 
 
12.                    [2] 
(a) State the role of DNA ligase in biotechnology. 
(b) What happens when Meloidegyne incognitia consumes cells with RNAi gene? 
 
13. Draw a schematic diagram of a part of double stranded dinucleotide DNA chain having 
all the four nitrogenous bases and showing the correct polarity.                 [2] 
 
14. Name of parasite that causes filariasis in humans. Mention its two diagnostic symptoms. 
How is this transmitted to others?                                    [2] 
 
15. Name the source of streptokinase. How does this bioreactor molecule function in our 
body?                  [2] 
OR 
How do Mycorrhizae act as biofertilizers? Explain. Name a genus of fungi that forms a  
mycorrhizal association with plants. 
 
16.                    [2] 
(a) State the difference between meiocyte and gamete with respect to chromosome 
number. 
(b) Why is a whiptail lizard referred to as parthenogenetic? 
 
17. Explain the work carried out by Cohen and Boyer that contributed immensely in 
biotechnology.                 [2] 
 
18. Where is sporopollenin present in plants? State its significance with reference to its 
chemical nature.                             [2] 
  
 
 
 
 
  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
 
SECTION C 
 
19. Write the function of each of the following:                          [3] 
(a) Middle piece in human sperm. 
(b) Tapetum in anthers. 
(c) Luteinizing hormone in human males. 
 
20. Given below is the representation of amino acid composition of the relevant translated 
portion of ß - chain of haemoglobin, related to the shape of human red blood cells.    [3] 
                                   
 
(a) Is this representation indicating a normal human or a sufferer from certain related 
genetic disease? Give reason in support of your answer. 
(b) What difference would be noticed in the phenotype of the normal and the sufferer 
related to this gene? 
(c) Who are likely to suffer more from the defect related to the gene represented the 
males, the females or both males and females equally? And why? 
 
21. Draw a schematic sketch of pBR 322 plasmid and label the following in it:                     [3] 
(a) Any two restriction sites. 
(b) Ori and rop genes. 
(c) An antibiotic resistant gene. 
 
22. It is established that RNA is the first genetic material. Explain giving three reasons.     [3] 
OR 
(a) Name the enzyme responsible for the transcription of tRNA and the amino acid the 
initiator tRNA gets linked with. 
(b) Explain the role of initiator tRNA in initiation of protein synthesis. 
  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
23. Study a part of the life cycle of malarial parasite given below. Answer the questions that 
follows:                              [3] 
 
(a) Mention the roles of, ‘A' in the life cycle of the malarial parasite. 
(b) Name the event 'C' and the organ where this event occurs. 
(c) Identify the organ 'B' and name the cells being released from it. 
 
24. State the theory of Biogenesis. How does Miller's experiment support this theory?   [3] 
 
25. Name the genes responsible for making Bt cotton plants resistant to bollworm attack. 
How do such plants attain resistance against bollworm attacks? Explain         [3] 
 
26. How does an algal bloom cause eutrophication of a water body? Name the weed that 
can grow in such a eutrophic lake.              [3] 
 
27. Name the two different categories of microbes naturally occurring in sewage water. 
Explain their role in cleaning sewage water into usable water.          [3] 
 
Page 5


  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
CBSE  
Class XII Biology (Theory) 
Board Paper 2012 – Delhi (Set 2) 
Time: 3 hour    Total Marks: 70              Total Marks: 70 
 
General Instructions: 
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 
weightage. 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. Cucurbits and papaya plants bear staminate and pistillate flowers. Mention the 
categories they are put under separately on the basis of the type of flowers they 
bear. [1] 
 
2. A garden pea plant (A) produced inflated yellow pod, and another plant (B) of the same 
species produced constricted green pods. Identify the dominant traits.         [1] 
 
3. Write what do phytophagous insects feed on.              [1] 
 
4. What is the interaction called between Cuscuta and shoe flower bush?         [1] 
 
5. When do the oogenesis and the spermatogenesis initiate in human females and males 
respectively?                 [1] 
 
6. How does smoking tobacco in human lead to oxygen deficiency in their body?        [1] 
 
7. State the significance of the study of fossils in evolution.           [1] 
 
8. Name the following:                 [1] 
(a) The semi-dwarf variety of wheat is high-yielding and disease-resistant. 
(b) Anyone inter-specific hybrid mammal. 
 
 
 
  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
 
SECTION B 
9. [2] 
(a) Highlight the role of thymus as a lymphoid organ. 
(b) Name the cells that are released from the above mentioned gland. Mention how they 
help in immunity. 
 
10. Why do clown fish and sea anemone pair up? What is this relationship called?        [2] 
 
11. Some organisms suspend their metabolic activities to survive in unfavourable 
conditions. Explain with the help of any four examples.           [2] 
 
12.                    [2] 
(a) State the role of DNA ligase in biotechnology. 
(b) What happens when Meloidegyne incognitia consumes cells with RNAi gene? 
 
13. Draw a schematic diagram of a part of double stranded dinucleotide DNA chain having 
all the four nitrogenous bases and showing the correct polarity.                 [2] 
 
14. Name of parasite that causes filariasis in humans. Mention its two diagnostic symptoms. 
How is this transmitted to others?                                    [2] 
 
15. Name the source of streptokinase. How does this bioreactor molecule function in our 
body?                  [2] 
OR 
How do Mycorrhizae act as biofertilizers? Explain. Name a genus of fungi that forms a  
mycorrhizal association with plants. 
 
16.                    [2] 
(a) State the difference between meiocyte and gamete with respect to chromosome 
number. 
(b) Why is a whiptail lizard referred to as parthenogenetic? 
 
17. Explain the work carried out by Cohen and Boyer that contributed immensely in 
biotechnology.                 [2] 
 
18. Where is sporopollenin present in plants? State its significance with reference to its 
chemical nature.                             [2] 
  
 
 
 
 
  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
 
SECTION C 
 
19. Write the function of each of the following:                          [3] 
(a) Middle piece in human sperm. 
(b) Tapetum in anthers. 
(c) Luteinizing hormone in human males. 
 
20. Given below is the representation of amino acid composition of the relevant translated 
portion of ß - chain of haemoglobin, related to the shape of human red blood cells.    [3] 
                                   
 
(a) Is this representation indicating a normal human or a sufferer from certain related 
genetic disease? Give reason in support of your answer. 
(b) What difference would be noticed in the phenotype of the normal and the sufferer 
related to this gene? 
(c) Who are likely to suffer more from the defect related to the gene represented the 
males, the females or both males and females equally? And why? 
 
21. Draw a schematic sketch of pBR 322 plasmid and label the following in it:                     [3] 
(a) Any two restriction sites. 
(b) Ori and rop genes. 
(c) An antibiotic resistant gene. 
 
22. It is established that RNA is the first genetic material. Explain giving three reasons.     [3] 
OR 
(a) Name the enzyme responsible for the transcription of tRNA and the amino acid the 
initiator tRNA gets linked with. 
(b) Explain the role of initiator tRNA in initiation of protein synthesis. 
  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
23. Study a part of the life cycle of malarial parasite given below. Answer the questions that 
follows:                              [3] 
 
(a) Mention the roles of, ‘A' in the life cycle of the malarial parasite. 
(b) Name the event 'C' and the organ where this event occurs. 
(c) Identify the organ 'B' and name the cells being released from it. 
 
24. State the theory of Biogenesis. How does Miller's experiment support this theory?   [3] 
 
25. Name the genes responsible for making Bt cotton plants resistant to bollworm attack. 
How do such plants attain resistance against bollworm attacks? Explain         [3] 
 
26. How does an algal bloom cause eutrophication of a water body? Name the weed that 
can grow in such a eutrophic lake.              [3] 
 
27. Name the two different categories of microbes naturally occurring in sewage water. 
Explain their role in cleaning sewage water into usable water.          [3] 
 
  
 
CBSE XII |  Biology 
Board Paper 2012 – Delhi – Set 2 
 
     
SECTION D 
28.                     [5] 
(a) Draw a 'pyramid of numbers' of a situation where a large population of insects feed 
upon a very big tree. The insects in turn, are eaten by small birds which in turn are 
fed upon by big birds. 
(b) Differentiate giving reason, between the pyramid of biomass of the above situation 
and the pyramid of numbers that you have drawn. 
OR 
(a) What are the two types of desirable approaches to conserve biodiversity? Explain 
with examples bringing out the difference between the two types. 
(b) What is the association between the bumble bee and its favourite orchid Ophrys? 
How would extinction or change of one affect the other? 
 
29. What is the inheritance pattern observed in the size of starch grains and seed shape of 
Pisum sativum? Workout the monohybrid cross showing the above traits. How does 
this pattern of inheritance deviate from that of Mendelian law of dominance?         [5] 
OR 
State the aim and describe Messelson and Stahl's experiment. 
 
30. The following is the illustration of the sequence of ovarian events (a - i) in a human 
female.                         [5] 
 
(i) Identify the figure that illustrates ovulation and mention the stage of oogenesis it 
represents. 
(ii) Name the ovarian hormone and the pituitary hormone that have caused the above 
mentioned event. 
(iii) Explain the changes that occur in the uterus simultaneously in anticipation. 
(iv) Write the difference between 'c' and 'h'. 
(v) Draw a labeled sketch of the structure of a human ovum prior to fertilization. 
OR 
How does the megaspore mother cell develop into 7-celled, 8 nucleate embryo sac in an 
angiosperm? Draw a labeled diagram of a mature embryo sac.