CBSE Class 12 Biology 2022 question paper (57/4)
Maximum marks 35 · Time 2 hours · 3 sets
Try each question first, then open its model answer. Where the paper offers a choice, both questions are shown with OR between them.
Section A
2 marks each
- Q.12 marksExplain, giving two reasons, how immune response by "vaccine" is different from that by "antitoxin" in humans.
- Q.2 (a)2 marksMention the common bacterium found in the anaerobic sludge during sewage treatment and also in the rumen of cattle. How is this bacterium commercially useful ?
OR
Q.2 (b)2 marksName the effective biocontrol agents of several plant pathogens belonging to group of viruses. Also write about the ways they support the environment.- Q.32 marksSome of the microbes used as biofertilizers are prokaryotes. Name the taxonomic group they come under. With the help of an example, mention how they act as biofertilizers.
- Q.42 marksDifferent species belonging to genus Trichoderma are useful to humans as well as to plants. Justify their roles by giving one instance of each.
- Q.52 marksThe figures given below show the results of a lab experiment in which two microbial species A and B belonging to same genus were grown in three petri dishes having same culture medium. In Petri dish-I, Species-A was grown alone for 8 weeks. In Petri dish-II, Species-B was grown alone for 8 weeks. In Petri dish-III, both the species were grown together with the same number as Petri dish-I and Petri dish-II for 8 weeks. What conclusion will you draw from the graphs in terms of impact of interaction on growth ? Explain, giving reason.
- Q.6 (a)2 marksThe graphs given below, A and B, represent population of elephants in two different National Parks (a hypothetical situation) at different times. Study the graphs and comment upon the pattern of growth observed. Mention the possible reason for such patterns seen in nature.
OR
Q.6 (b)2 marksAs per a recent newspaper report, a particular country showed declining population growth rate. According to you, what could be the two most possible reasons for this decline and why ?
Section B
3 marks each
- Q.7 (a)3 marksThe graph given below shows species-area relationship of a certain region. (i) Study the graph and explain what it represents. (ii) After a while, a small area was taken for constructing a road which divided the region into two. Write the impact this construction would have on species richness of the region.
OR
Q.7 (b)3 marksHow did Dr. David Tilman relate experimentally, the stability of a community and its species richness ? Explain.- Q.83 marksWhat are the consequences of loss of biodiversity in a region ? Explain.
- Q.93 marksBacillus thuringiensis plays an important role in Integrated Pest Management strategy. Explain how. Name any two crops that are protected efficiently from pests.
- Q.103 marksWith the help of a storyboard or a flowchart only, explain all the stages of how human insulin is produced through r-DNA technology.
- Q.113 marks(a) Explain the roles of (i) primary, and (ii) secondary lymphoid organs that are responsible for developing defence to combat the action of pathogens/foreign antigens which enter our body. (b) Doctors generally advise not to undergo surgery of tonsils. Why ?
- Q.123 marksCausative agents of HIV-AIDS and COVID-19 belong to the same group of viruses. To diagnose and amplify the genetic material for further study of COVID-19 virus, 'RT-PCR' test is carried out. (a) What does 'RT-PCR' stand for ? (b) Explain the various steps of PCR technique.
Section C
- There are two different farm lands, one where Bt-cotton crop was cultivated and the other where non Bt-cotton crop (indigenous) was cultivated. Farmers responsible for this experimental cultivation were free to use the farming practices of their choice. During the cultivation period, the data was collected with respect to the amount of pesticide used, water required for irrigation and at harvesting time, the crop productivity. Based on the data collected, a bar graph was plotted which is shown below.Q.13 (a) (i)3 marksWrite your interpretation, with reason, on the basis of the three parameters plotted in the graph.
- Q.13 (a) (ii)1 markWhich one of the crops would you like to cultivate in your farm and why ?
- Q.13 (a) (iii)1 markWhich one out of these two crops would a farmer from Rajasthan like to cultivate and why ?
OR
Gene of interest/alien gene is introduced by a cloning vector into a host cell to bring about a desired phenotypic expression in a host cell. The cloning vectors used are plasmid and bacteriophages. Biotechnologists in their labs, for desired results engineered specialised cloning vectors. One such vector is pBR322. Study the diagram carefully and answer the questions that follow.Q.13 (b)5 marks(i) What do 'EcoR I', 'BamH I' and 'Hind III' represent ? State their functions. (ii) Identify the gene you would select for the role of a selectable marker in pBR322. Explain why. (iii) Write the property/characteristic of plasmid and bacteriophage that makes them efficient cloning vectors. (iv) Biotechnologists always insert 'ori' gene in their engineered cloning vector. Justify the statement. (v) Will the experiment be successful if the alien DNA is ligated at Hind III restriction site ? Give reason in support of your answer.
Section A
2 marks each
- Q.12 marksHow does Human Immuno deficiency Virus cause immuno deficiency in the human body ?
- Q.22 marksDifferent species belonging to genus Trichoderma are useful to humans as well as to plants. Justify their roles by giving one instance of each.
- Q.3 (a)2 marksThe graphs given below, A and B, represent population of elephants in two different National Parks (a hypothetical situation) at different times. Study the graphs and comment upon the pattern of growth observed. Mention the possible reason for such patterns seen in nature.
OR
Q.3 (b)2 marksAs per a recent newspaper report, a particular country showed declining population growth rate. According to you, what could be the two most possible reasons for this decline and why ?- Q.42 marksTo survive unfavourable conditions, some organisms hibernate and others go into aestivation. How is hibernation different from aestivation ? Give one example of each.
- Q.5 (a)2 marksMention the common bacterium found in the anaerobic sludge during sewage treatment and also in the rumen of cattle. How is this bacterium commercially useful ?
OR
Q.5 (b)2 marksName the effective biocontrol agents of several plant pathogens belonging to group of viruses. Also write about the ways they support the environment.- Q.62 marksExplain, giving two reasons, how immune response by "vaccine" is different from that by "antitoxin" in humans.
Section B
3 marks each
- Q.73 marks"Genetically modified plants are considered to be superior to non-genetically modified plants." Explain, giving three reasons why.
- Q.83 marks(a) Explain the roles of (i) primary, and (ii) secondary lymphoid organs that are responsible for developing defence to combat the action of pathogens/foreign antigens which enter our body. (b) Doctors generally advise not to undergo surgery of tonsils. Why ?
- Q.9 (a)3 marksThe graph given below shows species-area relationship of a certain region. (i) Study the graph and explain what it represents. (ii) After a while, a small area was taken for constructing a road which divided the region into two. Write the impact this construction would have on species richness of the region.
OR
Q.9 (b)3 marksHow did Dr. David Tilman relate experimentally, the stability of a community and its species richness ? Explain.- Q.103 marksCausative agents of HIV-AIDS and COVID-19 belong to the same group of viruses. To diagnose and amplify the genetic material for further study of COVID-19 virus, 'RT-PCR' test is carried out. (a) What does 'RT-PCR' stand for ? (b) Explain the various steps of PCR technique.
- Q.113 marksBacillus thuringiensis plays an important role in Integrated Pest Management strategy. Explain how. Name any two crops that are protected efficiently from pests.
- Q.123 marksWith the help of three examples, explain the 'broadly utilitarian' argument for conservation of biodiversity.
Section C
- There are two different farm lands, one where Bt-cotton crop was cultivated and the other where non Bt-cotton crop (indigenous) was cultivated. Farmers responsible for this experimental cultivation were free to use the farming practices of their choice. During the cultivation period, the data was collected with respect to the amount of pesticide used, water required for irrigation and at harvesting time, the crop productivity. Based on the data collected, a bar graph was plotted which is shown below.Q.13 (a) (i)3 marksWrite your interpretation, with reason, on the basis of the three parameters plotted in the graph.
- Q.13 (a) (ii)1 markWhich one of the crops would you like to cultivate in your farm and why ?
- Q.13 (a) (iii)1 markWhich one out of these two crops would a farmer from Rajasthan like to cultivate and why ?
OR
Gene of interest/alien gene is introduced by a cloning vector into a host cell to bring about a desired phenotypic expression in a host cell. The cloning vectors used are plasmid and bacteriophages. Biotechnologists in their labs, for desired results engineered specialised cloning vectors. One such vector is pBR322. Study the diagram carefully and answer the questions that follow.Q.13 (b)5 marks(i) What do 'EcoR I', 'BamH I' and 'Hind III' represent ? State their functions. (ii) Identify the gene you would select for the role of a selectable marker in pBR322. Explain why. (iii) Write the property/characteristic of plasmid and bacteriophage that makes them efficient cloning vectors. (iv) Biotechnologists always insert 'ori' gene in their engineered cloning vector. Justify the statement. (v) Will the experiment be successful if the alien DNA is ligated at Hind III restriction site ? Give reason in support of your answer.
Section A
2 marks each
- Q.12 marksWhat are Interferons ? State their role in the treatment of cancer.
- Q.2 (a)2 marksThe graphs given below, A and B, represent population of elephants in two different National Parks (a hypothetical situation) at different times. Study the graphs and comment upon the pattern of growth observed. Mention the possible reason for such patterns seen in nature.
OR
Q.2 (b)2 marksAs per a recent newspaper report, a particular country showed declining population growth rate. According to you, what could be the two most possible reasons for this decline and why ?- Q.32 marksExplain, giving two reasons, how immune response by "vaccine" is different from that by "antitoxin" in humans.
- Q.4 (a)2 marksMention the common bacterium found in the anaerobic sludge during sewage treatment and also in the rumen of cattle. How is this bacterium commercially useful ?
OR
Q.4 (b)2 marksName the effective biocontrol agents of several plant pathogens belonging to group of viruses. Also write about the ways they support the environment.- Q.52 marksDifferent species belonging to genus Trichoderma are useful to humans as well as to plants. Justify their roles by giving one instance of each.
- Q.62 marksWhy are predators considered to be 'prudent' in nature ? Explain.
Section B
3 marks each
- Q.73 marksHow are the advanced ex-situ techniques helping in conserving threatened species ? Give three examples.
- Q.83 marksWith the help of a storyboard or a flowchart only, explain all the stages of how human insulin is produced through r-DNA technology.
- Q.93 marks(a) Explain the roles of (i) primary, and (ii) secondary lymphoid organs that are responsible for developing defence to combat the action of pathogens/foreign antigens which enter our body. (b) Doctors generally advise not to undergo surgery of tonsils. Why ?
- Q.10 (a)3 marksThe graph given below shows species-area relationship of a certain region. (i) Study the graph and explain what it represents. (ii) After a while, a small area was taken for constructing a road which divided the region into two. Write the impact this construction would have on species richness of the region.
OR
Q.10 (b)3 marksHow did Dr. David Tilman relate experimentally, the stability of a community and its species richness ? Explain.- Q.113 marksBacillus thuringiensis plays an important role in Integrated Pest Management strategy. Explain how. Name any two crops that are protected efficiently from pests.
- Q.123 marksOnly with the help of a labelled diagram, show the steps of formation of recombinant DNA by the action of restriction endonuclease enzyme EcoR I.
Section C
- There are two different farm lands, one where Bt-cotton crop was cultivated and the other where non Bt-cotton crop (indigenous) was cultivated. Farmers responsible for this experimental cultivation were free to use the farming practices of their choice. During the cultivation period, the data was collected with respect to the amount of pesticide used, water required for irrigation and at harvesting time, the crop productivity. Based on the data collected, a bar graph was plotted which is shown below.Q.13 (a) (i)3 marksWrite your interpretation, with reason, on the basis of the three parameters plotted in the graph.
- Q.13 (a) (ii)1 markWhich one of the crops would you like to cultivate in your farm and why ?
- Q.13 (a) (iii)1 markWhich one out of these two crops would a farmer from Rajasthan like to cultivate and why ?
OR
Gene of interest/alien gene is introduced by a cloning vector into a host cell to bring about a desired phenotypic expression in a host cell. The cloning vectors used are plasmid and bacteriophages. Biotechnologists in their labs, for desired results engineered specialised cloning vectors. One such vector is pBR322. Study the diagram carefully and answer the questions that follow.Q.13 (b)5 marks(i) What do 'EcoR I', 'BamH I' and 'Hind III' represent ? State their functions. (ii) Identify the gene you would select for the role of a selectable marker in pBR322. Explain why. (iii) Write the property/characteristic of plasmid and bacteriophage that makes them efficient cloning vectors. (iv) Biotechnologists always insert 'ori' gene in their engineered cloning vector. Justify the statement. (v) Will the experiment be successful if the alien DNA is ligated at Hind III restriction site ? Give reason in support of your answer.