CBSE Class 12 Biology 2022

Marks by chapter

Counted from the 106 questions listed below, as the 2022 papers print them. CBSE allocates marks per unit, not per chapter — this is what was observed, not an official CBSE weightage. Every year compared →

106 questions from 2022

• Q1Many members of genus Glomus form a mycorrhizial association with plants. Elaborate how is this association beneficial…2 mk
• Q1Name the diseases and their mode of transmission in human by (i) common round worm and (ii) filarial worm.2 mk
• Q1Explain, giving two reasons, how immune response by "vaccine" is different from that by "antitoxin" in humans.2 mk
• Q1Though filariasis is not fatal, but the disease in humans is responsible for considerable suffering, gross deformities…2 mk
• Q1Mention the parts of human body that get affected by Pneumonia and common cold infections. Write the causative agents…2 mk
• Q1How does Human Immuno deficiency Virus cause immuno deficiency in the human body?2 mk
• Q1What are Interferons? State their role in the treatment of cancer.2 mk
• Q1A patient who has undergone an organ transplant is put on 'immunosuppressant'. Name the 'immunosuppressant' and its…2 mk
• Q1A boy developed some allergic reactions when he straight entered into his air conditioned room after a game of football…2 mk
• Q1Observe the schematic representation given above and answer the following questions: (i) Identify A and B. (ii)…2 mk
• Q1Give your interpretation of the message given by ecologist Paul Ehrlich through his analogy "rivet popper hypothesis"…2 mk
• Q1State the most important contribution of the following microbes for human welfare: Monascus purpureus Trichoderma…2 mk
• Q1Lactic Acid Bacteria (LAB) sets milk into curd and also plays a very beneficial role for human health. Give any two…2 mk
• Q1Ringworm is one of the most common infectious fungal disease in humans. Name any two genera of fungi which cause…2 mk
• Q2Mention the common bacterium found in the anaerobic sludge during sewage treatment and also in the rumen of cattle. How…2 mk
• Q2"Curd is easier to digest by humans than milk." Justify, giving two suitable reasons.2 mk
• Q2What are proto oncogenes and why are they called so?2 mk
• Q2Mention the two types of acquired immune responses present in our body. Give one major role of each.2 mk
• Q2Can we use slurry of human excreta instead of cowdung slurry to produce biogas in a typical biogas plant? Support your…2 mk
• Q2State the impact of constant mechanical agitation and pumping of air in the aeration tank on the sewage during the…2 mk
• Q3(i) Write the observations made at the end of Connell's field experiment on barnacles on the rocky sea coasts of…2 mk
• Q3A person suffering from AIDS dies of opportunistic infections (ARC) i.e., infections that could have been otherwise…2 mk
• Q3(i) Write the Scientific name of the plant from where natural cannabinoids are obtained. (ii) Mention the parts of the…2 mk
• Q3State the mode of action of cocain on human body. Write the scientific name of the source plant it is obtained from. OR…2 mk
• Q3Some of the microbes used as biofertilizers are prokaryotes. Name the taxonomic group they come under. With the help of…2 mk
• Q3Farmers are often suggested to use the following organisms in their crop land so as to improve the soil fertility. (i)…2 mk
• Q3Give an example of viral biocontrol agent. Why are they considered to be desirable when an ecologically sensitive area…2 mk
• Q4Name the source organism (scientific name) that produces statins. Mention its use in medical field and how does it act.2 mk
• Q4State two morphological attributes observed in the leaves of desert plants that enable them to survive in extreme…2 mk
• Q4Organic farmer use Trichoderma and Baculovirus as biological control agents. Explain.2 mk
• Q4What is the importance of female Anopheles mosquitoes in the life of a malarial Parasite Plasmodium?2 mk
• Q4Study the given diagrams of Biogas plants – 'A' and 'B' and answer the questions that follow: Which one of the two…2 mk
• Q4To survive unfavourable conditions, some organisms hibernate and others go into aestivation. How is hibernation…2 mk
• Q4What are flocs? State their role in biological treatment of sewage.2 mk
• Q4Different species belonging to genus Trichoderma are useful to humans as well as to plants. Justify their roles by…2 mk
• Q5How are 'in-situ' and 'ex-situ' approaches of biodiversity conservations different from each other?2 mk
• Q5Study the given diagram of Sewage Treatment Plant (S.T.P.) and answer the questions that follow: S.T.P. (Sewage…2 mk
• Q5Explain the two physiological attributes which enable a kangaroo rat to survive in desert conditions.2 mk
• Q5The figures given below show the results of a lab experiment in which two microbial species A and B belonging to same…2 mk
• Q5When tourists go to places of high altitude like Rohtang Pass or Mansarovar, they are advised not to venture out for…2 mk
• Q5Write the best method to measure the population density of a single Banyan tree in comparison to 20 Parthenium weeds in…2 mk
• Q5Observe the schematic representation given above and answer the following questions: (i) Identify A and B. (ii)…2 mk
• Q5Mammals are capable of maintaining homeostasis. But, very few smaller animals can survive in polar regions. Give…2 mk
• Q6Study the given graphs (X) and (Y) depicting the annual variation in solar radiation on Earth from January to December…2 mk
• Q6Why are predators considered to be 'prudent' in nature? Explain.2 mk
• Q6Explain the role of ' B ' and ' T ' lymphocytes in providing immunity to humans.2 mk
• Q6What would be the best method to measure the total population density of a dense bacterial culture in a petridish and…2 mk
• Q6The graphs given below, A and B, represent population of elephants in two different National Parks (a hypothetical…2 mk
• Q6What would be the best method to measure the total population density of the number of fishes in river and why?2 mk
• Q6The histogram given below representing the data for annual shark harvest in the great barrier reef / coral reef located…2 mk
• Q6Study the graph given below, showing the population growth curves 'A' and 'B' respectively. Answer the following…2 mk
• Q7"Genetically modified plants are considered to be superior to non-genetically modified plants." Explain, giving three…3 mk
• Q7Different types of antibodies are produced in our body by the B-lymphocytes in response to a pathogen that enters in…3 mk
• Q7'An HIV patient normally doesn't die of 'AIDS', but death is caused due to many other infections.' Do you agree with…3 mk
• Q7Many people experience allergic symptoms of sneezing or wheezing on exposure to certain substances in the environment.…3 mk
• Q7Read the account of a natural large forest area that underwent many changes from the year 2002 to 2014 and answer the…3 mk
• Q7Plasmodium enters the human body through the bite of infected female Anopheles. Trace its life cycle till the onset of…3 mk
• Q7How are the advanced ex-situ techniques helping in conserving threatened species? Give three examples.3 mk
• Q7The graph given below shows species-area relationship of a certain region. (i) Study the graph and explain what it…3 mk
• Q7When Plasmodium sp. (malarial parasite) enters the human body, it reproduces asexually and increases its number. During…3 mk
• Q7Over the last century, vaccination has been the most effective medical strategy to control infectious diseases. Explain…3 mk
• Q7The data collected based on the survey conducted for species richness of group of mammals, in three different climatic…3 mk
• Q7Restriction endonucleases are used in genetic engineering to form recombinant DNA. Explain only with the help of a flow…3 mk
• Q7What does the equation dN / dt=rN express in terms of population growth? Write the significance of 'r' in a population…3 mk
• Q8Why do doctors have to carry many tests for selecting a person to be a suitable donor for someone who is going for an…3 mk
• Q8Name and state the type of immunity that acts as a 'biological shield' to the developing foetus against many infections…3 mk
• Q8Bio-diversification of life started to occur almost 3 billion years ago. Since then new species have been evolving and…3 mk
• Q8Write the complete name of the diagnostic test for AIDS. Explain the principle it works on. Name the type of genetic…3 mk
• Q8What are the consequences of loss of biodiversity in a region? Explain.3 mk
• Q8A patient complains of suffering from constipation, stomach ache, stool with blood clots and excess mucous. The…3 mk
• Q8Development of recombinant DNA technology has made the expression of protective protein antigens (to be used as…3 mk
• Q9Given below is the stepwise schematic representation of the process of electrophoresis. Identify the 'alphabets'…3 mk
• Q9Explain giving reason the action plan followed by organic farmers that support their key belief "biodiversity furthers…3 mk
• Q9Bacillus thuringiensis plays an important role in Integrated Pest Management strategy. Explain how. Name any two crops…3 mk
• Q9Name two naturally occurring sources, one that transfers pathogenic genes into a plant cells and the other into an…3 mk
• Q9What are cry-proteins? With the help of a suitable example, explain how it acts as a biological pesticide.3 mk
• Q9A cell free method of amplifying DNA first developed in the mid 1980's revolutionized the field of biotechnology. Name…3 mk
• Q9With the advent of sophisticated techniques of genetic engineering, we can now readily purify and isolate DNA. Name and…3 mk
• Q10Given below is an equation describing the Species-Area relationship between species richness and area for a wide…3 mk
• Q10With the help of a storyboard or a flowchart only, explain all the stages of how human insulin is produced through…3 mk
• Q10Explain how recombinant human insulin was prepared in 1983 by Eli Lily an American company.3 mk
• Q10"Some species in an ecosystem exert greater influence in driving major ecosystem services than others." How did Paul…3 mk
• Q10Explain the property of contact inhibition and its effect on normal human cells and cancerous cells. Why are biological…3 mk
• Q10Enumerate the main sources of bio-fertilisers giving one example of each.3 mk
• Q10Write the inference drawn by Alexander von Humboldt after his extensive explorations of South American jungle. Study…3 mk
• Q11Non viral and non vector methods are sometimes used to transfer genes or alien DNA into a plant cell. Explain one such…3 mk
• Q11Name any three techniques used for introducing an alien DNA into a host cell and mention how?3 mk
• Q11"Large scale production of recombinant DNA requires the use of bioreactors. " Draw a labelled diagram of a simple…3 mk
• Q11Explain the concept of "co-extinction" by taking two examples. OR "Forests provide intangible benefits to us." Explain…3 mk
• Q11(i) Name three molecular diagnostic techniques for diagnosis of a disease. (ii) List three advantages of molecular…3 mk
• Q11How does a gene therapy involving direct modification of the cells, in order to achieve a therapeutic goal is used in…3 mk
• Q11Explain the roles of (i) primary, and (ii) secondary lymphoid organs that are responsible for developing defence to…3 mk
• Q12Enlist two criteria that are used to identify a region for maximum protection as 'Biodiversity hotspots'. Name any two…3 mk
• Q12An application of biotechnology in agriculture involves production of pest resistant plants using 'cry' genes from a…3 mk
• Q12Causative agents of HIV-AIDS and COVID-19 belong to the same group of viruses. To diagnose and amplify the genetic…3 mk
• Q12Given below is a picture of a natural large habitat that is being continuously broken into smaller patches. This…3 mk
• Q12With the help of three examples, explain the 'broadly utilitarian' argument for conservation of biodiversity.3 mk
• Q12Only with the help of a labelled diagram, show the steps of formation of recombinant DNA by the action of restriction…3 mk
• Q12(i) State the role of a selectable marker in r-DNA technology. (ii) Name one such selectable marker which is considered…3 mk
• Q12An application of biotechnology in agriculture involves production of pest resistant plants using 'cry' genes from a…3 mk
• Q12"For ethical reasons, biodiversity must be conserved." Do you agree? Write your views in support of your answer. Write…3 mk
• Q13There are two different farm lands, one where Bt-cotton crop was cultivated and the other where non Bt-cotton crop…5 mk
• Q13Cloning of genes, play a very significant role in genetic engineering, helping the transfer of desirable foreign genes…5 mk
• Q13Development of recombinant DNA technology has opened gates to many breakthroughs in the fields of medicine and…5 mk
• Q13Read the paragraph given below and answer the questions that follow: Enzyme Taq polymerase, is extracted from a…5 mk
• Q13To save the crop plant from the attack of various insect pests the biotechnologists have developed many pest resistant…5 mk