CBSE Class 12 Biology Question Paper 2020 Set D Solved

Read and download CBSE Class 12 Biology Question Paper 2020 Set D Solved designed as per the latest question paper pattern and Class 12 examination guidelines issued by CBSE, NCERT and KVS. The past year Question Papers for Class 12 Biology have been provided with solutions which will help students to assess their performance and find out topics in Biology Class 12 which they need to improve to get better marks in Class 12 exams. After solving these last year papers also refer to solved Sample Papers for Class 12 Biology available on our website to build strong understanding of the subject

Biology Question Paper Class 12

Students can refer to the below Class 12 Biology Question Paper designed to help students understand the pattern of questions that will be asked in Class 12 exams. Please download CBSE Class 12 Biology Question Paper 2020 Set D Solved

Biology Class 12 Question Paper

SECTION A
 
1 How can an alien piece of DNA made to multiply in a host cell? 
 
2 If adenine constitutes 30% of an isolated DNA fragment, then what is the expected % of the base cytosine in it?
 
3 What is the relationship between egret and grazing cattle? Why?
 
OR
 
How is competition avoided in Nature? Give example.
 
4 A male honeybee has 16 chromosomes whereas its female has 32 chromosomes. Give one reason. 
 
5 Name the vector of Chikungunya disease. 
 
SECTION B
 
6 How does geitonogamy differ from xenogamy in plants? 
 
7 How are transgenic animals made useful in chemical safety testing and studying diseases? 
 
8 What is meant by germplasm Collection? Describe its significance in plant breeding programmes.
 
OR
 
Name two alcoholic drinks produced in each of the following ways. (i) by distillation and (ii) without distillation.
 
9 A person shows unwelcome immunogenic reactions while exposed to certain substances. (a) Name this condition. (b) What common term is given to the substances responsible for this condition? (c) Name the cells and the chemical substances released which cause such reactions.
 
10 Monocistronic structural genes in eukaryotes have interrupted coding sequences, Explain. How are they different in prokaryotes?
 
11 Name two types of animals based on their temperature tolerance. 
 
12 Categories the following pairs of examples as convergent or divergent evolutions: (a) Eyes of octopus and mammals. (b) Wings of butterfly and birds. (c) Tuber of sweet potatoes and potato.
(d) Thorns in bougainvillea and tendrils in cucurbits.
 
SECTION C
 
13 How is Biotechnology used to produce Bt cotton? Explain. 
 
14 How does paleontological evidence support evolution of organisms on Earth? 
 
15 Explain free nuclear endosperm development.
 
OR
 
Mention any three differences between spermatogenesis and oogenesis.
 
16 Explain the role of S and P in the experiments conducted by Hershey and chase?
 
OR
 
Explain the mechanism of sex determination in honeybees.
 
17 Describe the three different practices under natural methods of birth control. 
 
18 How do mycorrhizae function as biofertilisers? Explain with example. Name one cyanobacteria that can be used as a biofertiliser.
 
19 How is Agrobacterium tumifaciens used in rDNA technology? Explain ii) What and how are other pathogens are used for the purpose. State two other methods by which host organism can be transformed.
 
20 After a rainy day Shruti found many dragonflies flying over stagnant water. She thinks these flies
come to drink water. i) Is Shruti,s explanation correct? Give your views
ii) Write the significance of your view in organic farming.
 
OR
 
What is biochemical oxygen demand (BOD) test? At what stage of Sewage treatment this test is performed? BOD level of three samples of water labelled as A, B and C are 30 mg/ L, 10mg/L and 500 mg/L respectively. Which sample of water is most polluted?
 
21 a) Taking one example each of habitat loss and fragmentation, explain how the two are responsible for biodiversity loss. b) Explain two different ways of biodiversity conservation.
 
22 What are statins? Name the microorganism that produces this substance. How is it medically important?
 
23 What are the producers in grass land and oceans .How is GPP different from NPP? Why is the productivity in oceans lesser than on land?
 
24 What will be the genotype and phenotype of the offspring if a colour blind man marries a carrier woman? Show the cross.
 
OR
 
How do histones acquire positive charge?
 
SECTION D
 
25 With the help of a cross find out the F2 offsprings produced by crossing homozygous red flower of Snapdragon when crossed with a homozygous white flower. Write the phenotypic and genotypic ratio. State the pattern of inheritance.
 
OR
 
Describe DNA replication and draw the diagram of a replication fork.
 
26 Describe the development of male gametophyte in angiosperms.
 
OR
 
What is placenta? What is its role? Justify Placenta as an endocrine tissue.
 
27 With a flow chart explain the process of decomposition. What factors affect this process?
 
OR
 
In Arcata, the town’s people have created an integrated waste water treatment process within a natural system. A citizen group called FOAM helps in upkeep of this project.
(a) What are the main steps in waste water management done in this way? (b) Ecosan in Kerala and Sri Lanka is also an initiative for water conservation. How?


Please click on below link to downloadCBSE Class 12 Biology Question Paper 2020 Set D Solved

CBSE Class 12 Biology Question Paper 2020 Set D Solved

We hope you liked the above provided CBSE Class 12 Biology Question Paper 2020 Set D Solved. To get an understanding of the type of questions which were asked in previous year exams, it is important for Class 12 students to refer to CBSE Class 12 Biology Question Paper 2020 Set D Solved that we have provided above. Students can download all the Question Papers for Class 12 Biology which were issued in the exams so that you can practise them and solve all types of questions which have been asked till now. By doing all CBSE Class 12 Biology Question Paper 2020 Set D Solved PYP (previous year papers) you will understand the regular questions and MCQ questions for Class 12 Biology which are always asked and learn them so that you can get full marks in those questions. You can download CBSE Class 12 Biology Previous Year Question Papers and Class 12 Biology Sample Papers in PDF. You should attempt all the last year question paper for Class 12 and Class 12 Biology MCQ Test in examination conditions at home and then compare their answers with the solutions provided by our teachers.
 

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