Biology Sample Question Paper for Class 12

Sample Question Paper - 2




Time: 02 Hours                       Marks: 35

General Instructions:

Ø All questions are compulsory.

Ø The question paper has three sections and 13 questions. All questions are compulsory.

Ø Section–A has 6 questions of 2 marks each; Section–B has 6 questions of 3 marks each; and Section–C has a case-based question of 5 marks.

Ø There is no overall choice.  However, internal choices have been provided in some questions. A student has to attempt only one of the alternatives in such questions.

Ø Wherever necessary, neat and properly labeled diagrams should be drawn


Q.1.      How a Monarch butterfly does defend itself from predators? Explain. Complete the table given below:


Enzymes involved

(a)   Cutting of DNA segments at specific sites


(b)   Dissolve fungal cell wall



Name the first transgenic cow developed and explain the improvement in the quality of the product produced by it.

Q.2.      A schematic representation of PCR upto the extension stage is given below. Answer the questions that follow:

 (i) Name the process ‘a’

(ii) Identify ‘b’

(iii) Identify ‘c’ and mention its importance in PCR

Q.3.      Identify the areas labelled (i) to (iv) in the pie chart given below representing the biodiversity of plants showing their proportionate number of species of major taxa.

Q.4.      Why do clown fish and sea anemone pair up? What is this relationship called ?

Q.5.      Why must bacterial cells be first made ‘competent’ in rDNA technology? How is the process carried out?


Give a schematic representation of the transformation of a proinsulin into insulin


Q.6.      How do you visualise DNA on an agarose gel? Why Agrobacterium is mediated genetic transformation described as natural genetic engineering in plants?


How did RNAi help to control the nematode from infecting roots of tobacco plants? Explain

Q.7.      How do Snails, Seeds, Bear and zooplanktons adapt to unfavourable conditions for their survival ?

Q.8.      Why do lepidopterans die when they feed on Bt cotton plant? Explain

Q.9.      From the diagram given below answer the following questions:

(a)   Name the organism in which the vector shown is inserted to the copies of the desired genes.

(b)   Mention the area labelled in the vector responsible for controlling the copy number of inserted genes.

(c)    Name and explain the role of selectable marker in the vector shown

Q.10.  A forest hardly has any carnivores .Census of herbivorous animals was taken and plotted as graph as shown below:

(a)   Identify the curve that will explain the population growth of herbivores. Give reason for your answer.

(b)   Define ‘K’ in the graph.

(c)    Which growth curve is more realistic and why? Write the equation for the same.

Q.11.  Alien species are highly invasive and are a threat to indigenous species. Substantiate this statement with any three examples.


Q.12.  Two children A & B aged 4 and 5 years old respectively visited a hospital with a similar genetic disorder. The girl A was provided enzyme replacement therapy and was advised to revisit hospital for further treatment. The girl B was how ever given a therapy that did not required revisit for further treatment.

(a)   Name the ailments the two girls were suffering from?

(b)   Why the treatment did provided to girl a required repeated visits?

(c)    How was the girl B cured permanently?


When we conserve and protect the whole ecosystem, its biodiversity at all levels is   protected .We save the entire forest to save the tiger. This approach is called in-situ conservation. However, when there are situations where an animal or plant is endangered and needs urgent measures to save it from extinction, some other measures are taken which are away from their natural habitat.

(a)   In your opinion, which is the most effective way to conserve the genetic diversity of a plant of an area?

(b)    Differentiate the two approaches mentioned in the above case.

(c)    What are biodiversity Hotspots?

(d)   “Nature’s biological library is burning even before we catalogue the titles of all the books stocked there”. Explain it.

Marking Scheme

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