CBSE SAMPLE QUESTION PAPER Biology (Theory) Class XII (Code C)

 

Time: 3 Hours                                                                                                                                    Max. Marks: 70

 

General Instructions:

1.   All the questions are compulsory.

2.   The question paper consists of four sections A, B, C and D.

      Section A contains 8 questions of 1 mark each.

      Section B is of 10 questions of 2 marks each.

      Section C has 9 questions of 3 marks each.

      Whereas Section D is of 3 questions of 5 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      three questions of 5 marks weight age. 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.         What is first human being like hominid called?   

2.         Distinguish between primary and secondary follicles.     

3.         State an example of anthropogenic action and its significance w.r.t. evolution.    

4.         Expand PMNL and IF.

5.         What are sticky ends?

6.         Name the restriction endonuclease, which was discovered first.

7.         Define geitnogamy.      

8.         Name the hypothesis in which the ecosystem is compared with aeroplane and species with its wings.     

 

                                    SECTION - B

9.         State the changes which occur in embryo immediately after implantation.           

10.       What is allergy? Name the drugs which can reduce the symptoms.        

11.       Distinguish between transformation and Gene gun.        

                        OR

            How is genetically engineered insulin produced?           

12.       p2 + 2pq + q2 = 1      

            What does this equation or expression show? In which two conditions can it be disrupted?

13.       Describe the cause and symptoms of Turner’s syndrome.         

14.       Give the biological oxygen demand in ppm of   

            (i) Very polluted water.

            (ii) Moderately clean water

15.       How are biofertilisers advantageous from fertilisers such as NPK that we buy in the market? Justify the role of azolla-anabaena             as a biofertiliser.         

16.       What is biofortification? How will biofortification improve agronomic properties of crops?         

17.       The figure below shows energy flow in a simple food chain. on the basis of following diagram, answer the following             questions.                                

           

 

            (a) What is ultimate source of energy?

            (b) How much energy is transferred from one trophic level to other?

18.       The graph below represent organism’s response to changing external conditions. Identify the organisms that represent              and .                        

           

 

                                    SECTION – C

19.       What is chemical evolution? Name three conditions were created by Miller which simulated primitive earth?

20.       What are key concepts of Darwinian theory of evolution. How does the evolution by saltation differ from the earlier views on             evolution?                  

21.       According to 2001 census report, our population growth rate is 1.7 percent. This would lead to scarcity of basic requirements as             food,shelter, clothing. The most important step is to motivate smaller families using contraceptive methods. A very effective and             popular method is IUD. What are the different  types and explain their action?              

22.       What is meant by gene therapy? Explain its practical application by giving an example.  

                                    OR

            Distinguish between cross breeding, out breeding and interspecific hybridisation.

23.       MOET is a technique for herd improvement. Explain the procedure of this techniques by filling the blanks

            (i)         ______ is done by administering ___________ like hormone to induce 6 - 8 egg production.

            (ii)        Mating with ___________ bull or ___________ inseminated.

            (iii)       Transferring fertilised eggs at ___________ cell stage recovered non-surgically into ___________ mothers.

24.       A tall pea plant was crossed with a tall plant and 2 types of offspring, i.e., tall and dwarf are produced in ratio of 3 : 1. What are             genotypes of parent?  Explain the law of segregation. 

25.       Who observed that within a region species richness increases with increasing explored area, but only upto a limit? Write an             equation for species area  relationship. In vertebrates which group constituted species?  

26.       (a) Write an equation for exponential growth where N = population size and r = intrinsic rate of natural increase.           

            (b) Draw a graph for a population when responses are limiting, the growth plot is logistic and K is carrying capacity.           

27.       (a) A population growing in a habitat with limited resources show intially a lag phase followed by phase of acceleration,                  deceleration and finally on  asymptote, where the population density reaches the carrying capacity. This type of population                  growth is called verhulstpearl logistic growth. Write an equation for this. 

            (b) Broad-based pyramids like India’s populations are characteristic.    

            (c) Which biome support maximum number of species?

 

                                    SECTION - D

28.       Describe the chance migration is one of the mechanisms of origin of new species.          

                                                OR

            Write the name of various steps involved in rDNA technology. Describe isolation of DNA.

29        (a) Draw the embryo sac of flowering plant and label.

                        (i) Egg apparatus         

                        (ii) Antipodal cell         

                        (iii) Central cell

            (b) Even though each pollen grains has two male gametes, why at least 100 pollen grains and not 50 pollen grains are required to                  fertilise100 egg present in   anatropous ovule of 100 carpels?   

                                                OR

            (a) What are transgenics?         

            (b) What is biochip?    

            (c) What are linkers? explain.   

            (d) What are pseudoalleles? Give example.      

30.       (a) What are the some of the ethical, legal and social challenges presented by human genetic information?          

            (b) How will the human genome project impact medicine?        

            (c) What is a genome? And why it is important?

            (d) How many genes are in human genome?     

                                                OR

            (a) How do the process of eutrophication proceeds?    

            (b) What is BOD?

            (c) Why biodiversity is rich in tropics? Give some reasons in support of your answer.    

 

 

Tips: 1. Read question paper before solving it and select the questions that can be solved by you easily. 2. Now solve these questions on priority. 3. The diagram should be neatly made using different color pens & should be well labeled. 4. Underline the important portion of the answer. 5. At the end, attempt those questions that are remaining (to get bonus marks) 6. First of all read the paper properly. 7. First of all read the paper properly. ÙæðÅUÑ- ØãU °·¤ âñ{ÂÜ ÂðÂÚU ãñU ÁM¤ÚUè ÙãUè´ ç·¤ §âè ×ð´ âð ÂÚUèÿææ ×ð´ ÂýàÙ ¥æ°Ð

Piyush Gupta Biology