SAMPLE QUESTION PAPER OF BIOLOGY FOR 2018 EXAMINATION

BIOLOGY PRACTISE PAPER
FOR
CBSE BOARD EXAMINATION

SESSION – 2017-18














PREPARED BY

VIMAL KUMAR SHARMA
M.Sc.; Bed. ;  NET               .
 PGT – BIOLOGY










UNIT WISE QUESTION PAPER OF BIOLOGY
SET – 1 FOR UNIT - I
SECTION - A
1. How do the pollen grains of Vallisnaria protect themselves?
2. Sperms have a tail whereas eggs do not. Why so?
3. Offspring derived by asexual reproduction are called clones. Justify giving two reasons.
4. Name an IUD that you would recommend to promote the cervix hostility to the sperms.
5. Date palm is a dioecious plant. Comment on its sexuality.
SECTION – B
6. Draw and label the parts of the head region only of a human sperm.
7. Banana is a parthenocarpic fruit whereas oranges show polyembryony. How are they different from each other with
respect to seeds?
8. The cell division involved in gamete formation is not of the same type in different organisms. Justify.
9. Mention the number of cells in the following embryonic stages; zygote, morula, blastocyst.
OR
Some angiosperm seeds are said to be ‘albuminous’, whereas few others are said to have a perisperm. Explain
each with the help of an example.
10. A couple where both husband and wife are producing functional gametes, but the wife still unable to conceive, is
seeking medical aid. Describe any one method that you can suggest to this couple to become happy parents.
SECTION - C
11. (a) Name and explain the role of the inner and middle walls of the human uterus.
(b) Write the location and function of Sertoli cells in humans.
12. (a) What is the mode of reproduction in Chlamydomonas..
(b) Explain the function of scutellum in a monocot seed.
13. Differentiate between geitonogamy and xenogamy in plants. Which one between the two will lead to inbreeding
depression and why?
14. A woman has certain queries as listed below, before starting with contraceptive pills. Answer them :
 (a) What do contraceptive pills contain and how do they act as contraceptives?
(b) What schedule should be followed for taking these pills?
15.

Read the graph given above and correlate the uterine events that take place according to the hormonal levels on
(i) 6-15 days     (ii) 16-25 days    (iii) 26-28 days (if the ovum is not fertilised).
(b) Specify the sources of the hormones mentioned in the graph.
16. (a) Mention the site in a flowering plant where the following developments take place.
(i) Deposition of sporopollenin         (ii) Megasporogenesis
(b) Draw a labelled diagram of a male gametophyte of an angiosperm.
17. (a) Name the human embryonic stage shown below.  Identify ‘A’ and ‘B’ in it.

 (b) Mention the part of the above embryonic stage that forms the fetus.
(c) Name the embryonic stage that gets implanted in the uterine wall of human female.
18. (a) Mention the problems that are taken care of by Reproduction and Child Health Care Programme.
(b) What is amniocentesis and why there is a statutory ban on it?
19. List the changes each part of the fertilised ovule undergoes to develop into a seed.
OR
(a) Why do algae and fungi shift to sexual mode of reproduction just before the onset of adverse conditions?
(b) Unicellular organisms are immortal, whereas multicellular organisms are not. Justify.
20. State the significance of pollination. List any four differences between wind-pollinated and animal-pollinated flowers.
21. State any four methods to overcome infertility in human couples.
22. Describe the events of oogenesis with the help of schematic representation.
SECTION - D
23. Your school has been selected by the Department of Education to organise and host an interschool seminar on “Reproductive Health-Problems and Practices”. However, many parents are reluctant to permit their wards to attend it. Their argument is that the topic is “too embarrassing”. Put forth four arguments with appropriate reasons and explanation to justify the topic to be very essential and timely.
SECTION - E
24. (a) Draw a diagram of an enlarged view of T.S. of one microsporangium of an angiosperm and label the following parts:       (i) Tapetum (ii) Middle layer    (iii) Endothecium (iv) Microspore mother cells
(b) Mention the characteristic features and function of tapetum.
(c) Explain the following with reasons:
(i) Pollen grains are well preserved as fossils.
(ii) Pollen tablets are in use by people these days.
OR
(a) Explain any three outbreeding devices in flowering plants.   (b) Suggest the advantages to a farmer of using apomictic seeds of hybrid varieties.
25. (a)

The above given diagram shows a part of the human female reproductive system.
(i) Name the gamete cells that would be present in ‘X’ in a new born baby.
(ii) Name ‘Y’ and write its function.
(iii) Name ‘Z’ and write the event that take place here.
(b) Explain the process of fertilisation of an ovum in humans.
OR
(a) How is placenta formed in the human female?    (b) How is the placenta connected to the embryo?
(c) Comment on the role of placenta as an endocrine gland.
26. (a) Explain the role of accessory glands in human male reproductive system.
(b) Explain the role of pituitary and sex hormones in the  process of spermatogenesis.
OR
(a) Why is fertilisation in an angiosperm referred to as double fertilisation? Mention the ploidy of the cells involved.
(b) A flower of brinjal plant following the process of sexual reproduction produces 360 viable seeds.
Answer the following questions giving reasons.
(i) How many megaspore mother cells are involved?     (ii) How many male gametes are involved in the above case?      (iii) How many microspore mother cells must have undergone reduction division prior to dehiscence of anther in the above case?











UNIT WISE QUESTION PAPER OF BIOLOGY
SET – 2 FOR UNIT - I
SECTION - A
1. A scientist studied two semen samples A and B and found that sample A lacked fructose while sample B lacked citric acid. What could be the reason?
2. State two methods of apomictic development in seeds.
3. Write the names of hormones which stimulate milk production and milk ejection respectively.
4. Name the type of ovule in which body of the ovule gets inverted, and micropyle and funiculus lie side by side.
5. Give an example where an organism despite being hermaphrodite copulates in order to reproduce.
SECTION - B
6. Differentiate between monocarpic and polycarpic plants.
7. What is parturition? Where does the signals for parturition start from?
8. Name the IUDs which release mineral ions. Why they are considered good contraceptives?
9. A bilobed dithecous anther contains 50 pollen mother cells (PMCs) per microsporangium. How many male gametophytes can be produced by this anther?
10. Study the given figure and answer the following questions.
(i) Name the type of reproduction shown in the figure.
(ii) Write two advantages of this type of reproduction.
(iii) Give name of another animal which shows same type of reproduction.
OR
The chances of survival of offspring of viviparous animals are more than the offspring of oviparous animals. Justify the statement with reasons.
SECTION - C
11. (i) Draw a well labelled diagram of a human sperm.
(ii) Which part of the sperm provides energy for its movement?
12. ‘Viviparity limits the number of offspring in a litter’. Explain.
13. Write a short note on fertilizin-antifertilizin reaction. What is the significance of fertilisation?
14. (i) Where is acrosome present in human sperm?
(ii) Name the organelle that contributes in its formation.
(iii) State its function.
15. How does the megaspore mother cell develop into an embryo sac? Elaborate.
16. Males in whom testes fail to descend to the scrotum are generally infertile. Why?
17. What deter the persons infected of STDs from going for timely detection and proper treatment? What complications it can lead to, in future?
18. Why menstruation does not occur during pregnancy?
19. Mention the function of each of the following:
(i) Tassels of corn cob   (ii) Sertoli cells of seminiferous tubules    (iii) Tapetum in microsporangium
OR
Give an example of one organism each which reproduces by the following modes of asexual reproduction:
(i) Fragmentation (ii) Budding (iii) Conidia formation
20. “Gametogenesis and meiosis are always linked”. Justify the statement.
21. Give an account of foetal ejection reflex.
22. Discuss the mode of action of hormonal contraceptives.
SECTION - D
23. Abhay and his wife Anu are married for the last 8 years, but they do not have their own child. They have undergone various tests in infertility clinics and the reports showed Abhay to be infertile. However, Anu’s in-laws are not accepting this truth and are blaming Anu for being childless.
(i) Do you think Anu’s in-laws are correct for not accepting the truth and blaming her for the infertility? Give reasons in support of your answer.
(ii) What are the ways by which this couple could be assisted to have their own child?
SECTION - E
24. Define polyembryony and its types.
OR
(i) At what stage the ovum is released from the ovary? When and where does the maturation of this stage occurs?
(ii) Give a schematic representation of menstrual cycle.
(iii) Write a note on test tube baby programme.
25. Describe the post-zygotic events leading to implantation and placenta formation in humans. Mention any two functions of placenta.
OR
Diagrammatically explain the process of gametogenesis in both males and females.
26. Give reasons why:
(i) Most zygotes in angiosperms divide only after certain amount of endosperm is formed.
(ii) Micropyle remains as a small pore in the seed coat of a seed.
(iii) Integuments of an ovule harden and water content is highly reduced as the seed matures.
(iv) Anthers of angiospermic flowers are described as dithecous.
(v) Organisms produced due to sexual reproduction adapt better to the changing environmental conditions.
OR
(i) Name the hormonal composition of the oral contraceptive pills used by human females. Explain how does it act as a contraceptive.
(ii) Amniocentesis for sex determination is banned in our country. Is this ban necessary? Comment.
(iii) During evolution, sexual reproduction seems to gradually dominate asexual reproduction. Similarly internal fertilization replaced external fertilisation in higher organisms. Elaborate the possible reasons.



































UNIT WISE QUESTION PAPER OF BIOLOGY
SET – 1 FOR UNIT - II
SECTION - A
1. Mendel succeeded in all his experiments on pea plant for selected traits and concluded the three laws without any exception. What main factor would you attribute behind his success?
2. Name the type of speciation that occurs when a part of population becomes isolated from the main population.
3. Write the positively charged and negatively charged components of a nucleosome.
4. State any two important differences between phenomenon of codominance and dominance.
5. Name the DNA polymerase required in eukaryotes for (a) initiation of DNA replication (b) repairing of mitochondrial DNA.
SECTION - B
6. Wings of an insect are analogous to wings of a bird. Yes or no. Give reason to support your answer.
7. What is an adapter molecule? State the significance of the following in an adapter molecule.
(a) DHU loop
(b) TYC loop
8. Mention how the various factors affect linkage.
9. Explain the biogenetic law with the help of an example.
10. Differentiate between XX-XY type and ZW-ZZ type of sexdetermination mechanism.
OR
State the role of any two enzymes involved in DNA replication.
SECTION - C
11. (a) Draw a schematic representation of transcription unit showing its important components.
(b) State the function of structural gene in a transcription unit.
12. A cross between a normal couple resulted in a son who was haemophilic and a normal daughter. In course of time, when the daughter was married to a normal man, to their
surprise, the grandson was also haemophilic.
(a) Represent this cross in the form of a pedigree chart. Give the genotypes of the daughter and her husband.
(b) Write the conclusion you draw form the inheritance pattern of this disease.
13. (a) Darwin's theory of natural selection is based on the salient features of 'Survival of the fittest'. Explain this theory of mechanism of evolution with the help of an example.
(b) Theory of continuity of germplasm discarded the concept of theory of inheritance of acquired characters.
Give reasons for this.
14. Discuss the objectives of human genome project.
15. (a) (i) Which period of palaeozoic era is called as "Age of amphibians"?
(ii) In which era of geological time scale were dinosaurs originated?
(iii) State the significance of coelacanth in palaeozoic era.
(b) Rearrange the following in an ascending order of evolution: Horsetails, Mosses, Herbs, Conifers, Marine algae.
16. Linkage and crossing over of genes are alternative to each other. Justify the statement.
17. (a) Give a schematic representation of evolution of man.
(b) Mention any two characteristics of Cro-Magnon man.
(c) State any three characteristics of Heidelberg man. Mention its evolutionary significance also.
18. (a) A cross was carried out between two pea plants showing the contrasting traits of height of the plant. The result of the cross showed 50% of parental characters.
(i) Work out the cross with the help of a Punnett square.
(ii) Name the type of the cross carried out.
(b) How does a test cross helps in identifying the genotype of the organism? Explain.
19. (a) Genetic code is universal and degenerate. Explain.
(b) Of the total number of codons, how many codons code for amino acids?
(c) Discuss the role of AUG in protein synthesis.
20. (a) Name the kind of diseases/disorders along with any one
of the symptom that are likely to occur in humans if :
(i) mutation in the gene that codes for an enzyme phenylalanine hydrolase occurs
(ii) there is an extra copy of chromosome 21         (iii) the karyotype is XXY.
(b) Give an example of autosomal recessive trait. Discuss its inheritance pattern with the help of a cross.
21. How does the gene ‘I’ control ABO blood groups in humans? Write the effect that the gene imparts to red blood cells.
OR
Given below is a schematic representation of lac operon:

 (a) Identify 'i' and 'p'.
(b) Name the ‘inducer’ for this operon and explain its role.
(c) What kind of regulation does this lac operon shows? Explain.
22. (a) What is satellite DNA? Discuss the role of satellite DNA in DNA fingerprinting technique.
(b) Expand VNTR and state how is it different from a DNA probe?
SECTION - D
23. Supriya disclosed her wish to marry Sumit to her parents. Her parents opposed her decision as Sumit's family is known to inherit haemophilia. Supriya told her parents that Sumit is not haemophilic, still her parents resisted and opposed her decision. But she convinced her parents by giving proper scientific explanation for this.
(a) Why is haemophilia a cause of concern for Supriya's parents?
(b) What values do Supriya reflect from this incident?
(c) Is her parents' fear justified? How do you think she might have convinced them? Explain.
SECTION - E
24. Illustrate the steps of DNA packaging in eukaryotes.
OR
What do you mean by reproductive isolation? Discuss its various sub-types.
25. Explain the process of protein synthesis.
OR
State three principles of Mendel's law of inheritance. Using Punnett square demonstrate the law of independent assortment in a dihybrid cross involving two heterozygous parents.
26. Discuss the Hershey and Chase experiment. State the conclusion they drew after the experiment.
OR
Who proposed the 'Mutation theory of evolution'? What does it state? List the salient features of mutation theory.



















UNIT WISE QUESTION PAPER OF BIOLOGY
SET – 2 FOR UNIT – II
SECTION – A
Enlist the steps of controlled cross pollination. Would emasculation be needed in a cucurbit plant? Give reasons for your answer.
The pedigree chart given below shows a particular trait which is absent in parents but present in the next generatoin irrespective of sexes. Draw your conclusion on the basis of the pedigree.
A, B, D are three independently assorting genes with their recessive alleles a, b, d, respectively. A cross was made between individuals of Aa bb DD genotype with aa bb dd. Find out the type of genotypes of the offspring produced.
Name the components A and B in the nucleotide with a purine, given below.

Write the Oparin and Haldane’s hypothesis about the origin of life on earth. How does meteorite analysis favour this hypothesis?
SECTION - B
A. Divergent evolution leads to homologous stmctures. Explain with the help of an example
B. Convergent evolution leads to analogous stmctures. Explain with the help of an example.
.(i) Explain adaptive radiation with the help of suitable example. (ii)Cite an example where more than one adaptive radiations have occurred in an isolated geographical area. Name the type of evolution your example depicts and state why it is so
Given below is a diagrammatic representation of the experimental set-up used by SL Miller for his experiment

(i)Write the names of different gases contained and the conditions set for the reaction in the flask A. (ii)State the type of organic molecule he collected in the water at B.
9..(i) Why is fRNA called an adapter? (ii) Draw and label a secondary structure of fRNA. How does the actual structure of t-RNA look like?
10. .(i) Explain DNA polymorphism as the basis of genetic mapping of human genome.   (ii) State the role of VNTR in DNA fingerprinting.
OR
Given below are the sequence of nucleoside in a particular mRNA and amino acids coded by it UUUAUGUU CGAGUUAGUGUAA Phe – Met – Phe – Glu – Leu – Val Write the properties of genetic codes that can be and that cannot be correlated from the above given data.
SECTION - C
11. A normal visioned woman, whose father is colour blind, marries a normal visioned man. What would be probability of her sons and daughters to be colour blind? Explain with the help of a pedigree chart.
12. Define aneuploidy. How is it different from polyploidy? Describe the individuals having following chromosomal abnormalities.
13. .(i) Describe the various steps of Griffith’s experiment that led to the conclusion of the ‘transforming principle’. (ii)How did the chemical nature of the ‘transforming principle’ get established? or (i)Write the conclusion drawn by Griffith at the end of his experiment with Streptococcus pneumoniae. (ii)How did O Avery, C MacLeod and M McCarty prove that DNA was the genetic material? Explain.    or Describe Frederick Griffith’s experiment on Streptococcus pneumoniae. Discuss the conclusion he arrived at.                      Or
Study the flow chart given below and answer the questions that follow :

(a)Name the organism  and differentiate between, its two strains R and S respectively. (b)Write the result A and B obtained in step (iii) and (iv) respectively. (c)Name the scientist  who performed the steps (i), (ii) and (iii) (d)Write the specific conclusion drawn from the step (iv).
14. Describe the Hershey and Chase’s experiment. Write the conclusion drawn by the scientists after their experiment.               or Name the scientists,who proved experimentally that DNA is the genetic material.Describe their  Experiment.            or (i)Describe Hershey and Chase’s experiment.            (ii)Write the aim of the experiment.
15. .(i)Explain the role of DNA dependent RNA polymerase in initiation, elongation and termination during transcription in bacterial cell.       (ii) How is transcription a more complex process in eukaryotic cells? Explain.
16. Study the figure given and answer the questions


(i)How does the repressor molecule get inactivated? (ii)When does the transcription of lac mRNA stop? (iii)Name the enzyme transcribed by the gene
17. .(i) Which human chromosome has   maximum number of genes and   which one has fewest genes?
(ii) Write the scientific importance of single nucleotide polymorphism identified in human genome.
18. Given below are the sequence of nucleoside in a particular mRNA and amino acids coded by it UUUAUGUU CGAGUUAGUGUAA      Phe – Met – Phe – Glu – Leu – Val Write the properties of genetic codes that can be and that cannot be correlated from the above given data.
19. Prior to industrialisation, there were for more white-winged moths on trees than melanised moths in England. However, after industrialisation, the distribution pattern of these two kinds of moths reversed. What does the above observation indicate? Explain giving reasons
20. (a) Draw a schematic representation of transcription units showing its three components.
(b) Mention the function of promoter gene.
21. "The sex of the child is determined by the father and not by the mother." Justify the statement.
22. (a) State the "Theory of Spontaneous Generation".
(b) Name the scientists who experimentally disproved this theory.
SECTION - D
23. Ravi and Aabha are a happily married couple. A child suffering from sickle cell anaemia is born to them, but only Aabha was blamed by the family for delivering a sick child.
(a) What is sickle-cell anaemia?
(b) How would you counsel the family to not blame Aabha for delivering a child suffering from sickle-cell anaemia? What good values would your counselling propagate in the family?
SECTION - E
24. Describe the mechanism of inheritance of ABO blood groups in humans.
OR
EXPLAIN THE process of replication in Prokaryotes and differentiate with Eukaryotes?
25. (a) Who discovered coacervates? List the biological properties of coacervates.
(b) Write short note on vestigial organs, fossils as evidences giving example.
OR
Name the technique used for determining nucleotide sequence unique to an individual. Who gave this technique? Explain the procedure involved.
26. (a) Describe the process of Transcription in Eukaryotes and compare with prokaryotes?
(b) What are the three types of RNA? Mention their role in protein synthesis.
OR
(a) Differentiate between adaptive radiation and adaptive convergence.
(b) Explain reproductive isolation. What is its significance?









































UNIT WISE QUESTION PAPER OF BIOLOGY
SET – 1 FOR UNIT – III
SECTION - A
1. Name any two modes of transmission of amoebiasis.
2. Write the name of the following:
(a) Honeybee species in domestic state.
(b) A milch breed found in Gujarat and Rajasthan.
3. Which microbe is used to ripen Swiss cheese?
4. Define smoother crops.
5. What is an immunodeficiency disease? Give an example.
SECTION - B
6. List the symptoms of filariasis. How does a healthy person acquire this infection?
7. Differentiate between pureline selection and mass selection.
8. Mention any four important advantages of biogas generation.
9. Why are fungal spores ideal for marketing? Mention any two of them.
OR
Mention the effects of consumption of alcohol and hashish together as a mixture of drugs.
10. Define inbreeding depression. Also explain how it can be overcome.
SECTION - C
11. (a) Write the scientific names of any two microorganisms which cause pneumonia.
(b) How do they affect the body of infected persons?  (c) How does the disease spread?
12. Briefly explain the process of Multiple Ovulation Embryo  Transfer Technology (MOET).
13.

(a) Identify the labelled part 'A' and 'B'. (b) What does the diagram illustrate?
(c) Mention the type of immune response provided by the given structure.
14. List the differences between somaclones and somatic hybrids. Mention one example for each.
15. (a) Explain briefly the steps involved in micropropagation.
(b) Enlist the important advantages of micropropagation.
16. (a) Name the two microbes used as biocontrol agents.   (b) Explain how the two microbes act as biocontrol agents.  Describe why biopesticides are preferred over chemical pesticides.
17. (a) Write the scientific name of the source plant of following drugs:
(i) Marijuana (ii) Opium   (iii) Cocaine (iv) LSD
(b) Name any two natural hallucinogens and mention their effects on human body.
OR
What is single cell protein? How is it produced? Discuss its importance to human beings.
18. (a) Mention important functions of activated sludge in a sewage treatment plant.
(b) What is the role of flocs in sewage treatment?
19. Define plant breeding. How plant breeding helps in improving the public nutritional health?
20. Write the names of the microbes from which the following enzymes are obtained.
(i) Protease (ii) Amylase   (iii) Rennet  (iv) Lactase (v) Streptokinase (v) Lipase
21. (a) What is cancer? Mention one property on the basis of which cancer cells differ from normal cells.
(b) Differentiate between benign and malignant tumour.
22. (a) Discuss the role of plant breeding technique in improving the quality of sugarcane grown in North India.  (b) Name the diseases to which the following varieties of crops are resistant
(i) Himgiri (ii) Pusa Shubra
SECTION - D
23. Sumit was one of the best students in the class. His father wanted him to qualify NEET. Despite his efforts he was not doing well in school examinations. He got frustrated with his results and resorted to drugs. He started misbehaving with his parents and friends. His friends started neglecting him. The principal of school counselled Sumit which helped him a lot to come out from this tough situation. His parents
thereafter took him to a rehabilitation centre. After a few months, he recovered and came back home.
(a) Mention any two values that the principal reflect through his initiative towards Sumit.
(b) What is drug abuse? Give the names of four commonly abused drugs and their sources.
(c) What should be the attitude of Sumit's parents after his recovery?
SECTION - E
24. (a) Differentiate between inbreeding and outbreeding.
(b) What are the merits and demerits of inbreeding in cattle? Explain.
OR
(a) Spleen acts as a lymphoid organ. Justify the statement.
(b) Differentiate between the following    (i) Innate and acquired immunity
(ii) B - lymphocytes and T - lymphocytes
(c) What are antigen presenting cells? Mention its types.
25. How sewage water is treated before it could be discharged into natural water bodies?
OR
List the main steps involved in the procedure of a plant breeding experiments.
26. (a) How do mycorrhizae act as biofertilisers? Explain. Give an example.
(b) (i) Why are the fruit juices bought from market clearer as compared to those made at home?
(ii) Name the bioactive molecules produced by Trichoderma polysporum and Monascus purpureus.
OR
Write short notes on the following:  (a) Vaccine (b) Lymphoid organs  (c) AIDS (d) Organ transplantation






























UNIT WISE QUESTION PAPER OF BIOLOGY
SET – 1 FOR UNIT – IV
SECTION - A
1. Name the technique developed by Kary Mullis. What is the objective of this technique?
2. What is the role of ethidium bromide during agarose gel electrophoresis?
3. The milk produced by the transgenic cow Rosie is better than natural cow milk. Why?
4. Why do DNA fragments move towards the anode during gel electrophoresis?
5. Golden rice is a transgenic variety of rice. What is its characteristic property?
SECTION - B
6. (a) How is an exonuclease functionally different from an endonuclease?
(b) Give example of any two endonucleases other than Sal I.
7. (a) Illustrate the recognition sequence of Eco R I. Mention the term used for such sequences.
(b) How does restriction endonuclease act on a DNA molecule?
8. What are shuttle vectors?
9. (a) Why are transgenic animals so called?
(b) Name the scientist who introduced the term vaccine. What are edible vaccines?
OR
Name the transgenic variety of tomato. How it remains fresh for longer period than normal variety?
10. How is insertional inactivation of an enzyme used as a selectable marker to differentiate recombinants from non-recombinants?
SECTION - C
11. Refer to the given figure and answer the following questions.
(a) Name the organism in which the vector is inserted to get the copies of the desired gene.
(b) Mention the area labelled in the vector responsible for controlling the copy number of the inserted gene.
(c) Name and explain the role of a selectable marker shown in the vector.

12. How is gene therapy being used in treating ADA deficient patients?
13. What are bioreactors? List five growth conditions that a bioreactor provides for obtaining the desired product.
14. Differentiate between type I, II and III restriction endonucleases.
15. (a) Name the bacterium which produces Bt toxin. What is the significance of this toxin?
(b) Name the gene which codes for this toxin. Why this toxin does not kill the bacterium?
(c) Name the genes that prevent infection by cotton bollworms and corn borers in pest resistant plants.
16. Explain molecular farming or molecular harvesting.
17. Name and explain the technique used in the separation and isolation of DNA fragments to be used in recombinant DNA technology.
18. (a) What do you mean by the term biopiracy?
(b) What measures are being taken by the Indian Government to prevent biopiracy?
19. What are the basic requirements of a polymerase chain reaction?
OR
How Agrobacterium tumefaciens has been made a useful cloning vector to transfer DNA to plant cells?
20. (a) How is mature insulin different from proinsulin secreted by pancreas in humans?
(b) How human functional insulin is produced using rDNA technology?
(c) Why is the functional insulin thus produced, considered better than the ones used earlier by
diabetic patients?
21. DNA being hydrophilic cannot pass through the cell membranes of a host cell. Explain how does recombinant DNA get introduced into the host cell to transform the latter.
22. Explain the process of RNA interference.
SECTION - D
23. Neeraj was having a debate with Mohit regarding the advantages and disadvantages of transgenic animals. Neeraj was of the view that production of transgenic animals violates the integrity of species and animals suffer from cruelty so, it is unethical. On the other hand, Mohit emphasised the benefits that transgenic animals provide to the human race in various fields especially medicine.
(a) How do transgenic animals benefit humans?
(b) List the ethical issues related with the production of transgenic animals.
(c) What values are shown by Neeraj and Mohit?
SECTION - E
24. What is cloning vector? Why is it used? Explain the technique of using such a vector in E.coli.
OR
Describe the process of recombinant DNA technology with the help of a neatly labelled diagram.
25. A desired gene was identified in an organism for some experiments. Explain the processes that should be used for
(a) cutting this desired gene at specific locations.
(b) synthesis of multiple copies of this desired gene.
OR
(a) Briefly explain the principle and the role of ELISA.
(b) How transgenic animals proved to be beneficial in:
(i) Production of biological products       (ii) Chemical safety testing?
(c) Diagrammatically show synthesis of cDNA from RNA.
26. (a) How recombinant DNA technology helps in detecting the presence of mutated gene in cancer patients?
(b) Explain any three methods to force ‘alien’ or recombinant DNA into host cells.
OR
(a) List five advantages of using genetically modified plants over conventional ones. What are the health
risks on humans by GM plants?
(b) Describe the responsibility of GEAC, set up by the Indian Government.
























UNIT WISE QUESTION PAPER OF BIOLOGY
SET – 2 FOR UNIT – IV
SECTION - A
1. What are the two main techniques of modern biotechnology?
2. How are lysing enzymes different from cleaving enzymes?
3. There are three types of restriction endonucleases. Which among the three is/are used in recombinant DNA technology?
4. Name the transgenic plant from which hirudin is extracted.
5. Name two transgenic microorganisms that have been used for large scale production of amino acids.
SECTION - B
6. What are the useful applications of Bt cotton?
7. Why some of the genes are called 'selectable markers'? Name two genes which are useful for 'selectable markers'.
8. Describe the biological tools used in recombinant DNA technology.
9. Why are bacteriophage vectors more preferred over plasmid vectors?
OR
What is gene therapy? Briefly describe its types also.
10. How is 'Rosie' considered different from a normal cow? Explain.
SECTION - C
11. What do you mean by ADA deficiency? How genetic engineering helped patients suffering from this disease?
12. Differentiate between plasmid DNA and chromosomal DNA.
13. Define polymerase chain reaction (PCR). Explain the working mechanism of PCR.
14. Define the following:
(a) Biopiracy (b) Biopatent (c) Biowar
OR
Differentiate between upstream processing and downstream processing.
15. (a) What is the full form of ELISA?
(b) Name the principle on which ELISA technique is based.
(c) How does it help in early detection of a disease?
16. (a) What is a bioreactor? Write an advantage and a disadvantage of it.
(b) Name the types of commonly used bioreactors.
17. Name and explain the technique by which male gamete carrying Y chromosome is preferentially selected and inseminated into female.
18. Describe the technique used for separation and isolation of DNA fragments.
19. What is the full form of GEAC? Describe the main objectives of GEAC set up by the Indian government.
20. What is Ti plasmid? Mention its role in genetic engineering.
21. Why is transgenic mice most preferred for research work on gene transfer?
22. Write the recognition sites of the given restriction enzymes.
(i) Bam HI (ii) Eco RI (iii) Eco RII     (iv) Hae III (v) Hind II (vi) Sal I
SECTION - D
23. In a group discussion held between the students of class 12th, group A explained the advantages of transgenic organisms to human beings in the field of  medicine, industry, etc. Group B discussed the various controversies related to transgenic organisms.
(a) Which of the two groups according to you is justified? Explain with reasons.
(b) What kind of ethical issues are concerned with the production of transgenic animals?
SECTION - E
24. Read the following base sequence of a certain DNA strand and answer the questions that follows :
5′ - A-A-G-A-A-T -T-C-A-A - 3′
3′ - T -T-C- T- T- A-A-G-T- T - 5′
(a) What is ‘palindromic sequence’ in a DNA?
(b) Write the palindromic nucleotide sequence shown in the given DNA strand and mention the enzyme that will recognise such sequence.
(c) State the significance of enzyme that identifies palindromic nucleotide sequences.
OR
Describe the structure of human insulin. How insulin is synthesised? Diagrammatically explain the production of human insulin by rDNA technology.
25. (a) Draw schematic diagrams of segments of a vector and a foreign DNA with the sequence of nucleotides recognized by EcoR I. Also show rDNA formed by joining sticky ends of vector DNA and foreign DNA.
(b) Describe restriction modification system.
OR
(a) What are genetically modified crops? Write two advantages of technique of producing GM crops.
(b) What are the disadvantages of genetically modified plants?
26. (a) Write short note on the following:     (i) Transgenic tomato   (ii) ANDI    (iii) Transgenic sheep
(b) To which virus is transgenic chicken resistant?
OR
(a) Explain the important methods of gene transfer into the host cell without using a vector.
(b) Diagrammatically show steps involved in RNA interference.








































UNIT WISE QUESTION PAPER OF BIOLOGY
SET – 1 FOR UNIT – V
SECTION - A
1. Define standing crop and standing state.
2. Write two different ways for the disposal of e-wastes.
3.

Name the labelled parts X, Y and Z in the pie chart (given above) representing the global biodiversity of vertebrates showing the proportionate number of species of major taxa.
4. Ecology is basically concerned with four levels of biological organisation. Name them.
5. In a pond, there were 40 lotus plants. If 10 lotus plants died in a week, reducing the current population to 30, then calculate the death rate of lotus population for the said period.
SECTION - B
6. What type of interaction is seen between fig and wasp? Explain.
7. Write any four measures that can control vehicular air pollution in cities.
8. Differentiate between in situ and ex situ conservation.
OR
State differences between net primary productivity and gross primary productivity.
9. Name the interaction in each of the following:
(a) Calotropis producing highly poisonous chemicals   (b) Pilot fish accompanies shark
(c) Pluvianus enters the open mouth of crocodile (d) Association of Anabaena with Azolla
10. The pyramid of energy is always upright. Justify the statement.
SECTION - C
11. With the help of a flow chart, describe the phenomenon of biomagnification of DDT in an aquatic food chain.
12. David Tilman proved experimentally that stability of a community depends on its species richness. Explain.
13. Explain how does a primary succession start on a bare rock and reach a climax community.
14. Enumerate how human activities cause desertification.
15. What are the causes of global warming? Also explain why is it a warning to mankind.
OR
Compare narrowly utilitarian and broadly utilitarian approaches to conserve biodiversity with the help of suitable examples.
16. Study the population growth curves shown below.

 (a) Identify curves A and B.      (b) Mention the conditions responsible for the curves A and B respectively.
(c) Give the necessary equation for the curve B.
17. Differentiate between xerarch and hydrarch succession.
18. Construct a pyramid of energy when 10,000 joules of energy  is available at the producer level. Label all its trophic levels.
19. (a) Name the two types of nutrient cycle existing in nature. Where are their reservoirs present? State the functions of reservoirs.
(b) Explain the two ways by which carbon is returned to the atmosphere.
20. (a) Name the two metals used in a catalytic converter that help in keeping the environment clean.
(b) Lichens are regarded as pollution indicators. Explain.
21. (a) Differentiate between grazing and detritus food chain.
(b) Herbivores are considered similar to predators in the ecological context. Explain.
22. Define the following:
(a) Allen's rule (b) Photochemical smog (c) Diapause (d) Hotspots
SECTION - D
23. Rekha was waiting at a bus stop. Many passengers along with their kids were on the way to school. A bus passing by, ejected dark black smoke from the exhaust pipe. Rekha immediately stopped the bus and called the conductor and driver to show what they were contributing to the environment. Passengers waiting at the bus stop supported Rekha. She explained the driver about use of CNG and catalytic converters which help in reduction of vehicular emission.
(a) Why one should use CNG instead of petrol or diesel? (b) How do catalytic converters reduce vehicular gas emission? (c) We often see some cars with Bharat stage IV stickers. What does it imply?
(d) What values are shown by Rekha through her action?
SECTION - E
24. (a) How does the algal bloom choke the water body in an industrial area?
(b) What preventive measures should be taken to stop algal bloom?
(c) Why Eicchornia crassipes is also known as "Terror of Bengal"?
OR
With the help of a simplified model, explain how carbon cycle is a biogeochemical event occurring in nature.
25. What are the different ways by which organisms manage with abiotic stresses in nature?
OR
(a) Explain why is the ozone layer required in the stratosphere. How does it get depleted?
(b) How ozone depletion is a threat to mankind?
26. Enumerate the advantages of a healthy ecosystem.
OR
How does a hydrarch succession progresses from hydric to mesic condition to form a stable climax community?
























UNIT WISE QUESTION PAPER OF BIOLOGY
SET – 2 FOR UNIT – V
SECTION - A
1. Identify the type of diversity in the following:
(a) 1000 varieties of mango in India    (b) rain forests, mangroves and coral reefs.
2. Humming birds are not found in polar regions. Give reason.
3. In which layer of atmosphere is ozone present? Name two ozone depleting substances responsible for thinning of ozone layer.
4. Despite being primary consumers, all the primary productivity is not available to herbivores. Justify the statement.
5. Plants like Calotropis have evolved adaptations for defence against grazers. Explain.
SECTION - B
6. The pyramid of energy is upright whereas pyramid of biomass in sea is inverted. Explain how is this possible.
7. How introduction of alien species leads to loss of biodiversity? Explain with example.
8. List the attributes exhibited by a population but not by an individual.
9. An orchid plant is growing on the branch of mango tree. Describe the relationship being shown by the two.
OR
Name the two types of nutrient cycles present in nature. Also describe the two stores of nutrients.
10. Write a short note on photochemical smog.
SECTION - C
11. Who proposed the 'Rivet popper hypothesis'? Briefly describe the hypothesis and its aim.
12. Consider an incidence of 1,000,000 joules of solar energy in an ecosystem. Construct a pyramid of energy showing the amount of energy being transferred to each trophic level.
13. (a) The growth of a population shows specific and predictable pattern with time. Describe the two growth models representing population growth, with the help of a graph only.
(b) Which of the above growth models represent the human population growth and why?
14. (a) What measures should be taken to remove air pollution?  (b) How scrubbers are helpful in removing pollutants?
OR
All biotic successions proceed towards a similar semiclimax community. Justify the statement.
15. (a) Why do we need to conserve biodiversity?
(b) How do religious beliefs help in conservation of biodiversity?
16. Mutualism is observed to involve co-evolution of mutualist species. Support your answer with the help of an example.
17. Write short notes on the following:      (a) Eutrophication    (b) Biological magnification
18. Name the person who attempted to put a price tag on ecosystem services. What values are estimated for the various services?
19. Identify and briefly describe the interaction in following cases:
(i) Cuscuta growing on a shoe flower plant. (ii) Clown fish in tentacles of sea anemone.
(iii) Koel laying its eggs in crow's nest.
20. (a) Define primary productivity and discuss its types.    (b) Enlist the factors affecting primary productivity.
21. Discuss the greenhouse effect. What are the main greenhouse gases contributing to it?
22. (a) Differentiate between genetic and species diversity.
(b) Show the relationship between species richness and area with the help of graph.
SECTION - D
23. Kiran was on a visit to her native village during her summerholidays. While walking through the fields she observed some farmers spraying DDT in the fields. She approached them and requested to immediately stop it. But the farmers were furious due to intervention of little stranger. Kiran still insisted on explaining the harmful affects of their action.
(a) What harmful affects or phenomenon is Kiran referring to, that are caused by spraying DDT?
(b) State the adverse consequences that can result from above said phenomenon.
(c) What values are being reflected by Kiran?
SECTION - E
24. (a) With reference to three ecological age groups present in a population, discuss the types of population on the basis of its ratio. Support your answer with a graphical representation, in each case.
(b) Mention the attribute that contributes to the change in size of population at a given time period.
OR
Describe the carbon cycle or Phosphorus cycle or Nitrogen cycle.
25. Write a note on:    (a) Biosphere reserves     (b) Hot spots.
OR
(a) Briefly discuss how Joint Forest Management (JFM) help in conservation of forests.
(b) State the consequences of deforestation.
26. (a) Elaborate the steps involved in the process of decomposition.
(b) Differentiate between primary and secondary productivity.
OR
Give an account of mechanisms by which living organisms are able to cope up with stressful or adverse environmental conditions.








































CBSE CLASS 12 BIOLOGY
QUESTION PAPER SET – 044-01
SECTION - A
1. What is the role of filiform apparatus in embryo sac?
2. Arrange the following primates in increasing order of brain capacity.
Neanderthal man, Homo habilis, Homo erectus
3. Mention two basic amino acids present in histones.
4. Mother's milk is considered very essential for the new born infant. Why?
5. Suggest a technique to a researcher who has cut DNA into fragments by restriction enzyme and now needs to separate them.
SECTION - B
6. How does pollination take place in cleistogamous flowers?
7. Draw a sketch of a transcription unit.
OR
What is the role of coelacanth in evolution?
8. What is the source of statins? Mention the action of statins.
9. Identify 'A', 'B', 'C', 'D' in the given table.

10. Give an example of following types of interactions -  (a) Commensalism (b) Mutualism
SECTION - C
11. What is placenta? How does it act as an endocrine gland during pregnancy?
12. Diagrammatically represent the process of transcription in bacteria.
13. Briefly explain any two chromosomal disorders in human.
14. What is parthenocarpy? How does parthenocarpy differ from agamospermy?
15. Define biogeography. How do Darwin's finches provide the biogeographical evidence in favour of evolution?
16. How has MOET programme resulted in herd improvement?
OR
Mention some special techniques which can assist infertile couples to have children. Why test tube baby technique is called IVF?
17. Explain the role of baculoviruses as biological control agents. Describe their role in integrated pest management programmes.
18. Name the type of immunity that is present at the time of birth in human. Explain any three ways by which it is accomplished.
19. Explain how gene therapy has cured adenosine deaminase (ADA) deficiency in humans.
20. Refer to the given diagram of E. coli  cloning vector pBR322.  Answer the following questions:

(a) Indicate the antibiotic resistant genes. State the role of these genes.
(b) Indicate restriction site of EcoRI.            (c) Indicate the gene involved in the replication of plasmid.
21. Explain any three methods to force 'alien' or recombinant DNA into host cells.
22. List and explain the factors due to which the density of a population in a given habitat during a given period fluctuates.
SECTION - D
23. The air quality of your city has significantly improved now in comparison to what existed few years back. This is the result of a lot of conscious human efforts. You are being asked to conduct an awareness programme in your locality wherein you will comment on the steps taken by local Government
to improve the air quality.
(a) Write any two of your comments.
(b) List any two ways that you would include in your programme so as to ensure the maintenance of good quality of air.
(c) State any two values which your programme will inculcate in the people of your locality.
SECTION - E
24. A flower of brinjal plant following the process of sexual reproduction produces 360 viable seeds. Answer the following questions giving reasons:
(a) How many ovules are minimally involved?
(b) How many megaspore mother cells are involved?
(c) What is the minimum number of pollen grains that must land on stigma for pollination?
(d) How many male gametes are involved in the above case?
(e) How many microspore mother cells must have undergone reduction division prior to dehiscence of anther in the above case?
OR
(a) Explain the menstrual phase in a human female. State the levels of ovarian and pituitary hormones during this phase.
(b) Why is follicular phase in the menstrual cycle also referred to as proliferative phase? Explain.
(c) Explain the events that occur in a Graafian follicle at the time of ovulation and thereafter.
(d) Draw diagram of Graafian follicle and label antrum and secondary oocyte.
25. Describe Meselson and Stahl’s experiment that was conducted on E coli  in 1958.
OR
(a) Differentiate between homology and analogy giving one example each of plant and animal, respectively.
(b) Briefly explain how are they considered as an evidence in support of evolution.
26. (a) Name the population growth pattern represented by the equation  . What does “r” represent in the equation? Write its importance in population growth.
(b) By using population Verhulst-Pearl logistic growth curve explain the principle of carrying capacity.
OR
(a) Explain how a hydrarch succession progresses from hydric to mesic condition and forms a stable climax community.
(b) Why is the rate of secondary succession faster than that of primary succession?



















CBSE CLASS 12 BIOLOGY
QUESTION PAPER SET – 044-02
SECTION - A
1. Which cell organelle is modified to form the acrosome? Also name the chemical secreted by it.
2. Name two basic amino acids that provide positive charge to histone proteins.
3. Agrobacterium tumefaciens is known as a natural genetic engineer. Give reason to support the statement.
4. Name any two organisms which can occupy more than one trophic level in an ecosystem.
5. What causes swelling of the lower limbs in patients suffering from filariasis?
SECTION - B
6. State the role of ethidium bromide and UV-light during gel electrophoresis of DNA fragments.
7. What is a transgenic crop ? Name the plant which is used to produce blood anticoagulant protein. What is this protein called?
8. What are turions? What is their significance?
9. Curd is more nutritious than milk. Justify.
10. Identify a, b and c in the table given below:

OR
What does the comparison between the eyes of octopus and those of mammals say about their ancestry and evolution?
SECTION - C
11. Identify the type of the given ecological pyramid and give one example each of pyramid of number and pyramid of biomass in such cases.

12. Name the type of pollination taking place in coconut plant. List five characters of the flowers of coconut plant favouring this type of pollination.
13. Refer to the given structure of an antibody molecule and answer the following.

(a) Identify the regions marked as A, B, C and D.     (b) What is the role of region A and C in an antibody molecule?    (c) Name the two most abundant antibodies found in our body and mention their location and function.
14. When a garden pea plant with violet flowers was crossed with another plant with white flowers, 50% of the progeny bore violet flowers.
(a) Work out the cross.      (b) Name the type of cross and mention its significance.
(c) How does the inheritance pattern of flower colour in  snapdragon differ from the above?
15. (a) When does the corpus luteum degenerate? Explain   the immediate consequences of its degeneration in human  female.
(b) Mention the sites of action and function of the hormones  GnRH and FSH during spermatogenesis in human males.
16. A and B are the two different cloning vectors in two different bacterial colonies cultured in chromogenic substrate. Bacterial colonies with cloning vector A were colourless whereas those with B were blue coloured. Explain the cause of the difference in colour that appeared in two colonies.
17. MOET programme has helped in increasing the herd size of the desired variety of cattle. List the steps involved in conducting the programme.
18. (a) Discuss the causes and effects of carbon dioxide fertilisation on plants.
(b) Define accelerated eutrophication. Mention any two consequences of this phenomenon.
19. (a) Identify the instrument shown in the given figure and correctly label its parts P, Q, R, S and T.
(b) How is it used in gene transfer methods?
(c) State its significance in r-DNA technology.
OR
How is gene therapy being used in treating ADA deficient patients ?
20. A childless couple has agreed for a test tube baby programme.
List only the basic steps the procedure would involve to conceive the baby.
21. (a) What do you mean by regulation of gene expression?
(b) State the different levels, at which regulation of gene expression can be exerted in eukaryotes.
22. (a) Show graphical representation of species area relationship as given by Alexander von Humboldt.
(b) What do steeper slopes mean in the context of biodiversity?
SECTION - D
23. Rahul, 14 years old teenager is good in academics. However, there are few boys in his class who go to pubs for late night parties, consume alcohol and also take drugs. From last few days, Rahul’s mother noticed his drop in academic performance, lack of interest in personal hygiene, aggressive and rebellious behaviour, his loss of interest in hobbies, and changed sleeping and eating habits.
(a) What do you think may be the possible reason for Rahul's changed attitude?
(b) What are the different measures that should be taken by parents to protect their children from substance abuse?
SECTION - E
24. (a) Give a diagrammatic representation of spermatogenesis in humans.
(b) At which stage of life does gametogenesis begin in human males and females respectively?
(c) Name the organs where gametogenesis gets completed in human males and females respectively.
OR
Give reasons for the following.
(a) Most zygotes in angiosperms divide only after certain amount of endosperm is formed.
(b) Micropyle remains as a small pore in the seed coat of a seed.
(c) Integuments of an ovule harden and water content is highly reduced as the seed matures.
(d) Anthers of angiosperm flowers are described as dithecous.
(e) Organisms produced due to sexual reproduction adapt better to the changing environmental conditions.
25. (a) Why are herbivores considered similar to predators in the ecological context? Explain the relationship between the two.
(b) Differentiate between the following interspecific interactions in a population :
(i) Mutualism and parasitism      (ii) Commensalism and amensalism
(c) Define brood parasitism.
OR
(a) Define alien plant species. Name three alien plant species introduced in India.
(b) What are endangered species? Give two examples of Indian endangered animal species.
(c) In an era where the use of fossil fuels has been proven to be harmful to the environment and humans, alternative sources of energy are sought. Mention briefly any two such non-polluting sources of power generation.
26. (a) Rahul, a 3 years old child suffers from a chromosomal disorder with the following features :
Short stature with small round head, furrowed tongue and partially open mouth. His palm is broad with the
characteristic palm crease.
(i) Mention the name and cause of the disease from which Rahul is suffering.
(ii) Who described this disorder for the first time?
(b) A non-haemophilic couple was informed by their doctor that there is possibility of a haemophilic child be born to them. Explain the basis on which the doctor conveyed this information. Give the genotypes and the phenotypes of all the possible children who could have born to them.
OR
Explain how does the process of natural selection affect Hardy-Weinberg equilibrium. List the other four factors that disturb the equilibrium.

















































CBSE CLASS 12 BIOLOGY
QUESTION PAPER SET – 044-03
SECTION - A
1. A person is short-statured with small round head and partially open mouth. Name the defect the person is suffering from and also mention its cause.
2. State the cause of speciation according to Hugo de Vries.
3. What is the role of activated sludge in sewage treatment?
4. State the role of temperature and soil moisture in the regulation of decomposition process.
5. Humming bird is not found in polar regions. Give reason.
SECTION - B
6. In Vallisneria, female flowers are long stalked while male flowers are short stalked. How does this help in pollination in Vallisneria?
7. State the difference in mechanism of sex determination in mammals and birds.
8. A person is suffering from constipation, abdominal pain and cramps, appearance of excess mucous and blood clots in stool. Name the disease he is suffering from, its causal organism and the mode of transmission.
9. Name the disease resistant varieties of these crops.   (a) Wheat (b) Brassica (c) Chilli (d) Cowpea
10. Name the steps involved in genetically modifying an organism.
OR
How is Bt cotton made to attain resistance against bollworm?
SECTION - C
11. State three ways by which the flowering plants have solved the problem of inbreeding depression naturally.
12. Thomas Hunt Morgan carried out several dihybrid crosses on Drosophila. Morgan hybridised yellow-bodied white eyed females to brown bodied, red-eyed males and intercrossed their F1 progeny. He observed that the F2 ratio deviated very significantly from Mendelian dihybrid ratio of 9 : 3 : 3 : 1. Explain the phenomenon behind this deviation.
13. (a) State four criteria a molecule must fulfill to act as a genetic material.
(b) Among DNA and RNA which one is better genetic material? Explain.
14. Briefly explain any three evidences for organic evolution.
15. How are the primary and secondary immune responses carried out when our body encounters a pathogen?
16. State the source and role in medicine of each of the following.
   (a) Streptokinase    (b) Cyclosporin A   (c) Statins
OR
Explain the role of microbes as biofertilisers.
17. What is biofortification? Mention the objectives undertaken for improving nutritional quality. Give the name of some crops in which biofortification has been done.
18. Describe the process by which the bacterial cells are made competent to take up recombinant DNA.
19. Explain the steps involved in the technique of amplification of DNA.
20. Explain the technique involved in prevention of infection of tobacco plants by Meloidogyne incognita.
21. Explain phosphorus cycle in an ecosystem with the help of a simplified diagram.
22. Tropical regions account for greater biological diversity than temperate regions. Give three reasons.
SECTION - D
23. Your school has been selected by the Department of Education to organise and host an inter-school seminar on “Reproductive Health-Problems and Practices”. However, many parents are reluctant to permit their wards to attend it. Their argument is that the topic is “too embarrassing”. Put forth four arguments
with appropriate reasons and explanation to justify the topic to be very essential and timely.
SECTION - E
24. Give reasons why:
(a) most zygotes in angiosperms divide only after certain amount of endosperm is formed
(b) groundnut seeds are exalbuminous and castor seeds are albuminous
(c) micropyle remains as a small pore in the seed coat of a seed
(d) integuments of an ovule harden and the water content is highly reduced, as the seed matures
(e) apple and cashew are not called true fruits.
OR
(a) How is ‘oogenesis’ markedly different from ‘spermatogenesis’ with respect to the growth till puberty in the humans?
(b) Draw a sectional view of human ovary and label the different follicular stages, ovum and corpus luteum.
25. (a) Why is haemophilia generally observed in human males? Explain the conditions under which a human female can be haemophiliac.
(b) A pregnant human female was advised to undergo MTP It was diagnosed by her doctor that the fetus she is carrying has developed from a zygote formed by an XX-egg fertilised by Y-carrying sperm. Why was she advised to undergo MTP?
OR
Describe the process of transcription in a bacterium.
26. Study the table given regarding population interactions and answer the questions that follow.

 [Note : (+) plus = beneficial interaction; (–) minus = detrimental
interaction; (0) zero = neutral interaction]
(a) Identify the interactions (i) to (v).     (b) Briefly explain each one of them.
OR
(a) What is an ecological pyramid? Compare the pyramids of energy, biomass and numbers.
(b) Write any two limitations of ecological pyramids.





























CBSE CLASS 12 BIOLOGY
QUESTION PAPER SET – 044-04
SECTION - A
1. BOD of two samples of water A and B were 120 mg/L and 400 mg/L respectively. Which sample is more polluted?
2. How can retroviruses be used efficiently in biotechnology experiments inspite of them being disease causing?
3. The microscopic pollen grains of the past are obtained as fossils. Mention the characteristic of the pollen grains that makes it happen.
4. All the primary productivity is not available to a herbivore. Give one reason.
5. Thymus of a new born child was degenerating right from birth due to a genetic disorder. Predict its impact on the health of the child.
SECTION - B
6. In a dihybrid cross white eyed, yellow bodied female Drosophila crossed with red eyed, brown bodied male Drosophila produced in F2 generation 1.3 percent recombinants and 98.7 percent progeny with parental type combinations. This observation of Morgan deviated from Mendelian F2 phenotypic dihybrid ratio. Explain, Morgan’s observations.
7. How do ‘implants’ act as an effective method of contraception in human females? Mention its one advantage over contraceptive pills.
8. List any four objectives that you would recommend for biofortification.
9. Nematode-specific genes are introduced into the tobacco plants using Agrobacterium vectors to develop resistance in tobacco plants against nematodes. Explain the events that occur in tobacco plant to develop resistance.
OR
In England, before industrialisation set in, there were more white winged moths than dark winged moths. However the number reversed in the same area when industrialisation set in. How does this observation support natural selection?
10. Name the pioneer and the climax species in a hydrosere. Mention the changes observed in the biomass and the biodiversity of the successive seral communities developing in the water body.
SECTION - C
11. Distinguish between the following:
(a) Hibernation and Aestivation        (b) Ectotherms and Endotherms
12. (a) Name the labels a, b, c, d and e in the diagram of seminiferous tubule.

(b) Explain the hormonal regulation of the process ofspermatogenesis in humans.
13. The base sequence in one of the strands of DNA is   TAGCATGAT.
(a) Give the base sequence of its complementary strand.
(b) How are these base pairs held together in a DNA molecule?
(c) Explain the base complementarity rules. Name the scientist who framed this rule.
14. (a) List any two situations when a doctor would recommend injection of preformed antibodies into the body of a patient. Name this kind of immunisation and mention its advantages.
(b) Name the kind of immunity attained when instead of antibodies weakened antigens are introduced into the body.
OR
Explain the pattern of inheritance of haemophilia in humans. Why is the possibility of a human female becoming haemophiliac extremely rare? Explain.
15. (a) Explain the role of baculoviruses as biological control agents. Mention their importance in organic farming.
(b) Why do farmers prefer biofertilisers to chemical fertilisers these days? Explain.
16. (a) Why are the colourful polysterene and plastic packaging used for protecting the food, considered an
environmental menace?
(b) Write about the remedy found for the efficient use of plastic waste by Ahmed Khan of Bengaluru.
17. State the significance of pollination. List any four differences between wind-pollinated and insect-pollinated flowers.
18. Study the schematic representation of evolutionary history of plant forms given below and mention :

(a) The plant form to which ferns and conifers are most related to.
(b) The nearest ancestors of flowering plants.
(c) The most primitive group of plants.
(d) Common ancestry of Psilophyton provides to.
(e) The common ancestor of Psilophyton and seed ferns.
(f) The common ancestors of mosses and tracheophytes.
19. Outcrossing and cross-breeding are two breeding practices  in animal husbandry. How are the two practices different from each other and of what advantage are they to the breeders? Explain.
20. (a) A forest hardly has any carnivores. Census of herbivorous mammals was taken and plotted as a graph
shown below. Identify the curve that will explain the population growth of herbivores. Give reason to your
answer.

(b) Certain species of wasps are seen to frequently visit fig trees. What type of interaction is seen between them and why?
21. EcoRI is used to cut a segment of foreign DNA and that of a vector DNA to form a recombinant DNA. Show with the help of schematic diagrams.
(a) The set of palindromic nucleotide sequence of base pairs, the EcoRI will recognise in both the DNA segments. Mark the site at which EcoRI will act and cut both the segments.
(b) Sticky ends formed on both the segments where the two DNA segments will join later to form a recombinant DNA.
22. A couple with normal vision was informed by their doctor that there is possibility of a colourblind child be born to them. Explain the basis on which the doctor conveyed this information. Give the genotypes and the phenotypes of all possible children who could have born to them.
SECTION - D
23. Sanjay lives in a village on a river bank, who earns his livelihood by fisheries. He applied the idea of ecosystem based fisheries management given by one person from an NGO working in village.
(a) What are the values shown by Sanjay by implementing such advice?
(b) What is ecological objective of such an idea?
SECTION - E
24. (a) Study the flow chart given below. Name the hormones involved at each stage and explain their functions.       Hypothalamus
          􀁰
    Pituitary
         􀁰
     Ovary
         􀁰
 Pregnancy
(b) Describe the process of parturition in humans.
OR
(a) Draw a diagram of an enlarged view of T.S. of microsporangium of an angiosperm and label the following parts:
(i) Tapetum (ii) Middle layer (iii) Endothecium (iv) Microspore mother cells
(b) Mention the characteristic features and function of tapetum.
(c) Describe the sequence of the process of microsporogenesis in angiosperms.
25. (a) (i) Why are grasshopper and Drosophila said to show male heterogamety? Explain.
(ii) Explain female heterogamety with the help of an example.
(iii) Show mechanism of sex determination in honeybees with the help of flow chart.
(b) (i) List the symptoms exhibited by Turner’s syndrome sufferer. Explain the cause of this disorder.
(ii) How chromosomal disorders are different from Mendelian disorders?
OR
(a) Draw a schematic representation of the structure of a transcription unit and show the following in it:
(i) Direction in which the transcription occurs (ii) Polarity of the two strands involved
(iii) Template strand (iv) Terminator gene
(b) Mention the function of promoter gene in transcription.
(c) Explain the role of DNA-dependent RNA polymerase in transcription.
(d) Write a note on post-transcriptional modifications.
26. (a) “All successions proceed to a similar climax community–the mesic.” Explain.
(b) What are exotic species? Explain with the help of two examples how the exotic species disturb the native species of an ecosystem?
OR
(a) Mention the role of vectors in recombinant DNA technology. Give examples.
(b) With the help of diagrammatic representation only, show the steps of recombinant DNA technology.
(c) Biopiracy should be prevented. State why and how.




















CBSE CLASS 12 BIOLOGY
QUESTION PAPER SET – 044-05
{SOLVED}
SECTION – A
1. Name any two vertebrate body part that are homologous to human forelimbs.
Ans. Forelimbs of horse/ cow/ dog/ cat…, Wings of birds/ bat. Flippers of dolphins/ whale/ seal...
2. When and why do some animals like snails go into aestivation?
Ans. Summer,  To survive from heat / to escape from desiccation.
3. What is the economic value Spirulina?
Ans. Food rich in proteins// single cell protein// reduces pollution if grown in large quantities in waste  waters.
4. What was the speciality of the milk produced by the transgenic cow Rosie?
Ans. Contains humans alpha lactalbumin, More balanced nutritionally than normal cow milk.
5. How do neutrophils act as a celluler barrier to pathogen in humans?
Ans. Phagocytose/ kill/ destroy microbes.
6. Mention the polarity of the DNA strands a-b and c-d shown in the replicating fork given below.

Ans. a-b = 3 ‘- 5 ‘ c-d = 5’ - 3’
7. Mention any two significant roles predation plays in nature.
Ans. Conduits of energy transfer to the next trophic level/prey is kept under control/help in biological/ maintains species diversity. (Any two)
8. Why is the polar region not a suitable habitat for tiny humming birds?
Ans. When volume is considered surface area is large of heat is more cooler region/ difficult to generate more heat.
SECTION B
9. (a) Expand IUD.
(b) Why is hormone releasing IUD considered a good contraceptive to space children?
Ans. (a) Intra Uterine Device.
(b) Increases phagocytosis of sperms, reduces sperm mobility, makes utreus unsuitable for implantation, makes cervix hostile to sperms (Any two)
10. Name the interaction in each of the following:
(a) Cuscuta growing on a shoe flower plant
(b) Mycorrhizai living on the roots of higher plants
(c) Clown fish living among the tentacles of sea anemone
(d) Koel laying her eggs in crow's nest
Ans.(a) Parasitism.
(b) Mutualism
(c)Commensalism
(d)Brood parasitism.
11. A plant of Antirrtinum majus with red flowers was crossed with another plant of the same species with white flowers.The plants of the F1 generation bore pink flowers.Explain the pattern of inheritance with help of a cross.
Ans.

Because gene for red is not completely dominant over the recessive gene.
Pattern of inheritance-Incomplete dominance
OR
A women with blood group O married a man AB group.Show the blood group of the progency.List the alleles involved in this inheritance.
Ans.

Possible blood groups - A, B
Alleles – Ia,  Ib  and  i
12. Why do sportspersons often fall a victim to cocaine addiction?
Ans. Cocaine being a stimulant, enhances performance.
13. State the difference between the fìrst trophic levels of detritus food chain and grazing food chain.
Ans. DFC - Dead and decaying organic matter/ Dead remains of plants and animals
GFC - Living green plants/ producers
14. Coconut palm is monoecious while date palm is dioecious.Why are they called so?
Ans. Coconut palm- product(unisexual) male and female flowers in the same plant,
Date palm- produced (uinsexual) male and female flowers in separate plants.
15. How can DNA segment,separated by get electrophoresis, be visualizes and isolated?
Ans. Visualised by stanining the DNA fragmants with ethidium bromide, exposing them to UV radiation (appear as bright orange bands).
Band are cut out from agarose get, extracted from gel piece(by elution)
16. How do Darwin’s finches illustrate adaptive radiation?
Ans. Orignal stock of seed eating finches migrated to different habitats(of Galapagos Island), adapted to different feeding methods, by altered, by altered beak structure, evolved into different type of finches.
17. Name the blank spaces a,b,c and d from the table below:

Ans. a – Lactobacillus b - Trichoderma polysporum
c – Yeas d - Peniciliin
18. DDT content in the water of a lake that supplies drinking water to the near by village, is found to be 0.003 ppm. The kingfishers of that area are reported to have 2 ppm of DDT. Why has the concentration increased in these birds? What harm will this cause to the bird population? Name the phenomenon.
Ans. DDT neither excreted nor metbolised, interferes with Calcium metabolism, decline in
bird population/ due of thinning of egg/shell/ premature breaking of eggs, bio-magnification.
SECTION C
19. (a)

Read the graph given above and correlate the utcrinc events that take place according
to the hormonal levels on
(i) 6-15days
(ii) 16-25days
(iii) 26 - 28 days (if the ovum is not fertilised)
(b) Specify the sources of the hormones mentioned in the graph.
Ans. (a) (i) Regeneration of endometrium.
(ii) Uterus gets highly vascularised, ready for embryo implantation
(iii) Disintegration of the endometrium
(b) Estrogen - by ovarian follicle.   Progesterone - Corpus luteum
20. Explain the role of baculoviruses as biological control agents. Mention their importance in organic farming.
Ans. Baculoviruses produce narrow spectrum insecticides kill insect and other arthropods which are species specific, does not affect non target organisms / no negative impact on other insects, mammals, birds. Or fish.
Eliminates Use use of chemical pesticides, / conserves beneficial insects/ integrated pest management.
21. (a) Draw the structure of the initiator tRNA adaptor molecule.
(b) Why is tRNA called an adaptor molecule?
Ans. (a) Clover leaf shape

b. On one hand it reads the code
On the other hand it binds to specific amino acid.
22.



Study the population growth curves shown above.
(i) identify curves ‘a’ and ‘b’.    (ii) Mention the conditions responsible for the curves ‘a’ and ‘b’ respectively,   (iii) Give the necessary equation for the curve ‘b’.
Ans. (i) a-exponential curve
b-logistic curve
(ii) a - unlimited food resource/ responses are not limiting the growth.
b-limited food resource/ responses are liming the growth.
(iii)  


23.why is Agrobacterium tumefaciens good cloning vector? Explain.
Ans. If any desired/ foreign gene is linked with, Ti plasmid of Agrobacterium tumifaciens the bacterium is modified into non-pathogenic, plasmid is cloned into multiple copies, can be delivered into a variety of plants, desired chemical will be produced.
OR
Explain the importance of (a) ori, (b) and (c) rop in the E. coli vector shown below:

Ans. (a) ori-origin of replication.
(b) anipR - ampicillin antibiotic resistant gene
(c) rop - gene to produce the proteins involved in the replication of the plasmid.
24.

Study the mRNA segment given above which is complete to be translated into a
polypeptide chain.
(í) write the codons ‘a’and ‘b’
(ii) What do they code for?
(ìii) How is peplidc bond formed between two amino acids in the ribosome?
Ans. (i) a - AUG
b-UAA/ UAG/ UGA
(ii) AUG codes for Methionine.
UAA/ UAG/ UGA - Stop codon/ Nonsense codon/ Does not code for any amino acid.
(iii) Charged tRNAs arc brought closer together on mRNA in the ribosomes, ribosome acts as a catalyst (ribozyme) forming peptide bond.
25. (a) Name the infective stage of Plasmodium which mosquito takes in along with the blood meal from an infected human.
(b) Why docs the infection cause fever in humans?
(c) Give a flow chart of the part of the life- cyclc of this parasite passed in the insects.
Ans. (a) Gametocyte
(b) Haemozoin released during the rupture of RBC causes fever
(c)

26. A factory drains its waste water into the nearby lake. It has caused algal bloom.
(a) How was the algal bloom caused?
(b) What would be the consequences?
(c) Name the phenomenon that caused it.
Ans. (a) Nutrients in the waste water causes / extensive growth or proliferation of planktonic
or free floating algac.
(b) Algae use O2 BOD value goes high, deterioration of water quality, high fish mortality,
scum and unpleasant odour/ lake gets choked/ faces death (any four)
(c) Eutrophication.

27. Study the given pedigree chart and answer the question that follow.

 (a) Is the trait recessive or dominant?
(b) Is the trait sex-linked or autosomal?
(c) Give the genotypes of the parents in generation I and of their and fourth and fourth
child in generation II.
Ans. (a) a - Reccessive
(b) b-Autosomal
(c) C- Parents Aa and Aa
      Third child -aa
      Fourth child – Aa
Any other alphabet can be taken in piacc of A and a.
SECTION D
28. (a) Draw a schematic labelled diagram of a fertilised embryo sac of an Angiosperm.
(b) Describe the stages in embryo development in a dicot plant.
Ans. (a)

 (b) The zygote divides unequally to form to cells,
The smaller cell divides repeatedly to produce a row of 4-8 cells,
The terminal cell divides to produce a cluster of cells called the globular embryo/ proembryo
The remaining cells constitute the suspensor,
A few cells of the proembyo nearest of the suspensor develop into hypocotyl and radicle
while other cells give rise to epicotyl, plumule and cotyledons.

OR

(a) Draw a labelled diagram of a sectional view of human seminiferous tubule.
(b) Differentiate between gametogenesis in human males and females on the basis of
(i) time of initiation of the process.
(ii) products formed at the end of the process.

Ans. (a)

 (b) (i) Male-puberty
Female-foetal/ embroyic stage
(ii) Male-sperm/ spermatozoan
Female-ovum
29. Explain the steps involved in the production of genetically engineered insulin.
Ans. Gene for chain A and gene for chain B of insulin are prepared, inserted into plasmid, of  E.coli separately. E.coli cultured and chain extracted,combined by disulphide bond (to produce human insulin).
OR
(a) Name the nematode that infest and damage tobacco roots.
(b) How are transgenic tobacco plants produced to solve this problem?
Ans.(a) Meloidegyme incognitia
(b) Nematode specific genes isolated cloned and introduced into tobacco plants, ds RNA are produced and RNAi interference initiated, mRNA translation silenced.
survival of the nematode not possible in the host plants.
30. What is ‘semi-conservative’ DNA replication? How was it experimentally proved and by whom?
Ans. After the completion of replication (of one DNA molecule into two) each DNA molecule will have one parental strand and one newly synthesized strand.
Messelson and Stahl
Explain complete experiment.

OR

A homozygous tall pea plant with green seeds is crossed with a dwarf pca plant with yellow seeds.
(i) What would bc the phenolypc and genotype of F1?
(ii) Work out the phenotypic pic ratio of F2 generation with the help of a Punnett square.
Ans. (i) Phenotype of F1 -Tall and Yellow
Genotype of F1 -TtYy

(ii)

Male gametes= 1/2
Female gametes = 1/2
Punnett square = 1/2
Foure phenotype = 2
Ratio = ½





































CBSE CLASS 12 BIOLOGY
QUESTION PAPER SET – 044-06
SECTION – A
1. Mention any two significant roles predation plays in nature.
2. Between amphibians and birds, which will be able to cope with global warming? Give reason.
3. Name the two type so cells in which the HIV multiplies after gaining entry into the human body.
4. Name any two vertebrate body parts that arc homologous to human forelimbs.
5. What was the speciality of the milk produced by the transgenic cow Rosie?
6. What is replication fork?
7. A multinational company outside India tried to sell new varieties of turmeric without proper patent rights. What is such an act referred to?
8. What is the economic value of Spirualina?
SECTION B
9. A plant of Antirrhinum majus with red flowers was crossed with another plant of the same species with white flowers. The plants of the F1 generation bore pink flowers. Explain the pattern of inheritance with the help of a cross.
OR
A woman with blood group O married a man with AB group. Show the possible blood groups of the progeny. List the alleles involved in this inheritance.
10. Certain species of wasps are seen to frequently visit flowering fig trees. What type of interaction is seen between them and why?
11. State the difference between the first trophic levels of detritus food chain and grazing food chain.
12. How can DNA segments, separated by gel electrophoresis, be visualised and isolated?
13. Coconut palm is monoecious while date palm is dioecious. Why are they called so?
14. (a) Expand IUD.
(b) Why is hormone releasing IUD considered a good contraceptive to space children?
15. How do Darwin’s finches illustrate adaptive radiation?
16. How do sportsperson often fall a victim to cocain addiction?
17. DDT content in the water of a take that supplies drinking water to the nearby villages, is found to be 0.003 ppm. The kingfishers of that area are reported to have 2 ppm of DDT. Why has the concentration increased in these birds? What harm will this cause to the bird population? Name the phenomenon.
18. Draw flow chart showing process of Plant Breeding?
SECTION C
19. (a) Draw the structure of the initiator tRNA adaptor molecules.
(b) Why is tRNA called an adaptor molecule?
20. Name the pathogen that cause amoebiasis in humans.Give the symtoms and the mode transmission of the disease.
21.Explain the transformation experiment with biochemical conclusion?
22. How does Darwin’s theory of Natural Selection explain the appearance of new forms of life on earth?
23. How is the bacterium Thermus aquaticus employed in recombinant DNA technology?
OR
DNA being hydrophilic cannot pass through the cell membrane of a host cell. Explain how does recombinant DNA get introduced into the host cell to transform the latter.
24. A factory’ drains its waste water into the nearby lake it has caused algal bloom,
(a) How was the algal bloom caused?            (b) What would be the consequences?
(c) Name the phenomenon that caused it.
25. Explain the difference between the spermatogenesis and oogenesis?
26.Explain the age pyramids.
27. Explain the role of baculoviruses as biological control agents. Mention their importance in organic farming.
SECTION D
28. Explain the step involved in the production of genetically engineered insulin.
(a) Name thc nematode that infests and damages tobacco roots.
(b) How arc transgenic tobacco plants produced to solve this problem?
29. A tall pea plant with yellow seeds (heterozygous for both the traits) is crossed with a dwarf pea plant with green seeds. Using a Punnett square work out the cross to show the phenotypes and the genotypes of F1 generation.
Or
(a) Why is DNA molecule a more stable genetic material than RNA? Explain?
(b) "Unambiguous", "degenerate" and "universal" are some of the salient features of genetic code. Explain?

















































CBSE CLASS 12 BIOLOGY
QUESTION PAPER SET – 044-07
SECTION – A
Q1. The microscopic pollen grains of the past are obtained as fossils. Mention the characteristic of the pollen grains that makes it happen.
Q2.

Name the unlabelled areas ‘a’ and ‘b’ of the pie chart (given above) representing the global biodiversity of invertebrates shoeing their proportionate number of species of major taxa.
Q3. Some allergens trigger sneezing and wheezing in human beings. What causes this type of response by the body?
Q4. Name the group of organisms and the substrate they act on to produce biogas.
Q5. Are the thorn of Bougainvillea and tendril of Cucurbita homologous or analogous? What type of evolution has brought such a similarity in them?
Q6. Mention the two additional processing which hnRNA needs to undergo after splicing so as to become functional.
Q7. Mention the pollinating agent of an inflorescence of small dull coloured flowers with well exposed stamens and large feathery stigma. Give any one characteristic of pollen grains produced by such flowers.
Q8. Which of the following is a free living bacteria that can fix nitrogen in the soil?
Spirulina, Azospirillum, Somalia
SECTION – B
Q9.

(i) What does the above diagram illustrate?
(ii) Name the parts labeled ‘a’ and ‘b’.
(iii) Name the type of cells that produce this molecule.
Q10. Name the muscular and the glandular layers of human uterus. Which one of these layers undergoes cyclic changes during menstrual cycle? Name the hormone essential for the maintenance of this layer.
OR
Name the hormonal composition of the oral contraceptive used by human females. Explain how does it act as contraceptive.
Q11. Explain accelerated eutrophication. Mention any two consequences of this phenomenon.
Q12. Study the figure given below and answer the questions:

(a) How does the repressor molecule get inactivated?
(b) When does the transcription of lac mRNA stop?
(c) Name the enzyme transcribed by the gene ‘Z’.
Q13. Describe the responsibility of GEAC, set up by the Indian Government.
Q14. (a) What is “r” in the population equation given below?     dN/ dt = rN
(b) How does the increase and the decrease in the value of ‘r’ affect the population size?
Q15. During the secondary treatment of the primary effluent how does the significant decrease in BOD occur?
Q16. How is the translation of mRNA terminated? Explain.
Q17. List the specific symptoms of amoebiasis. Name the causative organism.
Q18. Explain the contribution of Thermus aquatics in the amplification of a gene of interest.
SECTION – C
Q19. (a) Name the respective forms in which the malarial parasite gains entry into
(i) Human body and
(ii) Body of female Anopheles.
(b) Name the hosts where the sexual and the asexual reproductions of malarial parasite occur respectively.
(c) Name the toxin responsible for the appearance of symptoms of malarial in humans. Why do these symptoms occur periodically?
Q20.

(a) Identify the selectable markers in the diagram of E. coli vector shown above.
(b) How is the coding sequence of - galactosidase considered a better marker than the ones identified by you in the diagram? Explain.
Q21. Haemophilia is a sex lined recessive disorder of humans. The pedigree chart given below shows the inheritance of haemophilia in one family. Study the pattern of inheritance and answer the questions given.

(a) Give all the possible genotypes of the members 4, 5 and 6 in the pedigree chart.
(b) A blood test shows that the individual 14 is carrier of haemophilia. The member numbered 5 has recently married the member numbered 14. what is the probability that their first child will be a haemophilic male?
OR
Inheritance pattern of ABO blood groups in humans shows dominance, codominance and multiple allelism. Explain each concept with the help of blood group genotypes.
Q22. Construct an ideal pyramid of energy when 1, 000, 000 joules of sunlight is available. Label all its tropic levels.
Q23. Study the figure given below and answer the questions that follow:
(a) Name the stage of human embryo the figure represents.
(b) Identify ‘a’ in the figure and mention its function.
(c) Mention the fate of the inner cell mass after implantation in the uterus.
(d) Where are the stem cells located in this embryo?
Q24. Explain the causes of global warming. Why is it a warning to mankind?
Q25.

(a) Mention the specific geographical region where these organisms are found.
(b) Name and explain the phenomenon that has resulted in the evolution of such diverse species in the region.
 (c) Explain given reasons the existence of placental wolf and Tasmanian wolf sharing the same habitat.
Q26. Draw a labeled schematic sketch of replication fork of DNA. Explain the role of the enzymes involved in DNA replication.
Q27. Name the pioneer species on a bare rock. How do they help in establishing the next type of vegetation? Mention the type of climax community that will ultimately get established.
SECTION – D
Q28. (a) What did Meselson and Stahl observe when
(i) They cultured E. coil in medium containing 15NH4Cl for a few generations and centrifuged the content.
(ii) They transferred one such bacterium to the normal medium of NH4Cl and cultured for 2 generations?
(b) What did Meselson and Stahl conclude from this experiment? Explain with the help of diagrams.
(c) Which is the first genetic material? Give reasons in support of your answer.
OR
You are given a red flower – bearing pea plant and a red flower bearing snapdragon plant.
How would you find the genotypes of these two plants with respect to the colour of the flower? Explain the help of crosses. Comment upon the pattern of inheritance seen in these two plants.
Q29. (a) Draw a labeled diagram of a mature embryo sac.
(b) Why does a pollen grain posses two male gametes? Explain.
OR
(a) Draw a schematic diagram of a human sperm and label the cellular components. Give the functions of any three parts.
(b) Where are the sperm heads found embedded to survive after spermatogenesis?
Q30. One of the main objectives of biotechnology is to minimize the use of insecticides on cultivated crops. Explain with the help of a suitable example how insect resistant crops have been developed using techniques of biotechnology.
OR
(a) How is mature insulin different from proinsulin secreted by pancreas in humans?
(b) Explain how was human functional insulin produced using rDNA technology.
(c) Why is the functional insulin thus produced considered better than the ones used earlier by diabetic patents?
CBSE CLASS 12 BIOLOGY
QUESTION PAPER SET – 044-08
SECTION – A
1. Name the condition in vertebrates where the body attacks self-cells.
2. Write the function of a Bioreactor.
3. A colour blind boy is born to a couple with a normal colour vision. Write the genotype of the parents.
4. Mention any two conditions that enhance the chances of syngamy in organisms exhibiting external fertilization.
5. Write the conclusion Griffith arrived at the end of his experiment with Streptococcus pneumoniae.
SECTION - B
6. Plants like potato, sugarcane do not require seeds for producing new plants. How do they produce new plants ? Give two other examples where new plants are produced in the same way.
7. Explain the role played by predators in a community.
8. Name the first antibiotic discovered and by whom.
9. What happens when chromatids fail to segregate during cell division cycle ? Explain your answer with an example.
OR
ABO blood groups is a good example of co-dominance. Justify.
10. What is the pathogenic property of baculovirus, used as a biological agents ? Name the genus of these organisms.
SECTION - C
11. a. What is an “allergic reaction” ?
b. Name any two drugs used to quickly reduce the symptoms of allergy.
c. Why do more and more children in metro cities of India suffer from allergies and asthma ?
12. Explain the biofertilizers and biocontrollers with examples?
13. list any two types of IUDs that are available for human females and state their mode of action.
14. Mention the role of (i) selectable marker, (ii) Ori and (iii) rop in E. coli cloning vector pBR322.
15. Write the aim with which animal breeding programmes are carried. Describe the essential steps to be followed in Poultry management.
16. a. Draw a diagram of a sectional view of human ovary and label (i) Primary follicle;
(ii) Tertiary follicle; (iii) Graafian follicle and (iv) Corpus luteum.
b. Write the function of corpus luteum.
OR
a. (a) Draw a diagram of Pistil showing pollen tube growth in angiosperm and label
(i) Stigma; (ii) male gametes; (iii) micropyle and (iv) Ovule.
b. (b) Write the function of micropyle.
17. What was the challenge for production of insulin using rDNA techniques ? How did Eli Lilly produce insulin using rDNA technology ?
18. Explain Harshey and Chase Experiment?
19. Name the organism from which the ‘cry’ genes are isolated. Mention with the help of suitable example why and how bio-technologists have made use of ‘cry’ genes.
20. Excessive and continuous use of pesticides has resulted in evolution of some new species of pests. Explain what must have led to this. What is this type of evolution called?
21. Explain with the help of two examples how certain plants have evolved morphological and chemical defenses against primary consumers such as cows and goats.
22. What type of organs eye of an Octopus and that of a human called ? Give another example from the animal group and one from the plants of such organs. Name and explain the evolutionary process they exhibit.
SECTION - D
23. With the revolution in information technology, now it has become an integral part of everybody’s life, living in rural and urban India. You are asked to address the gathering of students of eco-clubs of your neighbourhood schools on generation and management of e-waste.
a. Write how e-waste is generated.
b. Explain how would you address the awareness issue of e-waste management amongst the students.
c. How have the developed countries exploited the developing countries with respect to e-waste managements ?
SECTION - E
24.a. Explain the steps involved in in vitro fertilisation popularly known as test tube baby programme.
b. State the importance of this programme.
OR
a. State one difference and one similarity between geitonogamy and xenogamy.
b. Explain any three devices developed in flowering plants to discourage self pollination and encourage cross pollination.
25. a. Hershey and Chase carried their experiment in three steps : infection, blending, centrifugation. Explain each step.
b. Write the conclusion and interpretation of the result they obtained.
OR
Taking an example of white-winged moths and dark-winged moths of England in pre and post industrialised era, explain evolution by natural selection.
26.1. Write the percentage of land area that was covered by forests by the end of the last century.
2. Describe any two practices that led to deforestation.
3. State the consequences of deforestation.
4. Suggest a method to overcome deforestation.
OR
a. Comment on the pattern in which all communities undergo a change in composition and structure with changing environmental conditions.
b. Explain ‘Climax community’ and ‘sere’.
c. Differentiate between primary and secondary successi


CBSE CLASS 12 BIOLOGY
QUESTION PAPER SET – 044-09
SECTION – A
1. Name the stage of Plasmodium that gains entry into the human when bitten by an infected female Anopheles.
2. List any two characters of Pea plants used by Mendel in his experiments other than height of the plant and the colour of the seed.
3. Mention the role of Restriction Enzymes in Recombinant DNA technology.
4. Name the disorder caused due to the absence of one of the X-chromosomes in a human female.
5. Name the type of asexual reproduction where the parent cell ceases to exist.
SECTION-B
6. Name and state the effect of a drug that is often medically prescribed, but its overuse leads to drug dependence and drug abuse.
7. Differentiate between pericarp and perisperm.
8. “Niche is a part of a habitat.” Explain with the help of an example.
9. Name the type of immunity a baby is born with. How is it different from the one he gets from the mother’s milk after birth?
10. State the roles of AUG codon at 5' end and UAG at 3' end of a certain m-RNA during translation.
OR
‘Degenerate’ and ‘Universal’ are salient features of a genetic code. Explain.
SECTION-C
11. Write the three basic facts that are highlighted in Mendel’s Law of Dominance.
12. a. Name the causative agent of amoebiasis and mention its symptoms.
b. Write how does it spread.
13.a. What is green revolution ? Mention the steps that led to it.
b. Name the scientist whose contribution led to development of semi-dwarf wheat varieties in India.
14. Are humming birds and fish regulators or conformers ? Give reasons in support of your answer.
15. GM plants are useful in many ways. How would you convince farmers to grow GM plants on their field ? Explain giving three reasons.
16. Name the male accessory glands in humans and write their functions.
17. Write in what context did Darwin use the terms ‘fitness’, ‘survival’ and ‘selection’ while elaborating on the mechanism of evolution.
18. State the objective with which a dairy farm is set up. Describe the essential steps to be followed for dairy farm management.
19. When Morgan conducted dihybrid cross on Drosophila like Mendel did with pea plants, the F2 ratios deviated significantly from that of Mendel’s F2 ratio. Write the explanation Morgan and his group gave to the observations they obtained from their experiment.
20. Draw a diagram of a typical agarose gel electrophoresis showing migration of undigested and digested sets of DNA fragments. Label
a. the digested and undigested DNA fragments, b. Anode and cathode ends of the plate. Mention the role of electrophoresis in biotechnology.
21. a. Name a terminal method to prevent pregnancy in humans.
b. Describe the procedure of the terminal method carried in human male and female.
OR
a. (a) Do all pollen grains remain viable for the same length of time? Support your answer with two suitable examples.
b. (b) How are pollen grains stored in pollen banks? State the purpose of storing pollen grains in these banks.
22. Expand ‘ELISA’. Why is this method preferred over conventional methods of diagnosis of diseases?
SECTION - D
23. Waste Disposal and Waste Management poses a major problem in present times. Generation of garbage and its disposal is a major threat and consequently leads to severe environmental issues. The problem is not with biodegradable and recycled wastes. We realise that the need is to reduce non-biodegradable wastes.
a. Why is there a great concern of managing non-biodegradable waste in comparison to biodegradable waste? Explain.
b. As a member of eco club of your school, suggest any two ways that you will discuss with your fellow members to organise for a “Zero garbage day” once in a month in the school.
24.

a. Identify the parts labelled 1, 2 and 3 in the diagram given.
b. Draw a labelled diagram of a human blastocyst.
c. What is parturition and how is it induced at the end of pregnancy in a human female?
OR
a. With labelled diagrams, depict stages in embryo development in a dicotyledenous plant.
b. Endosperm development precedes embryo development. Why ?
25.a. How are polygenic inheritance and multiple allelism different ? Explain with thehelp of an example each.
b. List the criteria a chemical molecule must fulfill to be able to act as a genetic material.
OR
State the hypothesis proposed by Oparin and Haldane. How was it experimentally proved by S.L. Miller ? Explain.
26. What does an Ecological Pyramid indicate? Explain the three different types of upright Pyramids in nature with the help of an example each.
OR
a. (a) Indiscriminate human activities such as alien species invasion, fragmentation and habitat loss have accelerated the loss of biodiversity. Justify by taking one example for each.
b. (b) State the importance of
(i) IUCN Red data list and (ii) Hot spots in conservation of biodiversity.



CBSE CLASS 12 BIOLOGY
QUESTION PAPER SET – 044-10
[SOLVED]
SECTION – A
Q1. Write the two specific codons that a translational unit of mRNA is flanked by one on either sides.
Ans. Start codon-AUG,             Stop codon- UAA/UGA/UAG
Q2. State the type of interaction that exists between ticks and dogs.
Ans. (Ecto)Parasitism
Q3. Write the chromosomal defect in individuals affected with Klinefelter’s syndrome.
Ans. (Male) additional copy of X chromosome / XXY
Q4. Identify the picture and mention the vegetative part that helps it to propagate.

Ans. Rhizome of ginger/ underground stem, axillary bud grows from the node
Q5. State the economic value of Saccharum officinarum in comparison to S. barberi.
Ans. Higher sugar content/thicker stem
Section B
Q6. State the functions of Ribozyme and release factor in protein synthesis respectively.
Ans. Ribozyme- helps in peptide bond formation,Release factor- terminates translation/ releases polypeptide from ribosome.
Q.7 Write the functions of
(a) cry 1AC gene
(b) RNA interference (RNAi)
Ans. (a) It produces inactive pro-toxin in the host cell /produces proteins to control cotton bollworms.
(b) It produces ds RNA which silences host mRNA/cellular defence mechanism/prevents infestation by nematodes.
Q8.

(a) Expand CFC
(b) How does it reduce ozone to oxygen?
Ans. a) Chloroflurocarbons
b) It releases Chlorine atoms which degrades ozone to release oxygen
Q9. What happens to corpus luteum in human female if the ovum is (i) fertilized, (ii) not fertilized?
OR
Write the difference between the tender coconut water and the thick, white kernel of a mature coconut and their ploidy.
Ans. i) Corpus luteum continues to secrete progesterone to maintain pregnancy/ it persists and produces progesterone
ii) it disintegrates/ changes into corpus albicans
OR
Coconut water from the tender coconut has free nuclear endosperm, kernel has the cellular endosperm Ploidy of the endosperms- 3n/ Triploid
Q10. State the evolutionary relationship giving reasons between the thorn of Bougainvillea and tendril of cucurbit.
Ans. Divergent evolution/ Homologous organs, Similar in origin but perform different function
Section C
Q11. Mention the cause of ADA deficiency in humans. How has genetic engineering helped patients suffering from it?
Ans. Deletion/ mutation of the gene which forms the enzyme –adenosine deaminase. Lymphocytes from the blood of the patient, can be grown in a culture outside the body, ADA, cDNAgene can be inserted into the lymphocyte using retroviral vector, then lymphocytes can be returned to the patient .(They can start producing ADA)
Q.12 Drinking water problem in our urban areas is caused mainly because we fail to protect our water bodies. Explain how accelerated eutrophication chokes our water bodies to death.
Ans. Sewage and industrial wastes are added to the lake, nitrates and phosphates act as plant nutrients, promotes algal bloom, dissolved oxygen depletes, less oxygen and pollutants poison the aquatic life , decomposing remains choke the lake to death.
13. (a) Differentiate between benign and malignant tumours.
(b) Why is colostrum a boon to the newborn baby?
Ans. (a) Benign tumour- remains confined to original location/does not spread to other part of the body/ not cancerous1 Malignant tumour-mass of proliferating (neoplastic)cells that invade and damage surrounding tissues/cancerou tumour/ tumour showing property of metastasis.
(b) Colostrum contains antibodies/that provides resistance (immunity) to new born babies.
Q.14. This diagram above shows a part of the human female reproductive system.

(a) Name the gamete cells that would be present in ‘X’ if taken from a newborn baby.
(b) Name ‘Y’ and write its function.
(c) Name ‘Z’ and write the events that take place here.
Ans. (a) X= Primary oocytes
(b) Y= Fimbriae, collection of ovum
(c) Z=ampullary- isthumic junction/fallopian tube, the ovum encounters the sperm/fertilisation takes place.
Q.15 How does the study of fossils support evolution? Explain.
OR
What does Hardy-Weinberg Principle of equilibrium indicate? List any two factors that could alter the equilibrium. What would such an alteration lead to?
Ans. Fossils are remains/ hard parts of life forms, found in sedimentary rocks, some of them appear similar to modern organisms /some represent extinct organisms, study of fossils in different sedimentary layers indicates the geological period in which they existed ( provide palaentological evidence)
OR
(a) Allele frequencies are stable and constant from generation to generation /the gene pool (total genes and their alleles in a population) remains a constant/ sum total of all allelic frequencies is one.
Factors– Gene migration, gene flow, genetic drift, mutation, genetic recombination, natural selection (b) Leads to –Evolution
Q.16 Mention any two human diseases caused by round worms. Name their causative agents and their mode of transmission into the human body.
Ans. Ascariasis, Ascaris, contaminated water /vegetables/fruits,
Elephantiasis/filariasis, Wuchereria bancrofti /filarial worm, bite by female mosquito vectors
Q.17 (a) Differentiate between exons and introns.
(b) What is a plasmid? Why is it selected as a vector?
Ans. a) Exons are the coding or expressed sequences that appear in mature or processed RNA, introns are intervening sequences that do not appear in mature or processed RNA//Exons are codons that code for amino acid sequence, introns do not code for amino acids.
b) Autonomously replicating circular DNA / extra chromosomal DNA,exclusively present in bacteria.
It takes in alien DNA/acts as vector, and delivers is into a host cell.
Q.18 What is ecological succession? Where and why would the rate of succession be faster in newly created pond or a forest destroyed by a forest fire?
Ans. Gradual/predictable change in the species composition of a given area, Rate of succession would be faster in a forest destroyed by a forest fire, Such disturbances create new conditions that encourage some species and discourage or eliminate other species /since after a forest fire some soil is already present and succession is faster than primary succession.
Q.19 High yielding cattle is a good solution for food enhancement. How does the MOET technology help to increase the herd size?
Ans. High yielding female administered with FSH, 6-8 eggs / multiple eggs produced, inseminated, fertilised eggs recovered non-surgically, at 32-cell stage, transferred to surrogate mother (for development).
Q.20 If there is a history of haemophilia in the family, the chances of male members becoming haemophilic are more than that of the females.
(a) Why is it so?
(b) Write the symptoms of the disease.
Ans. a) Defective gene is on X chromosome, in case the carrier female (mother) passes Xh to the son he suffers, if she passes Xh to the daughter, she has the other X(from father ) to make it heterozygous so the daughters escape as carriers.
b) The blood does not clot in the affected person after an injury or a small cut.
Q.21 Why do tribes who live in high altitude of Himalayas experience discomfort in respiration? How do they get adapted to survive in such a situation?
Ans. Atmospheric pressure is low, content is lower at high attitude. Body increases RBC production, decreases binding capacity of haemoglobin, increases breathing rate (any two)
Q.22 Explain the events in a normal woman during her menstrual cycle on the following days:
(a) Pituitary hormone levels from 8 to 12 days.
(b) Uterine events from 13 to 15 days.
(c) Ovarian events from 16 to 23 days.
Ans. a) FSH and LH levels – low
b) Endometrium is highly vascularised / proliferative phase of uterine lining.
c) Formation of corpus luteum / secretion of progesterone.
Section D
Q.23 Peer pressure plays a negative role in triggering smoking habits in adolescents. As a school captain list any two activities you would like to organize with the help of senior students of your school and any other two activities you would like your school authorities to organize for the students to tackle this problem. Explain how these activities will help in doing so.
Ans. Students activities- Poster making, slogan writing, essay writing, processions, display of banners, highlighting its ill- effects during assembly, power-point presentation on harmful effects of tobacco (any two)
School activities – Seminars, workshops, talks-by doctors, counsellors, psychologists, government officials, vigilant supervision, value education through class teachers (any two)
This will help in bringing about awareness/ prevent diseases associated with smoking /provide alternatives / help the smokers in doing away with this habit(Any other relevant point to be evaluated) (any two)
Section E
Q.24(a) What is Central dogma? Who proposed it?
(b) Describe Meselson and Stahl’s experiment to prove that the DNA replication is semiconservative.
OR
(a) A couple with blood groups ‘A’ and ‘B’ respectively have a child with blood group ‘O’.
Work out a cross to show how it is possible and the probable blood groups that can be
expected in their other off-springs.
(b) Explain the genetic basis of blood groups in human population.
Ans. (a) Central dogma    Given by Francis Crick

b)

(Same value points to be awarded in an explanation)
OR
(a)Father =IAi
Child=ii
IAi (Father) X Mother=IBi
Phenotypes of all off springs= AB, B, A and O blood group


(b)Genetic basis of blood groups ;

Three alleles of one gene / multiple alleles/ gene IA, IB , i
A and B are co-dominant / expressed together
Q.25 Explain the application of rDNA technology to produce insulin.
OR
(a) Describe the different steps in one complete cycle of PCR.
(b) State the purpose of such an amplified DNA sequence.
Ans. Human insulin is synthesised as a pro- hormone, the pro-hormone contains an extra Cpeptide, the C- peptide is not present in mature insulin, and is removed during maturation, Eli-Lily-an American company prepared two DNA sequences, corresponding to A and B chains of human insulin, and introduced them in plasmids of E.coli to produce insulin chains, Chain A and B were produced separately, extracted and combined, by creating disulphide bonds
OR
(a)

(b)Purpose –used to ligate with a vector for further cloning/ detection of bacteria or virus by amplification of their DNA/detection of HIV in AIDS patient/to detect mutation in genes in suspected cancer patients. (any two)
Q.26 (a) Describe in sequence the process of microsporogenesis in angiosperms.
(b) Draw a labelled diagram of a two celled final structure formed.
OR
(a) Draw a sectional view of a seminiferous tubule of human. Label sertoli cell,
spermata gonia and leydig cell on it and write their functions.
(b) Explain the role of pituitary and sex hormones in the process of spermatogenesis.
Ans. (a) Microsporogenesis-Each microspore mother cell divides meiotically, to form 4 haploid cells or tetrad, each microspore divides into two unequal cells- large vegetative cell and smaller generative cell; at this 2- celled stage the pollen grains are shed. Sometimes the generative cell divides mitotically to give rise to two haploid male gametes, that are shed at 3 - celled stage.
b)

OR
(a)Label sertoli cells, spermatogonia, Leydig cells

Functions –Sertoli cells -secrete factors which help in the process of spermiogenesis/ provide nutrition to germ cells.     Spermatogonia-divide to produce spermatids /sperms   Leydig cells-synthesis or secretion of androgens/testosterone   b) Pituitary hormones– LH/luteinising hormone- acts on Leydig cells and stimulates synthesis and secretion of androgens,    FSH/follicle stimulating hormone- acts on sertoli cells and simulates secration of some factor that help in spermiogenesis   Sex hormone –(Androgen/testosterone) stimulate process of spermatogenesis.
CBSE CLASS 12 BIOLOGY
QUESTION PAPER SET – 044-11


CBSE CLASS 12 BIOLOGY    QUESTION PAPER SET – 044-12



CBSE CLASS 12 BIOLOGY    QUESTION PAPER SET – 044-13



CBSE CLASS 12 BIOLOGY    QUESTION PAPER SET – 044-14



CBSE CLASS 12 BIOLOGY  
QUESTION PAPER SET – 044-15










CBSE CLASS 12 BIOLOGY  
QUESTION PAPER SET – 044-15