Students must start practicing the questions from RBSE 12th Biology Model Papers Set 8 with Answers in English Medium provided here.
RBSE Class 12 Biology Model Paper Set 8 with Answers in English
Time : 2.45 Hours
Maximum Marks : 56
General Instruction to the Examinee:
- Candidate must write first his/her Roll No. on the question paper compulsorily.
- All the questions are compulsory.
- Write the answer to each question in the given answer book only.
- For questions having more than one part the answers to those parts are to be written together in continuity.
- If there is any error/difference/contradiction in Hindi & English version of the question paper, the question of the Hindi version should be treated valid.
Section – A
Select the correct option of the following questions and write in notebook. (1 × 9 = 9)
(i) Starfish regenerates an entire new starfish from a single arm by the process of: 
(ii) The process of double fertilization was discovered by: 
(a) G. Domagk
(b) S.G. Nawaschin
(d) O. Smith
(b) S.G. Nawaschin
(iii) Mendel studied seven contrasting characters for his breed experiment with Pisum sativum, which of the following character did he not use? 
(a) Pod colour
(b) Pod shape
(c) Leaf shape
(d) Plant height
(c) Leaf shape
(iv) A nucleoside differs from a nucleotide. It lacks the : 
(c) phosphate group
(c) phosphate group
(v) Ascaris is most commonly found in: 
(d) and b
(vi) The vector of break bone fever is- 
(d) None of these
(vii) Which one of the following is a marine fish? 
(d) Common Carp
(viii) Restriction enzyme cut the nucleotide between: 
(ix) Bt toxin produced from: 
(c) E. coli
(d) B. thuringiensis
(d) B. thuringiensis
Fill in the blanks. (1 × 4 = 4)
(i) …………….. is leaf and stripe rust resistance variety of wheat. 
(ii) Wildlife includes animals, plants and …………….. 
(iii) Triplet of bases on mRNA codes for one amino acid, is called …………….. 
(iv) Common detritivores in our ecosystem are …………….. 
Give the answers of the following questions in one word or one line. (1 × 8 = 8)
(i) On what basis is the skin colour in humans considered polygenic? 
Because it is under the control of many genes.
(ii) What is the genotype of person having Klinefelter’s syndrome. 
Genotype of person having Klinefelter’s syndrome = 47 + XXY.
(iii) Name two biological agents that cause diseases. 
- Virus and
- Bacteria, many genes.
(iv) What is plant tissue culture? 
Plant tissue culture is a technique of growing plant cells, tissues, organs in an artificial nutrient medium under aseptic conditions.
(v) Who made the recombinant DNA first time? 
First recombinant DNA made by Paul Berg in 1972, combining DNA from monkey virus with lambda virus.
(vi) What is Bt toxin? 
Bt toxin is a intracellular crystal protein produced by Bacillus thuringiensis.
(vii) Name two abiotic factors in an ecosystem. 
(viii) Define extinction. 
Extinction is the disappearance of a species or a taxonomic group.
Section – B
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? [1.5]
(a) Contraceptive pills contain progesterone or progesterone-oestrogeh combination. They act by either of the following ways :
- inhibit ovulation.
- inhibit implantation.
- Alter quality of cervical mucus to prevent or retard entry of sperms.
(b) Contraceptive pills should be taken daily for a period of 21 days starting within first five days of menstrual cycle.
Is sex education necessary in schools? Why? [1.5]
Yes, sex education is necessary in schools. It is because of the following reasons :
- To provide scientific information about reproductive system and reproductive health to students in order to save them from misconceptions and myths about sex related topics.
- Provides appropriate knowledge about adolescence, reproductive organs and related concepts.
- Create awareness amongst students about the need for hygienic and safe sexual practices, sexually transmitted diseases. This helps students, specifically those in adolescence to lead to healthy reproductive life.
What is meant by the term ‘breed’? What are the objectives of animal breeding? [1.5]
Breed refers to a group of animals within a species that exhibit same ancestral characters like size, physique etc. The main objectives of animal breeding is to increase the yield of animals and improving desirable qualities of animal products such as milk, meat, eggs and wool etc.
Name the methods employed in animal breeding. According to you which of the method is best? Why? [1.5]
Two types of methods are employed in animal breeding. These are :
(a) Natural Method : These include : (i) Inbreeding and (ii) Outbreeding.
(b) Artificial Method : These methods include the artificial insemination and new techniques such as Multiple Ovule Embryo Transfer (MOET), super ovulation and Embryo transfer and cryopreservation.
The best method to carry out animal breeding is artificial method because they help to overcome problems of normal mating and have a high success rate of crossing between mature male and female.
Principle behind the working of gel electrophoresis. [1.5]
A technique use to separate DNA fragments according to their size is gel electrophoresis. “It is a process which enables the shorting of molecules bases on size using an electric field through a gel (agarose) medium.” Principle – “The principle behind this technique is that the negatively charged molecules of DNA moves towards the anode and get separated. They arranged on gel in the form of bonds according to their size.
Draw a schematic sketch of pBR322 plasmid. [1.5]
What are cry proteins? Name an organism that produce it. How has man exploited this protein to his benefits? [1.5]
Cry proteins are produced by a cry gene family which is found in Bacillus thuringiensis bacteria. These are toxic genes produce protein crystals encoded by gene CryIAc and CryIIAb. Different Bacillus thuringiensis produce different strains of toxin. Which are harmful for different insects like butterflies, boliworm, moths etc. Man exploited gene by isolated this from bacteria and introduced in cotton plant. Which makes the plant resistant to insects variety called Bt coiton. In India mostly Boliworm resistant Bt cotton plants are cultivated.
What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency. [1.5]
Gene therapy is a medical field which focuses on the utilisation of the therapeutic delivery of nucleic acid (gene) into patient’s cell as a drug to treat disease.
Very first experiment of gene therapy performed on 4 year old girl with ADA deficiency. This enzyme is very crucial for immune system. Permanent gene therapy can be done by replacement of ADA gene from bone marrow cells of early embryonic stages. It is parmanent and fully successed.
(a) Name three man made ecosystems.
(b) List three parameters used for constructing ecological pyramid. [1.5]
(a) Man-made ecosystems
- Agriculture land
- Kitchen garden
(b) The three parameters used are:
- Number of individuals in a trophic level.
- Biomass of individuals in a trophic level.
- Rate of flow of energy in a trophic level.
Draw a pyramid of energy in which primary producers get 10000 J solar energy. [1.5]
Why are sacred groves highly protected? [1.5]
Sacred groves basically the forest areas in particular which are set aside by the government in order to protect the biodiversity with special religious importance in a particular culture. These are also mythologically important. These are undisputed and undisturbed forests without any human interventions because these are highly protected hence they include many rare, endangered and endemic species of that area.
How over exploitation is a cause of loss of biodiversity? [1.5]
Over Exploitation : Every species depends on the nature for their daily needs of food and shelter. This concept is equally applied on to the human beings. Over the period of human development human has used nature for all his needs but humans have started overexploiting the nature to fulfill his needs which leads to the degradation and extinction of natural resources. Many species extinct in the last 500 years for example : Steller’s sea cow and Passenger pigeon were due to over exploitation by humans. At present marine fish populations around the world are over harvested, endangering the continued existence of some commercially important species.
Section – C
Distinguish between asexual and sexual reproduction. 
Define the following:
(i) Ovipary (ii) Vivipary (iii) Parthenogenesis
Differences between Asexual and Sexual Reproduction
|Asexual Reproduction||Sexual Reproduction|
|1.||Asexual reproduction involves the participation of single individual.||Sexual reproduction involves participation of two separate parents.|
|2.||In this gametes are not formed.||In this gametes are formed.|
|3.||In this fertilization does not take place.||In this fertilization takes place.|
|4.||It involves only mitosis.||It involves both mitosis and meiosis.|
|5.||It is a fast process.||It is a slow process.|
|6.||Daughter organisms are genetically identical produced by asexual reproduction.||Daughter organisms are different to parent.|
Explain the following terms with example :
(b) Incomplete dominance. 
Explain the inheritance of haemophilia with an example. 
(a) Co-dominance : When both the contrasting alleles of a gene pair are equally expressed, this phenomenon is called as co-dominance. For example, human blood group, both A and B are equally dominant and when present together exhibit the AB blood group instead of either A or B.
(b) Incomplete dominance : When a dominant allele does not completely mask the effects of a recessive alleles and the organisms resulting physical appearance shows a blending of both allele. It is called incomplete dominance. For example, flower colour in Snapdragon plant, Red flower colour (R) is incompletely dominant over the white (r). When both alleles R and r are present together. R is unable to completely suppress r and therefore the resulting phenotype is pink coloured flower.
Nametnetsatnosenoi AIDS.Write down the mode of transmission of AIDS. 
What are tranquiiizers ? Explain two tranquilizers. 
Pathogen or Causal Organism:
American scientist identified and named the causal organism of AIDS as HCLV-III (Human cell leukemia virus-III), but now the name of the virus changed to HIV (Human Immuno Deficiency Virus).
Mode of Transmission: AIDS is not contagious disease. It does not spread through contact, caring of infected persons, sharing meals, kissing, mosquito bites, handshake, bite of insect, etc. But AIDS can transmitted in following ways :
- Sexual Intercourse : Unprotected sexual intercourse with an infected partner, (if there is tissue injury to permit blood contact).
- Sharing Needles : Use of contaminated needles and syringes to inject drugs or vaccines.
- Sharing Utensils : Use of contaminated razors for shaving.
- Transfusion of Blood and blood Products : Transfusion of HIV contaminated blood can infect the recipient.
- Mother to Child : A woman infected with HIV may spread the disease through breastfeeding.
- Use of contaminated needles for boring pinnae.
- Organ Transplant: The organs of infected person spread HIV to recipient through organ transplant.
- Perturition from mother to baby due to rupturing of blood vessels.
Section – D
Write 4 differences between self pollination and cross pollination. 
What is entomophily? Write down four adaptations in flowers for entomophily. Give two examples of this process. 
Difference between Self¬pollination and Cross-pollination
|1.||Pollen grains are transferred from anther to stigma of the same flower or another flower bom on the same plant.||Pollen grains are transferred from anther of one flower to stigma of another flower born on a different plant of same species.|
|2.||Bisexual flowers or monoecious conditions are required for self-pollination.||For cross-pollination, bisexual flowers or hermaphrodite plants may not be required.|
|3.||Both anthers and stigma mature at the same time.||The anthers and stigma of a flower mature at different time.|
|4.||For self-pollination coloured, bright, large and attractive flowers are not necessary.||For cross-pollination coloured, bright, large and attractive flowers are necessary.|
Differentiate between prokaryotic DNA and eukaryotic DNA. 
How Griffith concluded that DNA is the genetic material? Explain in brief. 
Difference between Prokaryotic and Eukaryotic DNA
|Prokaryotic DNA||Eukaryotic DNA|
|1.||It occurs inside the cytoplasm.||It occurs inside the nucleus.|
|2.||It is circular and double stranded.||It is linear or double stranded.|
|3.||DNA is naked without histones.||DNA associated with histone to form nucleoprotein fibre.|
|4.||It exists singly.||It exists in pairs.|
|5.||G ≡ C contents are more than A = T.||A = T pairs are more than G ≡ C pairs.|
|6.||Noncoding introns are absent.||Coding segments (exons) are interrupted by non coding introns.|
|7.||Repetitive segments are absent.||Repetitive base sequences or junk DNA is more than functional DNA.|
|8.||On heating, this DNA is denatured into a tangled mass.||This DNA on heating is denatured into two strands.|
|9.||It is found in bacteria, mitochondria and chloroplasts.||Linear DNA is found only in the chromosomes of eukaryotes.|