View note:cbse-Biology-class-12



Questions of this subject!.

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1)Name the type of cross that would help to find the genotype of a pea plant bearing violet flowers. cbse-Biology-class-12

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2)State two postulates of Oparin and Haldane with reference to origin of life. cbse-Biology-class-12

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3)State two postulates of Oparin and Haldane with reference to origin of life. cbse-Biology-class-12

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4)A herd of cattle is showing reduced fertility and productivity. Provide one reason and one suggestion to overcome this problem cbse-Biology-class-12

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5)What are Cry genes? cbse-Biology-class-12

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6)In which organism are Cry genes present? cbse-Biology-class-12

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7)An electrostatic precipitator in a thermal power plant is not able to generate high voltage of several thousands. Write the ecological implication because of it. cbse-Biology-class-12

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8)A pollen grain in angiosperm at the time of dehiscence from an anther could be 2-celled or 3-celled. Explain. cbse-Biology-class-12

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9)How are the cells placed within the pollen grain when shed at a 2-celled stage? cbse-Biology-class-12

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10)Differentiate between the genetic codes given below: cbse-Biology-class-12

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11)Differentiate between the genetic codes given below: cbse-Biology-class-12

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12)Mention one application for each of the following: cbse-Biology-class-12

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13)Mention one application for each of the following: cbse-Biology-class-12

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14)Name the microbes that help production of the following products commercially: cbse-Biology-class-12

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15)Name the microbes that help production of the following products commercially: cbse-Biology-class-12

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16)List four benefits to human life by eliminating the use of CFCs. cbse-Biology-class-12

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17)Suggest two practices giving one example of each that help protect rare or threatened species. cbse-Biology-class-12

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18)(a)Can a plant flowering in Mumbai be pollinated by pollen grains of the same species growing in New Delhi? Provide explanations to your answer. cbse-Biology-class-12

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19)Draw the diagram of a pistil where pollination has successfully occurred.Label the parts involved in reaching the male gametes to its desired destination. cbse-Biology-class-12

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20)Both Haemophilia and Thalassemia are blood related disorders in humans. Write their causes and the difference between the two. cbse-Biology-class-12

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21)Name the category of genetic disorder both Haemophilia and Thalassemia come under. cbse-Biology-class-12

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22)List the two methodologies which were involved in human genome project. Mention how they were used. cbse-Biology-class-12

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23)Expand cbse Biology class 12

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24)Write the characteristics of Ramapithecus, Dryopithecus and Neanderthal man. cbse-Biology-class-12

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25)Name a human disease, its causal organism, symptoms (any three) and vector, spread by intake of water and food contaminated by human faecal matter. cbse-Biology-class-12

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26)Why is there a fear amongst the guardians that their adolescent wards may get trapped in drug/alcohol abuse? cbse-Biology-class-12

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27)Explain

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28)Write the desirable characters a farmer looks for in his sugarcane crop. cbse-Biology-class-12

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29)How did plant breeding techniques help north Indian farmers to develop cane with desired characters? cbse-Biology-class-12

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30)Secondary treatment of the sewage is also called Biological treatment. Justify this statement and explain the process. cbse-Biology-class-12

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31)Explain the significance of „palindromic nucleotide sequence‟ in the formation of recombinant DNA. cbse-Biology-class-12

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32)Write the use of restriction endonuclease in the above process. cbse-Biology-class-12

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33)Describe the roles of heat, primers and the bacterium Thermus aquaticus in the process of PCR. cbse-Biology-class-12

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34)Explain the various steps involved in the production of artificial insulin. cbse-Biology-class-12

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35)“Organisms may be conformers or regulators.” Explain this statement and give one example of each. cbse-Biology-class-12

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36)Why are there more conformers than regulators in the animal world? cbse-Biology-class-12

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37)Describe the inter-relationship between productivity, gross primary productivity and net productivity. cbse-Biology-class-12

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38)Explain the reasons that you feel are behind such embarrassment amongst some parents to freely discuss such issues with their growing children. cbse-Biology-class-12

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39)By taking one example of a local plant and animal, how would you help these parents to overcome such inhibitions about reproduction and sexuality? cbse-Biology-class-12

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40)When a seed of an orange is squeezed, many embryos, instead of one are observed. Explain how it is possible. cbse-Biology-class-12

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41)Explain the following phases in the menstrual cycle of a human female: cbse-Biology-class-12

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42)Are these embryos genetically similar or different? Comment. cbse-Biology-class-12

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43)A proper understanding of menstrual cycle can help immensely in family planning. Do you agree with the statement? Provide reasons for your answer. cbse-Biology-class-12

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44)Compare, giving reasons, the J-shaped and S-shaped models of population growth of a species. cbse-Biology-class-12

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45)Explain “fitness of a species” as mentioned by Darwin. cbse-Biology-class-12

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46)What is an ecological pyramid? cbse-Biology-class-12

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47)Compare the pyramids of energy, biomass and numbers. cbse-Biology-class-12

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48)Write any two limitations of ecological pyramids. cbse-Biology-class-12

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49)Describe the structure and function of a t-RNA molecule. Why is it referred to as an adapter molecule? cbse-Biology-class-12

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50)Explain the process of splicing of hn-RNA in a eukaryotic cell. cbse-Biology-class-12

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51)Write the different components of a lac-operon in E.coli. Explain its expression while in an „open‟ state. cbse-Biology-class-12

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52)A male honeybee has 16 chromosomes whereas its female has 32 chromosomes. Give one reason. cbse-Biology-class-12

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53)Mention the role of ‘genetic mother’ in MOET. cbse-Biology-class-12

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54)What is biopiracy? cbse-Biology-class-12

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55)Mention two advantages for preferring CNG over diesel as an automobile fuel. cbse-Biology-class-12

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56)Write the probable differences in eating habits of Homo habilis and Homo erectus. cbse-Biology-class-12

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57)A single pea plant in your kitchen garden produces pods with viable seeds, but the individual papaya plant does not. Explain. cbse-Biology-class-12

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58)Following are the features of genetic codes. What does each one indicate? cbse-Biology-class-12

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59)Suggest four important steps to produce a disease resistant plant through conventional plant breeding technology. cbse-Biology-class-12

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60)Name a genus of baculovirus. cbse-Biology-class-12

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61)Why are genus of baculovirus considered good bio-control agents? cbse-Biology-class-12

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62)Explain the relationship between CFC’s and Ozone in the stratosphere. cbse-Biology-class-12

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63)Why are scared groves highly protected? cbse-Biology-class-12

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64)Name the organic material exine of the pollen grain is made up of. How is this material advantageous to pollen grain? cbse-Biology-class-12

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65)Still it is observed that it does not form a continuous layer around the pollen grain. Give reason. cbse-Biology-class-12

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66)How are ‘pollen banks’ useful? cbse-Biology-class-12

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67)Mention the problems that are taken care of by Reproduction and Child Health Care programme. cbse-Biology-class-12

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68)What is amniocentesis and why there is a statutory ban on it? cbse-Biology-class-12

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69)What is a test cross? How can it decipher the heterozygosity of a plant? cbse-Biology-class-12

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70)What do ‘Y’ and ‘B’ stand for in ‘YAC’ and ‘BAC’ used in Human Genome Project (HGP). Mention their role in the project. cbse-Biology-class-12

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71)Write the percentage of the total human genome that codes for proteins and the percentage of discovered genes whose functions are known as observed during HGP. cbse-Biology-class-12

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72)Expand ‘SNPs’ identified by scientists in HGP cbse-Biology-class-12

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73)Differentiate between homology and analogy. Give one example of each. cbse-Biology-class-12

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74)Explain giving reasons the basics of such immunity in an individual. Name this kind of immunity. cbse-Biology-class-12

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75)What are interferons? Mention their role. cbse-Biology-class-12

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76)Write the two limitations of traditional breeding technique that led to promotion of micro propagation. cbse-Biology-class-12

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77)Mention two advantages of micro propagation. cbse-Biology-class-12

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78)Give two examples where it is commercially adopted. cbse-Biology-class-12

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79)How do organic farmers control pests? Give two examples. cbse-Biology-class-12

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80)State the difference in their approach from that of conventional pest control methods. cbse-Biology-class-12

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81)Name the selectable markers in the cloning vector pBR322? Mention the role they play. cbse-Biology-class-12

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82)Why is the coding sequence of an enzyme beta - galactosidase a preferred selectable marker in comparison to the ones named above? cbse-Biology-class-12

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83)Why must a cell be made ‘competent’ in biotechnology experiments? How does calcium ion help in doing so? cbse-Biology-class-12

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84)State the role of ‘biolistic gun’ in biotechnology experiments. cbse-Biology-class-12

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85)Explain enzyme – replacement therapy to treat adenosine deaminase deficiency. cbse-Biology-class-12

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86)Mention two disadvantages of enzyme – replacement therapy procedure. cbse-Biology-class-12

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87)Name and explain the type of interaction that exists in mycorrhizae and between cattle egret and cattle cbse-Biology-class-12

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88)Differentiate between primary and secondary succession provided one example of each. cbse-Biology-class-12

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89)State any two reasons responsible for the cause of infertility cbse-Biology-class-12

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90)Why in your opinion the female partner is often blamed for such situations in India? Mention any two values that you as a biology student can promote to check this social evil. cbse-Biology-class-12

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91)Suggest a technique that can help the couple to have a child where the problem is with male partner cbse-Biology-class-12

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92)Explain the menstrual phase in a human female. State the levels of ovarian and pituitary hormones during this phase. cbse-Biology-class-12

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93)Why is follicular phase in the menstrual cycle also referred as proliferative phase? Explain. cbse-Biology-class-12

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94)Explain the events that occur in a graafian follicle at the time of ovulation and thereafter. cbse-Biology-class-12

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95)Draw a graafian follicle and label antrum and secondary oocyte cbse-Biology-class-12

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96)List the different steps that you would suggest and provide reasons for each of the item. cbse-Biology-class-12

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97)Draw a diagram of a section of a megasporangium of an angiosperm and label funiculus, Micropyle, embryo sac and nucleus. cbse-Biology-class-12

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98)Describe Meselson and Stahl’s experiment that was carried in 1958 on E.Coli. Write the conclusion they arrived at after the experiment. cbse-Biology-class-12

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99)Describe the process of transcription in bacteria cbse-Biology-class-12

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100)Explain the processing the hnRNA needs to undergo before becoming functional mRNA eukaryotes. cbse-Biology-class-12

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101)What are the careers to explore except doctor after doing Biology in 12th?

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102)Write the dual purpose served by Deoxyribonucleoside triphosphates in polymerisation. -cbse-Biology-class-12

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103)Name two diseases whose spread can be controlled by the eradication of Aedes mosquitoes -cbse-Biology-class-12

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104)How do cytokine barriers provide innate immunity in humans ? -cbse-Biology-class-12

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105)Write the names of the following: -cbse-Biology-class-12

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106)Mention the chemical change that proinsulin undergoes, to be able to act as mature insulin. -cbse-Biology-class-12

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107)With the help of an algebraic equation, how did Hardy-Weinberg explain that in a given population the frequency of occurrence of alleles of a gene is supposed to remain the same through generations ? -cbse-Biology-class-12

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108)Although a prokaryotic cell has no defined nucleus, yet DNA is not scattered throughout the cell. Explain. -cbse-Biology-class-12

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109)You have obtained a high yielding variety of tomato. Name and explain the procedure that ensures retention of the desired characteristics repeatedly in large populations of future generations of the tomato crop. -cbse-Biology-class-12

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110)Name the source plant of heroin drug. How is it obtained from the plant ? -cbse-Biology-class-12

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111)Write the effects of heroin on the human body. -cbse-Biology-class-12

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112)Draw a diagram of a mature human sperm. Label any three parts and write their functions -cbse-Biology-class-12

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113)Expand VNTR and describe its role in DNA fingerprinting. -cbse-Biology-class-12

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114)List any two applications of DNA fingerprinting technique. -cbse-Biology-class-12

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115)Differentiate between Parthenocarpy and Parthenogenesis. Give one example of each. -cbse-Biology-class-12

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116)Medically it is advised to all young mothers that breastfeeding is the best for their newborn babies. Do you agree ? Give reasons in support of your answer. -cbse-Biology-class-12

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117)Explain the mechanism of ‘sex determination’ in birds. How does it differ from that of human beings ? -cbse-Biology-class-12

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118)How has the development of bioreactor helped in biotechnology ? -cbse-Biology-class-12

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119)Name the most commonly used bioreactor and describe its working. -cbse-Biology-class-12

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120)Explain the roles of the following with the help of an example each in recombinant DNA technology : (a) Restriction Enzymes (b) Plasmids -cbse-Biology-class-12

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121)Explain out-breeding, out-crossing and cross-breeding practices in animal husbandry. -cbse-Biology-class-12

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122)Organic farmers prefer biological control of diseases and pests to the use of chemicals for the same purpose. Justify. -cbse-Biology-class-12

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123)Give an example of a bacterium, a fungus and an insect that are used as biocontrol agents. -cbse-Biology-class-12

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124)Differentiate between analogous and homologous structures -cbse-Biology-class-12

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125)Select and write analogous structures from the list given below : (i) Wings of butterfly and birds (ii) Vertebrate hearts (iii) Tendrils of bougainvillea and cucurbita (iv) Tubers of sweet potato and potato -cbse-Biology-class-12

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126)‘‘India has greater ecosystem diversity than Norway.’’ Do you agree with the statement ? Give reasons in support of your answer. -cbse-Biology-class-12

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127)Write the difference between genetic biodiversity and species biodiversity that exists at all the levels of biological organisation. -cbse-Biology-class-12

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128)Explain the effect on the characteristics of a river when urban sewage is discharged into it. -cbse-Biology-class-12

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129)How has the use of Agrobacterium as vectors helped in controlling Meloidegyne incognitia infestation in tobacco plants ? Explain in correct sequence. -cbse-Biology-class-12

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130)Describe any two devices in a flowering plant which prevent both autogamy and geitonogamy. -cbse-Biology-class-12

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131)Explain the events upto double fertilisation after the pollen tube enters one of the synergids in an ovule of an angiosperm. -cbse-Biology-class-12

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132)Explain menstrual cycle in human females. -cbse-Biology-class-12

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133)How can the scientific understanding of the menstrual cycle of human females help as a contraceptive measure ? -cbse-Biology-class-12

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134)Write the scientific name of the organism Thomas Hunt Morgan and his colleagues worked with for their experiments. Explain the correlation between linkage and recombination with respect to genes as studied by them. -cbse-Biology-class-12

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135)How did Sturtevant explain gene mapping while working with Morgan ? -cbse-Biology-class-12

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136)State the ‘Central dogma’ as proposed by Francis Crick. Are there any exceptions to it ? Support your answer with a reason and an example. -cbse-Biology-class-12

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137)Explain how the biochemical characterisation (nature) of ‘Transforming Principle’ was determined, which was not defined from Griffith’s experiments. -cbse-Biology-class-12

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138)Explain how the biochemical characterisation (nature) of ‘Transforming Principle’ was determined, which was not defined from Griffith’s experiments. -cbse-Biology-class-12

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139)Following are the responses of different animals to various abiotic factors. Describe each one with the help of an example. (i) Regulate (ii) Conform (iii) Migrate (iv) Suspend -cbse-Biology-class-12

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140)If 8 individuals in a population of 80 butterflies die in a week, calculate the death rate of population of butterflies during that period. -cbse-Biology-class-12

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141)What is a trophic level in an ecosystem ? What is ‘standing crop’ with reference to it ? -cbse-Biology-class-12

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142)Explain the role of the ‘first trophic level’ in an ecosystem -cbse-Biology-class-12

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143)How is the detritus food chain connected with the grazing food chain in a natural ecosystem ? -cbse-Biology-class-12

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144)Name the process of formation of male gametes in flowering plants. -cbse-Biology-class-12

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145)List the two ways that have been used and resulted in Sahiwal cows in Punjab from ancestral wild cows. -cbse-Biology-class-12

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146)Give an example of an organism that exhibits XO-type of sex determination. What is this sex determination designated as ? -cbse-Biology-class-12

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147)How does Gambusia fish help in controlling the spread of Malaria ? -cbse-Biology-class-12

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148)Name the first discovered restriction endonuclease and state its specific role -cbse-Biology-class-12

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149)(a) State the primary requirement to ensure cross breeding experiments in plants. (b) Name the techniques which help to achieve this requirement -cbse-Biology-class-12

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150)What is a cistron ? Why is the structural gene in a transcription unit of eukaryotes called monocistronic and that in prokaryotes/bacteria called polycistronic ? Give reasons. -cbse-Biology-class-12

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151)How is e-waste generated ? Suggest a method for disposal of e-waste. -cbse-Biology-class-12

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152)Name the flowering plant which employs ‘sexual deceit’ to get pollinated by a species of bee. Write how pollination occurs in this flower. -cbse-Biology-class-12

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153)Differentiate between Commensalism and Mutualism. Give an example of each from the plant kingdom. -cbse-Biology-class-12

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154)Expand GPP and NPP. Differentiate between the two -cbse-Biology-class-12

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155)Name and write the functions of the paired accessory glands in human male reproductive system. -cbse-Biology-class-12

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156)Name the cell from which the endosperm develops in a coconut. Mention its ploidy. Explain the process of endosperm development in a coconut. -cbse-Biology-class-12

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157)Explain initiation, elongation and termination in the process of transcription in bacteria -cbse-Biology-class-12

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158)Why did Hershey and Chase work with bacteriophages in their experiments to prove that DNA is the genetic material ? Explain. -cbse-Biology-class-12

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159)Name and explain the phenomenon of evolution exhibited by Australian marsupials. -cbse-Biology-class-12

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160)Tobacco smoking, chewing or snuffing is very injurious to health of humans. Justify. -cbse-Biology-class-12

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161)List the three traits or characters that plant breeders have tried to incorporate into crop plants. -cbse-Biology-class-12

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162)Explain the different steps involved in the primary treatment of sewage. -cbse-Biology-class-12

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163)Write the three basic steps involved in genetically modifying an organism -cbse-Biology-class-12

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164)Write the importance of gel electrophoresis in biotechnology. -cbse-Biology-class-12

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165)Explain the different steps carried in gel electrophoresis to get the desired results -cbse-Biology-class-12

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166)How are ‘competent’ bacteria transformed with recombinant DNA ? Explain. -cbse-Biology-class-12

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167)What is Altitude Sickness ? How does your body physiologically adapt to overcome it ? -cbse-Biology-class-12

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168)Where and how does the Primary Succession occur ? Explain -cbse-Biology-class-12

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169)The practice of defecation in the open fields is not advised due to many reasons. Such a practice affects human health by causing and spreading diseases. Name a disease thus caused with any two symptoms and mode of infection. Also name the causative organism -cbse-Biology-class-12

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170)Seeds offer several advantages to angiosperms. Describe any three such advantages -cbse-Biology-class-12

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171)Why is banana called a parthenocarpic fruit ? Would you call banana a true fruit ? Give reason in support of your answer. -cbse-Biology-class-12

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172)Describe ovarian events in the menstrual cycle of the female reproductive system in humans -cbse-Biology-class-12

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173)Explain the role played by pituitary hormones during the events described above. -cbse-Biology-class-12

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174)Mention the traits in pea plants, where a single gene product produces more than one phenotypic effect. Write their effect in homozygous dominant and homozygous recessive states. -cbse-Biology-class-12

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175)Taking an example of human blood groups, explain dominance, co-dominance and multiple allelism -cbse-Biology-class-12

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176)How can the comparative study made of the fore limbs of different mammals be considered an evidence for evolution ? -cbse-Biology-class-12

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177)Describe how DDT undergoes biological magnification -cbse-Biology-class-12

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178)How does DDT cause a decline in bird populations ? Explain -cbse-12-biology

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179)(a) Why is the pyramid of energy always upright ? Explain. -cbse-Biology-class-12

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180)What are the limitations of ecological pyramids ? -cbse-Biology-class-12

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