done 12th Biology Principle Of Inheritance And Variation

• question_answer1)
  Mention the advantages of selecting pea plant for experiment by Mendel. 
  View Answer play_arrow

• question_answer2)
  Differentiate between the following: (a) Dominance and Recessive (b) Homozygous and Heterozygous (c) Monohybrid and Dihybrid  
  View Answer play_arrow

• question_answer3)
  Explain Law of Dominance using a monohybrid cross. 
  View Answer play_arrow

• question_answer4)
  Define and design a test-cross. 
  View Answer play_arrow

• question_answer5)
  Using a Punnet Square, workout the distribution of phenotypic features in the first filial generation after a cross between a homozygous female and heterozygous male for a single locus. 
  View Answer play_arrow

• question_answer6)
  When a cross is made between tall plant with yellow seeds (TtYy) and tall plant with green seed (Ttyy), what proportions of phenotype in offspring could be expected to be : (a) Tall and green (b) Dwarf and green  
  View Answer play_arrow

• question_answer7)
  Two heterozygous parents are crossed. If the two loci are linked what would be the distribution of phenotypic features in F generation for a dihybrid cross? 
  View Answer play_arrow

• question_answer8)
  Briefly mention the contribution of T.H. Morgan in genetics. 
  View Answer play_arrow

• question_answer9)
  What is pedigree analysis? Suggest how such an analysis, can be useful. 
  View Answer play_arrow

• question_answer10)
  How is sex determined in human beings? 
  View Answer play_arrow

• question_answer11)
  A child has blood group O. If the father has blood group A and mother blood group B. Work out the genotypes of parents and the possible genotypes of other parents. 
  View Answer play_arrow

• question_answer12)
  Explain the following terms with example: (a) Co-dominance (b) Incomplete dominance.  
  View Answer play_arrow

• question_answer13)
  What is point mutation? Give one example. 
  View Answer play_arrow

• question_answer14)
  Who had proposed the chromosomal theory of inheritance? 
  View Answer play_arrow

• question_answer15)
  Mention any two autosomal genetic disorders with their symptoms. 
  View Answer play_arrow

• question_answer16)     All genes located on the same chromosome (a) form different groups depending upon their relative distance (a)form one linkage group (b)will not from any linkage group (c)form interactive groups that affect the phenotype

  View Answer play_arrow

• question_answer17)   Conditions of a karyotype 2n ± 1 and 2n ± 2 are called (a) aneuploidy                       (b) polyploidy                (c) allopolyploidy              (d) monosomy

  View Answer play_arrow

• question_answer18)   Distance between the genes and percentage of recombination shows (a) a direct relationship                                                 (b) an inverse relationship (c) a parallel relationship                                               (d) no relationship      

  View Answer play_arrow

• question_answer19)   If a genetic disease is transferred from a phenotypically normal but carrier female to only some of the male progeny, the disease is (a) autosomal dominant                                               (b) autosomal recessive (c) sex-linked dominant                                                (d) sex-linked recessive

  View Answer play_arrow

• question_answer20)   In sickle-cell anaemia glutamic acid is replaced by valine. Which one of the following triplet codes for valine? (a) G G G                            (b) A A G                              (c) G A A                              (d) G U G

  View Answer play_arrow

• question_answer21)   Person having genotype  would show the blood group as AB. This is because of (a) pleiotropy                   (b) codominance              (c) segregation                  (d)incomplete dominance  

  View Answer play_arrow

• question_answer22)   ZZ/ZW type of sex determination is seen in (a) platypus                        (b) snails                              (c) cockroach                     (d) peacock

  View Answer play_arrow

• question_answer23)   A across between two tall plants resulted in offspring having few dwarf plants. What would be the genotypes of both the parents?                 (a)TTandTt                          (b) Tt and Tt                       (c) TT and TT                       (d) Tt and tt

  View Answer play_arrow

• question_answer24)   In a dihybrid cross, if you get 9 : 3 : 3 : 1 ratio it denotes that (a) the alleles of two genes are interacting with each other (b) it is a multiple inheritance (c) it is a case of multiple allelism (d) the alleles of two genes are segregating independently

  View Answer play_arrow

• question_answer25)   Which of the following will not result in variations among siblings? (a) Independent assortment of genes                                   (b) Crossing over (c) Linkage                                                                          (d) Mutation

  View Answer play_arrow

• question_answer26)   Mendel's law of independent assortment holds good for genes situated on the (a) non-homologous chromosomes                        (b) homologous chromosomes (c) extra nuclear genetic element                             (d) same chromosome

  View Answer play_arrow

• question_answer27)   Occasionally, a single gene may express more than one effect. The phenomenon is called (a) multiple allelism              (b) mosaicism               (c) pleiotropy                         (d) polygeny

  View Answer play_arrow

• question_answer28)   In a certain taxon of insects some have 17 chromosomes and the other shave 18 chromosomes. The 17 and 18 chromosome-bearing organisms are (a) males and females, respectively                        (b) females and males, respectively (c) all males                                                                        (d) all females

  View Answer play_arrow

• question_answer29)   The inheritance pattern of a gene over generations among humans isstudied by the pedigree analysis. Character studied in the pedigree analysis is equivalent to (a) quantitative trait       (b) Mendelian trait          (c) polygenic trait             (d) maternal trait

  View Answer play_arrow

• question_answer30)   It is said that Mendel proposed that the factor controlling any character is discrete and independent. This proposition was based on the (a) results of F3 -generation of a cross (b) observations that the offspring of a cross made between the plants having two contrasting characters shows only one character without any blending (c) self-pollination of F1, off springs (d) cross-pollination of F1 -generation with recessive parent

  View Answer play_arrow

• question_answer31)   Two genes 'A' and 'B' are linked. In a dihybrid cross involving these two genes, the  heterozygote is crossed with homozygous recessive parental type (aa bb). What would be the ratio of offspring in the next generation? (a) 1 : 1 : 1 : 1                      (b) 9 : 3 : 3 : 1                      (c) 3 : 1                                  (d) 1 : 1

  View Answer play_arrow

• question_answer32)   In the -generation of a Mendelian dihybrid cross the number of phenotypes and genotypes are (a) phenotypes-4, genotypes-16                              (b) phenotypes-9, genotypes-4 (c) phenotypes-4, genotypes-8                                 (d) phenotypes-4, genotypes-9

  View Answer play_arrow

• question_answer33)   Mother and father of a person with 'O' blood group have 'A' and 'B' blood group respectively. What would be the genotype of both mother and father? (a) Mother is homozygous for 'A' blood group and father is heterozygous for 'B' (b) Mother is heterozygous for 'A' blood group and father is homozygous for 'B' (c) Both mother and father are heterozygous for 'A' and 'B' blood group respectively (d) Both mother and father are homozygous for 'A' and 'B' blood group respectively

  View Answer play_arrow

• question_answer34)   What is the cross between the progeny of and the homozygous recessive parent called? How is it useful?

  View Answer play_arrow

• question_answer35)   Do you think Mendel's Laws of inheritance would have be- different in the characters that he chose were located on the same chromosome.

  View Answer play_arrow

• question_answer36)   Enlist the steps of controlled cross-pollination. Would emasculation be needed in a cucurbit plant? Give reasons for your answer.

  View Answer play_arrow

• question_answer37)   A person has to perform crosses for the purpose of studying inheritance of a few traits/characters. What should be the criteria for selecting the organisms?

  View Answer play_arrow

• question_answer38)   The pedigree chart given below shows a particular trait which is absent in parents but present in the next generation irrespective of sexes. Draw your conclusion on the basis of the pedigree.  

  View Answer play_arrow

• question_answer39)   In order to obtain the F1 -generation Mendel pollinated a pure-breeding all plant with a pure-breeding dwarf plant. But for getting the F2 -generation, he simply self-pollinated the tall  plants. Why?

  View Answer play_arrow

• question_answer40)   'Genes contain the information that is required to express a particular trait.' Explain.

  View Answer play_arrow

• question_answer41)   How are alleles of particular gene differ from each other? Explain its significance.

  View Answer play_arrow

• question_answer42)     In a monohybrid cross of plants with red and white flowered plants. Mendel got only red flowered plants. On self-pollinating these F1 plantsgot both red and white flowered plants in 3:1 ratio. Explain the basis of using RR and rr symbols to represent the genotype of plants of parental generation.  

  View Answer play_arrow

• question_answer43)   For the expression of traits genes provide only the potentiality and the environment provides the opportunity. Comment on the veracity of the statement.

  View Answer play_arrow

• question_answer44)   A, B, D are three independently assorting genes with their recessive alleles a, b, d, respectively. A cross was made between individuals of Aabb DD genotype with aa bb dd. Find out the type of genotypes of the offspring produced.

  View Answer play_arrow

• question_answer45)     In our society a woman is often blamed for not bearing male child. Do you think it is right? Justify.

  View Answer play_arrow

• question_answer46)   Discuss the genetic basis of wrinkled phenotype of pea seed.

  View Answer play_arrow

• question_answer47)   Even if a character shows multiple allelism, an individual will only have two alleles for that character. Why?

  View Answer play_arrow

• question_answer48)   How does a mutagen induce mutation? Explain with example.

  View Answer play_arrow

• question_answer49)   In a Mendelian monohybrid cross, the -generation shows identical genotypic and phenotypic ratios. What does it tell us about the nature of alleles involved? Justify your answer.

  View Answer play_arrow

• question_answer50)   Can a child have blood group '0' if his parents have blood group 'A' and 'B' Explain.

  View Answer play_arrow

• question_answer51)   What is Down's syndrome? Give its symptoms and cause. Why is it that the chances of having a child with Down's syndrome increases if the age of the mother exceeds forty years?

  View Answer play_arrow

• question_answer52)   How was it concluded that genes are located on chromosomes?

  View Answer play_arrow

• question_answer53)   A plant with red flowers was crossed with another plant with yellow flowers. If Fl showed all flowers orange in colour, explain the inheritance.

  View Answer play_arrow

• question_answer54)     What are the characteristic features of a true-breeding line?

  View Answer play_arrow

• question_answer55)   In peas ,tallness is dominant over dwarfness, and red colour of flowers is dominant over the white colour. When a tall plant bearing red flowers was pollinated with a dwarf plant bearing white flowers, the different phenotypic groups were obtained in the progeny in numbers mentioned against them Tall, Red = 138 Tall, White =132 Dwarf, Red = 136 Dwarf, White =128 Mention the genotypes of the two parents and of the four offspring types.

  View Answer play_arrow

• question_answer56)   Why is the frequency of red-green colour blindness is many times higher in males than that in the females?

  View Answer play_arrow

• question_answer57)   If a father and son are both defective in red-green colour vision, is it likely that the son inherited the trait from his father? Comment.

  View Answer play_arrow

• question_answer58)   Discuss why Drosophila has been used extensively for genetical studies?

  View Answer play_arrow

• question_answer59)   How do genes and chromosomes share similarity from the point of view of genetical studies?

  View Answer play_arrow

• question_answer60)   What is recombination? Discuss the applications of recombination from the point of view of genetic engineering.

  View Answer play_arrow

• question_answer61)   What is artificial selection? Do you think it affects the process of natural selection? How?

  View Answer play_arrow

• question_answer62)   With the help of an example differentiate between incomplete dominance and co-dominance.

  View Answer play_arrow

• question_answer63)     It is said, that the harmful alleles get eliminated from population over a period of time, yet sickle-cell anaemia is persisting in human population. Why?                 

  View Answer play_arrow

• question_answer64)       In a plant tallness is dominant over dwarfness and red flower is dominant over white. Starting with the parents work out a dihybrid cross. What is standard dihybrid ratio? Do you think the values would deviate if the two genes in question are interacting with each other?

  View Answer play_arrow

• question_answer65)   (a) In humans, males are heterogametic and females are homogametic, Explain. Are there any examples where males are homogametic and females heterogametic? (b) Also describe as to, who determines the sex of an unborn child? Mention whether temperature has a role in sex determination.

  View Answer play_arrow

• question_answer66)   A normal vision 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.

  View Answer play_arrow

• question_answer67)   Discuss in detail the contributions of Morgan and Sturvant in the area of genetics.  

  View Answer play_arrow

• question_answer68)   Define aneuploidy. How is it different from polyploidy? Describe the individuals having following chromosomal abnormalities. (a) Trisomy of 21st Chromosome    (b) XXY        (c) XO                

  View Answer play_arrow