PSEB Class 12 Biology Elements Of Heredity And Variations Multiple Choice Questions

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Question 1. Which of die following Mendel’s law has not been proven to be true in all the cases?

  1. Law of segregation
  2. Law of independent assortment
  3. Law of dominance
  4. None of these.

Answer: 3. Law of dominance

Question 2. When the tall red plant is crossed with a dwarf white plant, all the plants of F1 generation are found to be tall red. Which of the following ratios will be available when a test cross is made?

  1. 1: 1 : 1: 1
  2. 1 : 2: 1
  3. 3: 1
  4. 1: 2: 2:1.

Answer: 1.1: 1 : 1: 1

Question 3. The three important laws of heredity proposed by Mendel relate to :

  1. Gene linkage, character segregation and independent assortment
  2. Gene linkage, dominance and segregation
  3. Segregation, independent assortment and dominant recessiveness
  4. Segregation, independent assortment and gene linkage.

Answer: 3. Segregation, independent assortment and dominant recessiveness

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Question 4. Which one of the following statements is true of Mendel’s theory but not of Darwin’s theory of natural selection?

  1. The original theory was modified later on
  2. The theory immediately and strongly influenced other areas of human knowledge
  3. Clearly defined laws were proposed during the early stages of the theory.
  4. The theory was based mostly on pathological studies.

Answer: 3. Clearly defined laws were proposed during the early stages of the theory.

PSEB Class 12 Biology Elements Of Heredity And Variations MCQs

PSEB Class 12 Biology Elements Of Heredity And Variations Multiple Choice Questions

Question 5. Lethal genes are those which cause :

  1. Die death of the homozygous infant being formed
  2. Night blindness
  3. Colour blindness
  4. Linkage and crossing over.

Answer: 1. Die death of the homozygous infant being formed

Question 6. There is a resemblance between parents and offspring but not the exact likeness. This is because of:

  1. Variations produced by crossing over at the time of gamete formation
  2. Variations produced by chance distribution of chromosomes to the two  poles of meiosis I
  3. Both the above  and  points
  4. None of the above points.

Answer: 3. Both the above  and the points

Question 7. When one gene pair hides the effect of another pair, this phenomenon is referred to as :

  1. Mutation
  2. Epistasis
  3. Dominance
  4. None of the above.

Answer: 2. Epistasis

Question 8. In a dihybrid cross, Fj individuals arc self-crossed, phenotypic ratio  comes to be 15: 1. It is due to :

  1. Duplicate genes
  2. Supplementary genes
  3. Dominant epistasis
  4. Recessive epistasis

Answer: 1. Duplicate genes

Question 9. An Execution of Mendel’s law is:

  1. Independent assortment
  2. Dominance
  3. Purity of gametes
  4. Linkage.

Answer: 4. Linkage.

Question 10. Complementary genes show a ratio of :

  1. 1: 1
  2. 3 :1
  3. 9: 7
  4. 9:3:3: 1.

Answer: 3. 9: 7

Elements Of Heredity And Variations Multiple Choice Questions PSEB Class 12

Question 11. If 3n is the number of genotypes where ‘n’ is the number of different chromosome pairs with each carrying one heterozygous allele, what would be the different genotypes produced by garden pea plant?

  1. 310
  2. 312
  3. 314
  4. 37

Answer: 4. 37

Question 12. If a dihybrid for the character is crossed to a homozygous recessive  individual for the same character, the phenotypic ratio of the progeny  would be :

  1. 1:1:1:1
  2. 1:2:1
  3. 3: 1
  4. 13:3.

Answer: 1. 1:1:1:1

Question 13.Genes which have similar phenotypic effects when present separately but interact to produce a new phenotype when present together are known as :

  1. Supplementary genes
  2. Complementary genes
  3. Epistatic genes
  4. Inhibitory genes.

Answer: 2. Complementary genes

Question 14. In a green pod of pea, the seed-coat colour changed from grey to white. This is an example of:

  1. Chlorosis
  2. Spontaneous mutation
  3. Pleiotropic mutation
  4. Transformation.

Answer: 2. Spontaneous mutation

Question 15. If the genotype of an individual is AA Bb CC, it is a :

  1. Trihybrid
  2. Monohybrid
  3. Dihybrid
  4. None of the above.

Answer: 2. Monohybrid

Question 16. An individual heterozygous for two alleles (Aa Bb) produces two million sperms; how many of the sperms will have both the recessive alleles :

  1. 1 million
  2. 2 million
  3. 0.5 million
  4. 0.25 million.

Answer: 3. 0.5 million

Question 17. If the frequency of a dominant phenotype in a stable population is 75%, the frequency of a dominant allele in the population would be: 

  1. 37.5%
  2. 75%
  3. 9.4%
  4. 50%.

Answer: 4. 50%.

Elements Of Heredity And Variations Multiple Choice Questions PSEB Class 12

Question 18. If two hybrids for the same quantitative character are crossed the phenotypic ratio of progeny would be ;

  1. 1:4 : 6: 4: 1
  2. 15: 1
  3. 12:3:1
  4. 9: 7.

Answer: 1. 1:4 : 6: 4: 1

Question 19.In a cross between a pure tall pea plant with a green pod and a pure short plant with a yellow pod, how many short plants you would expect in F2, generation?

  1. 4
  2. 9
  3. 3
  4. 1.

Answer: 1. 4

Question 20. From a single car of com, a far nu’r planted 200 kernels which produced NO tall and 10 short plants. The genotypes of these offspring are most likely :

  1. TT and Tt only
  2. IT, Tt and tl
  3. tt and tt only
  4. TT and tt only.

Answer: 2. IT, Tt and tl

Question 21. An individual with genotype Aa Bb Co will produce ; 

  1. Four types of gametes
  2. All gametes of the same type
  3. Eight different types of gametes
  4. Four gametes of one type and the remaining gametes Of the same type.

Answer: 3. Eight different types of gametes

Question 22. Mendel was successful in formulating the laws of inheritance whereas his predecessors were not because :

  1. Of the right choice of material
  2. They studied one clear-cut character at a time with no intermediates
  3. The characters studied by him were present on separate chromosomes and  showed no linkage
  4. All the above.

Answer: 4. All the above.

Question 23. A test cross : 

  1. Is commonly used to investigate the genotype of the diploid individual
  2. Involves mating one genotype to another homozygous for all dominant  genes under consideration
  3. Involves mating one genotype to another homozygous for recessive  alleles of all genes under consideration
  4. Both 1 and 3

Answer: 4. Both 1 and 3

Class 12 Biology Chapter Elements Of Heredity And Variations MCQs

Question 24. Mendel formulated the laws of heredity considering seven pairs of characters in the pea plant. If he had studied an eighth pair, the law  which would have been altered is:

  1. Law of segregation
  2. Law of independent assortment
  3. Law of dominance
  4. Law of unit character.

Answer: 2. Law of independent assortment

Question 25. In the F2 generation, genotypic and phenotypic ratios are identical in M case of:

  1. Mendelian nanohybrids
  2. Mendelian dihybrids
  3. Incomplete dominance
  4. None of the above.

Answer: 3. Incomplete dominance

Question 26. The segregation of paired hereditary factors that Mendel postulated occurs during :

  1. Prophase of first meiotic division
  2. Anaphase of first meiotic division
  3. During interphase between two meiotic divisions
  4. Metaphase of the second meiotic division.

Answer: 2. Anaphase of first meiotic division

Question 27. The independent assortment of two pairs of genes located on  non-homologous chromosomes occur as a result of the random orientation of chromosomes during :

  1. Metaphase of the first meiotic division
  2. Telophase of the first meiotic division
  3. The brief interphase between the two meiotic- divisions
  4. Prophase of the second meiotic division.

Answer: 1. Metaphase of the first meiotic division

Question 28. Appearance of hidden character in some progeny of F2 generation proclaims:

  1. Law of Independent assortment
  2. Law of Dominance
  3. Law of Fiuily ol gametes
  4. None of the above,

Answer: 3. Law of Fiuily ol gametes

Question 29. Mendelian recombinations are due to :

  1. Linkage
  2. Modifications
  3. Independent assortment of characters
  4. Mutation.

Answer: 3. Independent assortment of characters

Question 30. Mendel law of segregation is based upon the F2 ratio of:

  1. 1: 2
  2. 1:2:1
  3. 9:3:1
  4. 3: 1

Answer: 4. 3: 1

Class 12 Biology Chapter Elements Of Heredity And Variations MCQs

Question 31. Which one of the following characters in man is controlled by a  recessive gene?

  1. Woolly hair
  2. Brachydactyly
  3. Colour blindness
  4. Night blindness.

Answer: 3. Colour blindness

Question 32. The constriction on chromosomes where the spindle fibres attach during cell division arc :

  1. Chromatids
  2. Chromonemata
  3. Centromere
  4. Chromomere.

Answer: 3. Centromere

Question 32. As a result of linkage and crossing over:

  1. Chromatids become chromosomes
  2. Nuclear divisions come to a close
  3. Chromosomes become half in number
  4. Exchange of chromosomal material occurs.

Answer: 4. Exchange of chromosomal material occurs.

Question 33. Gene P and Q are necessary for normal hearing. A deaf man marries a deaf woman and all their children have normal hearing. The genotypes of the parents are :

  1. PPqq x PPqq
  2. Ppqq x ppQq
  3. PPqq x ppQQ
  4. ppQQ x ppQq.

Answer: 3. PPqq x ppQQ

Question 34.A plant with Aa Bb composition, on self-pollination results in which of the following genetic frequencies among the dominant phenotypes?

AABB : AABb : Aa BB : AaBb

  1. 1 : 2 : 2 : 4
  2. 1 : 2 : 2 : 1
  3. 1 : 1 : 1 : 1
  4. 2:2 :2:3.

Answer: 1. 1 : 2 : 2 : 4

Question 35. “Like begets like” is an important and universal phenomenon of life, is due to :

  1. Euthenics
  2. Inheritance
  3. Dominance
  4. Eugenics.

Answer: 1. Euthenics

Question 36. The father of genetics G.J. Mendel is famous for propounding :

  1. Theory of acquired character
  2. Cell theory
  3. Laws of inheritance
  4. Origin of species.

Answer: 3. Laws of inheritance

PSEB Class 12 Biology Genetics MCQs with Answers

Question 37. The frequency of a mutant gene in a population is expected to increase if the gene is:

  1. Dominant
  2. Recessive
  3. Favourably selected
  4. Sex-linked.

Answer: 1. Dominant

Question 38. Genetic information is carried out by a long chain of molecules made up of:

  1. Enzymes
  2. Nucleotides
  3. Amino acids
  4. Chromosomes.

Answer: 2. Nucleotides

Question 39. Mendel studied seven contrasting characters for his breeding experiments: which of the following characters he did not study?

  1. Plant height
  2. Pod colour
  3. Pod shape
  4. Leaf shape.

Answer: 4. Leaf shape.

Question 40. A normal plant suddenly started producing Parthenon genetically. the number of chromosomes of the second generation compared to the parent plant will be :

  1. Double
  2. One half
  3. One fourth
  4. Same.

Answer: 2. One half

Question 41. Why were pea plants more suitable than dogs for Mendel’s experiments?

  1. There were no pedigree records of dogs
  2. Pea plants can be self-pollinated
  3. Dogs have many genetic traits
  4. All pea plants are diploid.

Answer: 2. Pea plants can be self-pollinated

Question 42. Suppose pea plant’s tallness is dominant over dwarfness, to determine whether a tall pea plant is homozygous or heterozygous, it should be crossed with the:

  1. A homozygous tall pea plant
  2. A homozygous dwarf pea plant
  3. Any tall pea plant
  4. Any pea plant.

Answer: 2. A homozygous dwarf pea plant

Question 43. The term gene was given by :

  1. Bateson
  2. Johannsen
  3. Punnet
  4. Darlington.

Answer: 2. Johannsen

PSEB Class 12 Biology Genetics MCQs with Answers

Question 44. The term back cross refers to :

  1. A cross between F| hybrid and either of the parents
  2. A cross between one Fj-and another Fj hybrid
  3. A cross between Fj hybrid and Fj individuals
  4. None of these.

Answer: 1. A cross between F| hybrid and either of the parents

Question 45. A cross between unlike organisms is called as :

  1. Hybridisation
  2. Heterosis
  3. Backcross
  4. Test cross.

Answer: 1. Hybridisation

Question 46. If Mendel had, by chance, chosen to study two traits determined by linked genes, he would have not been able to derive the :

  1. Law of dominance
  2. Law of independent assortment
  3. Law of unit character
  4. Law of segregation.

Answer: 2. Law of independent assortment

Question 47. The character which predominates and is seen in F, generation is said to be :

  1. Common
  2. Dominant
  3. Special
  4. Recessive.

Answer: 2. Dominant

Question 48. The ratio of recessive epistasis :

  1. 9:3:4
  2. 13:3
  3. 12:3: I
  4. 15: 1.

Answer: 2.13:3

PSEB Class 12 Biology Genetics MCQs with Answers

Question 49. A pure tall pea plant was reared in soil poor in nutrition and reached the size of the pure dwarf pea plant. If this pea plant is selfed  then the phenotype in the F| generation is most likely to be :

  1. All tall
  2. 50% tall and 50% dwarf
  3. All dwarf
  4. Data are insufficient.

Answer: 1. All tall

Question 50. In a monohybrid cross, 2 heterozygous individuals were crossed,  phenotype ratio comes to be 2: 1. It is due to :

  1. Dominant lethal genes in homozygous condition
  2. Dominant lethal genes in heterozygous individuals
  3. Dominant epistasis
  4. None of the above.

Answer: 1. Dominant lethal genes in homozygous condition

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