Q1. Identify the correct statements for 'Polygenic Inheritance': (i) Controlled by three or more genes. (ii) Influence of environment is taken into account. (iii) Phenotype reflects the additive effect of each allele.
Correct Answer: (a)
Characteristics of quantitative traits like human skin color (Page 19).
Q2. Mendel's work remained unrecognised until the year:
Correct Answer: (b)
Mendel's work, published in 1865, remained unrecognised till 1900 (Page 14).
Q3. Assertion: Haemophilia is more common in males.
Reason: It is an X-linked recessive disorder and males have only one X chromosome.
Correct Answer: (a)
Single recessive allele on X expresses in males (Page 24).
Q4. Which of the following is correct for 'Klinefelter's syndrome'? (i) Presence of an additional copy of X-chromosome. (ii) Karyotype is 47, XXY. (iii) Development of breast (Gynaecomastia) occurs.
Correct Answer: (a)
Chromosomal disorder in males (Page 26).
Q5. Identify true statements for 'Turner's syndrome': (i) Absence of one X chromosome. (ii) Karyotype is 45 with X0. (iii) Ovaries are rudimentary.
Correct Answer: (a)
Chromosomal disorder in females (Page 26).
Q6. Alfred Sturtevant used the frequency of ______ to map the position of genes.
Correct Answer: (c)
Sturtevant used recombination frequency to map gene positions (Page 17).
Q7. Regarding 'Chromosomal Theory of Inheritance': (i) Behaviour of chromosomes is parallel to genes. (ii) Chromosomes as well as genes occur in pairs. (iii) Two alleles are located on homologous sites.
Correct Answer: (a)
Sutton and Boveri's key arguments (Page 15).
Q8. Match the following for Drosophila:
Feature
Description
A. Life cycle
(I) 2 weeks
B. Media
(II) Simple synthetic
C. Sexes
(III) Easily distinguishable
Correct Answer: (a)
Characteristics of Drosophila (Page 17).
Q10. Regarding 'Pleiotropy', which are correct? (i) Single gene exhibits multiple phenotypic expressions. (ii) Effect of gene on metabolic pathways. (iii) Example is Phenylketonuria.
Correct Answer: (a)
Mechanism of pleiotropic genes (Page 19).
Q11. A true-breeding line is one that has undergone continuous ______.
Correct Answer: (b)
A true-breeding line is one that, having undergone continuous self-pollination, shows stable trait inheritance (Page 4).
Q12. Identify the correct phylum/group being described: (i) They are male heterogametic (XY). (ii) Female has a pair of XX chromosomes. (iii) Determinant of male characteristic is the Y chromosome.
Correct Answer: (a)
Standard human sex determination (Page 21).
Q13. Match the organism with its sex determination type:
Column-I
Column-II
A. Humans
(I) ZW type
B. Grasshopper
(II) XY type
C. Birds
(III) XO type
Correct Answer: (a)
Sex determination mechanisms (Page 20).
Q14. Correct statements for 'Haemophilia' include: (i) Sex-linked recessive disease. (ii) Single protein of the blood clotting cascade is affected. (iii) Heterozygous female is a carrier.
Correct Answer: (a)
Features of the royal disease (Page 24).
Q15. Match the Following for Thalassemia:
Type
Affected Chromosome
A. Alpha-thalassemia
(I) Chromosome 11
B. Beta-thalassemia
(II) Chromosome 16
Correct Answer: (a)
Genetics of Thalassemia (Page 25).
Q16. The phenotypic ratio of a typical Mendelian monohybrid cross in F2 generation is:
Correct Answer: (c)
The monohybrid F2 phenotypic ratio is 3:1 (Tall:Dwarf) (Page 8).
Q17. Assertion: A dihybrid cross involves two pairs of contrasting traits.
Reason: Mendel crossed round yellow seeds with wrinkled green seeds.
Correct Answer: (a)
The example perfectly illustrates the definition (Page 12).
Q18. Identify the features of 'Down's Syndrome': (i) Short statured with small round head. (ii) Furrowed tongue and partially open mouth. (iii) Palm is broad with characteristic palm crease. (iv) Caused by monosomy of chromosome 21.
Correct Answer: (a)
Down's syndrome is caused by Trisomy (47 chromosomes), not monosomy (Page 26).
Q19. Who proposed the Chromosomal Theory of Inheritance?
Correct Answer: (c)
Sutton and Boveri argued that chromosome behavior explains Mendel's laws (Page 17).
Q20. In Snapdragon (Antirrhinum sp.), the F1 generation of a cross between red and white flowers is:
Correct Answer: (c)
In incomplete dominance, the F1 (Rr) is pink (Page 10).
Q21. The process by which characters are passed from parent to progeny is:
Correct Answer: (c)
Inheritance is the process by which characters are passed from parent to progeny; it is the basis of heredity (Page 3).
Q22. Which are correct for 'Mendel's Law of Independent Assortment'? (i) Applies to traits combined in a hybrid. (ii) Segregation of one pair of characters is independent of the other. (iii) Dihybrid ratio is 9:3:3:1.
Correct Answer: (a)
Mendel's second generalisation (Page 14).
Q23. Assertion: Alleles are slightly different forms of the same gene.
Reason: They occupy different sites on different chromosomes.
Q24. Identify correct features of 'Aneuploidy': (i) Gain or loss of a chromosome. (ii) Caused by failure of chromatid segregation. (iii) Example is Down's Syndrome.
Q25. Regarding 'Phenylketonuria': (i) Autosomal recessive trait. (ii) Lack of enzyme phenyl alanine hydroxylase. (iii) Accumulation of phenylalanine in brain.
Correct Answer: (a)
Haplodiploidy in bees (Page 21).
Q27. Which of the following is correct? (i) James Watson and Francis Crick proposed the double helix DNA structure in 1953. (ii) They received Nobel Prize in 1962. (iii) Sutton and Boveri proposed the chromosomal theory.
Correct Answer: (a)
Key milestones in the history of genetics (Pages 2, 17).
Q28. Which of the following is correct regarding 'Sex determination in Honey bees'? (i) Males are haploid (16 chromosomes). (ii) Females are diploid (32 chromosomes). (iii) Males produce sperms by meiosis.
Correct Answer: (a)
In honey bees, males produce sperms by mitosis (Page 21).
Q29. Assertion: Male honey bees have 16 chromosomes.
Reason: They are produced by parthenogenesis and are haploid.
Correct Answer: (a)
Haplodiploidy system in bees (Page 21).
Q30. Assertion: Down's syndrome is a chromosomal disorder.
Reason: It is caused by the trisomy of chromosome 21.
Correct Answer: (a)
Aneuploidy (extra chromosome) defines it as chromosomal (Page 26).
Q31. Assertion: Turner's syndrome occurs in females.
Reason: It is caused by the absence of one of the X chromosomes (45, XO).
Correct Answer: (a)
Monosomy of X leads to sterile females (Page 26).
Q32. Match the blood genotypes with their phenotypes:
Column-I (Genotype)
Column-II (Phenotype)
A. IA i
(I) AB
B. IA IB
(II) A
C. ii
(III) B
D. IB i
(IV) O
Correct Answer: (a)
Based on Table 4.2.
Q33. Match the syndrome with its chromosomal composition:
Q34. Assertion: Human skin colour is a polygenic trait.
Reason: It is controlled by three genes (A, B, C) and shows additive effects.
Correct Answer: (a)
The gradient of colors results from multiple allele contributions (Page 19).
Q35. In Honey bees, the unfertilised egg develops as a male (drone) by:
Correct Answer: (c)
An unfertilised egg develops as a male by means of parthenogenesis (Page 21).
Q36. Assertion: Klinefelter's syndrome individuals are sterile.
Reason: They have a karyotype of 47, XXY.
Correct Answer: (a)
The extra X in a male leads to sterility and gynaecomastia (Page 26).
Q37. Match the Following terms:
Term
Meaning
A. Genotype
(I) Observable characteristic
B. Phenotype
(II) Genetic makeup
C. Alleles
(III) Contrasting traits of a gene
Correct Answer: (a)
Standard genetics vocabulary.
Q38. Thomas Hunt Morgan worked with which organism?
Correct Answer: (c)
Morgan worked with the tiny fruit flies, Drosophila melanogaster (Page 17).
Q39. Correct statements about 'Thalassemia' include: (i) Autosome-linked recessive blood disease. (ii) Results in reduced rate of globin synthesis. (iii) It is a qualitative problem.
Correct Answer: (a)
Thalassemia is a quantitative problem (Page 25).
Q40. Assertion: Drosophila is an ideal material for genetic studies.
Reason: It can be grown on simple synthetic medium and has a short life cycle.
Correct Answer: (a)
These practical advantages made it popular for Morgan's research (Page 17).
Q41. Assertion: Variation is the degree by which progeny differ from their parents.
Reason: Inheritance is the basis of heredity.
Correct Answer: (a)
Both are fundamental definitions in genetics (Page 3).
Q42. Assertion: Polyploidy is often seen in plants.
Reason: It results from the failure of cytokinesis after telophase.
Correct Answer: (a)
Failure of cell division leads to a whole set increase (Page 25).
Q43. Identify true statements for 'Chromatin': (i) nucleoprotein fibres. (ii) Observed in the interphase nucleus. (iii) Stained by basic dyes.
Correct Answer: (a)
Description of nuclear material (Page 15/Chapter 5 context).
Q44. Match the Following scientists with their contribution:
Column-I
Column-II
A. Henking
(I) X-ray Diffraction of proteins
B. Alfred Sturtevant
(II) Chromosome mapping
C. Francis Crick
(III) Discovery of X-body
Correct Answer: (a)
History of genetics section (Pages 2, 17, 19).
Q45. Assertion: Point mutation involves a change in a single base pair of DNA.
Reason: Sickle cell anemia is caused by a point mutation in the beta-globin gene.
Correct Answer: (a)
Both are true, but the second is an example, not the structural explanation of the first (Page 22).
Q46. Match the Mendelian ratios:
Column-I
Column-II
A. F2 Monohybrid Phenotypic
(I) 1:2:1
B. F2 Monohybrid Genotypic
(II) 9:3:3:1
C. F2 Dihybrid Phenotypic
(III) 3:1
Correct Answer: (a)
Standard Mendelian ratios.
Q47. Assertion: In ABO blood groups, alleles IA and IB are co-dominant.
Reason: Both IA and IB express their own types of sugars when present together.
Correct Answer: (a)
Co-dominance is defined by the simultaneous expression of both alleles (Page 11).
Q48. Which of the following statements about 'Incomplete Dominance' is correct? (i) The F1 phenotype is in between the two parents. (ii) The genotypic ratio is 1:2:1. (iii) The phenotypic ratio is 3:1.
Correct Answer: (a)
In incomplete dominance, the phenotypic ratio is also 1:2:1 (Page 10).
Q49. Assertion: Phenylketonuria results in mental retardation.
Reason: It is caused by the accumulation of phenylalanine in the brain.
Correct Answer: (a)
The metabolic block leads to toxic accumulation (Page 25).
Q50. Assertion: The symbol of a solid square in a pedigree chart represents an affected male.
Reason: In pedigree analysis, females are represented by circles.
Correct Answer: (a)
Both are true conventions (Figure 4.13), but representing females as circles doesn't explain why a solid square is an affected male.
Q51. Gregor Mendel conducted hybridisation experiments on garden peas for how many years?
Correct Answer: (c)
Mendel conducted hybridisation experiments on garden peas for seven years (1856-1863) (Page 4).
Q52. Henking (1891) observed a specific nuclear structure during spermatogenesis and called it:
Correct Answer: (b)
Henking named the structure the X body, later identified as the X chromosome (Page 19).
Q53. Assertion: Aneuploidy results in the gain or loss of a chromosome.
Reason: It is caused by the failure of segregation of chromatids during cell division.
Correct Answer: (a)
Non-disjunction leads to extra or missing chromosomes (Page 25).
Q54. In polygenic inheritance, the phenotype reflects the contribution of each allele, meaning the effect is:
Correct Answer: (c)
In a polygenic trait, the effect of each allele is additive (Page 19).
Q55. Genes which code for a pair of contrasting traits are known as:
Correct Answer: (b)
Genes which code for a pair of contrasting traits are known as alleles (Page 6).
Q56. Match the Following types of dominance:
Column-I
Column-II
A. Incomplete Dominance
(I) ABO Blood groups
B. Co-dominance
(II) Pea plant height
C. Law of Dominance
(III) Snapdragon flower color
Correct Answer: (a)
Examples provided in Section 4.2.
Q57. How many genotypes are possible for the human ABO blood types?
Correct Answer: (c)
There are six different genotypes of the human ABO blood types (Page 11).
Q58. Humans knew as early as 8000-1000 B.C. that variation was hidden in:
Correct Answer: (b)
Humans knew as early as 8000-1000 B.C. that one of the causes of variation was hidden in sexual reproduction (Page 3).
Q59. Which cross is used to determine the genotype of a tall plant at F2?
Correct Answer: (b)
To determine the genotype of a tall plant at F2, Mendel crossed it with a dwarf plant. This is called a test cross (Page 8).
Q60. Match the symbols used in pedigree analysis:
Symbol
Meaning
A. Empty Circle
(I) Affected male
B. Solid Square
(II) Mating
C. Horizontal line between square and circle
(III) Female
Correct Answer: (a)
Based on Figure 4.13.
Q61. Regarding 'Sickle-cell Anaemia', which are true? (i) Controlled by a single pair of alleles, HbA and HbS. (ii) homozygous HbS individuals show the disease. (iii) It is an X-linked recessive disorder.
Correct Answer: (a)
It is an autosomal linked recessive trait, not X-linked (Page 24).
Q62. Select the correct statements for 'Mendel's Law of Segregation': (i) Alleles do not show any blending. (ii) A gamete receives only one of the two factors. (iii) Both characters are recovered as such in F2.
Correct Answer: (a)
Universal law of inheritance based on monohybrid crosses (Page 9).
Q63. Regarding ABO blood grouping, which statement is true? (i) It is controlled by three alleles IA, IB and i. (ii) IA and IB are completely dominant over i. (iii) IA and IB are co-dominant to each other. (iv) Allele i produces a different form of sugar than IA.
Correct Answer: (a)
Allele i does not produce any sugar (Page 11).
Q64. The term used to describe the physical association of genes on a chromosome is:
Correct Answer: (b)
Morgan coined the term linkage to describe physical association (Page 17).
Q65. Which of the following is being described by the given statements? (i) They are the units of inheritance. (ii) They contain information required to express a particular trait. (iii) Mendel called them 'factors'.
Correct Answer: (b)
Genes (factors) are the carriers of genetic information (Page 6).
Q66. Assertion: Sex-linked genes do not show independent assortment.
Reason: They are located on the same chromosome (X).
Correct Answer: (a)
Linkage on the same chromosome prevents independent assortment (Page 17).
Q67. Match theFollowing linkage results from Morgan's study:
Cross
Recombination %
A. White and Yellow
(I) 37.2%
B. White and Miniature wing
(II) 1.3%
Correct Answer: (a)
Values from section 4.3.3 (Page 17).
Q68. Assertion: Thalassemia is a quantitative problem of globin synthesis.
Reason: It involves the synthesis of incorrectly functioning globin.
Correct Answer: (a)
Thalassemia is quantitative (too few molecules); Sickle-cell is qualitative (incorrect function) (Page 25).
Q69. Mendel’s Law of Independent Assortment is based on which type of cross?
Correct Answer: (b)
Independent assortment is based on observations of dihybrid crosses (Page 14).
Q70. In birds, the sex determination mechanism is:
Q71. Identify the correct statements regarding Drosophila melanogaster as an experimental tool: (i) They complete their life cycle in about two weeks. (ii) A single mating could produce a large number of progeny. (iii) The male and female flies are easily distinguishable. (iv) It cannot be grown on simple synthetic medium.
Correct Answer: (a)
Drosophila can be grown on simple synthetic media (Page 17).
Q72. Assertion: The genetic makeup of the sperm determines the sex of the child in humans.
Reason: Males produce two types of gametes (50% X and 50% Y).
Correct Answer: (a)
Male heterogamety is the basis of human sex determination (Page 21).
Q73. Match the Following for Phenylketonuria:
A. Enzyme missing
Phenyl alanine hydroxylase
B. Accumulation
Phenylpyruvic acid
Correct Answer: (a)
Metabolic block in Phenylketonuria (Page 25).
Q74. The ABO blood groups in humans are controlled by the gene:
Correct Answer: (d)
ABO blood groups are controlled by the gene I (Page 11).
Q75. Phenylketonuria is an example of:
Correct Answer: (b)
Phenylketonuria is a pleiotropic disease caused by a single gene mutation (Page 19).
Q76. Mendel selected how many true-breeding pea plant varieties?
Correct Answer: (b)
Mendel selected 14 true-breeding pea plant varieties, as pairs which were similar except for one character (Page 4).
Q77. Which of the following is correct for 'Linkage' and 'Recombination'? (i) Recombination describes the generation of non-parental gene combinations. (ii) Recombination is higher for loosely linked genes. (iii) Linkage describes the physical association of genes on a chromosome.
Correct Answer: (a)
Findings of Morgan on Drosophila (Page 17).
Q78. Match the characters with their recessive traits in Pea plant:
Column-I (Character)
Column-II (Recessive Trait)
A. Stem height
(I) Terminal
B. Flower position
(II) Dwarf
C. Pod shape
(III) Yellow
D. Pod colour
(IV) Constricted
Correct Answer: (a)
Based on Figure 4.1 and Table 4.1.
Q80. Which statement is true for 'Test Cross'? (i) Crossing dominant phenotype with recessive parent. (ii) Used to find the genotype of the organism. (iii) Ratio is always 3:1.
Correct Answer: (a)
Test cross ratio for a monohybrid is 1:1 (Page 8).
Q81. Grasshopper is an example of which type of sex determination?
Correct Answer: (c)
Grasshopper is an example of XO type of sex determination (Page 20).
Q82. Match the Following chromosomal abnormalities:
A. 2n + 1
Trisomy
B. 2n - 1
Monosomy
C. 3n or 4n
Polyploidy
Correct Answer: (a)
Definitions of aneuploidy and polyploidy (Page 25).
Q83. Select correct statements about 'Mutation': (i) Alteration of DNA sequences. (ii) Results in changes in genotype and phenotype. (iii) UV radiation is a mutagen.
Correct Answer: (a)
General principles of mutation (Page 22).
Q84. Match the Following Mendelian Disorders with their nature:
Q85. Assertion: Mendel’s true-breeding lines showed stable trait inheritance.
Reason: They underwent continuous self-pollination for several generations.
Correct Answer: (a)
Self-pollination leads to homozygosity and stability (Page 4).
Q86. Match the following for Mendel's traits:
Character
Dominant Trait
A. Seed shape
(I) Full
B. Pod shape
(II) Round
C. Seed colour
(III) Yellow
Correct Answer: (a)
Based on Table 4.1.
Q87. Assertion: The law of segregation is also known as the law of purity of gametes.
Reason: Alleles do not show any blending and are recovered as such in F2.
Correct Answer: (a)
The discrete nature of alleles ensures gametes carry only one factor (Page 9).
Q88. Which of the following is a dominant trait in the pea plants studied by Mendel?
Correct Answer: (c)
According to Figure 4.1, Violet flower color is a dominant trait, while white is recessive (Page 4).
Q89. Assertion: Colour blindness is a sex-linked recessive disorder.
Reason: It is more common in males (8%) than females (0.4%).
Correct Answer: (a)
The frequency distribution is a consequence, not the definition (Page 23).
Q90. Assertion: Pedigree analysis is useful in human genetics.
Reason: Control crosses cannot be performed in human beings.
Correct Answer: (a)
Family history is the only ethical way to study inheritance in humans (Page 22).
Q91. Assertion: Sickle cell anemia is a Mendelian disorder.
Reason: It is caused by the substitution of Glutamic acid by Valine.
Correct Answer: (a)
It is Mendelian because it follows single gene inheritance patterns (Page 24).
Q92. Match the Following inheritance patterns:
Pattern
Example
A. Multiple Alleles
(I) Human skin colour
B. Polygenic inheritance
(II) ABO blood groups
C. Pleiotropy
(III) Phenylketonuria
Correct Answer: (a)
Based on Chapter 4 sections.
Q93. Assertion: Mendel's laws were based on statistical analysis.
Reason: He used a large sampling size which gave greater credibility to his data.
Correct Answer: (a)
Mendel applied mathematical logic to biology for the first time (Page 4).
Q94. Starch grain size in pea seeds is an example of:
Correct Answer: (b)
Heterozygotes (Bb) produce starch grains of intermediate size, showing incomplete dominance (Page 12).
Q95. Which are correct for 'Multiple Alleles'? (i) More than two alleles governing the same character. (ii) Found only when population studies are made. (iii) Example is ABO blood groups.
Correct Answer: (a)
Extension of Mendelian genetics (Page 12).
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