2nd Year Biology Chapter 22 Variation & Genetics Question And Answer
Short And Simple Question Answer
Q 1. Difference between phenotype and genotype?
Ans. Phenotype is how a trait looks, genotype is the genetic makeup.
Q 2. Define population?
Ans. A group of interbreeding organisms of the same species.
Q 3. What is the product rule?
Ans. Multiply probabilities of individual phenotypes for independent events.
Q 4. Name types of dominance relations among alleles?
Ans. Complete, incomplete, codominance, overdominance.
Q 5. Who discovered ABO blood group?
Ans. Karl Landsteiner in 1901.
Q 6. What is epistasis?
Ans. When one gene interferes with the effect of another gene.
Q 7. What are polygenetic traits?
Ans. Traits influenced by multiple genes.
Q 8. What is Crossover or recombinant frequency?
Ans. Proportion of recombinant types between genes.
Q 9. Organism lacking sex chromosomes?
Ans. Some eukaryotic microorganisms like yeast.
Q 10. True color blindness: monochromacy or dichromacy?
Ans. Monochromacy is true color blindness.
Q 11. Why did Mendelian factors behave like chromosomes?
Ans. Mendelian factors (genes) are located on chromosomes.
Q 12. How is sexual dimorphism exhibited in Drosophila?
Ans. Male and female Drosophila have distinct morphology.
Q 13. Difference between gene and genome?
Ans. Gene is a unit of biological information, genome is an organism’s genetic material.
Q 14. What are genes and alleles?
Ans. Genes are parts of DNA, alleles are gene variants.
Q 15. Difference between Monohybrid and dihybrid?
Ans. Monohybrid involves one trait, dihybrid involves two.
Q 16. Difference between Homozygous and heterozygous?
Ans. Homozygous has identical alleles, heterozygous has different alleles.
Q 17. Difference between Dominance and epistasis?
Ans. Dominance is the effect of an allele, epistasis is gene interaction.
Q 18. Difference between Autosome and sex chromosome?
Ans. Autosomes are non-sex chromosomes, sex chromosomes determine gender.
Q 19. Difference between Allele and multiple allele?
Ans. Alleles are gene variants, multiple alleles have more than two options.
Q 20. Difference between Sex limited and sex influenced trait?
Ans. Sex-limited traits occur in one sex due to anatomy, sex-influenced traits occur in both sexes but may be more common in one.
Q 21. Incomplete dominance vs. codominance?
Ans. Incomplete: Heterozygote’s phenotype is in between. E.g., 4 O’clock flower. Codominance: Both alleles expressed. E.g., MN blood type.
Q 22. Dominant vs. recessive trait?
Ans. Dominant: Appears in hybrids. Recessive: Suppressed in hybrids.
Q 23. Continuous vs. discontinuous variations?
Ans. Continuous: Many phenotypes (e.g., human height). Discontinuous: Two distinct phenotypes (e.g., Mendel’s pea shape).
Q 24. Wild type vs. mutant?
Ans. Wild type: Normal traits. Mutant: Trait due to mutation.
Q 25. What is a gene pool?
Ans. All alleles in a population.
Q 26. Why was pea lucky for Mendel?
Ans. 7 traits, 7 pairs of chromosomes. Independent assortment. Deviation with 8 traits.
Q 27. What is a test cross?
Ans. Cross for genotype of dominant phenotype.
Q 28. Consequences of non-segregation at meiosis?
Ans. Non-disjunction affects gamete purity.
Q 29. Missing combinations without independent assortment?
Ans. Recombination is missing.
Q 30. Equal chance for alleles in gametes?
Ans. Meiosis and segregation.
Q 31. Dominant allele effect on recessive?
Ans. Dominant doesn’t modify recessive.
Q 32. Which traits assort independently?
Ans. Traits on different chromosomes.
Q 33. Why blood group phenotype constant?
Ans. Genes don’t change throughout life.
Q 34. Universal blood donor?
Ans. O blood group individuals.
Q 35. ABO incompatibility and Rh protection?
Ans. ABO incompatibility can protect against Rh incompatibility.
Q 36. Genes not obeying independent assortment?
Ans. Genes on the same chromosome.
Q 37. Separating linked genes?
Ans. Crossing over.
Q 38. Multifactorial inheritance?
Ans. Trait influenced by genes and environment.
Q 39. What is MODY?
Ans. Early-onset diabetes with genetic cause.
Q 40. Child’s intelligence vs. parents?
Ans. Child may have higher intelligence.
Q 41. What is Locus?
Ans. Gene’s position on a chromosome.
Q 42. What are Alleles?
Ans. Gene partner variations.
Q 43. Why is Mendel famous?
Ans. Discovered laws of heredity.
Q 44. Mendel’s law of segregation?
Ans. Alleles separate in gametes.
Q 45. What is Punnett square?
Ans. Tool for genetic trait predictions.
Q 46. Mendel’s Law of independent Assortment?
Ans. Alleles for different traits assort independently.
Q 47. What is Linkage group?
Ans. Genes on the same chromosome.
Q 48. What is Over dominance?
Ans. Heterozygote exceeds both homozygotes.
Q 49. Who discovered ABO blood group?
Ans. Karl Landsteiner.
Q 50. Why is Bernstein famous?
Ans. Explained ABO genetic basis.
Q 51. Antigens produced by IA, IB, and i alleles?
Ans. IA – Antigen A, IB – Antigen B, i – No antigen.
Q 52. ABO blood system genotypes and phenotypes?
Ans. IAIA or IAi – Phenotype A, IBIB or IBi – Phenotype B, ii – Phenotype O.
Q 53. Why blood group phenotype doesn’t change?
Ans. Genes active from early embryonic stage.
Q 54. Antibodies in A, B, AB, and O blood?
Ans. A – Anti-B, B – Anti-A, AB – None, O – Anti-A and Anti-B.
Q 55. What is antiserum?
Ans. Serum with antibodies.
Q 56. Why is O called universal donor?
Ans. O has no antibodies, can donate to all.
Q 57. Why are AB individuals universal recipients?
Ans. AB can receive from all blood types.
Q 58. What is Rh blood group?
Ans. Defined by Rh-factor on RBCs.
Q 59. What is Erythroblastosis foetalis?
Ans. Mother’s Rh antibodies harm Rh+ foetus.
Q 60. Why called erythroblastosis foetalis?
Ans. Foetus releases immature erythroblasts.
Q 61. What is Bombay phenotype?
Ans. Like O but not genotypically O.
Q 62. Define pleiotropy?
Ans. One gene affecting multiple traits.
Q 63. W allele effect on cats?
Ans. White fur and deafness.
Q 64. Two aspects of phenotypic expression?
Ans. Qualitative and Quantitative.
Q 65. Environmental factors affecting wheat grain color?
Ans. Light, water, and nutrients.
Q 66. Tallness and shortness in humans?
Ans. Tallness is recessive, more shortness alleles = shorter.
Q 67. What is gene linkage?
Ans. Genes staying together on a chromosome.
Q 68. Define crossing over?
Ans. Exchange of chromosome segments.
Q 69. Human chromosome pairs?
Ans. 22 autosomes and 1 sex pair.
Q 70. What is SRY?
Ans. Male determining gene on Y-chromosome.
Q 71. Grasshopper chromosome numbers?
Ans. Female: 24 (XX), Male: 23 (XO).
Q 72. Homogametic vs. heterogametic?
Ans. Homogametic: Same sex chromosomes. Heterogametic: Different sex chromosomes.
Q 73. What is nullo gamete?
Ans. Gamete with no sex chromosome.
Q 74. XX-XY and WZ-ZZ sex determination in animals?
Ans. Common in birds, butterflies, and moths.
Q 75. XXY in humans and Drosophila?
Ans. XXY human: Sterile male (Klinefelter’s). XXY Drosophila: Fertile female.
Q 76. X:A ratio for females and males?
Ans. X:A > 1.0 for females, X:A < 0.5 for males.
Q 77. Monoecious vs. dioecious plants?
Ans. Monoecious has both sexes, dioecious has separate male and female plants.
Q 78. Why is Correns famous?
Ans. Discovered sex-determining pollen.
Q 79. Why is T.H. Morgan famous?
Ans. Found sex linkage in Drosophila supporting chromosomal theory.
Q 80. Why can a single X-linked recessive allele express in males?
Ans. Y chromosome lacks the gene.
Q 81. What are Sex-linked and X-linked traits?
Ans. Traits on X chromosome, often called sex-linked.
Q 82. Pattern of sex-linked inheritance?
Ans. Passes from maternal grandfather to grandson.
Q 83. What are Y-linked genes?
Ans. Genes unique to the Y chromosome.
Q 84. X- and Y-linked genes?
Ans. Genes on both X and Y chromosomes.
Q 85. Why are X- and Y-linked genes called pseudoautosomal?
Ans. Their inheritance pattern resembles autosomes.
Q 86. X-linked dominant and recessive traits?
Ans. Haemophilia is X-linked recessive, while others are X-linked dominant.
Q 87. What is haemophilia?
Ans. Blood clotting disorder.
Q 88. Types of haemophilia?
Ans. A, B, and C.
Q 89. Percentage of haemophilia types?
Ans. A: 80%, B: 20%, C: <1%.
Q 90. Which haemophilia affects men more?
Ans. Haemophilia A and B.
Q 91. When can a woman have haemophilia A or B?
Ans. If she’s homozygous for the recessive allele.
Q 92. Pattern of inheritance of haemophilia?
Ans. Zigzags from maternal grandfather to grandson.
Q 93. What are opsins?
Ans. Light-absorbing proteins in cone cells.
Q 94. What is dichromat? Types of dichromatic blindness?
Ans. Dichromat sees two primary colors but can’t perceive the third. Types: Protanopia, Deuteranopia, Tritanopia.
Q 95. Differentiate between protanopia, deuteranopia, and tritanopia?
Ans. Protanopia: Red color blindness. Deuteranopia: Green color blindness. Tritanopia: Blue color blindness.
Q 96. What are protanomalous and deuteranomalous?
Ans. Abnormal perception of red and green shades due to altered opsins.
Q 97. What is Monochromacy?
Ans. Can perceive only one color, true color blindness.
Q 98. What is Blue cone monochromacy?
Ans. Red and green cone cells are absent.
Q 99. Why is red-green color blindness more common in men?
Ans. Y chromosome lacks the alternate gene.
Q 100. Pattern of X-linked dominant inheritance?
Ans. More common in females, all daughters of affected father are affected.
Q 101. Pattern of Y-Linked inheritance?
Ans. Passes from father to son only.
Q 102. What are sex-limited traits?
Ans. Traits affecting structures or functions present in only one sex.
Q 103. What are sex-influenced traits?
Ans. Traits common but more prevalent in one sex due to hormonal differences.
Q 104. Risk of son inheriting pattern baldness?
Ans. Son has a high risk.
Q 105. What is Diabetes mellitus?
Ans. Hereditary disease with high blood sugar.
Q 106. Effects of diabetes?
Ans. Kidney failure, blindness, amputation, heart disease.
Q 107. What is Type I diabetes?
Ans. Early-onset, insulin-dependent diabetes.
Q 108. What is Type II diabetes?
Ans. Common in adults, non-insulin dependent diabetes.
