Genetics is one of the most fascinating and vital chapters in Bihar Board Class 12th Biology Genetics. It explains how traits are inherited from parents to offspring and the biological principles behind heredity and variation. Understanding this chapter helps students build a strong foundation for exams like Bihar Board, NEET, and competitive biology tests.
Below are 75 important objective questions from the Class 12 Biology Genetics chapter with options and one-word answers, followed by FAQs for your quick revision and better understanding.
Bihar Board Class 12 Biology Genetics Objective Questions with Answers | 75 MCQs with One Word Answers
1. Who is known as the Father of Genetics?
A. Darwin
B. Mendel
C. Morgan
D. Watson
Answer: Mendel
2. What is the study of heredity and variation called?
A. Cytology
B. Ecology
C. Genetics
D. Evolution
Answer: Genetics
3. The hybrid of F1 generation is called?
A. Test cross
B. Monohybrid
C. Dihybrid
D. Back cross
Answer: F1 hybrid
4. The physical appearance of an organism is known as?
A. Genotype
B. Phenotype
C. Allele
D. Character
Answer: Phenotype
5. The genetic makeup of an organism is called?
A. Character
B. Phenotype
C. Genotype
D. Trait
Answer: Genotype
6. Mendel conducted his experiments on which plant?
A. Maize
B. Wheat
C. Pea plant
D. Mustard
Answer: Pea plant
7. How many pairs of contrasting traits did Mendel study?
A. 5
B. 6
C. 7
D. 8
Answer: 7
8. Tallness and dwarfness in pea plants are examples of?
A. Characters
B. Traits
C. Alleles
D. Genes
Answer: Traits
9. The law of segregation was proposed by?
A. Darwin
B. Mendel
C. Lamarck
D. De Vries
Answer: Mendel
10. Which law states that alleles of different genes assort independently?
A. Law of dominance
B. Law of segregation
C. Law of independent assortment
D. Law of inheritance
Answer: Law of independent assortment
11. The term “gene” was coined by?
A. Mendel
B. Johannsen
C. Morgan
D. Darwin
Answer: Johannsen
12. What is the alternative form of a gene called?
A. Chromosome
B. Allele
C. Trait
D. Locus
Answer: Allele
13. Who discovered linkage?
A. Mendel
B. Morgan
C. Watson
D. Crick
Answer: Morgan
14. Crossing over occurs during which stage of meiosis?
A. Prophase I
B. Metaphase I
C. Anaphase I
D. Telophase I
Answer: Prophase I
15. The exchange of genetic material between homologous chromosomes is called?
A. Mutation
B. Crossing over
C. Duplication
D. Replication
Answer: Crossing over
16. The unit of inheritance is known as?
A. Chromosome
B. DNA
C. Gene
D. Protein
Answer: Gene
17. The chromosomal theory of inheritance was proposed by?
A. Sutton and Boveri
B. Mendel
C. Morgan and Bridges
D. Watson and Crick
Answer: Sutton and Boveri
18. Which blood group is known as a universal donor?
A. A
B. B
C. AB
D. O
Answer: O
19. Which blood group is called a universal recipient?
A. A
B. AB
C. B
D. O
Answer: AB
20. The sex of a child is determined by which chromosome?
A. X chromosome
B. Y chromosome
C. Both X and Y
D. Autosomes
Answer: Y chromosome
21. How many chromosomes are found in human cells?
A. 23
B. 44
C. 46
D. 48
Answer: 46
22. Who gave the concept of mutation theory?
A. Mendel
B. De Vries
C. Morgan
D. Darwin
Answer: De Vries
23. The XX chromosome combination represents?
A. Male
B. Female
C. Both
D. None
Answer: Female
24. The XY chromosome combination represents?
A. Male
B. Female
C. Child
D. None
Answer: Male
25. The term heredity means?
A. Study of genes
B. Transmission of characters
C. Variation among species
D. Study of evolution
Answer: Transmission of characters
26. The smallest unit of inheritance is?
A. Chromosome
B. Gene
C. DNA
D. RNA
Answer: Gene
27. The location of a gene on a chromosome is called?
A. Locus
B. Allele
C. Trait
D. Character
Answer: Locus
28. The F2 generation shows what type of ratio in a monohybrid cross?
A. 1:1
B. 3:1
C. 9:3:3:1
D. 1:2:1
Answer: 3:1
29. What is test cross used to determine?
A. Genotype
B. Phenotype
C. Character
D. Mutation
Answer: Genotype
30. A cross between two individuals differing in two traits is called?
A. Monohybrid cross
B. Dihybrid cross
C. Test cross
D. Back cross
Answer: Dihybrid cross
31. The phenomenon of blending of characters is called?
A. Dominance
B. Incomplete dominance
C. Co-dominance
D. Recessiveness
Answer: Incomplete dominance
32. Example of co-dominance in humans is?
A. Eye color
B. Hair type
C. Blood group
D. Skin color
Answer: Blood group
33. Genes are made up of?
A. Protein
B. DNA
C. RNA
D. Lipid
Answer: DNA
34. Sex-linked traits are carried by which chromosome?
A. X chromosome
B. Y chromosome
C. Autosomes
D. Both X and Y
Answer: X chromosome
35. The disorder caused by absence of one X chromosome is?
A. Down syndrome
B. Klinefelter syndrome
C. Turner syndrome
D. Hemophilia
Answer: Turner syndrome
36. Down’s syndrome is caused by?
A. Trisomy of chromosome 21
B. Monosomy of X
C. Trisomy of X
D. None
Answer: Trisomy of chromosome 21
37. The carrier of genetic information is?
A. Protein
B. DNA
C. Lipid
D. Enzyme
Answer: DNA
38. Mutation is a change in?
A. DNA sequence
B. Phenotype
C. Protein structure
D. Cell wall
Answer: DNA sequence
39. The process of formation of gametes is called?
A. Meiosis
B. Mitosis
C. Cytokinesis
D. Fusion
Answer: Meiosis
40. The scientist who rediscovered Mendel’s work was?
A. Hugo de Vries
B. Correns
C. Tschermak
D. All of these
Answer: All of these
41. The process of transfer of genetic information from DNA to mRNA is called?
A. Translation
B. Transcription
C. Replication
D. Mutation
Answer: Transcription
42. The process of protein synthesis is known as?
A. Transcription
B. Translation
C. Mutation
D. Duplication
Answer: Translation
43. Who proposed the operon model?
A. Jacob and Monod
B. Watson and Crick
C. Mendel
D. Morgan
Answer: Jacob and Monod
44. The hereditary material in most organisms is?
A. RNA
B. Protein
C. DNA
D. Carbohydrate
Answer: DNA
45. In humans, the sex is determined by?
A. Father
B. Mother
C. Both
D. Environment
Answer: Father
46. Which of the following is a sex-linked disease?
A. Diabetes
B. Hemophilia
C. Cancer
D. Asthma
Answer: Hemophilia
47. The type of inheritance where both alleles are expressed equally is called?
A. Dominance
B. Recessiveness
C. Co-dominance
D. Incomplete dominance
Answer: Co-dominance
48. The structural and functional unit of heredity is?
A. DNA
B. Gene
C. Chromosome
D. Nucleus
Answer: Gene
49. The number of autosomes in humans is?
A. 44
B. 46
C. 2
D. 22
Answer: 44
50. Genes are located on which structure?
A. Ribosome
B. Nucleus
C. Chromosome
D. Cytoplasm
Answer: Chromosome
51. The ratio obtained in a dihybrid cross is?
A. 3:1
B. 1:2:1
C. 9:3:3:1
D. 1:1
Answer: 9:3:3:1
52. The scientist who worked on fruit flies for genetic studies was?
A. Mendel
B. Morgan
C. De Vries
D. Darwin
Answer: Morgan
53. The chromosomal abnormality in Klinefelter’s syndrome is?
A. 44 + XXY
B. 45 + XO
C. 46 + XY
D. 47 + XXX
Answer: 44 + XXY
54. The chromosomal abnormality in Turner’s syndrome is?
A. 44 + XX
B. 45 + XO
C. 46 + XY
D. 47 + XXY
Answer: 45 + XO
55. The functional segment of DNA is known as?
A. Gene
B. Codon
C. Base pair
D. Locus
Answer: Gene
56. The basic structural unit of DNA is?
A. Gene
B. Nucleotide
C. Codon
D. Base
Answer: Nucleotide
57. The shape of DNA molecule is?
A. Linear
B. Circular
C. Double helix
D. Spiral rod
Answer: Double helix
58. DNA was discovered by?
A. Mendel
B. Miescher
C. Watson
D. Crick
Answer: Miescher
59. The full form of DNA is?
A. Deoxyribonucleic Acid
B. Deoxyriboprotein Acid
C. Dextrose Nucleic Acid
D. None
Answer: Deoxyribonucleic Acid
60. The full form of RNA is?
A. Ribonucleic Acid
B. Riboprotein Acid
C. Ribonitric Acid
D. None
Answer: Ribonucleic Acid
61. How many types of RNA are found in cells?
A. 1
B. 2
C. 3
D. 4
Answer: 3
62. The process of formation of identical DNA is known as?
A. Replication
B. Translation
C. Mutation
D. Duplication
Answer: Replication
63. Which base is not present in RNA?
A. Adenine
B. Cytosine
C. Thymine
D. Uracil
Answer: Thymine
64. Which base is found only in RNA?
A. Thymine
B. Uracil
C. Adenine
D. Cytosine
Answer: Uracil
65. Which disease is caused due to absence of clotting factor VIII?
A. Thalassemia
B. Hemophilia
C. Anemia
D. Sickle cell
Answer: Hemophilia
66. Sickle cell anemia is caused by?
A. Mutation in gene
B. Virus
C. Bacteria
D. Chromosome loss
Answer: Mutation in gene
67. Which scientist gave the concept of gene linkage and crossing over?
A. Morgan
B. Mendel
C. Watson
D. De Vries
Answer: Morgan
68. The number of base pairs in human DNA is approximately?
A. 3 million
B. 3 billion
C. 1 billion
D. 2 billion
Answer: 3 billion
69. The sugar present in DNA is?
A. Ribose
B. Glucose
C. Deoxyribose
D. Fructose
Answer: Deoxyribose
70. The sugar present in RNA is?
A. Ribose
B. Deoxyribose
C. Glucose
D. Sucrose
Answer: Ribose
71. The scientist who proposed the double helix model of DNA?
A. Watson and Crick
B. Morgan and Sturtevant
C. Mendel and Darwin
D. Sutton and Boveri
Answer: Watson and Crick
72. How many nitrogen bases are found in DNA?
A. Two
B. Three
C. Four
D. Five
Answer: Four
73. In DNA, adenine always pairs with?
A. Cytosine
B. Thymine
C. Guanine
D. Uracil
Answer: Thymine
74. In DNA, cytosine pairs with?
A. Guanine
B. Adenine
C. Thymine
D. Uracil
Answer: Guanine
75. The process responsible for variation in organisms is?
A. Mutation
B. Segregation
C. Dominance
D. Assortment
Answer: Mutation
Conclusion-Bihar Board Class 12 Biology Genetics Objective Questions with Answers
The Genetics chapter of Class 12 Biology is highly important for the Bihar Board Examination. These 75 objective questions with one-word answers will help students strengthen their understanding of heredity, genetic principles, and molecular mechanisms. Revise them regularly to boost your preparation and secure top marks in exams.
FAQs-Bihar Board Class 12 Biology Genetics Objective Questions with Answers
1. How many marks are given for objective questions in Bihar Board Class 12 Biology?
Usually, 35 marks are allotted for objective questions in the Bihar Board Biology paper.
2. Which is the most important topic in the Genetics chapter?
The Laws of Inheritance, Mendelian experiments, and Chromosomal theory of inheritance are the most important topics.
3. Who is called the Father of Modern Genetics?
Gregor Johann Mendel is known as the Father of Modern Genetics.
4. What is the difference between genotype and phenotype?
Genotype refers to the genetic constitution, while phenotype means the observable characteristics of an organism.
5. Is the Genetics chapter important for NEET and competitive exams?
Yes, Genetics is a high-weightage chapter in both Bihar Board and NEET Biology exams