Genetics MCQs: Practice Genetics with 100 MCQs and answers covering Mendelian inheritance, DNA, RNA, chromosomes, mutations, and genetic disorders—ideal for students and competitive exams.
Genetics is a vital branch of biology that explains how traits are passed from parents to offspring through genes and chromosomes. A clear understanding of genetic concepts such as Mendelian inheritance, DNA and RNA structure, mutations, and genetic disorders is essential for students and competitive exam aspirants. This article offers 100 well-structured Genetics MCQs with answers, designed to strengthen fundamental concepts, support quick revision, and improve exam performance. These genetics multiple choice questions are ideal for school exams, entrance tests, and general biology preparation.
Here are 100 MCQs on Genetics with four options and correct answers, written clearly in English and suitable for exams, students, and general knowledge.
1. Genetics is the study of:
A. Cells
B. Tissues
C. Heredity and variation
D. Evolution
Answer: C
2. Who is known as the Father of Genetics?
A. Charles Darwin
B. Gregor Mendel
C. Robert Hooke
D. Watson
Answer: B
3. Mendel conducted his experiments on:
A. Maize
B. Pea plant
C. Wheat
D. Rice
Answer: B
4. The basic unit of heredity is:
A. Cell
B. Chromosome
C. Gene
D. DNA
Answer: C
5. Genes are located on:
A. Ribosomes
B. Chromosomes
C. Mitochondria
D. Cytoplasm
Answer: B
6. Which term refers to observable characteristics?
A. Genotype
B. Phenotype
C. Allele
D. Chromosome
Answer: B
7. Alternative forms of a gene are called:
A. Traits
B. Chromatids
C. Alleles
D. Loci
Answer: C
8. A dominant allele is one that:
A. Always disappears
B. Expresses itself in heterozygous condition
C. Is always recessive
D. Is non-functional
Answer: B
9. A recessive allele expresses itself when:
A. Dominant allele is present
B. In heterozygous condition
C. In homozygous condition
D. In all conditions
Answer: C
10. The genetic makeup of an organism is called:
A. Phenotype
B. Genotype
C. Trait
D. Allele
Answer: B
11. Which law states that alleles separate during gamete formation?
A. Law of Dominance
B. Law of Independent Assortment
C. Law of Segregation
D. Law of Mutation
Answer: C
12. Which law explains the inheritance of two traits?
A. Law of Segregation
B. Law of Dominance
C. Law of Independent Assortment
D. Law of Variation
Answer: C
13. Homozygous means:
A. Two different alleles
B. No alleles
C. Two identical alleles
D. Only dominant alleles
Answer: C
14. Heterozygous means:
A. Same alleles
B. Different alleles
C. No alleles
D. Only recessive alleles
Answer: B
15. A Punnett square is used to:
A. Study cells
B. Predict inheritance
C. Observe chromosomes
D. Identify mutations
Answer: B
16. Which molecule carries genetic information?
A. RNA
B. Protein
C. Lipid
D. DNA
Answer: D
17. DNA stands for:
A. Deoxyribo Nucleic Acid
B. Deoxyribonucleic Acid
C. Deoxyribose Acid
D. Double Nucleic Acid
Answer: B
18. RNA differs from DNA because it:
A. Has thymine
B. Is double-stranded
C. Contains ribose sugar
D. Is found only in nucleus
Answer: C
19. Which nitrogen base is present in RNA instead of thymine?
A. Cytosine
B. Adenine
C. Uracil
D. Guanine
Answer: C
20. DNA is found mainly in:
A. Cytoplasm
B. Ribosome
C. Nucleus
D. Vacuole
Answer: C
21. The shape of DNA is:
A. Single helix
B. Circular
C. Double helix
D. Linear
Answer: C
22. Who discovered the double helix structure of DNA?
A. Mendel
B. Watson and Crick
C. Darwin
D. Franklin
Answer: B
23. Chromosomes are made up of:
A. DNA and proteins
B. RNA and proteins
C. Lipids
D. Carbohydrates
Answer: A
24. Humans have how many chromosomes?
A. 44
B. 23
C. 46
D. 48
Answer: C
25. Sex chromosomes in humans are:
A. XX only
B. XY only
C. XX or XY
D. YY
Answer: C
26. Autosomes are:
A. Sex chromosomes
B. Body chromosomes
C. Mutated chromosomes
D. Extra chromosomes
Answer: B
27. A mutation is:
A. Normal growth
B. Change in DNA sequence
C. Cell division
D. Protein synthesis
Answer: B
28. Which mutation causes sickle cell anemia?
A. Chromosomal mutation
B. Gene mutation
C. Lethal mutation
D. Silent mutation
Answer: B
29. Down syndrome is caused by:
A. Gene mutation
B. Trisomy 21
C. Monosomy
D. Deletion
Answer: B
30. Crossing over occurs during:
A. Mitosis
B. Meiosis I
C. Meiosis II
D. Fertilization
Answer: B
31. Which process produces gametes?
A. Mitosis
B. Meiosis
C. Binary fission
D. Budding
Answer: B
32. Mitosis results in:
A. Four cells
B. Two identical cells
C. Gametes
D. Variation
Answer: B
33. Meiosis produces:
A. Somatic cells
B. Diploid cells
C. Haploid cells
D. Identical cells
Answer: C
34. Haploid number in humans is:
A. 46
B. 44
C. 23
D. 22
Answer: C
35. Which cell division creates variation?
A. Mitosis
B. Binary fission
C. Meiosis
D. Fragmentation
Answer: C
36. Carrier of a recessive disease is:
A. Homozygous dominant
B. Homozygous recessive
C. Heterozygous
D. Mutant
Answer: C
37. Color blindness is an example of:
A. Autosomal trait
B. X-linked trait
C. Y-linked trait
D. Dominant trait
Answer: B
38. Hemophilia is inherited as:
A. Autosomal dominant
B. Autosomal recessive
C. X-linked recessive
D. Y-linked
Answer: C
39. Which trait appears only when both alleles are recessive?
A. Dominant
B. Codominant
C. Recessive
D. Incomplete
Answer: C
40. ABO blood group system was discovered by:
A. Mendel
B. Landsteiner
C. Watson
D. Darwin
Answer: B
41. Which blood group is universal donor?
A. A
B. B
C. AB
D. O
Answer: D
42. Which blood group is universal recipient?
A. A
B. B
C. O
D. AB
Answer: D
43. Codominance is seen in:
A. Eye color
B. ABO blood group
C. Skin color
D. Height
Answer: B
44. In incomplete dominance:
A. One allele dominates
B. No allele expresses
C. Both alleles express fully
D. Intermediate phenotype appears
Answer: D
45. Polygenic traits are controlled by:
A. One gene
B. Two genes
C. Multiple genes
D. No genes
Answer: C
46. Skin color is an example of:
A. Monogenic trait
B. Polygenic trait
C. Recessive trait
D. Sex-linked trait
Answer: B
47. Which molecule helps in protein synthesis?
A. DNA
B. mRNA
C. Lipid
D. Glucose
Answer: B
48. Transcription occurs in:
A. Cytoplasm
B. Ribosome
C. Nucleus
D. Golgi body
Answer: C
49. Translation occurs in:
A. Nucleus
B. Ribosome
C. Mitochondria
D. Lysosome
Answer: B
50. Codon is made up of:
A. One base
B. Two bases
C. Three bases
D. Four bases
Answer: C
51. Anticodon is found on:
A. mRNA
B. tRNA
C. rRNA
D. DNA
Answer: B
52. Which base pairs with adenine in DNA?
A. Guanine
B. Cytosine
C. Thymine
D. Uracil
Answer: C
53. Which base pairs with guanine?
A. Adenine
B. Thymine
C. Uracil
D. Cytosine
Answer: D
54. Genetic engineering deals with:
A. Cells only
B. DNA manipulation
C. Protein digestion
D. Cell division
Answer: B
55. Cloning produces:
A. Variations
B. Mutations
C. Identical copies
D. Hybrids
Answer: C
56. Recombinant DNA technology involves:
A. Cell division
B. Gene transfer
C. Mutation
D. Fertilization
Answer: B
57. Which organism is commonly used in genetic studies?
A. Frog
B. Mouse
C. Fruit fly
D. Fish
Answer: C
58. DNA replication is:
A. Conservative
B. Dispersive
C. Semi-conservative
D. Random
Answer: C
59. The enzyme that unwinds DNA is:
A. Ligase
B. Polymerase
C. Helicase
D. Primase
Answer: C
60. DNA polymerase helps in:
A. Cutting DNA
B. Joining fragments
C. Synthesizing DNA
D. Unwinding DNA
Answer: C
61. Okazaki fragments are found in:
A. Leading strand
B. Lagging strand
C. RNA
D. Chromosomes
Answer: B
62. Which enzyme joins Okazaki fragments?
A. Helicase
B. Ligase
C. Polymerase
D. Primase
Answer: B
63. Genetic variation is important for:
A. Extinction
B. Adaptation
C. Disease
D. Cloning
Answer: B
64. Which disorder is sex-linked?
A. Diabetes
B. Sickle cell anemia
C. Color blindness
D. Down syndrome
Answer: C
65. The site of a gene on chromosome is called:
A. Allele
B. Locus
C. Trait
D. Codon
Answer: B
66. Multiple alleles are found in:
A. Pea plants
B. ABO blood group
C. Eye color
D. Height
Answer: B
67. Which genetic disorder affects clotting?
A. Thalassemia
B. Hemophilia
C. Leukemia
D. Asthma
Answer: B
68. Genetic material in viruses is:
A. Only DNA
B. Only RNA
C. DNA or RNA
D. Protein
Answer: C
69. The process of forming RNA from DNA is:
A. Translation
B. Transcription
C. Replication
D. Mutation
Answer: B
70. Which scientist proposed the concept of gene?
A. Mendel
B. Morgan
C. Watson
D. Crick
Answer: B
71. Linkage means:
A. Genes on different chromosomes
B. Genes on same chromosome
C. Independent genes
D. Mutated genes
Answer: B
72. Sex determination in humans depends on:
A. Mother
B. Father
C. Both parents equally
D. Environment
Answer: B
73. A karyotype shows:
A. DNA structure
B. Chromosome number and shape
C. Gene sequence
D. Protein structure
Answer: B
74. Extra chromosome leads to:
A. Mutation
B. Polyploidy
C. Aneuploidy
D. Deletion
Answer: C
75. Genetic counseling helps in:
A. Treatment
B. Diagnosis
C. Predicting genetic disorders
D. Surgery
Answer: C
76. Which base is absent in DNA?
A. Adenine
B. Thymine
C. Cytosine
D. Uracil
Answer: D
77. Which technique is used to amplify DNA?
A. Gel electrophoresis
B. PCR
C. Cloning
D. Hybridization
Answer: B
78. Which scientist discovered inheritance patterns?
A. Darwin
B. Mendel
C. Watson
D. Morgan
Answer: B
79. Genetic code is:
A. Universal
B. Variable
C. Random
D. Species-specific
Answer: A
80. Stop codons do not code for:
A. DNA
B. RNA
C. Amino acids
D. Proteins
Answer: C
81. Which disease is inherited?
A. Malaria
B. Tuberculosis
C. Sickle cell anemia
D. Cholera
Answer: C
82. Which process creates hybrids?
A. Self-pollination
B. Cross-breeding
C. Cloning
D. Mutation
Answer: B
83. Mendel’s experiments showed inheritance is:
A. Blending
B. Random
C. Particulate
D. Continuous
Answer: C
84. Chromatids are joined at:
A. Telomere
B. Centromere
C. Locus
D. Allele
Answer: B
85. Which term describes visible traits?
A. Genotype
B. Phenotype
C. Allele
D. Locus
Answer: B
86. Which process increases genetic diversity?
A. Mitosis
B. Binary fission
C. Meiosis
D. Cloning
Answer: C
87. A gene mutation affects:
A. Protein structure
B. Cell wall
C. Cytoplasm
D. Ribosome
Answer: A
88. Which disorder is caused by lack of hemoglobin?
A. Hemophilia
B. Thalassemia
C. Leukemia
D. Diabetes
Answer: B
89. What is heredity?
A. Growth of organism
B. Transfer of traits
C. Cell division
D. Adaptation
Answer: B
90. Genetic information flows from:
A. RNA → DNA → Protein
B. DNA → RNA → Protein
C. Protein → DNA → RNA
D. RNA → Protein → DNA
Answer: B
91. Which type of RNA carries amino acids?
A. mRNA
B. rRNA
C. tRNA
D. snRNA
Answer: C
92. Which trait skips generations?
A. Dominant
B. Recessive
C. Codominant
D. Polygenic
Answer: B
93. Which mutation does not change amino acid?
A. Silent
B. Missense
C. Nonsense
D. Frameshift
Answer: A
94. Which term refers to many genes controlling one trait?
A. Codominance
B. Polygenic inheritance
C. Linkage
D. Mutation
Answer: B
95. Human eye color is an example of:
A. Single gene trait
B. Polygenic trait
C. Sex-linked trait
D. Lethal trait
Answer: B
96. DNA fingerprinting is used for:
A. Cell division
B. Protein synthesis
C. Identification
D. Mutation
Answer: C
97. Which enzyme synthesizes RNA?
A. DNA polymerase
B. RNA polymerase
C. Ligase
D. Helicase
Answer: B
98. The term “allele” was coined by:
A. Mendel
B. Bateson
C. Morgan
D. Darwin
Answer: B
99. Which structure holds sister chromatids together?
A. Telomere
B. Locus
C. Centromere
D. Allele
Answer: C
100. Genetics helps explain:
A. Weather
B. Heredity and variation
C. Gravity
D. Motion
Answer: B
