Free Inheritance MCQs with Answers
1,238 Inheritance MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.
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- A. Segregation
- B. Independent assortment
- C. Both a and b
- D. None of these
Explanation: The principle of segregation states that each individual has two alleles for each gene, and these alleles segregate during gamete…
Correct answer: Segregation- A. Chromosomal disorder
- B. Dominant gene disorder
- C. Recessive gene disorder
- D. X-linked recessive gene disorder
Explanation: Hemophilias (e.g, factor VIII/IX defects) are caused by mutations on the X chromosome and show recessive inheritance - classic X-linked…
Correct answer: X-linked recessive gene disorder103. A pleiotropic gene:
- A. Controls a trait only in combination with another gene
- B. Controls multiple traits in an individual
- C. Is expressed only in primitive plants
- D. Is a gene evolved during the Pliocene
Explanation: Pleiotropy occurs when a single gene affects several different phenotypic traits (for example, one mutation causing multiple symptoms).
Correct answer: Controls multiple traits in an individual- A. Translocation
- B. Crossing over
- C. Inversion
- D. Duplication
Explanation: The correct answer is Translocation. This chromosomal abnormality involves the rearrangement of genetic material between non-homologous…
Correct answer: Translocation- A. A, B, AB, and O
- B. O only
- C. A and B only
- D. A, B, and AB only
Explanation: If parents are heterozygous (AO × BO) their gametes can produce IA , IB or i combinations giving A, B, AB or O offspring.
Correct answer: A, B, AB, and O- A. 25%
- B. 100%
- C. No chance
- D. 50%
Explanation: Thalassemia is an autosomal recessive disorder, meaning an affected child must inherit two recessive alleles (tt), one from each parent.
Correct answer: 25%- A. Three 'X' chromosomes
- B. Three copies of chromosome 21
- C. Monosomy
- D. Two 'Y' chromosomes
Explanation: Down's syndrome is caused by the presence of an extra copy of chromosome 21, a condition known as Trisomy 21.
Correct answer: Three copies of chromosome 21- A. Codominance
- B. Dihybrid cross
- C. Monohybrid cross with complete dominance
- D. Monohybrid cross with incomplete dominance.
Explanation: The F2 generation in a Mendelian cross with a 1:2:1 genotypic and phenotypic ratio indicates a monohybrid cross with incomplete dominance.
Correct answer: Monohybrid cross with incomplete dominance.- A. Determine the genotype of a plant at F2
- B. Predict whether two traits are linked
- C. Assess the number of alleles of a gene
- D. Determine whether two species or varieties will breed successfully or not
Explanation: A test cross is performed to determine the genotype of the F2 plant. In a typical test cross, an organism showing dominant phenotype and…
Correct answer: Determine the genotype of a plant at F2- A. Two X chromosomes
- B. Only one Y chromosome
- C. Only one X chromosome
- D. One X and one Y chromosome
Explanation: In human genetics, the presence of two X chromosomes (XX) in a zygote results in the development of a female child.
Correct answer: Two X chromosomes- A. Caused by substitution of valine by glutamic acid in the beta globin chain of haemoglobin.
- B. Caused by a change in a single base pair of DNA.
- C. Characterized by elongated sickle-like RBCs with a nucleus.
- D. An autosomal linked dominant trait.
Explanation: Sickle-cell anemia is a genetic disorder affecting the structure of hemoglobin, leading to sickle-shaped red blood cells.
Correct answer: Caused by a change in a single base pair of DNA.- A. Point mutation
- B. Polygenic inheritance
- C. Codominance
- D. Chromosomal aberration
Explanation: Polygenic inheritance involves multiple genes contributing to the expression of a single trait, such as skin color in humans.
Correct answer: Polygenic inheritance113. Test cross involves:
- A. Crossing between two genotypes with dominant trait
- B. Crossing between two genotypes with recessive trait
- C. Crossing between two F 1 hybrids
- D. Crossing the F 1 hybrid with a double recessive genotype
Explanation: Test cross is performed to determine the genotype of F 2 plant. In a typical test cross an organism showing dominant phenotype and whose…
Correct answer: Crossing the F 1 hybrid with a double recessive genotype- A. Round seeds with yellow cotyledons, and wrinkled seeds with green cotyledons
- B. Round seeds with yellow cotyledons, wrinkled seeds with yellow cotyledons, round seeds with green cotyledons, and wrinkled seeds with green cotyledons
- C. Only round seeds with green cotyledons
- D. Only wrinkled seeds with yellow cotyledons
Explanation: The correct answer is that the F2 generation will have four phenotypes: round seeds with yellow cotyledons, round seeds with green…
Correct answer: Round seeds with yellow cotyledons, wrinkled seeds with yellow cotyledons, round seeds with green cotyledons, and wrinkled seeds with green cotyledons- A. Skin colour in humans
- B. Flower colour in Mirabilis jalapa
- C. Production of male honey bee
- D. Pod shape in garden pea
Explanation: Polygenic inheritance refers to traits controlled by multiple genes, resulting in a broad range of phenotypes.
Correct answer: Skin colour in humans- A. Sex-linked dominant
- B. Sex-linked recessive
- C. Sex-limited recessive
- D. Autosomal dominant
Explanation: The correct answer is Sex-linked recessive. In this inheritance pattern, the disease is carried on the X chromosome.
Correct answer: Sex-linked recessive- A. Superfemales
- B. Triploidy
- C. Turner's syndrome
- D. Down's syndrome
Explanation: The correct answer is Down's syndrome, which results from trisomy 21, where an individual has an additional copy of chromosome 21…
Correct answer: Down's syndrome- A. A greater proportion of girls die in infancy
- B. This disease is due to an X-linked recessive mutation
- C. This disease is due to a Y-linked recessive mutation
- D. This disease is due to an X-linked dominant mutation
Explanation: Hemophilia is more commonly seen in males than females due to its inheritance pattern as an X-linked recessive disorder.
Correct answer: This disease is due to an X-linked recessive mutation- A. May be color blind or may have normal vision
- B. Must be color blind
- C. Must have normal color vision
- D. Will be partially color blind since he is heterozygous for the color blind mutant allele
Explanation: The correct answer is that the boy may be color blind or may have normal vision.
Correct answer: May be color blind or may have normal vision- A. Repulsion
- B. Recombination
- C. Linkage
- D. Crossing over
Explanation: The correct answer is linkage. Genetic linkage occurs when genes are located close together on the same chromosome, leading to their…
Correct answer: Linkage