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. Moderate increase in Y complement
- B. Large increase in Y complement
- C. Reduction in X complement
- D. Increase in X complement
Explanation: Mental retardation in men associated with sex chromosomal abnormalities is often the result of an increase in X complement, leading to…
Correct answer: Increase in X complement- A. 50%
- B. 75%
- C. 100%
- D. 25%
Explanation: The probability that the second child of a couple with normal skin pigmentation will also be an albino (aa) is 25%.
Correct answer: 25%- A. 3 : 1
- B. 7 : 1
- C. 1 : 1
- D. 2 : 1
Explanation: The female Drosophila possesses two homomorphic sex chromosomes (XX) and the male Drosophila contains two heteromorphic sex chromosomes…
Correct answer: 1 : 1- A. Sex-chromosome
- B. Cell organelles
- C. Autosome
- D. Nucleolus
Explanation: Sex chromosomes are those chromosomes whose presence, absence or particular form determines the sex of the individual in unisexual or…
Correct answer: Sex-chromosome- A. Collaborative genes
- B. Complementary genes
- C. Duplicate genes
- D. Supplementary genes
Explanation: Complementary genes are those nonallelic genes that independently show a similar effect but produce a new trait when present together in…
Correct answer: Complementary genes- A. Turner's syndrome
- B. Klinefelter's syndrome
- C. Down's syndrome
- D. Haemophilia
Explanation: In humans, sex chromosomal abnormality is due to gene carried on X-chromosome. Increase in X-complement leads to Klinefelter's syndrome.
Correct answer: Klinefelter's syndrome- A. All sons colour blind
- B. Some sons normal and some colour blind
- C. All colour blind
- D. All daughters normal
Explanation: In question where the genotype of the other parent is not mentioned then that should be considered as normal.
Correct answer: Some sons normal and some colour blind- A. Multiple alleles
- B. The parts of same gene
- C. Pseudoalleles
- D. Different genes
Explanation: E.B. Lewis in 1951 reported from a cross of apricot eyed and white eyed flies in Drosophila, he obtained F 1 having intermediate eye…
Correct answer: Pseudoalleles- A. Epistasis
- B. Dominance
- C. Suppression
- D. Inactivation
Explanation: Epistasis is the phenomenon of suppression of phenotypic expression of gene by a non-allelic gene which shows its own effect.
Correct answer: Epistasis- A. Down's syndrome
- B. Sickle cell anaemia
- C. Thalassaemia
- D. Night blindness
Explanation: Point mutation involves only the replacement of one nucleotide with another. One type of point mutation is missense mutation.
Correct answer: Sickle cell anaemia- A. Autosomal genes
- B. Holandric genes
- C. Completely sex-linked genes
- D. Mutant genes
Explanation: Despite differences in morphology, the XY chromosomes are homologous and synapse during zygotene.
Correct answer: Holandric genes- A. A and B
- B. A and A
- C. AB and O
- D. B and O
Explanation: O blood group of a child cannot be obtained from the parents having blood group O × AB.
Correct answer: AB and O- A. The Y-chromosome of males have the genes for distinguishing colours.
- B. Genes for characters are located on the sex chromosomes.
- C. The trait is dominant in males and recessive in females.
- D. None of the above.
Explanation: Colour blindness is produced by a recessive gene which lies on X chromosome.
Correct answer: Genes for characters are located on the sex chromosomes.- A. Zero
- B. 1/2
- C. 1/4
- D. 1/8
Explanation: Genotype of Mr. Kapoor will be Bbd hence one fourth of the sperms will have Bd.
Correct answer: 1/4- A. X-chromosome of father
- B. Y-chromosome of father
- C. one X-chromosome of mother
- D. both the X-chromosomes of mother.
Explanation: The gene is located on one X-chromosomes of mother. Cross between a hemophilic carrier female X h X and normal male would yield 50% of…
Correct answer: one X-chromosome of mother- A. Cis type
- B. Trans type
- C. Complete
- D. Absent/incomplete
Explanation: Two dominant non-allelic genes are 50 map units apart. The linkage is absent/incomplete.
Correct answer: Absent/incomplete- A. Skin colour
- B. Phenylketonuria
- C. Colour blindness
- D. Sickle cell anaemia.
Explanation: Polygenic (or Quantitative) inheritance is that type of inheritance in which the complete expression of a trait is controlled by two or…
Correct answer: Skin colour- A. Independent assortment principle may be wrong
- B. Mendel might not have studied all the combinations
- C. It is impossible
- D. Later studies may be wrong.
Explanation: Law of independent assortment states that when two individuals differ from each other in two or more pairs of factors, the inheritance of…
Correct answer: Mendel might not have studied all the combinations- A. By ovum
- B. At time of fertilization
- C. 40 days after fertilization
- D. Seventh to eight week when genitals differentiate in foetus
Explanation: Sex is determined in human beings at the time of fertilization. Sex of the baby depends upon the sperm which fertilizes the ovum.
Correct answer: At time of fertilization- A. I O I O
- B. I B I B
- C. I A I B
- D. I B I O
Explanation: The genotype of the child would be IOIO (recessive). Hence, the genotype of the father can only be IBIO.
Correct answer: I B I O