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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Read the Inheritance notesFree MDCAT chapter notes with key terms1,238 questions · page 9 of 62
- A. 50%
- B. 75%
- C. 25%
- D. 0%
Explanation: Woman with A whose father was O must be AO. Cross AO × OO → offspring AO (A) or OO (O) in 50% each.
Correct answer: 50%- A. AB+ve
- B. O-ve
- C. AB-ve
- D. O+ve
Explanation: O-negative RBCs lack A, B and Rh-D antigens, so they are least likely to provoke a hemolytic reaction and are used as universal emergency…
Correct answer: O-ve- A. RBCs
- B. Body fluids
- C. Saliva
- D. All A, B, C
Explanation: ABO antigens are present on RBC membranes and, in secretors, are also detectable in saliva and other body fluids.
Correct answer: All A, B, C- A. Length of stem in pea plant
- B. Blood group of the human being
- C. Shape of seed in pea plant
- D. Colour of flower in pea plant
Explanation: Human ABO blood type is controlled by multiple alleles (IA , IB , i). The listed pea traits are typically Mendelian with two alleles.
Correct answer: Blood group of the human being- A. BB × Bi
- B. BB × BB
- C. Bi × Bi
- D. Both A and C
Explanation: For a child to be OO (ii), both parents must carry i. Iᴮi × Iᴮi(both B phenotype but heterozygous) can produce ii offspring.
Correct answer: Bi × Bi- A. Human
- B. Monkey
- C. Rat
- D. Chimpanzee
Explanation: The Rh factor was named after the Rhesus monkey, in whose serum/antigens the factor was first studied; clinically it refers mainly to the…
Correct answer: Monkey- A. 3 genotypes; 4 phenotypes
- B. 4 genotypes; 3 phenotypes
- C. 4 genotypes; 4 phenotypes
- D. 3 genotypes; 3 phenotypes
Explanation: Gametes IA /IB × I /i produce genotypes IA IA, IA i, IAIB , IB i (4 genotypes).
Correct answer: 4 genotypes; 3 phenotypes- A. Klinefelter's syndrome
- B. Turner's syndrome
- C. Sickle cell anaemia
- D. Down's syndrome
Explanation: Down syndrome is trisomy 21, an autosomal nondisjunction event producing an extra chromosome 21.
Correct answer: Down's syndrome- A. 1840-1850
- B. 1857-1869
- C. 1870-1877
- D. 1856-1863
Explanation: Mendel performed his classic pea hybridization work approximately 1856-1863, later published (1866) as foundational genetics experiments.
Correct answer: 1856-1863- A. Inversion
- B. Duplication
- C. Translocation
- D. Crossing over
Explanation: Translocation transfers chromosome segments between non-homologous chromosomes, relocating genes to different linkage groups.
Correct answer: Translocation- A. 0
- B. 0.5
- C. 0.75
- D. 1
Explanation: Color blindness is X-linked recessive. A homozygous normal mother (XX) cannot pass the mutant X; sons get father's Y and mother's normal X…
Correct answer: 0- A. Somaclonal variation
- B. Polyteny
- C. Aneuploidy
- D. Polyploidy
Explanation: Failure of cytokinesis after nuclear division can produce whole extra sets of chromosomes, yielding polyploid cells - a common plant…
Correct answer: Polyploidy- A. The two genes are linked and present on the same chromosome
- B. Both of the characters are controlled by more than one gene
- C. The two genes are located on two different chromosomes
- D. Chromosomes failed to separate during meiosis
Explanation: Excess parental types vs recombinants indicates linkage; linked genes on the same chromosome are inherited together more often than they…
Correct answer: The two genes are linked and present on the same chromosome- A. Alleles that are recessive to each other
- B. Both alleles independently expressed in the heterozygote
- C. One allele dominant to the other
- D. Alleles tightly linked on the same chromosome
Explanation: Codominance means both alleles are fully expressed in heterozygotes (e.g, IA + IB → AB blood , producing distinct contributions from each…
Correct answer: Both alleles independently expressed in the heterozygote- A. G. Mendel
- B. W. Sutton
- C. T.H. Morgan
- D. T. Boveri
Explanation: T.H. Morgan experimentally demonstrated and popularized the concept of linkage (genes located on the same chromosome) using Drosophila.
Correct answer: T.H. Morgan176. What is the term for the different forms of a gene that occupy the same position on a chromosome?
- A. Alleles
- B. Genotype
- C. Phenotype
- D. Chromosome
Explanation: Alleles are alternative forms of a gene that occupy the same locus on a chromosome. They can result in different traits or characteristics.
Correct answer: Alleles177. Alleles are:
- A. Different molecular forms of a gene
- B. Heterozygotes
- C. Different phenotype
- D. True-breeding homozygotes
Explanation: Alleles are alternate DNA sequence versions at the same locus that produce variant forms of a trait.
Correct answer: Different molecular forms of a gene- A. Fusion of two ova and one sperm
- B. Fusion of two sperms and one ovum
- C. Formation of abnormal sperms in the father
- D. Formation of abnormal ova in the mother.
Explanation: XXX usually results from maternal nondisjunction producing an XX ovum fertilized by an X sperm - a maternal meiotic error.
Correct answer: Formation of abnormal ova in the mother.- A. 25%
- B. 0%
- C. 50%
- D. 75%
Explanation: The woman (mother's mother color-blind is a carrier (XcX). Sons receive X from mom and Y from dad, so each son has 50% chance of…
Correct answer: 50%- A. Metaphase I
- B. Anaphase II
- C. Prophase I
- D. Telophase I
Explanation: Crossing over in Prophase I (pachytene stage) introduces genetic variation by recombining maternal and paternal alleles.
Correct answer: Prophase I