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 2 of 62
- A. has many easily distinguished contrasting characters
- B. has an unusually long life cycle
- C. cannot self pollinate
- D. blends its characters in every generation
Explanation: Peas offer clear alternatives such as tall versus dwarf, self pollinate to give pure lines and produce many offspring quickly.
Correct answer: has many easily distinguished contrasting characters- A. genotype
- B. phenotype
- C. karyotype
- D. pedigree
Explanation: Phenotype is what can be seen or measured, while genotype is the allele combination behind it.
Correct answer: phenotype- A. homozygous dominant
- B. homozygous recessive
- C. heterozygous
- D. hemizygous
Explanation: Heterozygous means two unlike alleles at a locus, and such individuals are often called carriers when the recessive allele is hidden.
Correct answer: heterozygous- A. dihybrid cross
- B. test cross
- C. back cross
- D. monohybrid cross
Explanation: Mono means one character, such as height, and the classic F2 ratio of 3 to 1 comes from it.
Correct answer: monohybrid cross- A. 3/4
- B. 1/4
- C. 1/2
- D. All of them
Explanation: The cross gives TT, Tt, Tt and tt, so three of four genotypes contain a dominant allele and appear tall.
Correct answer: 3/4- A. dominant alleles always mask recessive ones
- B. the alleles of one pair separate into gametes independently of the alleles of other pairs
- C. genes on the same chromosome always recombine
- D. opposite traits blend together in the F1 generation
Explanation: During meiosis each pair of homologues lines up independently, so the allele a gamete gets for one character does not influence the other…
Correct answer: the alleles of one pair separate into gametes independently of the alleles of other pairs- A. 2
- B. 3
- C. 4
- D. 8
Explanation: Each gene pair contributes two choices, so 2 times 2 gives four gamete types: AB, Ab, aB and ab.
Correct answer: 4- A. complete dominance
- B. linkage
- C. crossing over
- D. codominance
Explanation: Both alleles express themselves side by side in the heterozygote, producing distinct red and white hairs rather than a blended colour.
Correct answer: codominance- A. only when present in the homozygous condition
- B. in both the heterozygous and homozygous conditions
- C. only in males
- D. only in the F1 generation
Explanation: In a heterozygote the dominant allele masks the recessive one, so the recessive trait appears only when both alleles are recessive.
Correct answer: only when present in the homozygous condition30. However many alleles of a gene exist in a population, a diploid human individual can carry at most
- A. one
- B. two
- C. three
- D. four
Explanation: Each person inherits one allele from each parent, so only two can be present, one on each homologue.
Correct answer: two- A. genome
- B. gene pool
- C. linkage group
- D. gene family
Explanation: A linkage group is everything that travels together on one chromosome during meiosis unless crossing over intervenes.
Correct answer: linkage group- A. two sister chromatids of the same chromosome
- B. any two chromatids chosen at random
- C. the two strands of one DNA molecule
- D. non sister chromatids of homologous chromosomes
Explanation: Exchange between non sister chromatids of homologues shuffles maternal and paternal alleles, creating recombinant gametes.
Correct answer: non sister chromatids of homologous chromosomes33. The visible cross shaped points at which homologous chromatids have exchanged segments are called
- A. chiasmata
- B. centromeres
- C. kinetochores
- D. telomeres
Explanation: Chiasmata can be seen under the microscope in prophase one and mark where crossing over has occurred.
Correct answer: chiasmata- A. micrometres
- B. map units, or centiMorgans
- C. nanometres
- D. base pairs per gamete
Explanation: One map unit, one centiMorgan, equals one per cent recombination between two genes.
Correct answer: map units, or centiMorgans- A. no recombination at all
- B. complete linkage in every meiosis
- C. a higher recombination frequency than genes lying close together
- D. fewer crossing overs than genes lying close together
Explanation: The longer the stretch of chromosome between two genes, the more likely a crossover will fall between them, so distant genes recombine…
Correct answer: a higher recombination frequency than genes lying close together36. The chromosomal basis of linkage was worked out mainly through breeding experiments on Drosophila by
- A. Gregor Mendel
- B. Jean Baptiste Lamarck
- C. James Watson
- D. Thomas Hunt Morgan
Explanation: Morgan showed that certain Drosophila characters were inherited together and tied to the sex chromosomes, founding chromosome mapping.
Correct answer: Thomas Hunt Morgan- A. parental combinations of characters
- B. equal numbers of all four combinations
- C. recombinant combinations only
- D. non viable zygotes
Explanation: Because linked genes usually travel together, parental combinations outnumber recombinants, and the size of the minority reveals how far…
Correct answer: parental combinations of characters- A. 46
- B. 23
- C. 22
- D. 44
Explanation: One linkage group corresponds to each kind of chromosome in the haploid set, so humans have 23.
Correct answer: 23- A. 25 per cent
- B. 40 per cent
- C. 50 per cent
- D. 100 per cent
Explanation: Once genes are far enough apart that a crossover happens between them in every meiosis, half the gametes are recombinant, the same figure…
Correct answer: 50 per cent- A. autosomal
- B. Y linked
- C. mitochondrial
- D. X linked
Explanation: The X chromosome carries many genes unrelated to sex, and their inheritance is distinctive because males have only one copy.
Correct answer: X linked