• 57 questions

AP Bio Genetics Practice Test

Unofficial multiple-choice practice for Unit 5 of AP Biology, Heredity: meiosis, Mendelian and non-Mendelian genetics.

How many rounds of DNA replication and of cell division make up meiosis?

Pick an answer, then press Check answer. Then you see Correct or Not quite, with the reason. Keys: A to D pick, Enter checks.

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Unofficial practice questions, not affiliated with the College Board. Bank checked October 9, 2026.

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All 57 questions

Topic 5.1: Meiosis 10

  • A cell with 2n = 6 has just finished meiosis I. Which describes each of the two cells formed? Nature Education, Scitable, "Meiosis, Genetic Recombination, and Sexual Reproduction"; Wikipedia, "Meiosis"; course topic 5.1
  • An animal has a diploid number of 2n = 8. How many chromosomes does each of its gametes carry? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Gamete"; course topic 5.1
  • How do the daughter cells of mitosis compare with the products of meiosis? Nature Education, Scitable, "Mitosis, Meiosis, and Inheritance"; course topic 5.1
  • How does metaphase I of meiosis differ from metaphase of mitosis? Nature Education, Scitable, "Meiosis, Genetic Recombination, and Sexual Reproduction"; course topic 5.1
  • How many rounds of DNA replication and of cell division make up meiosis? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Meiosis"; Wikipedia, "Meiosis"; course topic 5.1
  • In an animal, which cells are made by meiosis? Nature Education, Scitable, "Mitosis, Meiosis, and Inheritance"; course topic 5.1
  • What restores the diploid number of chromosomes in each generation of a sexually reproducing species? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Gamete" and "Haploid"; course topic 5.1
  • What separates during anaphase I of meiosis? Nature Education, Scitable, "Meiosis, Genetic Recombination, and Sexual Reproduction"; Wikipedia, "Meiosis"; course topic 5.1
  • What separates during meiosis II? Wikipedia, "Meiosis"; Nature Education, Scitable, "Meiosis, Genetic Recombination, and Sexual Reproduction"; course topic 5.1
  • Which event of prophase I of meiosis does not take place in mitosis? Nature Education, Scitable, "Meiosis, Genetic Recombination, and Sexual Reproduction"; course topic 5.1
Show all 57 questions (47 more)

Topic 5.2: Meiosis and genetic diversity 8

  • A chromosome from the mother carries alleles A and B, and its homolog from the father carries a and b. After one crossover between the two genes, which chromatids appear that neither parent supplied? Wikipedia, "Chromosomal crossover"; course topic 5.2
  • An organism has three pairs of homologous chromosomes. Leaving crossing over aside, how many different combinations of chromosomes can its gametes carry? Wikipedia, "Mendelian inheritance"; Nature Education, Scitable, "Mitosis, Meiosis, and Inheritance"; course topic 5.2
  • Because of nondisjunction, a gamete carries one extra chromosome (n + 1). It is fertilized by a normal gamete. What is the zygote? Wikipedia, "Nondisjunction"; Nature Education, Scitable, "Mitosis, Meiosis, and Inheritance"; course topic 5.2
  • Crossing over and independent assortment create variety among gametes. Which process adds further variation after meiosis is complete? Nature Education, Scitable, "Mitosis, Meiosis, and Inheritance"; course topic 5.2
  • During which phase of meiosis does crossing over occur? Nature Education, Scitable, "Mitosis, Meiosis, and Inheritance" and "Meiosis, Genetic Recombination, and Sexual Reproduction"; course topic 5.2
  • What is exchanged during crossing over? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Crossing Over"; Wikipedia, "Chromosomal crossover"; course topic 5.2
  • What is nondisjunction? Wikipedia, "Nondisjunction"; course topic 5.2
  • What physically underlies independent assortment of chromosomes? Wikipedia, "Meiosis", section "Metaphase I"; course topic 5.2

Topic 5.3: Mendelian genetics 17

  • A cross is expected to give 300 tall and 100 short plants. A student counts 290 tall and 110 short. What is the chi-square value? Nature Education, Scitable, "Genetics and Statistical Analysis"; course topic 5.3
  • A cross is expected to give two phenotype classes. How many degrees of freedom does a chi-square test of the result have? Nature Education, Scitable, "Genetics and Statistical Analysis"; course topic 5.3
  • A test cross yields 52 offspring with the dominant phenotype and 48 with the recessive phenotype. What was the genotype of the parent being tested? Wikipedia, "Test cross"; course topic 5.3
  • A trait is observable in every generation of a pedigree, and each affected person has an affected parent. What does the pattern suggest? Nature Education, Scitable, "Gregor Mendel and the Principles of Inheritance"; National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Pedigree"; course topic 5.3
  • An individual has the genotype AaBb, and the two genes assort independently. Which gametes does it make? Nature Education, Scitable, "Gregor Mendel and the Principles of Inheritance"; course topic 5.3
  • Before Mendel, most people thought offspring were a blend of their parents. Which of his observations argued against blending? Nature Education, Scitable, "Gregor Mendel and the Principles of Inheritance"; course topic 5.3
  • Both parents are heterozygous (Aa). What is the probability that their first two children are both aa? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Carrier"; course topic 5.3 (the multiplication rule for independent events is on the course formula sheet)
  • In a pedigree, two parents who do not show a trait have a child who does. What does this pattern suggest about the trait? Nature Education, Scitable, "Gregor Mendel and the Principles of Inheritance"; course topic 5.3
  • In a test cross, an individual with the dominant phenotype is bred with an individual of which genotype? Wikipedia, "Test cross"; course topic 5.3
  • Mendel crossed pure-breeding round-seeded and wrinkled-seeded peas, and every F1 seed was round. He let the F1 plants self-fertilize. What did the F2 show? Nature Education, Scitable, "Gregor Mendel and the Principles of Inheritance"; course topic 5.3
  • Mendel's law of independent assortment holds for two genes when they Wikipedia, "Genetic linkage"; course topic 5.3
  • Two carriers of an autosomal recessive trait have a child. What is the chance that the child is also a carrier who does not show the trait? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Carrier"; Wikipedia, "Dominance (genetics)"; course topic 5.3
  • Two heterozygotes are crossed (Aa x Aa). What ratio of genotypes is expected among the offspring? Wikipedia, "Dominance (genetics)"; course topic 5.3
  • Two plants heterozygous for two unlinked genes are crossed (AaBb x AaBb). What fraction of the offspring is expected to show both dominant traits? Wikipedia, "Mendelian inheritance"; course topic 5.3
  • Two plants show the same dominant trait. One has the genotype AA and the other Aa. What do they share? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Phenotype" and "Heterozygous"; course topic 5.3
  • Which statement expresses Mendel's law of segregation? Wikipedia, "Mendelian inheritance"; Nature Education, Scitable, "Gregor Mendel and the Principles of Inheritance"; course topic 5.3
  • With 1 degree of freedom the critical chi-square value at p = 0.05 is 3.84. A student calculates 1.33 for a cross expected to give a 3:1 ratio. What should the student conclude? Nature Education, Scitable, "Genetics and Statistical Analysis"; course topic 5.3

Topic 5.4: Non-Mendelian genetics 17

  • A man who shows an X-linked recessive trait has children with a woman who does not carry the allele. Which statement is correct? Wikipedia, "Sex linkage"; course topic 5.4
  • A person with blood type AB has one A allele and one B allele, and both are expressed. Which pattern of inheritance is this? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Codominance"; course topic 5.4
  • A test cross of an AaBb individual gives mostly the two parental types and only a few recombinants, far from the 1:1:1:1 ratio expected. What is the best explanation? Wikipedia, "Test cross" and "Genetic linkage"; course topic 5.4
  • A trait is caused by a gene in mitochondrial DNA. How is it inherited in animals? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Mitochondrial DNA"; course topic 5.4
  • A woman who carries an X-linked recessive allele has children with a man who does not have the trait. What is expected? Wikipedia, "Sex linkage"; course topic 5.4
  • Carl Correns found that leaf color in four o'clock plants always followed the branch that bore the seed, whatever plant supplied the pollen. Why? Nature Education, Scitable, "Non-nuclear Genes and Their Inheritance"; course topic 5.4
  • In a test cross, 120 of 1,000 offspring are recombinant for two linked genes. How far apart are the genes? Nature Education, Scitable, "Thomas Hunt Morgan, Genetic Recombination, and Gene Mapping"; National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Centimorgan"; course topic 5.4
  • In bees, wasps and ants, males develop from unfertilized eggs. What follows for the chromosomes of a male? Wikipedia, "Haplodiploidy"; course topic 5.4
  • In birds, sex is set by Z and W chromosomes. Which parent's gamete sets the offspring's sex? Wikipedia, "ZW sex-determination system"; course topic 5.4
  • In four o'clock plants, true-breeding red and white parents have pink offspring. Two of the pink F1 plants are crossed. What is expected in the F2? Wikipedia, "Dominance (genetics)", section "Incomplete dominance"; course topic 5.4
  • In genetics, what does linkage refer to? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Linkage"; course topic 5.4
  • In pea plants a single gene affects the color of the seed coat, the flowers and the leaf axils. What is this called? Nature Education, Scitable, "Pleiotropy: One Gene Can Affect Multiple Traits"; course topic 5.4
  • Three linked genes are mapped. A and B are 5 map units apart, B and C are 10 apart, and A and C are 15 apart. What is the order of the genes? Nature Education, Scitable, "Thomas Hunt Morgan, Genetic Recombination, and Gene Mapping"; course topic 5.4
  • What recombination frequency is expected for two genes that lie on different chromosomes? Wikipedia, "Genetic linkage"; course topic 5.4
  • Why are closely linked genes usually inherited together? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Linkage"; course topic 5.4
  • Why do X-linked recessive traits appear more often in males than in females? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Sex Linked"; course topic 5.4
  • Why is mitochondrial DNA usually inherited from the mother alone? Wikipedia, "Extranuclear inheritance"; course topic 5.4

Topic 5.5: Environmental effects on phenotype 5

  • A Himalayan rabbit reared at 20 degrees C has dark fur on its ears, nose and feet. One reared above 30 degrees C has no dark fur. What does this show? Nature Education, Scitable, "Environmental Influences on Gene Expression"; course topic 5.5
  • A plant grown in soil poor in nutrients puts more of its growth into roots than a genetically identical plant grown in rich soil. What is this an example of? Wikipedia, "Phenotypic plasticity"; course topic 5.5
  • Identical twins share a genotype, yet as adults they differ slightly in height. What is the best explanation? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Phenotype" and "Polygenic Trait"; course topic 5.5
  • In crocodilians and many turtles, the temperature at which the eggs are incubated determines which feature of the hatchlings? Wikipedia, "Temperature-dependent sex determination"; course topic 5.5
  • What is phenotypic plasticity? Wikipedia, "Phenotypic plasticity"; course topic 5.5

How this list was compiled: Our own questions, written to Unit 5 (Heredity) of the College Board's AP Biology Course and Exam Description, effective fall 2025, https://apcentral.collegeboard.org/media/pdf/ap-biology-course-and-exam-description.pdf, read 2026-10-09. Each fact was read on 2026-10-09 in the public page named under its question: the Talking Glossary of Genomic and Genetic Terms of the National Human Genome Research Institute (genome.gov), Scitable by Nature Education and Wikipedia. Licence: Own work. Short quotations from the public documents named under each question.

How it works

This AP Bio genetics practice test has 57 questions of our own on Unit 5, which the course calls Heredity. It is unofficial: the College Board owns AP and has no connection with this site.

Read the full guide

What Unit 5 covers

Five topics make up Unit 5 in the course description the College Board put into force in fall 2025, read here on October 9, 2026: meiosis (10 questions), meiosis and genetic diversity (8), Mendelian genetics with probability and chi-square (17), non-Mendelian genetics (17) and environmental effects on phenotype (5). The description sets no weight for a topic, so the split is ours.

Checking an answer

Under every answer is its source: an entry in the genetics glossary of the National Human Genome Research Institute, a Scitable article from Nature Education or a Wikipedia article.

  • Write the gametes before the offspring. Most wrong answers in a cross come from skipping that step.
  • In any cross with a son and an X-linked gene, remember that his X came from his mother.

Questions and answers

What is Unit 5 in AP Bio?

Heredity: how meiosis passes genes from parents to offspring, and the Mendelian and non-Mendelian patterns of inheritance that follow. It carries 8 to 11% of the multiple-choice section, by the College Board's course page.

Is there an AP Biology meiosis practice test here?

Yes. The two meiosis topics hold 18 questions between them, on the phases of meiosis I and II, crossing over, independent assortment and nondisjunction.

What should an AP Biology genetics exam study guide cover?

Meiosis and how it makes gametes differ, Mendel's two laws, monohybrid, dihybrid and test crosses, the rules of probability, pedigrees, linkage and map units, sex-linked traits, inheritance through mitochondria and chloroplasts, and the effect of environment on phenotype.

Does AP Bio genetics include chi-square?

Yes. The course description lists chi-square hypothesis testing as a skill for the Mendelian and non-Mendelian topics. Three questions here work one through: the degrees of freedom, the value and the conclusion.

Are the questions taken from past AP Biology exams?

None is. Past exam questions are the property of the College Board. This bank was built from the published outline of Unit 5.

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