← Biology syllabus

United StatesBiology

Unit 5: Heredity

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do chromosomes carry genes, and what happens when their inheritance goes wrong?

Topic 5.6 Chromosomal Inheritance: explain the chromosomal basis of inheritance, including sex determination and the consequences of nondisjunction.
A focused answer to AP Biology Topic 5.6, covering the chromosome theory of inheritance, sex determination, linkage, nondisjunction and aneuploidy, with a worked example of nondisjunction.
10 min answer →

How does the environment influence the expression of a genotype?

Topic 5.5 Environmental Effects on Phenotype: explain how environmental factors can affect the phenotype produced by a given genotype.
A focused answer to AP Biology Topic 5.5, covering how temperature, nutrients, pH and other environmental factors influence phenotype, the genotype-by-environment interaction, and norms of reaction, with a worked example.
9 min answer →

How does meiosis generate genetic variation among gametes?

Topic 5.2 Meiosis and Genetic Diversity: explain how crossing over, independent assortment and random fertilization produce genetic variation.
A focused answer to AP Biology Topic 5.2, covering crossing over, independent assortment and random fertilization as the three sources of genetic variation, with a worked calculation of gamete combinations.
10 min answer →

How does meiosis halve the chromosome number and produce gametes?

Topic 5.1 Meiosis: explain how meiosis produces four haploid cells from one diploid cell, and how it differs from mitosis.
A focused answer to AP Biology Topic 5.1, covering the two divisions of meiosis, homologous chromosomes, the reduction from diploid to haploid, and how meiosis differs from mitosis, with a worked chromosome-count problem.
10 min answer →

How do Mendel's laws predict the inheritance of traits?

Topic 5.3 Mendelian Genetics: apply the laws of segregation and independent assortment to predict genotype and phenotype ratios.
A focused answer to AP Biology Topic 5.3, covering the laws of segregation and independent assortment, Punnett squares, monohybrid and dihybrid crosses, and the chi-square test for goodness of fit, with worked calculations.
11 min answer →

How do inheritance patterns depart from simple Mendelian ratios?

Topic 5.4 Non-Mendelian Genetics: explain inheritance patterns that depart from simple dominance, including incomplete dominance, codominance, sex linkage, polygenic traits and linkage.
A focused answer to AP Biology Topic 5.4, covering incomplete dominance, codominance, multiple alleles, sex-linked traits, polygenic inheritance and gene linkage, with a worked sex-linkage cross.
10 min answer →