AP Biology UNIT 5: Heredity

IMPORTANT NOTE: Students under the age of 18, parents, caregivers and guardians are required to purchase this course and allow their students to benefit from it!

The story of life is written in the language of heredity—the transmission of genetic information from one generation to the next. Unit 5 of our AP Biology course dives into the fundamental principles of heredity, connecting classical experiments with the molecular mechanisms that modern science has revealed. Here, we will explore how genetic traits are passed down, why offspring resemble their parents yet are never exact copies, and how patterns of inheritance drive diversity in populations.

We begin with Mendelian genetics, focusing on Gregor Mendel’s groundbreaking work with pea plants and the establishment of key principles such as dominance, segregation, and independent assortment. These concepts will be expanded into probability rules and Punnett squares, giving you the tools to predict and analyze inheritance patterns. From there, we’ll move into more complex scenarios, such as codominance, incomplete dominance, polygenic inheritance, and epistasis, which more accurately reflect the intricacies of real-world genetics.

Unit 5 also examines the chromosomal basis of inheritance, including how linkage, recombination, and nondisjunction can alter expected ratios. You’ll learn about human genetics through pedigree analysis and case studies of genetic disorders. At the molecular level, we connect genes to traits through the central dogma of biology: DNA → RNA → Protein.

By the end of this unit, you won’t just be able to solve inheritance problems—you’ll see genetics as the foundation for modern biology, from evolution to biotechnology. This is where biology becomes personal: the blueprint of life, written in your very cells, comes alive.