Biology foundations by Khan Academy

About this course

If biology has ever felt like a blur of unfamiliar terms, this course helps you build a clear foundation you can trust. You will connect big-picture ideas about life with the practical tools scientists use to investigate it, so the subject stops feeling like memorization and starts feeling like understanding. Designed for school-level learning, it supports you in developing confidence for homework, exams, and future science classes.

You begin by exploring what biology studies and how scientists turn questions into testable investigations. By focusing on the scientific method, hypotheses, and evidence-based reasoning, you learn how to judge claims using data instead of guesswork. You will also strengthen your ability to think about variables, controls, and fairness in testing, which is essential not only in biology labs but in everyday decision-making where evidence matters.

From there, the course bridges biology with the chemistry that powers living systems. You will make sense of elements and atoms, then move into the molecules of life: carbohydrates, proteins, lipids, and nucleic acids. Rather than treating these as separate definitions, you will see how their structures relate to their roles in organisms—how building blocks like amino acids and nucleotides help explain everything from energy use to heredity. You will also learn the difference between vitamins and minerals and why that distinction matters in human nutrition.

Finally, you focus on water and the chemical environment of cells. You will understand hydrogen bonding, why water is such an effective solvent, and how these properties make life as we know it possible. You will also learn what pH measures and why changes in acidity can affect biological systems. Along the way, practice questions help you check your understanding, spot gaps early, and study more efficiently. By the end, you will have a solid, connected framework that makes the rest of biology far easier to learn.