Although we've spent a lot of time in this series looking at human-made organic chemicals, the term "organic chemistry" was originally used to describe molecules isolated from living things. In this episode of Crash Course Organic Chemistry, we're going back to our roots to learn more about the best synthetic chemists: living things. We'll look at the biochemical building blocks of life from the nitrogenous bases, sugars, and phosphate groups that make up DNA and RNA, to amino acids and lipids, and we'll learn how to convert between Fischer and Haworth projections of carbohydrates.