Cracking the AP Biology Exam


The Chemistry of Life


The fourth class of organic compounds are the nucleic acids. Like proteins, nucleic acids contain carbon, hydrogen, oxygen, and nitrogen, but nucleic acids also contain phosphorus. Nucleic acids are molecules that are made up of simple units called nucleotides. For the AP Biology Exam, you’ll need to know about two kinds of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

DNA is important because it contains genes, the hereditary “blueprints” of all life. RNA is important because it’s essential for protein synthesis. We’ll discuss DNA and RNA in greater detail when we discuss heredity.