Building Biological Molecules (College Board AP® Biology): Study Guide

Building biological molecules

• Organisms take up atoms and small molecules from their environment; they use these elements to build new biological molecules

• Carbon, hydrogen, and oxygen are the elements that appear most frequently in biological molecules, e.g. in:

  • carbohydrates

  • proteins

  • lipids

• Other elements that are commonly taken up by organisms from the environment include

  • sulfur, which is present in some amino acids within proteins

  • phosphorus, which is used to build:

    • phospholipids

    • nucleic acids

  • nitrogen, which is needed to produce amino acids