Additional Amino Acids Questions 10. There are 20 common amino acids. In addition, two important amino acids, methionine and cysteine , also contain sulfur and can be phosphorylated. Explain your reasoning. Multiple Ring Structures Background Information 1.
Organic chemists use many shortcuts in drawing complex molecules.
They often do not include the letter C for carbon , for example. Cholesterol , shown below, is a steroid . Steroids are one type of molecule in the class of compounds known as lipids . Cholesterol plays an important role in membrane formation. The bonds between the carbons are shown.