Amino acids are made up of 4 hydrogen atoms, 1 nitrogen atom, 2 carbon atoms, and 2 oxygen atoms. The atoms are arranged in an amino group and a carboxyl group. Amino acids are important to life because they are the building blocks of proteins, which make up your muscles and organs and help them work. They also make up our hair and nails. They help repair our bodies’ tissues. Our bodies can even use amino acids for energy.