Aldehyde
Carbon doubly bonded to a oxygen and singularly bonded to a hydrogen
Hydroxyl
OH bonded to R group
Keto
Carbon doubly bonded oxygen
Carboxyl
Carbon doubly bonded to oxygen and singularly bonded to a hydroxyl(OH)
Amino
Nitrogen with two singular bonds to hydrogens
Phosphate
One phosphate bonded with 4 oxygens with 3 singular bonds and one double bond
Sulfhydryl
One sulfur bonded to a hydrogen