Common and important organic chemical functional groups found in biological molecules  (R -- any oganic group):

NAME	GROUP	EXAMPLE
hydroxyl:	-OH	ethanol:  CH3-CH2-OH
aldehyde:	-CHO	acetaldehyde:  CH3-CHO
	O   || -C-H
acid:	-COOH	acetic acid:  CH3-COOH
	O   || -C-OH <--->  O   || -C-O- <--->  O-   | -C=O
amine:	-NH2	methyl amine:  CH3-NH2
	(-NH3+)
ketone:	-CO-	pyruvic acid:  CH3-CO-COOH
	O   || -C-
ether:	-O-	ethyl ether:  CH3-CH2-O-CH2-CH3
ester:	-COOR	methyl ester of acetic acid:  CH3-CO-OCH3
	O   || -C-O-R
amide:	-CONH2	acetamide:  CH3-CONH2
	O   || -C-NH2
sulfhydryl:	-SH	2-mercaptoethanol: HO-CH2-CH2-SH
disulfide:	-S-S-	R-S-S-R
phenyl:		phenol:  C6H5-OH, or Ø-OH