BIOL 203 Functional Groups

Hydroxyl Group

(-OH) Polar functional group that forms hydrogen binds with water helping dissolve compounds such as sugars. The compound name is Alcohol and an example is Ethanol.

Carbonyl Group

(>C=O) sugars with ketone groups are called ketoses; those with aldehydes are called aldoses. The compound name is ketone (carbonyl group is within a carbon skeleton) or aldehyde (carbonyl group is at the end of the carbon skeleton). Acetone is an example of a ketone and Propanal is an aldehyde.

Carboxyl Group

(—COOH) Acts as an acid (can donate H+) because the covalent bond between oxygen and hydrogen is so polar.

Amino Group

(—NH2) Acts as a base; can pick up an H+ from the surrounding solution (water, in living organisms)l. The compound name is amine and an example is glycine (amino acid).

Methyl Group

(—CH3) affects the expression of genes when bonded to DNA or to proteins that bind to DNA. Affects the shape and function of male and female sex hormones. The compound name is Methylated Compound and an example is 5-Methylcytosine.

Sulfhydryl Group

(—SH) Two SH groups can react forming a “cross-link” that helps stabilize protein structure. Hair protein cross-links maintain the straightness or curliness of hair; in hair salons , “permanent” treatments break cross-links, then re-form them while the hair is in the desired shape. The compound name Thiol and an example is cysteine which is a sulfur'-containing amino acid.

Phosphate Group

(—OPO3²-) contributes to negative charge (1- when positioned inside a chain of phosphates; 2- when at the end). When attached, confers on a molecule the ability to react with water, releasing energy. The compound name is organic phosphate and an example is a glycerol phosphate.