Biology - R Groups

Hydroxyl Group

Why it’s important:

Consists of an oxygen and hydrogen

Commonly found in alcohols

Polar molecule

Makes compounds water soluble due to hydrogen bonding

Carbonyl Group

Consists of a carbon double bonded to an oxygen

If the group is at the end of the carbon skeleton, the compound is called an aldehyde

Otherwise called ketone

Carboxyl Group

Consists of a carbon double bonded to an oxygen also attached to a hydroxyl group

Compound with this group are called carboxylic acids or organic acids because they donate the H⁺ becoming a carboxylate ion

Amino Group

Consists of a nitrogen atom bonded to 2 hydrogen atoms

Compound with this group are called amines

They can act as bases by picking up H⁺ as the amino group becomes -NH₃⁺

Sulfhydryl Group

Consists of a sulfur atom bonded to a hydrogen atom

Compounds containing this group are called thiols

Phosphate Group

This is bonded to the carbon skeleton by an O^- attached to the phosphorus atom

Organic molecule + phosphate group = organic phosphate (as long as the molecule is carbon-based)

This is an anion

Methyl Group

Consists of a carbon bonded to 3 hydrogen atoms

Methylated compounds may have their function modified due to the addition of the group