BioNinja

B1.1.2
Production of macromolecules by condensation reactions that link monomers to form a polymer

Organic compounds are typically composed of recurring subunits (monomers) which are covalently joined to form polymers

The monomeric subunit of carbohydrates is a monosaccharide (single sugar unit)
Nucleic acids are composed of repeating nucleotides (containing a sugar, phosphate and nitrogenous base)
Proteins consist of linked chains of amino acids which differ according to a variable side chain (‘R’ group)
Lipids do not contain monomers but certain types may be composed of distinct subunits (fatty acid chains)

Monosaccharide

Fatty Acid

Nucleotide

Amino Acid

Polymers can be formed from monomeric subunits via condensation reactions

A hydroxyl group (-OH) on one monomer is combined with a hydrogen atom (-H) on another monomer
The two monomers become covalently bonded and a water molecule is produced as a by-product

B1.1.3
Digestion of polymers into monomers by hydrolysis reactions

Polymers are large macromolecules composed of smaller repeating subunits (called monomers) via condensation reactions

Carbohydrates: Monosaccharides are joined together to form polysaccharides via glycosidic linkages
Nucleic Acids: Nucleotides are connected by phosphodiester bonds to form polynucleotide chains (DNA or RNA)
Proteins: Amino acids are linked by peptide bonds to form polypeptide chains (proteins can possess multiple chains)
Lipids: Do not possess monomers but fatty acid chains can be connected by ester linkages to form triglycerides and phospholipids

Polymers can be broken down into their monomeric subunits via hydrolysis reactions

A water molecule is split to provide the -H and -OH groups required to break the covalent bond between two monomers