Biological Molecules

Monomers

smaller units from which larger molecules are made

Polymers

molecules made from a large number of monomers join together

Condensation

join two molecules together and eliminate a molecule of water

Hydrolysis

breaks a bond between molecules using a molecule of water

Disaccharides

formed by condensation of two monosaccharides

Maltose

two glucose

Sucrose

a glucose and a fructose

Lactose

a glucose and a galactose

𝛼 glucose

OH group linked below the ring

𝛽 glucose

OH group link above the ring

Polysaccharides

Condensation of many glucose unit

Glycogen

𝛼 glucose join by 1,4- and 1,6- glycosidic bond

branched, release stored glucose quickly

Compact, good storage of glucose

Starch

𝛼 glucose

Amylose, 1, 4- glycosidic, unbranded and coiled, compact good for storage

Amylopectin, 1,4- and 1,6- glycosidic, branched allow glucose release quickly

Cellulose

Long, unbranched chain of 𝛽 glucose join by 1,4- glycosidic bond

Hydrogen bond forms between straight chain, forming strong fibres for structural support

Benedict test - reducing sugar

Heat sample with Benedict solution

Colour change from blue to brick red

Benedict test - non reducing sugar

Heat sample with acid and neutralise

Heat with Benedict’s solution

Colour change from blue to brick red

Test for starch

Add iodine

Colour change from brown to blue black

Triglycerides

Condensation of one glycerol and three fatty acid

Ester bond

Condensation between glycerol and a fatty acid

Phospholipid

Condensation of one glycerol, two fatty acid and one phosphate-containing group

Saturated fat

No carbon-carbon double bond

Found in animal fat

Unsaturated fat

Contain carbon-carbon double bond, means molecule can bend so its liquid in room temperature

Found in plant

Phospholipid structure

Phosphate head - hydrophilic

Fatty acid tail - hydrophobic

Forms micelles when contact with water - polar

Forms bilayer of cell membrane

Emulsion test

Add ethanol to sample then add water and shake

Milky emulsion forms