Topic 1-Biological Molecules Flashcards
Test for reducing sugars
- heat sample with Benedict’s reagent
- sample forms green /orange/ yellow/ brick red precipitate.
If sample stays blue, no reducing present.
Test for non-reducing sugar
Following negative reducing sugar test,
- heat new sample with dilute hydrochloric acid then neutralise sample by adding sodium hydrogencarbonate.
- Heat sample with Benedict’s reagent.
-Sample forms green, yellow, orange, brick red precipitate- non- reducing present.
carbohydrates- Starch
Amylose + amylopectin
Insoluble
Storage in plants
Glycosidic bonds in condensation reaction
Carbohydrates- Cellulose
Condensation a beta glucose molecules
Insoluble
Straight cellulose chains linked with h bonds to form strong fibrils called microfibrils
Carbohydrates- glycogen
Animal store excess glucose as glycogen
Polysaccharide
Condensation reaction to form glycosidic bonds
Alpha-glucose
Branched structure for quick release of energy
Compact for storage
Condensation and hydrolysis reaction
A condensation reaction joins monomers together and forms a chemical bond and releases water
A hydrolysis reactions breaks a chemical bonds with the removal of water
Amino acids structure
Amine group
Carboxyl group
Variable group
Hydrogen
Dipeptide
Peptide bond by condesation reaction
And two amino codes linked together
Test for protein
Test solution, sodium hydroxide and copper (II) sulfate solution
If solution stays blue no protein present
If solution turns purple protein is present
Lipids
Not polymers
Contain hydrocarbons
Triglycerides and phospholipids
Ester bonds formed between glycerol and fatty acid
Triglycerides
Tail= hydrophobic
Insoluble in water
Saturated = single bonds
Unsaturated = double bonds
Fatty acids formula
CnH2nO2
Phospholipids
Two fatty acids and a phosphate group
Cell membranes
Phospholipid head - hydrophilic polar charged
Phospholipid tail- hydrophobic non polar
Test for lipids
Test substance add ethanol
Shake well
Add to water
Milky colour indicates lipids presence
