Biological Molecules Flashcards
Define condensation
When two monomers are joined together with the removal of a water molecule.
E.G of monomers
Glucose , amino acids and nucleotides (monosaccharides)
Define hydrolysis
Water is added to break a bond between two molecules
E.g. of disaccharides
Sucrose, maltose and fructose
E.g of polysaccharides
glycogen, starch and cellulose
Benedicts test (reducing sugar)
Add food sample and benedict’s reagent and gently heat. If solution turns brick red then reducing sugar is present.
Benedicts test (non- reducing sugar)
If there is no colour change then get a new sample and add HCl to break up disaccharides/polysaccharides and heat . Add NaHCO3 to neutralise the acid. Then add benedicts reagent and gently heat , if it turns brick red , non-reducing sugar is present.
Test for starch
Iodine , solution will turn blue-black from orange if starch is present
Properties of glycogen
Made from alpha glucose
1-4 + 1-6 glycosidic bonds
Branched (energy released easily)
Large and compact (store a lot of energy)
Insoluble (not affected by osmosis)
Properties of starch (amylose)
Made from a-glucose
Insoluble
Unbranched
1-4 glycosidic bond
Compact
Properties of starch (amylopectin)
Made from a-glucose
Branched
Insoluble
1-4 + 1-6 glycosidic bond
Properties of cellulose
Made from B- glucose
Unbranched
Can form microfibrils which are cellulose chains that run parallel to one another joined by hydrogen bonds for collective strength
Main type of lipids
Phospholipids and triglycerides
Saturated lipids have …
no carbon-carbon double bonds
Unsaturated lipids have..
carbon-carbon double bonds that allows it to bend and be a kinky molecule
How triglycerides structure is important for their function?
Large and non-polar , so isnt affected by osmosis
High ratio of H-O atoms , so triglycerides release water when they are oxidised and can provide an important source of water for organisms in dry environments.
Test for lipids
Add ethanol to smaple and shake to dissolve lipid in solution .
Add water and shake gently. White emulsions appear of lipid is present.
Globular proteins are…
enzymes and are compact
Fibrous protiens are…
long and used to form fibres like keratin
Test for proteins
Add Biuret reagent to sample, if a purple colouration appears a protein is present , If it remains blue no protein.
Factors that affect the rate of enzyme controlled reactions and why
- Temperature increases the rate of reaction but to high and enzyme becomes denatured due to breaking of bonds that holds the tertiary structure
2.pH every enzyme has an optimum pH too high or low enzyme denatures
- Enzyme/substrate concentration
- Inhibitors
