Biological molecules Flashcards
Hydrolysis reaction
Reaction which uses water to break down a polymer (incl. disaccharide or polysaccharide) into its constituent monomers by breaking glycocidic bonds
Condensation reaction
Reaction between monomer units to form polymers held together by glycosidic bonds, also forming small molecules of H20
Metabolism
The sum of all reaction in a cell or organism
Isotopes
Atoms of the same element with the same number of protons but different number of neutrons
General formula of a monosaccharide
(CH20)n where n=any number between 3 and 7
Isomer
Molecules with the same molecular formula but with atoms connected differently
Isomers of glucose
ALPHA glucose: on carbon 1 has H on top the OH
BETA glucose: on carbon 1 has OH on top then H
Glucose + glucose =
maltose
Glucose + fructose =
sucrose
Glucose + galactose =
lactose
Test for reducing sugars
- add benedict’s solution (copper (ii) suplfate) to food sample
- heat
- an insoluble red precipitate of copper (ii) oxide will form
Test for non-reducing sugars
- add Benedict’s solution to to foood sample
- heat
- if remains blue = no reducing sugar present
- add HCl + heat (HCl hydrolyses any disaccharides)
- add sodium hydrogencarbonate solution to neutralise
- check pH
- test with Benedict’s again
Test for starch
- add iodine
- if present = blue/black
which sugars are reducing?
all monosacharrides and some disaccharides
which sugars are non-reducing?
some disaccharides