biological molecules (carbohydrates) Flashcards
what elements are carbohydrates made from?
carbon, oxygen and hydrogen
what is a monomer?
repeating unit from which larger molecules are made
what is a polymer?
long chain of bonded, repeated monomers
what is the structure of starch?
made of two polysaccharides of alpha glucose- amylose and amylopectin
compact so large quantities can be stored
insoluble so doesn’t affect water potential
coiled and unbranched, or long and branched
what is the structure of glycogen?
polysaccharide of alpha glucose
side branches so releases energy quickly
compact so large quantities can be stored
what is the structure of cellulose?
polysaccharide of beta glucose
long, unbranched
has microfibrils for structural support
what is the difference between alpha and beta glucose?
H and OH are opposite
what happens in condensation?
two molecules are joined which releases water
what is hydrolysis?
breaking polymers apart using water
what is maltose made of?
2 alpha glucose
what is sucrose made of?
glucose and fructose
what is lactose made of?
glucose and galactose
how do you conduct a test for a reducing sugar?
add Benedict’s reagent to a sample
heat in a water bath that has been bought to the boil
if positive forms a coloured precipitate
goes from blue to brick red
how do you conduct a test for a non reducing sugar?
do the test for a reducing sugar
if negative, get a new sample of test solution
add dilute hydrochloric acid
heat in a water bath that has been bought to the boil
neutralise with sodium hydrocarbonate
carry out the Benedict’s test
if positive forms a coloured precipitate, if negative stays blue
how do you conduct a test for starch?
add iodine dissolved in potassium iodide to the test sample
if starch is present, the sample changes from a brown/orange to a blue/black colour
