carbohydrates Flashcards
3 main functions of carbohydrates
short term energy storage
long term energy storage
structural components
name 3 polysaccharides
glycogen starch and cellulose
which two polysaccharides can be digested and used for energy
starch and glycogen
what is the glycemic index
measurement of blood glucose level increase from consumption of carbohydrates
what are the 3 types of monosaccharides
3 carbons - triose
5 carbons - pentose
6 carbons - hexose
two isomers of glucose
alpha and beta
define an isomer
molecules that have the same molecular formula but have a different arrangement of atoms
what type of monosaccharide is glucose
hexose
what’s the difference between alpha and beta glucose
alpha - OH is below ring
beta - OH is above ring
2 other hexoses
fructose
galactose
what is a disaccharide
double sugar composed of pairs of monosaccharide units joined by a glycosidic bond. (joined by a condensation reaction)
what is maltose made of
two alpha glucoses
what is sucrose made of
glucose and fructose
what is lactose made of
glucose and galactose
define hydrolysis
chemical insertion of a molecule of water to split a disaccharide into its constituent monosaccharides
define reducing sugar
sugars that can donate an electron to another molecule
reducing sugars test
1) benedict’s reagent
2) shake, and heat for a few minutes at 95°c in a water bath
3) a precipitate (green,yellow,orange,red) indicates reducing sugar
is benedict’s test quantative or qualitative
qualitative
example of a non reducing sugar
sucrose
non reducing sugars test
1) first test for reducing, if negative continue
2) dilute hydrochloric acid
boil hydrolyse the glycosidic bond
3) add sodium hydrogen carbonate solution to neutralise
4) re test solution with benedict’s reagent
5) if non reducing sugar is present, solution will now change colour