carbohydrates, disaccharides & polysaccharides (1.3) Flashcards
1
Q
what are disaccharides?
A
monosaccharides joining as a pair
2
Q
how is the disaccharide ‘sucrose’ formed?
A
fructose bonding with glucose
3
Q
how is the disaccharide ‘lactose’ formed?
A
beta galactose bonding with an alpha glucose
4
Q
how are two monosaccharides formed?
A
through a condensation reaction
5
Q
what bond is created when a disaccharide is formed?
A
a glycosidic bond
6
Q
how are the constituent monosaccharides released from a glycosidic bond?
A
through hydrolysis
7
Q
what happens when non reducing sugars are heated with benedicts reagent?
A
they do not change its colour
8
Q
what must happen to detect if a sugar is non reducing?
A
the disaccharide must first be hydrolysed into its monosaccharide components
9
Q
how do you hydrolyse a disaccharide?
A
- complete the benedicts test, if the reagent doesn’t change colour, a reducing sugar is not present.
- add another 2cm cubed of the food sample to 2cm cubed of hydrochloric acid in a test tube and place it in the gently boiling water bath for five minutes.
