carbohydrates Flashcards
1
Q
How do you use the benedict’s test for reducing sugars?
A
- add benedicts reagant to a sample and heat in a gently boiling water bath
- will form a coloured precipitate if positive
- greater colour change = greater concentration
- filter and weigh or colorimeter for more accurate
2
Q
How do you prepare a non-reducing sugar for benedict’s test?
A
- break into monosaccharides by adding dilute hcl
- heat in gently boiling water bath
- neutralise by adding sodium hydrogencarbonate
3
Q
test for presence of starch
A
iodine, brown to blue-black
4
Q
What gives cellulose such high tensile strength?
A
The lines run parallel allowing hydrogen bonds to cross link the chains
5
Q
What makes starch and glycogen both suitable for glucose storage?
A
They are insoluble so don’t alter the water potential of the cell and can’t diffuse out of the cell due to being both large and insoluble.
