Carbohydrate Flashcards
1
Q
Biochemical test for non-reducing sugars [3]
A
- Add Benedicts reagent
- Precipitate remains blue
- Heat with acid and neutralise
- Add Benedicts reagent
- If precipitate is yellow -> red, a non-reducing sugar is present
2
Q
How to measure the quantity of non/reducing sugar [2]
A
- Filter and dry precipitate
- Find mass of precipitate
3
Q
Why would a calorimeter improve the repeatability/ accuracy of the experiment [1]
A
- Quantitive
OR - Colour change is subjective
4
Q
What is a monomer [1]
A
Small, basic unit from which polymers are made in a condensation reaction
5
Q
Two differences in the structure of cellulose and glycogen [2]
A
- Cellulose is made up of beta glucose chains whereas glycogen is made up of alpha glucose chains
- Glycogen is coiled whereas cellulose molecules are straight chains
6
Q
Two features of starch that make it a good storage molecule [2]
A
- Insoluble - doesnt affect water potential
- Insoluble - cant be lost from the cell easily
- Branched with free ends - quick hydrolysis
- Polymer of glucose - provides substrate for respiration
- Branched - compact
7
Q
Test for starch [1]
A
Iodine in potassium iodide
8
Q
Structure of glycogen [2]
A
- Chain of alpha glucose
- Joined by glycosidic bonds
9
Q
How does glycogen act as a source of energy [2]
A
- Polymer of alpha glucose - provides substrate of respiration when hydrolysed
10
Q
Difference in structure between cellulose and starch [2]
A
- Starch is formed from alpha glucose, cellulose is formed from beta glucose
- Position of hydrogen and hydroxyl groups on carbon 1 are inverted
11
Q
How are cellulose molecules adapted for their function in plant cells [3]
A
- Long and straight chains of beta glucose
- These become linked together by hydrogen bonds
- Form strong fibres called fibrils
- Provides strength to the cell wall
