unit 1 monomers, polymers and carbs

Question 1

What is hydrolysis?

Answer 1

1. Breaks a chemical bonds between two molecules;
2. Using water;

Question 2

Glycogen - Glycogen Structure (3)

Answer 2

1. Polysaccharide of α-glucose;
2. (Joined by) glycosidic bonds;
3. Branched structure

Question 2

What is a condensation reaction?

Answer 2

1. Creates a chemical bond
2. Removing a molecule of water

Question 3

Glycogen - Glycogen compared

with cellulose (4)

Answer 3

1. Cellulose is made up of β-glucose (monomers) and glycogen is made up of α-glucose (monomers);
2. Cellulose molecule has straight chain and glycogen is branched;
3. Cellulose molecule has straight chain and glycogen is coiled;
4. Glycogen has 1,4- and 1,6- glycosidic bonds and cellulose has only 1,4- glycosidic bonds

Question 4

Glycogen - Glycogen structure

related to function (5)

Answer 4

1. Insoluble (in water), so doesn’t affect water potential;
2. Branched / coiled / (α-)helix, so makes molecule compact;
3. Polymer of (α-)glucose so provides glucose for respiration;
4. Branched / more ends for fast breakdown / enzyme action;
5. Large (molecule), so can’t cross the cell membrane

Question 5

Starch – Relate 3 properties to its

function (6)

Answer 5

1. Insoluble;
2. Don’t affect water potential;
3. Helical;
4. Compact;
5. Large molecule;
6. Cannot leave cell

Question 6

Test for reducing sugar

Answer 6

1. Heat with Benedict’s reagent
2. colour change from blue to brick-red

Question 7

Test for a non reducing sugar

Answer 7

1. Heat with Benedict’s reagent and no colour change
2. boil with acid (HCl) and then neutralise with (NaHCO3)
3. re- heat with Benedict’s reagent and colour change from blue to brick-red

Question 8

Test for starch

Answer 8

1. Add iodine in potassium iodide solution
2. colour change from brown to blue-black