1. carbs and lipids

Question 1

what is a monomer

Answer 1

small identical or similar molecules which can be joined together to
make larger molecules called polymers.

Question 2

what is a polymer

Answer 2

large molecules made from joining many identical or similar monomers
together by condensation reactions.

Question 3

how are polymers broken down into their monomers

Answer 3

hydrolysis reaction, which involves adding one molecule of water to break the bond between two monomers.

Question 4

Two monosaccharides can join together in a condensation reaction and what does this form?

Answer 4

disaccharide

Question 5

Glucose +Glucose

Answer 5

maltose

Question 6

Galactose +Glucose

Answer 6

Lactose

Question 7

Glucose + Fructose

Answer 7

Sucrose

Question 8

what is a polysaccharide and example

Answer 8

a type of polymer formed by joining many monosaccharides
together. An example of a polysaccharide is starch.

Question 9

name 3 monosaccharides

Answer 9

Glucose
Fructose
Galactose

Question 10

name 3 disaccharides

Answer 10

Sucrose
Maltose
Lactose

Question 11

name 2 storage polysaccharides

Answer 11

Glycogen (Humans)
Starch (plants)

Question 12

name a structural polysaccharide

Answer 12

Cellulose

Question 13

what type of chains does Amylose have

Answer 13

Long and straight chains of alpha glucose which coil into a helix.

Question 14

what type of chain does Amylopectin have

Answer 14

Branched chain of alpha glucose molecules.

Question 15

why is amylose compact

Answer 15

so it is good for storage

Question 15

A starch molecule has a spiral shape.
Explain why this shape is important to its function in cells.

Answer 15

Compact/occupies small space/tightly packed;

Question 15

where is glycogen stored

Answer 15

muscles and liver

Question 15

why is amylopectin branched

Answer 15

provides a large surface area for rapid hydrolysis by enzymes.

Question 16

Explain one way in which starch molecules are adapted for their function
in plant cells

Answer 16

1.Insoluble;
2.Don’t affect water potential;
OR
3.Helical; (Accept form spirals)
4.Compact;
OR
5. Large molecule;
6.Cannot leave cell;

Question 17

where is Alpha glucose found

Answer 17

is the monomer found in STARCH and GLYCOGEN.

Question 18

where is Beta glucose found

Answer 18

found in CELLULOSE (in the cell wall)

Question 19

The structure of cellulose is related to its role in plant cell walls. Explain how.
(3)

Answer 19

Long/straight/unbranched chains (of glucose);
(Joined by) hydrogen bonds;
Form microfibrils
Provide rigidity/strength/support;

Question 20

Hydrogen bonds are important in cellulose molecules. Explain why.

Answer 20

1. Holds chains/cellulose molecules together/forms cross links between
   chains/cellulose molecules/forms microfibrils;
2. Providing strength/rigidity (to cellulose/cell wall);
3. Hydrogen bonds strong in large numbers;

Question 21

Describe how the student
would show that reducing
sugars were present in a
solution.

Answer 21

1. Add equal volumes of Benedict’s solution;
2. Heat to 95 ⁰C;
3. Red/orange/yellow/green precipitate (shows
   reducing sugar present);

Question 22

Describe how the student would show that a non-reducing sugar was present in a solution.

Answer 22

1. Add dilute hydrochloric acid (HCl) to sugar solution; 2. Boil sugar solution; 3. Add sodium hydrogen carbonate (NaHCO₃) to neutralise; 4. Add equal volumes of Benedict’s solution to the sugar solution; 5. Heat to 95 ⁰C; 6. Red/orange/yellow/green precipitate (shows reducing sugar present);

Question 23

Describe how you would produce a calibration curve and use it to obtain results

Answer 23

1. Make up several known concentrations of maltose/glucose/lactose/galactose/ fructose; 2. Carry out the Benedict’s test on each sample; 3. Use a colorimeter to measure the colour of each solution and plot a calibration curve; 4. Find the concentration of the unknown sample using the calibration curve;

Question 24

Describe how you would test a sample of food for the presence of starch.

Answer 24

1. Add iodine/potassium iodide solution to the food sample; 2. Blue/black/purple indicates starch is present;

Question 25

Omega-3 fatty acids are unsaturated. What is an unsaturated fatty acid?

Answer 25

Double bond(s); (Bonds) between carbons in the hydrocarbon chain;

Question 26

Some seeds contain lipids. Describe how you could use the emulsion test to show that a seed contains lipids. (3)

Answer 26

1. Crush/grind; 2. With ethanol/ alcohol; 3. Then add water/then add to water; 4. Forms a white emulsion;

Question 27

What are the differences between a triglyceride and a phospholipid?

Answer 27

1. Fatty acid removed 2. Replaced with a phosphate group