SPEC POINT 1.12

Question 1

What are carbohydrates?

Answer 1

Carbohydrates are biological macromolecules made up of smaller molecules called monomers, including only C, O and H atoms

Question 2

What are monosaccharides?

Answer 2

The monomers of carbohydrates, sugars formed from molecules with varying numbers of C atoms
General formula = (CH2O)n, where n is the number of carbon atoms in the molecule

Question 3

What is the function of monosaccharides?

Answer 3

To store energy within their bonds, so when broken during respiration, energy is released
They are rapidly absorbed and require little, or in the case of glucose, no change before being used in cellular respiration

Question 4

What are some examples of monosaccharides?

Answer 4

Glucose, galactose, fructose

Question 5

What are disaccharides?

Answer 5

Molecules formed when 2 monosaccharides join together via a condensation reaction, held together by a glycosidic bond

Question 6

What is the function of disaccharides?

Answer 6

To provide the body with a quick release source of energy as they are easily broken down by enzymes and absorbed into the bloodstream

Question 7

What are some examples of common disaccharides?

Answer 7

Sucrose (glucose and fructose) 1,2 glycosidic
Maltose (two glucose) 1,4 glycosidic
Lactose (glucose and galactose) 1,4 glycosidic

Question 8

Why does eating complex carbohydrates not cause the swings in blood sugar seen after eating monosaccharides?

Answer 8

Complex carbohydrates (polysaccharides and disaccharides) have to be digested into monosaccharides before being absorbed, which takes some time

Question 9

What are polysaccharides?

Answer 9

Carbohydrate polymers: repeated chains of many monosaccharides joined by glycosidic bonds

Question 10

What are the 3 main types of polysaccharide found in foods?

Answer 10

Starch and cellulose in plants, glycogen in animals

Question 11

What 2 molecules is starch made up of?

Answer 11

Amylose and amylopectin

Question 12

What is the structure of amylose (starch)?

Answer 12

1. Made of alpha glucose monomers
2. Joined by alpha 1-4 glycosidic bonds
3. Straight, unbranched chain
4. Forms a coiled molecule

Question 13

How does the structure of Amylose (starch) relate to its function?

Answer 13

1. It is insoluble so doesn’t affect water potential of cell
2. Stores glucose (hydrolysed for use in respiration) in plants
3. Compact so can be stored inside cells

Question 14

What is the structure of amylopectin?

Answer 14

1. Made of alpha glucose monomers
2. Joined by alpha 1-4 and alpha 1-6 (branchpoint) bonds
3. Branched molecule

Question 15

How does the structure of Amylopectin relate to its function?

Answer 15

1. Store of glucose in plants
2. Greater storage of glucose per volume
3. More terminal ends increase rate of hydrolysis, and rate of supply of glucose for respiration

Question 16

What is the structure of Glycogen?

Answer 16

1. Made of alpha glucose monomers
2. Joined by alpha 1-4 and alpha 1-6 (branchpoint) bonds
3. Heavily branched molecule

Question 17

How does the structure of Glycogen relate to its function?

Answer 17

1. Store of glucose in animals
2. Greater storage of glucose per volume
3. More terminal ends increase rate of hydrolysis, and rate of supply of glucose for respiration

Question 18

Why does glycogen give easy access to stored energy?

Answer 18

It has numerous side branches, meaning it can be rapidly hydrolysed to give access to it’s energy

Question 19

Why are starch and glycogen good storage molecules?

Answer 19

Compact spiral structure and insoluble nature means they are excellent storage molecules. Do not diffuse across cell membranes and have very little osmotic effect within the cell