Carbohydrates

Question 1

What is a carbohydrate

Answer 1

• a molecule that only contains carbon, hydrogen and oxygen

- also known as saccharides/sugars

Question 2

What is glucose

Answer 2

• glucose is a hexose monosaccharide
• chemical formula : C6 H12 O6
• glucose is polar and soluble in water, due to the hydroxyl groups forming hydrogen bonds with the water

Question 3

Describe the process of a condensation reaction forming disaccharide maltose

Answer 3

• an enzyme cleaves the hydroxide from from Carbon 1 of the first Glucose
• another enzyme cleaves a hydrogen from the OH group of carbon 4 of the second glucose
• Oxygen covalently bonds to carbon 1 and 4 forming a 1-4 glycosidic bond
• water is formed from the hydroxide and the hydrogen

Question 4

Fructose, galactose and glucose

Disaccharides they form

Answer 4

• all these sugars are hexose monosaccharides
• fructose and glucose form sucrose, used in plants,
• galactose and beta glucose form lactose found in milk products

Question 5

What is amylose structure and function

Answer 5

• amylose is made of alpha glucose
• it contains 1-4 glycosidic bonds only
• has a helix shape due to rotation at the bonds
• it is a large molecule
• it is INSOLUBLE
• it is COMPACT
• it’s compact shape makes it useful for storage and it’s insoluble in water allows it to be stores without disrupting osmosis

Question 6

What is Amylopectin

Answer 6

• Amylopectin is also made of alpha glucose
• it has 1-4 and occasional 1-6 glycosidic bonds
• more branches than amylose can be more rapidly hydrolysed
• starch is made up of amylose and amylopectin

Question 7

Starch is not used to store glucose in animals what is the polysaccharide that is

Answer 7

• glycogen is a chain of alpha glucose residues joined by 1-4 and 1-6 glycosidic bonds
• more 1-6 bonds than amylopectin can be more rapidly hydrolysed to glucose
• this makes it suitable for highly active mammals

Question 8

What is cellulose

Answer 8

• cellulose is formed from beta glucose
• every other beta glucose is turned 180 degrees so a 1-4 glycosidic bond can be formed
• beta glucose does not coil, it’s polymer is straight, this allows there to be many hydrogen bonds between polar OH groups on adjacent cellulose
• it has high tensile strength
• forms the cell wall of plants