Carbohydrates

Question 1

What are carbohydrates made from?

Answer 1

Monsaccharides

Question 2

What is the general formula of a monosaccharide?

Answer 2

[CH2O]n (n = 3-7)

Question 3

What kind of sugar is glucose?

Answer 3

6 carbon (hexose)

Question 4

What are some isomers of glucose

Answer 4

• Fructose
• Galactose

Question 5

What are examples of pentose sugars?

Answer 5

• ribose
• deoxyribose
• ribulose

Question 6

What are examples of triose sugars?

Answer 6

• glycerate phsphate
• glyceraldehyde

Question 7

What is a disaccharide?

Answer 7

Two monosaccharides joined with a glycosidic bond [C-O-C]

Question 8

What does a glycosidic bond involve?

Answer 8

• Condensation reaction
• Formation of a molecule of water

Question 9

Which chemical reaction is used to digest carbohydrates?

Answer 9

Hydrolysis (adding a water molecule)

Question 10

What are 3 examples of diasaccharides?

Answer 10

• Maltose
• Sucrose
• Lactose

Question 11

Describe maltose

Answer 11

• Glucose + Glucose
• Formed from the digestion of starch
• Via amylase enzyme

Question 12

How is starch broken down?

Answer 12

By amylase enzyme
- Starch (100s of glucose molecules)
- Dextrins (10s)
- Maltose (2)
- Glucose (1)

Question 13

Describe Sucrose

Answer 13

• Glucose + Fructose
• Main transport sugar in phloem vessels (leaves -> roots)

Question 14

Describe Lactose

Answer 14

• Glucose + Galactose
• Found in mammalian milk

Question 15

What is a polysaccharide?

Answer 15

Long chains of glucose monomers (often 1000s) joined by glycosidic bonds

Question 16

What are the two types of glucose?

Answer 16

Alpha and Beta

Question 17

What are 3 examples of polysaccharides?

Answer 17

• Starch
• Glycogen
• Cellulose

Question 18

Describe starch

Answer 18

• Storage in plants (in roots)
• Insoluble so does not change water potential of cells - doesn’t influence osmosis
• Mixture of amylose and amylopectin

Question 19

What is amylose?

Answer 19

• A poly [1-4] alpha glucose chain
• Coils into a helix held together by hydrogen bonds for stabilisation

Question 20

What is amylopectin?

Answer 20

• A poly [1-4] alpha glucose chain with [1-6]
• Has multiple ends so can be hydrolysed quickly by almylase enzymes (int maltose)

Question 21

Describe Glycogen

Answer 21

• Storage in muscle and liver (animal) cells
• Poly [1-4] alpha-glucose chain with [1-6] branches
• Multiple ends so can be hydrolysed quickly by enzymes (glycogen phosphorylase) to mobilise glucose for energy
• More branched than amylopectin because it is needed much more in the muscles and liver

Question 22

Describe Cellulose

Answer 22

• Main component of plant cell wells
• Poly [1-4] beta glucose chain
• Hydroxyl group on carbon 1 in a different position to alpha-glucose
• ALternate glucose molecules inverted to form a straight chain
• Hundreds of alternating chains are joined with hydrogen bonds
• Forms microfibrils which are very strong
• Beta-glycosidic bond is hydrolysed by enzyme cellulase - only bacteria have cellulase so herbivorous animals have mutualistic relationships with bacteria in order to break down their food