Mono and disaccharides

Question 1

Draw alpha glucose

Question 2

Describe the difference between alpha and beta glucose

Answer 2

Beta glucose has the right hand side hydroxyl and hydrogen groups inverted.

Question 3

Describe the biochemical test for a reducing sugar.

Answer 3

Add an equal volume of Benedicts solution and heat in a water bath. If glucose is present it will go from blue to green, to yellow, to orange, to brick red precipitate

Question 4

Describe the biochemical test for a non-reducing sugar

Answer 4

Add an equal volume of Benedicts solution and heat in a water bath. If a non-reducing sugar is present there will be no colour change. Take a fresh sample, hydrolyse by heating with acid, then add sodium hydrogen carbonate to neutralise. Add benedicts and heat, a positive result is a brick red precipitate.

Question 5

What is glucose used for?

Answer 5

To release ATP during aerobic respiration.

Question 6

Give the disaccharides and their monomers

Answer 6

Maltose, glucose and glucose. Sucrose, glucose and fructose. Lactose, glucose and galactose.

Question 7

What reaction joins two monosaccharides together

Answer 7

Condensation reaction releasing water.

Question 8

. What reaction breaks a disaccharide?

Answer 8

Hydrolysis, a water molecule is needed.

Question 9

What is the bond between two monosaccharides called?

Answer 9

Glycosidic bond

Question 10

Draw a glycosidic bond.

Question 11

What is it called when two molecules both have the same chemical formula e.g C6H12O6 but have different structures

Answer 11

Isomers