Carbohydrates

Question 1

which monomers form carbohydrates

Answer 1

monosaccharides

Question 2

Three monosaccharides

Answer 2

Glucose, galactose, fructose

Question 3

Formula of monosaccharides

Answer 3

C6H12O6

Question 4

bond formed due to the condensation reaction between two monosaccharides

Answer 4

glycosidic bonds

Question 5

2 glucose isomers

Answer 5

alpha glucose and beta glucose

Question 6

Definition of isomer

Answer 6

A substance with the the same chemical formula but a different structural formula

Question 7

condensation reaction between two monosaccharides

Answer 7

between the OH group of carbon 4 of one and the Carbon 1 group of another.
It forms a 1-4 glycosidic bond

Question 8

3 dissacharides

Answer 8

maltose,lactose,sucrose

Question 9

the monosaccharides which form maltose

Answer 9

alpha glucose + alpha glucose

Question 10

the monosaccharides which form lactose

Answer 10

galactose and glucose

Question 11

the monosaccharides which form sucrose

Answer 11

glucose and fructose

Question 12

What happens to carbohydrates in digestion

Answer 12

they are broken down into monosaccharides to be absorbed and used by the body.

Question 13

Use of monosaccharides in the body

Answer 13

glucose is needed for respiration.

Question 14

reducing sugars

Answer 14

glucose, galactose,lactose,maltose and fructose

Question 15

non reducing sugar

Answer 15

sucrose

Question 16

test for reducing sugars

Answer 16

heat the sample in Benedict’s solution to 95 degrees Celsius.
observe a colour change fro, BLUE to green/yellow/orange/red.

Question 17

test for non reducing sugars

Answer 17

boil fresh sample in HCl for a few minutes to hydrolyse the glycosidic bonds.
neutralise by adding solid sodium hydrogen carbonate.
then repeat the test for reducing sugars (describe fully in exam)
as the sucrose is hydrolysed into glucose and fructose which are reducing sugars.
The colour change will be from blue to brick red.

Question 18

test for starch

Answer 18

add iodine solution (potassium iodide) and there will be a colour change from orange to blue-black