Chapter 1.2 & 1.3: CARBOHYDRATES - MONOsaccharides, DIsaccharides and POLYsaccharides

Question 1

What elements is CARBO-HYDR-ATE made out of?

Answer 1

CARBON, HYDROGEN and OXYGEN

Question 2

What element determines an organic molecule?

Answer 2

CARBON

Question 3

Carbohydrate = “n”
What is n x 1?
What is n x 2?
What is n x (3

Answer 3

MONOSACCHARIDE
DISACCHARIDE
POLYSACCHARIDE

Question 4

Properties of MONOsaccharides…

Answer 4

• tastes sweet

- soluable

Question 5

What is the simple/general formula for MONOsaccharides?

Answer 5

(CH2O)n

Question 6

Name 3 examples of MONOsaccharides

Answer 6

GLUCOSE, FRUCTOSE and GALACTOSE

Question 7

What is the two different types of arrangements of glucose?

Answer 7

ALPHA glucose and BETA glucose

Question 8

What is the difference between both differently-structured type of glucose?

Answer 8

Starting from the CH*2OH going anti-clockwise. 
For ALPHA GLUCOSE; 
- OH facing down 
- OH facing up
- OH facing down 
- OH FACING DOWN

For BETA GLUCOSE;

• OH facing down
• OH facing up
• OH facing down
• OH FACING UP

Question 9

What is ALPHA glucose used for?

Answer 9

Used to make STARCH via CONDENSATION REACTION

Question 10

What is BETA glucose used for?

Answer 10

It is used to make CELLULOSE via CONDENSATION REACTION

Question 11

What are REDUCING SUGARS?

Answer 11

They have an OH group attached to the ANOMERIC CARBON so they can bind and react with other compounds

Question 12

What do you use to test reducing sugars?

Answer 12

BENEDICTS REAGANT (CuSO*4)
Blue

Question 13

When BENEDICT’S REAGENT reacts with reducing sugars, what change is produced?

Answer 13

The colour changes from BLUE -> ORANGE

Question 14

Describe of how the investigation for REDUCING SUGARS is carried out?

Answer 14

• add 2cm*3 of good sampling to be tested in a testube
• add an equal amount of BENEDICT’S REAGENT
• heat in a water bath
• if reducing sugar is present, it turns BLUE -> ORANGE/ BROWN

Question 15

What is ALPHA GLUCOSE + FRUCTOSE?

Answer 15

SUCROSE

Question 16

What is ALPHA GLUCOSE + GALACTOSE?

Answer 16

LACTOSE

Question 17

What is ALPHA GLUCOSE + GLUCOSE?

Answer 17

MALTOSE

Question 18

MONOsaccharides join via CONDENSATION REACTIONS. The linking bond between these MONOsaccharides are called “?”

Answer 18

GLYCOSIDIC BONDS

Question 19

What is an easier way to remember ALPHA GLUCOSE + GALACTOSE -> LACTOSE

Answer 19

GALActose
GALAXY
MILKY-way
LACTOSE

Question 20

Which one is right?
A: All MONOsaccharides and DIsaccharides are reducing sugars

B: Only All MONOsaccharides are reducing sugars

C: Some MONOsaccharides and some DIsaccharides are reducing sugars

D: All MONOsaccharides and some DIsaccharides are reducing sugars

E: Some MONOsaccharides and all DIsaccharides are reducing sugars

Answer 20

D

Question 21

Describe the method for testing NON-REDUCING SUGARS

Answer 21

• firstly add sodium hydroxide to the solution to neutralise
• then add hydrochloric acid to break the glycosidic bonds in between the saccharide molecules
• then add BENEDICT’S REAGENT and of the colour changes RED, it is a NON-REDUCING SUGAR
• if it does not change then it is NOT a NON-REDUCING SUGAR

Question 22

What is a POLYsaccharide?

Answer 22

Very large molecules of single MONOsaccharide molecules joined together forming a lot of GLYCOSIDIC BONDS