BMP: Introduction to Carbohydrates

Question 1

What are examples of carbohydrates?

Answer 1

• Starch
• Sucrose
• DNA/ RNA
• Lactose

Question 2

1. what are carbohydrates?
2. What is the empirical formula
3. What classes of sugars are they are how are these synthesised/ broken down

Answer 2

1. Carbohydrates are:
   
   • Made of C,O,H
   • C and O ratio approx equal (highly oxidised)
   • Natural molecules containing many hydroxyls and oxygen containing groups
2. (C(H20))n
3. Monosaccharides can’t be hydrolysed to smaller sugars and polysaccharides are polimerised monosacharides

Question 3

What is the naming system for carbohydrates?

Answer 3

1. -aldo or -keto
2. -hexa, -tetra, -hepta (chain length)
3. -ose

aldohexose

Question 4

How do you detemermine if a carbohydrate is L or D configuration from the fishcer projeciton?

Answer 4

• The C furtherest from aldo group but not very last (as no -OH)
• If Right = D
• If left = L

Question 5

In equilibrium between fischer and haworth projection what is observed?

Answer 5

1. 0% open chain
2. 0% 5 membered rings
3. 36% a 6 membered
4. 64% b 6 membered

Question 6

1. When converting from fischer to haworth projections how do you tell the position of the -OH group?
2. When converting from fischer to haworth, how do you detemrine position of -OH group?

Answer 6

1. FISCHER:
   
   • Right- down - a
   • Left - up - b
2. HAWORTH:
   
   • Up - B - equitorial
   • Down - a - axial

Question 7

What is the rotation of D-Glucose for a and b when plane polarised light is used?

Answer 7

a - +112.2

b- +18.7

Question 8

What is the rotation of a and b D-glucose in equilibruium?

Why is this?

Answer 8

+52.5

In between a and b but closer to B as 64% B

Question 9

What would be the rotation when either a or B D-glucose was dissolve din water?

Answer 9

52.5

Question 10

What do reducing sugars contain?

Answer 10

• a hemiacetial or hemiketal group

Question 11

What reactins can be used to determine difference between reducing and non-reducing sugars

Answer 11

• Reducing sugars under go colour change with the following when non-reducing sugars dont
• Fehilings solution (Ag+)
• Tollens reagent (CU2+)
• Benedicts reagent (Cu2+)

Question 12

What is an example of a reducing sugar?

Answer 12

Glucose