lecture 12 - carbohydrate structure

Question 1

what is an aldose?

Answer 1

If there is sugar which also has an aldehyde group on it

Question 2

what is a ketose?

Answer 2

if there is sugar which also has an ketone group attached to it

Question 3

What type of sugar is glucose and galactose?

Answer 3

aldoses

Question 4

What type of sugar is fructose?

Answer 4

ketose

Question 5

What is another name for glucose?

Answer 5

aldohexose

Question 6

What is the Fisher convention?

Answer 6

D sugars have the absolute configuration at the asymmetric centre farthest removed from there carbonyl group as doe D - Glyceraldehyde

Question 7

What does erythrose mean?

Answer 7

The same groups are on the same side as the Fisher projection

Question 8

What does threo mean?

Answer 8

The groups are on opposite sides of the Fisher projection

Question 9

What is an epimer?

Answer 9

sugars that differ by only the configuration around one atom

Question 10

What is a method for determining D and L isomers?

Answer 10

Optical rotation , if they rotate the light to the right its D (Dextro) . If the light rotates left the its L (levy)

Question 11

How to determine the number of isomers a compound has?

Answer 11

2^n . n = number of chiral centres

Question 12

How to form a hemiacetal?

Answer 12

Alcohol and aldehyde

Question 13

What is ring glucose?

Answer 13

hemiacetal

Question 14

How to form a hemiketal?

Answer 14

alcohol and ketone

Question 15

what is ring fructose?

Answer 15

hemiketal

Question 16

What is the name of a 6 membered ring with an oxygen in it?

Answer 16

pyranose

Question 17

what is the name of a 5 membered ring with an oxygen in it?

Answer 17

fruanose

Question 18

What are the 4 different forms of glucose ?

Answer 18

a-D- Glucopyranose
B-D - Glucopyranose
a-D-glucofuranose
B-D- Glucofuranose

Question 19

What are diastereomers?

Answer 19

Contain chiral centres which are non-superimposable but are NOT mirror images

Question 20

what type of epimer is galactose in relation to glucose ?

Answer 20

C4 epimer

Question 21

What type of epimer is Mannose in relation to Glucose?

Answer 21

C2 epimer

Question 22

What is another definition of an epimer?

Answer 22

chorally opposite centre

Question 23

which conformation isomer stable, the chair or the boat?

Answer 23

chair

Question 24

which from of glucose is more common In solution Furanose or pyranose?

Answer 24

pyranose (99%)

Question 25

which anomer is more common , a or B?

Answer 25

B (63%)

Question 26

What is an anomer?

Answer 26

An anomer is an epimer at the hemiacetal/acetal carbon in a cyclic saccharide,

Question 27

Which form Is fructose most commonly in ?

Answer 27

B -pyranose form (70%)

Question 28

What is the parent sugar for the aldose series?

Answer 28

3 carbon , glyceraldehyde

Question 29

What is the parent sugar for the ketose series?

Answer 29

dihydroxyacetone