Intro to Carbohydrates

Question 1

Monosaccharide structure

Answer 1

• 3-6 C atoms

- Carbonyl group & hydroxyl group

Question 2

Fischer projection

Answer 2

Most oxidised group at top (carbonyl)

Question 3

L & D notations

Answer 3

Side of OH on chiral furthest from carbonyl:

• Left = L
• Right = D

Question 4

Naturally occurring carbohydrate isomer

Answer 4

D isomer

Question 5

Aldoses

Answer 5

1 aldehyde group w hydroxyls

Question 6

Ketoses

Answer 6

1 ketone group w hydroxyls

Question 7

D-glucose

Answer 7

Aldohexose

Question 8

Epimers

• what
• example

Answer 8

• Differ at chiral centre (not one which determines L or D)

- D-glucose vs D-galactose (C4 = difference)

Question 9

Cylic structures

• when occur
• RHS goes…

Answer 9

• 5/6 C, often in solution

- RHS goes BELOW

Question 10

Anomers

• what
• example

Answer 10

• cyclic monosaccharides differing around C1/2

- glucose –> alpha vs beta

Question 11

Starch

• function
• 2 types

Answer 11

• Plant energy storage

- Amylose, amylopectin

Question 12

Amylose vs amylopectin

Answer 12

• Unbranched, only a-1-4
  vs
• Branched, a-1,4 & a-1,6

Question 13

Cellulose

Answer 13

b-1,4 linkages

Glucose = in inverted orientation (e.g. C6 = above, then below)

Question 14

Cellulose in mammals

Answer 14

Passes through as ‘roughage’

Question 15

Glycogen

• what
• function
• structure
• storage

Answer 15

• Most common polysaccharide in animals
• Storage form of glucose
• Branched –> glycosidic links a-1,4 and a-1,6
• In liver & muscles

Question 16

Reducing sugar

• ion change
• colour change
• reaction in monosaccharides

Answer 16

• Cu2+ reduced to Cu+
• Blue –> orange
• Carbonyl group donates electrons (is oxidised)

Question 17

Spectrophotometer measures concentration using…

Answer 17

• Absorbance

- Compare w absorbance of different known concentrations

Question 18

Measuring glucose conc over short time (example)

Answer 18

Urine dip-stick

Question 19

Galactosemia

• caused by
• effects
• solution

Answer 19

• Lack enzyme for galactose –> glucose SO accumulate galactose intermediates
• Toxic effects in liver, brain etc (as energy dependent)
• Avoid lactose

Question 20

Measuring glucose conc over long time (example)

Answer 20

Glycation

Question 21

How does glycation work x3

Answer 21

• glucose enters rbcs
• binds w haemoglobin
• more glucose = more binding

Question 22

Why is glycation long-term

Answer 22

Rbcs have life-span of ~3 months

Question 23

Lactose

• which monosaccharides
• where is link

Answer 23

• b-D-galatose + a/b-D-glucose

- b-1,4 glycosidic (b from galactose)

Question 24

Lactose intolerance

• why
• what happens
• symptoms
• causes

Answer 24

• lack of lactase
• lactose –> colon –> fermented by bacteria
• stomach cramps, bloating etc
• inherited OR developed