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Rx of Sugars

I. Introduction into Redox

Reactions

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Redox Reactions

•  All reactions exchange electrons

• The substrate that gains e- is reduced

• The substrate that loses e- is oxidized• Indicated by brackets

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 Another helpful acronym

"OIL RIG"

O Oxidation

I Is

L Loss of electrons

R Reduction

I Is

G Gain of electrons

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xample

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 Assigning !xidation numbers

• Ions"Ionic compounds# follo$ rules of group

number 

!%-  # -%

&a! # &a%' !%- so &a# '% !# -%

(b)S!*+%  (b# ,,,, S!*# ,,,, 

iatomic molecular compounds# neutral%/ !%  # 0

1onoatomic 1etals# neutral

1g# 0

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2hat about molecular

compounds3lectronegati4ity determines !5

Oxygen: )igh 5 6.7+ is al$ays -2Hydrogen: ) lo$ 5 is %.8+ is al$ays '8

&arbon# 4aries depending on bonding $ith

9!/ 9

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!xidation number of elements

in molecules

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(roblem# e- are in4isible:

;se transfer of ! and • Reduction# gain of H or loss of O

• !xidation# gain of O or loss of H

xample#

&arbon# oxidized lost

!xygen# reduced gained

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xample

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Reducing and !xidizing Agents

Reducing Agent

is a substance )

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!xidation of 1onosaccharidesTesting for reducting sugars: Benedicts Test

•?lucose is ,,,,,,,,,, and is a)n+,,,,,,,,agent

•&opper is ,,,,,,,,,,, and is a)n+ ,,,,,,,,agent

  &u%' copper is ),,,+ →&u%! copper ),,,+

&u'S!6

!u

2!

 #lue!O2

! u2O red

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!xidation of isaccharides

•  All disaccharides that ha4e an accessible @"

in the %nd monosacch. can open and oxidize

2hich of our 6 disaccharides can oxidize3

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!xidation of (olysaccharides

• do not oxidize

• are not reducing carbs