1. Lecture 4 Slides rh

2. Oxidation
and
Reduction
as it pertains to biochemistry

3. please read
Read The Slow Burn

4. fig 13-22

5. fig 13-22

6. reduction potential
can be measured
ref.
cell
test
cell
fig 13-23

7. Fe3+ + Cu+ Fe2+ + Cu2+ Cu2+ + e- Cu+ Fe3+ + e- Fe2+
Redox reactions as pairs of half-reactions
Fe Cu+
Fe Cu2+
The half-reactions:
Cu2+ + e-
Cu+
E'o = -.18
Fe3+ + e-
Fe2+
E'o = .77
always reductions! rh

8. Fe3+ + Cu+ Fe2+ + Cu2+ Cu+ Cu2+ + e- Fe3+ + e- Fe2+ Fe3+ + Cu+
Energetics calculated from half-reactions
Fe Cu+
Fe Cu2+
what is E'o for this reaction ?
Cu+
Cu2+ + e-
E'o =.18
Fe3+ + e-
Fe2+
E'o = .77
Fe3+ + Cu+
Fe2++ Cu2+
E'o =
( ) rh

9. rh

10. DG'o = -nFE'o relationship between free energy and reduction potential
one confusing thing: by the convention,
positive E means spontaneous reaction…
or negative DG. rh

11. Fe3+ + Cu+ Fe2+ + Cu2+ Cu+ Cu2+ + e- Fe3+ + e- Fe2+ Fe3+ + Cu+
Energetics calculated from half-reactions
Fe Cu+
Fe Cu2+
what is E'o for this reaction ?
Cu+
Cu2+ + e-
E'o = .18
Fe3+ + e-
Fe2+
E'o = .77
Fe3+ + Cu+
Fe2++ Cu2+
E'o = 0.95 rh

12. DG'o = -nFE'o
nFE'o rh

13. Fe2+ + Cu2+ Fe3+ + Cu+ rh familiar from earlier chemistry classes…
BUT WHAT ABOUT SOMETHING LIKE THIS?:
glucose rh

14. Oxidation of a "model" sugar molecule: CH2O
glucose
general:
let's make n=1, to aid understanding rh

15. Oxidation of a "model" sugar molecule: CH2O
1) removal of electrons from sugar rh

16. Oxidation of a "model" sugar molecule: CH2O
2) reduction of oxygen rh

17. Oxidation of a "model" sugar molecule: CH2O
3) production of CO2 rh

20. Table of Standard Reduction Potentials
TOP
MIDDLE
BOTTOM

21. NAD+ and NADH
fig 13-24

22. The business end of NAD and NADP
this moiety is from the vitamin niacin rh

23. moi·e·ty (moi-t)n.One of two or more parts into which something may be divided, such as the various parts of a vitamin or molecule. ?
this moiety is from the vitamin niacin rh

24. table 13-8

25. FAD and FADH2 (and FMN and FMNH2)
fig 13-27

26. isoalloxazine ring The business end of FAD or FMN rh
this moiety is from the vitamin riboflavin rh

27. fig 13-9