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HOMEWORK 3 is NOW Due on Tuesdaymorning!!!

Will have lots of office hours on Monday.

Office Hours Today? Let me know if youare coming by.

9:15-11, 1-1:30 3-4

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Table 4.3 Thermo. of Metabolism pp135-138: Like Problem S1.

361 Lec 21Fri., 5oct18

Hydrolysis

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Table 4.3 Thermo. of Metabolism pp135-138: Like Problem S1.

361 Lec 21Fri., 6oct17

Phosphorylations involvingATP

Hydrolysis

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Table 4.3 Thermo. of Metabolism pp135-138: Like Problem S1.

361 Lec 21Fri., 6oct17

Oxidation

Reduction

Reduction

Oxidations and Reductions involving NADHNAD+

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Table 4.3 Thermo. of Metabolism pp135-138: Like Problem S1.

361 Lec 21Fri., 6oct17

Dehydration

Decarboxylation

Isomerization

Dismuation

Isomerization

Isomerization

Isomerizations

10/08/12 6

Reverse the above and add it to the ATP equation

-14.3

Find ∆G0’ for the HYDROLYSIS of D-glucose-6-phosphate(A reaction that is NOT in the Table but can be deduced from what is.)

ATP ADP

PO43

- H2O

https://en.wikipedia.org/wiki/Glucose_6-phosphate

Hexokinase

Glucose 6 phosphatase

The first step of burning glucose is add a phosphate to the 6 positionThis a very uphill reaction, as can be seen for the ∆G0’

when coupled to hydrolysis of ATP.

Half of the -31 kJ/mol is used to put on the phosphate!

Problem S1 is no more complicated than this example!

Glucose

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But, ATP CANNOT drive this reaction WITHOUT an enzyme that COUPLES the two reactions.

No reaction will happen by putting ATP + glucose in water without enzymefor many years!

10/08/12

ATP is bound closeto glucose in a positonto transfer phosphate

Remember the statement:Enzymes are the pulleys ofbiochemistry?

810/08/12

I made up these numbers, but it must be somethinglike this.

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Adapted from D.A. Harris, Bioenergetics at a Glance;Blackwell, Oxford 1995

** * *

Thermodynamics of Metabolism pp135-138

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NADH is a more easily “Reduced Species”

Gluose is partly reducedand partly oxidized

Tim Vickers, Wikipedia

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http://en.wikipedia.org/wiki/Oxidative_phosphorylation

“... transport protons across the inner mitochondrial membrane, in a process called chemiosmosis. This generates potential free energy in the form of a pH gradient and an electrical potential...”

about 1000 mitrochondria /cell x 1014 cells in body = approx 1017 mitrochondriain our bodies. They cycle ~100 lbs of ADP---> ATP--->ADP per day.

Electron transferis coupled to PROTON transfer

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CITRIC ACID CYCLE (where the NADH comes from)

13http://en.wikipedia.org/wiki/Oxidative_phosphorylation

Electron transferis coupled to PROTON transfer

14http://en.wikipedia.org/wiki/Oxidative_phosphorylation

MORE Electron transferis coupled to PROTON transfer

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Myoglobin

16http://en.wikipedia.org/wiki/Oxidative_phosphorylation

Even MORE Electron transferis coupled to PROTON transfer, as electronsfinally arrive at O2

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Reading for Monday: Chapter 7: pp 241-247 (Electrochemistry)Why Electrochemistry in this course??: Useful work (wother) from harnessing electron transfer reactions

These voltages aremerely another wayto express GibbsFree Energy !!

Electron transfer

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Standard Reduction Potentials

electronsfrom H2(g)

electronsspontaneouslygo from negativeto positive potential

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Electrochemistry: Harnessing electron transfer reactionsConsider Zn(s) + Cu2+(aq) Zn2+(aq) + Cu(s)

Zn(s) Cu(s)

Cu2+ Zn2+e-

∆G0 = -214 kJ/mol ; What will happen?

on left: electrons flow from Zn(s) to Cu2+ , to the point of dissolvingdissolving all the Zn metal that is in the liquid.On left: NOTHING

Answer: + chargebuilds up in Zn andelectrons can’t getout.

Reading: Chapter 7: pp 241-247

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Zn(s) Cu(s)

Cu2+Zn2+e-

e- e-

Voltmeter

Consider Zn(s) + Cu2+(aq) Zn2+(aq) + Cu(s)

Make the electrons go the long way around and grab on to them

negative charge builds up has HIGH resistance

salt bridge

Voltage will build upbut still nothing happens.WHY?

On Monday:

Continue with ElectrochemistryChap. 5 pp 241-247

which will be on Exam 2

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361 Lec 22Mon., 5oct15

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max (reversible) Volts = J/coulomb is a measure of ∆G

∆G = -T ∆Suniv + wuseful at const T, P

for reversible process: -T ∆Suniv = 0 (as current---> 0)∆G = wother, rev = -nFξ = coulombs x volts= MAX useful work where n = moles of electrons and F = -96500 coulombs/mol

ξ = equilibrium voltage in J/coulomb

ξ = ∆G/(-nF) ξ0 = -∆G0/(nF) = STANDARD REDUCTION POTENTIALA very popular way among biochemists to talk about ∆G0 !!