Micros-Ch. 5.4-5.14

• (G): The energy released that is able to do work
• Delta G ⁰' : change in free energy @ standard conditions

• Exergonic - releasing free energy
• ex- conserved ATP
• Endergonic - requiring energy

• Delta G0' = Gf0 [C+D] - Gf0 [A+B]
• product - reactant

Delta G⁰' : standard conditions

• Delta G : under various conditions
• ( Delta G = Delta G⁰' + RT ln K )

Energy required for a reacion to occur

• A substance that lowers the activation energy
• --> increasing the rate of rxn
• ex- enzymes

• Biological catalysts
• made of protein
• Enzyme binds to a substrate
• @ the Activation site
• Increase the rate of rxn by 10^8-20

• 1. bind to the substrate
• 2. position the substrate

• small nonprotein molecules that aid in the catalysis.
• Prosthetic Group - tightly bound to enzyme
• ex- the heme group in Cytochrome

• Coenzyme - loosely bound to enzyme
• ex- derivative of niacin vitamin (NAD+/ NADH)

• Energy is conserved in cells from Redox rxn
• ex- ATP

• Oxidation - the removal of an e-: e- donor
• ex- H₂
• Reduction = the addition of an e- : e- acceptor
• ex- O₂

for every substance that is oxidized, one must go through reduction.

e- cant be by itself. so only half of the rxn can occur

• potential to accept or donate an e-.
• The more (+) V --> the more able to accept
• The more (-) V --> more donateable

They are expressed in half rxn.

ex: 2 H⁺ / H₂ or ¹/₂O₂ / H₂O

• H₂ is more of a donor
• O₂ is more of an acceptor

• listing of e- transfer rxn
• strongest reductant on top: (-) e -donors
• strongest oxidant on bottom: (+) e-acceptors

Some electron carriers are membrane-bound, whereas others, such as NAD⁺ / NADH, are freely diffusible coenzymes

intermediates between Redox rxn

• Two types:
• 1. Coenzyme - freely diffusible (ex-NAD, NADP)
• 2. prosthetic group -tightly bound within cytoplasmic membrane

• Freely diffusible carriers w/ 2e^- and 2H⁺
• 1.NAD ⁺ : (nicotinamide-adenine dinulceotide)

2. NADP ⁺: (NAD + phosphate)

NAD⁺ can be reduced to NADH then give away e-, making it NAD⁺ again

The most common of these compounds is ATP, the prime energy carrier in the cell. Longer-term stroage of energy is linked to the formation of polymers, which can be consumed to yield ATP

Adenosine triphosphate

ribonucleoside adenosime + 3 phosphate

• release 32kJ of energy per breakdown
• ATP --> ADP + Pi --> AMP

• energy-rich compounds
• ex - Acetyl CoA

ATP is continuously broken down to drive anabolic rxn, and resynthesize at the expense of catabolc rxn.

• Storage: insoluble polymers --> oxidized -->ATP
• EX - glycogen, 'polys' , sulfur (prokaryotes)
• starches and lipids (eukaryotes)

During these catabolic rxns, ATP is synthesized by either substrate-lvl phosphorylation(fermentation) or oxidatiive phosphorylation (respiration).

produces ATP in fermentation

**Does NOT rely on proton motive force**

produces ATP in respiration

**rely on proton motive force**

productionof ATP in phototrophs

**rely on proton motive force**

The end result of glycolysis is th release of a small amount of energy (2ATP) and production of fermented products.

fermentation of glucose (Glycolysis)

• 1. prepartory reaction
• 2. the production of NADH, ATP, and pyruvate
• 3. consumption of NADH and the production of fermented products

• yeast: pyruvate is reduced by NADH to ethanol, production of CO₂
• Lactic acid bacteria: pyruvate reduced by NADH to lactate

ALWAYS: NADH is reoxidized to NAD⁺

waste products

distillers, the brewers, and the cheese makers

Oxidation using O₂ as the terminal electron accpetor. very high yield of ATP produced.

• 1. the way e- are transferred from organic compounds to the terminal e- acceptor
• 2. the way organic carbon is converted to CO₂

• 1. mediates the transfer of e- from primary donor to terminal acceptors
• 2. conserve some energy to later make ATP

• NADH dehydrogenases
• flavoproteins
• iron-sulfur proteins
• cytochromes
• quinones

protein bound inside the surface of the cytoplasmic membrane

binds NADH --> NAD+ --> 2e^- + 2H⁺ move on.

• the next carrier of the 2e & 2H
• (keeps the 2H and passes on the 2e)

• contains riboflavin
• bound protein (prosthetic group)
• FMN & FAD

• proteins
• contain heme prothetic groups
• loses or gains e- through the Iron
• different classes: a, b, c,

• clustesr of iron and sulfur atoms
• ex- ferredoxin
• reduction potential varies
• carry electrons only

• hydrophobic
• non proteins
• in bacteria, they are related Vitamin K
• Accept 2 e- and 2 H+ but transfer only e-

Key electron carriers include: flavins, quinones, cytochrome, etc (depends on the organism)

**The cell uses the proton motive force to make ATP throught he activity of ATPsase

• pH gradient and electrochemical potential
• causing the membrane to be energized.-->ATP or just do work

• inside the membrane more negative and alkaline
• ouside the membrane more positive and acidic

Complexes I & II

• the complex that converst the proton motive force into ATP
• consists of 2 components:
• (1.) a multiprotein extramembrane complex called F₁
• (2) a proton-conducting intramembrane channel called F₀

• chemicals that affect the electron flow or the proton motive force.
• inhibitors: CO ad CN stops ETC
• uncoupling: lipid-soluble substances dinitrophenol and dicumarol - makes things leaky

reason why fermetnative organisms dont have ETC and cant do oxidative phosphorylation

instead function: generate the proton motive force

The citric acid cycle plays a major role in the respiration of organic compounds

glucose to pyruvate the same in glycolysis

no fermentation but pyruvate is oxidized to CO₂ (citric acid cyle)

Pyruvate --> acetyl CoA-->kreb's cycle