whether a chemical reaction COULD occur spontaneously (if it is favorable)

Which direction the NET reaction could proceed

• measure of how far the conditions are from equilibrium
• measure of how much energy is available in a chemical reaction

How does the sign of ∆G predict the direction of reactions?

(< > or =)

∆G < 0 means the reaction is exergonic (forward reaction)

∆G > 0 means the reaction is endergonic (reverse reaction)

∆G = 0 means reaction is at equilibrium

What different ∆H means

(negative and positive)

-∆H means more stable bonds are formed and heat released (exothermic)

+∆H means less stable bonds and heat absorbed (endergonic)

Entropy change

Change in randomness

∆G = -RT ln(K_eq)

or

∆G = -6 log(K_eq)

• how far from equilibrium
• how much energy is available as a reaction proceeds to equilibrium

enzymes can change rate and K_eq

(T or F)

ATP is kinetically stable

(T or F)

PEP

Phospate compound with high energy of hydrolysis

hydrolysis does not occur in glycolysis

1,3-diPGA

phosphate compound with high energy of hydrolysis

when phosphates are donated/received

(energy transfer potential)

High energy transfer potential donates phosphate

low energy transfer potential receives phosphate

ATP is in the middle (donate and receive)

Bonds are broke to yield energy

(T or F)

Net reaction of glycolysis

Glucose + 2NAD⁺ + 2ADP + 2P_i goes to...

Preparatory Phase

and

Payoff Phase

catalyzes the transition of phosphohexose to an isomer

(aldose to a ketose)

Phosphofructokinase

(what it does and ∆G)

Catalyzes the transfer of a phosphate group to a phosphofructose molecule

∆G = -14.2 kJ/mol

Aldolase

(What it does and the ∆G)

catalyzes the cleavage of an aldehyde (hexose) to 2 trioses (Dihydroxyacetone-P and Glyceraldehyde-3-P)

∆G = +23.8 kJ/mol

Triose Phosphate Isomerase (TPI)

(What it does and the ∆G)

catalyzes the transition of dihydroxyacetone-P to its isomer, Glyceraldehyde-3-P

∆G = +7.5 kJ/mol

Oxidation of Glyceraldehyde-3-P

(What occurs and ∆G)

removes a hydrogen and adds a phosphoryl group

∆G = +6.3 kJ/mol

ONLY REDOX REACTION IN GLYCOLYSIS

substrate level phosphorylation

∆G = -18.5 kJ/mol

Phosphoglycerate Mutase

(what it does and ∆G)

re-arrange molecule so the phosphate is in the high energy state allowing it to donate the phosphate to ATP

∆G = +4.4kJ/mol

helps form phosphoenolpyruvate by redistributing energy to raise the energy level

∆G = +7.5 kJ/mol

Pyruvate Kinase

(what it does and ∆G)

second payoff phase

Takes a phosphoryl group from pyruvate (PEP) and puts it on ADP to make ATP

∆G = -31.4 kJ/mol

enzymes can be used for a forward reaction or reverse, not both

"turn off" the enzyme when it isn't used in the direction

gain of ATP from glycolysis

(net and total)

net = 2 molecules of ATP

total = 2 molecules of ATP

NADH has low energy

(T or F)

Where is the energy in a molecule stored?

(type of bond)

Dehydrogenase

(What it does)

Aerobic produces 30 net ATP

Anaerobic produces 2 net ATP

Pyruvate Dehydrogenase mechanism

(Enzyme 1)

Pyruvate Dehydrogenase mechanism

(Enzyme 2)

Pyruvate Dehydrogenase mechanism

(Enzyme 3)

Which is not an importance of the citric acid cycle?

1. bulk of the energy comes from here
2. convergence of fats, carbs and proteins
3. precursors for biosynthesis/intermediates recycled
4. occurs in cytosol

Citrate Synthase

(What is does and ∆G)

makes citrates

∆G = -32.2 kJ/mol

Citrate synthesis is the first and committing step (regulated)

(T or F)

Aconitase

(What it does and ∆G)

converts citrate to isocitrate (isomerization catalyzed by water being removed/added)

∆G = +13.3 kJ/mol

Isocitrate Dehydrogenase

(What is it and ∆G)

isocitrate to alpha-ketoglutarate

∆G = -20.9 kJ/mol

pyruvate dehydrogenase...enzyme 1 and 2 are similar but enzyme 3 is exactly the same

all 5 cofactors are the same

Alpha-Ketoglutarate (AKG) Dehydrogenase Complex

(what is it and ∆G)

AKG goes to succinyl-CoA

∆G = -33.5 kJ/mol

Succinyl CoA synthetase

(What is it and ∆G)

Succinyl-CoA to succinate

∆G = -2.9 kJ/mol