BIOCHEM 5614 ---[L3&4: Bioenergetics]

Intro To Metabolism

Exergonic (free energy, spontaneous?)

Change in G < 0

Spontaneous

Endergonic (free energy, spontaneous?)

Change in G > 0

NOT spontaneous

Which reaction do regulations typically occur in?

Irreversible pathways

Irreversible pathways

Have high energy barrier to return to the original reactants and thus proceed primarily in one direction.

Thermodynamics is the relationships of what?

Reactants to products

Favorable Change in G (free energy) will occur AND it’ll tell you how quickly it goes (T/F)

False

It only tells you the occurence, NOT the speed

What tells you how quickly a reaction occurs?

Kinetics (activation energy)

Thermodynamic Equilibria (imageS)

Standard Condition (In Chemistry)

P= 1 atm

All molecules= 1M

T= 298K (25ºC)

Standard Condition (In Biochemistry)

P= 1 atm

All molecules= 1M

T= 298K (25ºC)

Water= 55.5M

H+= 10^-7 M (7.0 pH)

*if needed, Mg2+= 1mM

remeber, realife components are rarely all at 1M

Reversible free energy amount must be…..

close to value of 0 so energy barrier is going to go through back and forth (not quite but almost like equilibria)

Discrete reactions may be ______ through a common ______

coupled

intermediate

What is the basis for metabolic pathways

coupled reactions

What can link different pathways together

coupled reactions

A coupled reactions can occur as long as the…..

Overall free energy is less than 0, it will be spontaneous

VERY important in metabolism

What drives Glucose phosphorylation?

ATP hydrolysis

First step of glycolysis does what

phosphorylates glucose entering an intestinal cell via transporters will become glucose-6-phosphate (endergonic) due to an reaction to trap the molecule within the cell

The trapping of glucose-6-phosphate isn’t energetically favorable. Discuss next step.

Couple with ATP Hydrolysis (exergonic), this will gain a net negative, so the reaction is spontaneous.

Note: The net reaction has high negative (energy barrier) so it will still be trapped inside the cell