Energy and Metabolism

Chapter 6

Energy

• The capacity to do work

• Potential vs Kinetic

How is it measured?

• Heat

• Calorie

• Joule = 0.239 Calories

• Most energy is provided by the sun

Oxidation-reduction reactions

• AKA redox

• OilRig

Thermodynamics

• Energy changes• First Law of

Thermodynamics• Second Law of

Thermodynamics– How does this

apply to humans?

Free Energy

• The energy Available to do work

• Delta G= Delta H- TDelta S

• H= enthalpy which is the energy contained in the chemical bonds of a substance

• T= temperature kelvin

• S= entropy or the energy unavailable due to disorder

Endergonic vs Exergonic

• If Positive Delta G then the reaction is endergonic

• If Negative Delta G then the reaction is evergonic

Activation Energy

• Spontaneous Chemical Reactions Require activation energy

• Catalysts

You down with ATP????

• The energy currency of cells

• Hydrolysis drives endergonic reactions

• ATP cycles continously

Enzymes

• Biological Catalysts

• Ligand vs Substrate

• Active Sites

• Are they all proteins?

MultiEnzyme Complex

• Sounds familiar….

• 3 advantages– Increases the frequency with which the

enzyme collides with the substrate– Eliminates the possibility of unwanted

reactions– All reactions take place within the complex

can be controlled as a unit

Factors Affecting Enzyme Function

• Temperature

• pH

• Inhibitors and Activators– Allosteric Site

• Cofactors

Inhibitors and Activators

Cofactors and Conenzymes

• Assists enzyme function

• Cofactors are usually metal ions

• Coenzyme- a nonprotein organic molecule- can serve as an electron acceptor in a redox reaction

Metabolism

• Anabolic- use energy

• Catabolic- need energy

• Biochemical Pathways– Evolution of BP’s

Feedback Inhibition

• Regulates Biochemical Pathways

• Why Important?