An Introduction to Metabolism AP Biology

Metabolism The emergent property of life that arises from interactions between molecules within the orderly environment of a cell. A sum of all the chemical reactions within a cell.

Thermodynamics 1 st Law: – Energy can be transformed or transferred but not created or destroyed. – Conservation of energy 2 nd Law: – Every energy transformation or transfer increases the entropy (disorder) of the universe. How can we reconcile the fact that life is orderly with the 2 nd Law?

Free Energy The portion of a system’s energy that can be used to perform work. It is available for work but is spent at a cost to the universe.

Exergonic vs. Endergonic SpontaneousNon-spontaneous

STOP for a Vocabulary Check “Break down” reaction: – Catabolic – Spontaneous – Exergonic – Degradative process (breaking things down) – Downhill reaction – ∆G ‹ 0 Free energy is negative “Build up” reaction: – Anabolic – Non-spontaneous – Endergonic – Synthesis process (building things up) – Uphill reaction – ∆G › 0 Free energy is positive

Energy coupling Exergonic process drive an endergonic one.

Phosphorylation ATP performs work by transferring the inorganic phosphate to another molecule.

ATP Regeneration

Enzymes Serve as a catalyst to speed up the rate of reactions without being consumed by the reaction. They are reusable!

Activation Energy

Enzymes are Substrate Specific

Inhibition of Enzymes Allosteric site: location on an enzyme that can either increase or decrease an enzyme’s activity.

Feedback Inhibition