Introduction to Biochemistry, Page 5

Interactions between Biomolecules are Specific

•Macromolecules have unique binding pockets

•Only certain molecules fit in well and can bind

•Binding of chiral biomolecules is stereospecific

Unfavorable and Favorable Reactions

•Synthesis of complex molecules and many other metabolic reactions requires energy (endergonic)

•Creating order requires work and energy

•Breakdown of some metabolites releases significant

amount of energy (exergonic)

–Such metabolites (ATP, NADH, NADPH) can be

synthesizes using the energy from sunlight and fuels

Kinetics – Reaction Rate Acceleration

Higher temperatures

  Stability of macromolecules is limiting

Higher concentration of reactants

  Costly as more valuable starting material is needed

Change the reaction by coupling to a fast one

  Universally used by living organisms

Lower activation barrier by catalysis

  Universally used by living organisms

Catalysis

•A catalyst is a compound that increases the rate of a

chemical  reaction

•Catalysts lower the activation free energy

•Catalysis offers:

–Acceleration under mild conditions

–High specificity

Energy Flows through

ATP and redox carriers 

to couple  Catabolic and 

Anabolic Pathways

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