Metabolism

• Metabolic Pathways


  A sequence of chemical reactions catalyzed by enzymes
• Bond energy


  The energy required to break or form a chemical bond
• Generally, energy is released when a bond forms and energy is needed to break a bond
• If energy stored in chemical bonds were released, then absorbed
• Chemical potential energy


  Energy stored in chemical bonds
• Thermodynamics


  The study of transfer and transformation of thermal energy
• System


  An organism, a tissue, an organ, or a set of chemicals in a reaction
• Surroundings


  Everything in the universe outside of the system
• The First Law of Thermodynamics: Energy cannot be created nor destroyed, Energy can be transferred and can be transformed from one object to another
• All of the energy available at the start of a non-isolated system


  Can be accounted for after completion
• Energy


  Can be stored in chemical bonds, released when the bonds break
• Anabolism


  The process by which creation of complex molecules from simpler subunits (biosynthesis)
• Anabolism


  • Example?
• Catabolism

  The process by which complex molecules are broken down into simpler subunits
• Catabolism


  • Example?
• Metabolism


  Catabolism + Anabolism
• Catabolism


  Energy yielding reactions
• Anabolism


  Energy requiring reactions
• 2nd Law of Thermodynamics

  The law of entropy
• Entropy


  A measure of the randomness or disorder
• As entropy increases


  Disorder increases
• The entropy of the universe increases as matter becomes more random
• 2nd Law of Thermodynamics


  Related to Biology
• Potential energy diagram


  Shows the change in potential energy during a chemical reaction
• Activation energy


  The amount of energy needed to strain and break the reactants' bond
• Reactants have to get over the "hill" (ie. have at least the activation energy) to convert to products
• Endocrine glands include the pituitary gland, thyroid gland, parathyroid glands, adrenal glands (including the adrenal medulla), pancreas, ovaries/testes, and pineal gland.
• The main function of the endocrine system is to secrete hormones into the bloodstream, which then travel throughout the body.
• Anabolic


  Coupling reactions that provide the energy that drives reactions forward
• Catabolic


  Coupling reactions that provide the energy that drives reactions forward
• Adenosine triphosphate (ATP)


  The molecule of choice that provides the energy currency of the cell
• The amount of free energy released when the terminal phosphate is transferred from the ATP molecule is about 31 KJ/mol (AG = -31 kJ/mol)
• The amount of free energy released is more than enough for energy requiring reactions in cells without overheating the cell
• Functions of ATP


  • Chemical Work
  • Transport work
  • Mechanical work
• Structure of ATP


  • Energy for synthesis of macromolecules
  • Energy for pumps in cell membrane
  • Muscle contraction, cilia, flagella movement