Module 5: Energetics

• metabolism: sum of all reactions in a cell
• catabolism: generate energy and reducing power by breaking down molecules
• anabolism: synthesizing structures using energy and reducing power
• catabolism differentiates microorganisms
• anabolism is nearly universal
• favorable reaction has a negative delta G
• favorable reaction has a positive delta S, increase in entropy
• increasing reactants or decreasing products will cause a more favorable forward reaction
• enzymes increase activation energy by increasing substrate concentration at active site
• redox reaction: released electrons move from high to low PE
• released electrons in redox reactions release energy
• electron donor loses electrons and gets oxidized
• electron donor is energy source
• electron acceptor gains electrons, gets reduced
• a positive total potential energy means drop in PE, favorable reaction
• in an energy yielding reaction the donor has more - potential and the acceptor has more + potential
• oxidative level phosphorylation occurs in the membrane
• substrate level phosphorylation: ATP is synthesized from ADP using energy from catoblism coupled with substrate breakdown to release energy
• examples of catabolism:

  • activation of compounds by oxidation
  • fermentation
  • substrate level phosphorylation
• example of redox reaction: oxidize/remove e- to form double bond, NAD+ carrier accepts e-
• e- acceptor is lower on table than donor
• substrate level phosphorylation involves phosphate transfer from organic compound