BIOL 141 Lecture Notes - Lecture 20: Covalent Bond, Phosphorylation
Friday, November 17, 2017
BIOL 141
•Nonpolar covalent bond - higher PE state"
•Polar covalent bond - lower PE state"
•Respiration - controlled explosions analogy"
•Energy of activation barrier is overcome by enzymes"
•Burning sugar involves an uncontrolled rapid release of energy from chemical bonds"
•Cellular respiration involves the release of energy in discrete amounts due to enzyme
control of the process"
•Energy is transferred to energy-storing molecules ATP, NADH and FADH2"
•Redox reactions - transfer of electron increases potential energy of molecule"
•Phosphorylation - transfer P from ATP to substrate"
•Net change in G is negative in both"
•When an atom or molecule loses an electron, it is oxidized"
•When an atom or molecule gains an electron, it is reduced"
•Oxidation and reduction reactions are always coupled"
•Electron donors are always paired with electron acceptors"
•More reduced - higher PE, more oxidized - lower PE"
•CO2 - most highly oxidized state"
•Glucose is oxidized to form CO2, oxygen is reduced to form H2O"
•Electron carriers are used as intermediate molecules during respiration to transfer
electrons and transmit energy"
•NAD is reduced to form NADH"
•NADH readily donates electrons to other molecules and is thus called an electron
carrier and has “reducing power”"
•The reduced molecule gains a proton and has higher potential energy because of
additional covalent bonds"
•Fermentation is an anaerobic process, incomplete oxidation
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