CHAPTER 4 U3AOS2 (Biochemical Pathways)

• Lock-and-key model: A model of enzyme-substrate interactions in which the active site is complementary to the substrate.
• Induced-Fit model: The substrate causes the active site to change to attain an optimal fit.
• Amylase: A type of enzyme that breaks down starch into glucose.
• Protease: An enzyme that breaks down proteins into amino acids.
• Lipase: An enzyme that breaks down lipids into fatty acids and glycerol
• Co-Factor: A molecule that assists enzyme activity by helping the enzyme to fold properly or facilitate the reaction.
• Co-Enzymes: a small molecule that assists enzyme activity by carrying groups of atoms to or from the reaction.
• Loaded form of NAD+

  NADH
• Loaded form of ADP + Pi

  ATP
• Loaded form of FAD

  FADH2
• Loaded form of NADP+

  NADPH
• Activation energy


  The minimum energy required to start a chemical reaction
• Active site


  The specific region on an enzyme where the substrate binds and the reaction occurs
• Adenosine triphphosphate (ATP)


  The primary energy currency of cells, used to store and transport chemical energy
• Allosteric site


  A binding site on an enzyme that is different from the active site, where the binding of a molecule can regulate the enzyme's activity
• Anabolic reaction


  A chemical reaction that builds larger molecules from smaller ones, requiring energy
• ATP synthase


  An enzyme that uses the energy from hydrogen ions passing through to produce ATP
• Biochemical pathway


  A series of connected chemical reactions that occur within a cell
• Catabolic reaction

  A chemical reaction that breaks down larger molecules into smaller ones, releasing energy
• Catalyst


  A substance that increases the rate of a chemical reaction without being consumed or altered itself
• Cellular metabolism


  The chemical processes that occur within a living organism to maintain life
• Competitive inhibitor


  A molecule that binds to the active site of an enzyme, preventing the substrate from binding and slowing the reaction
• Endergonic reaction


  A chemical reaction that requires an input of energy to proceed
• Endothermic reaction


  A chemical reaction that absorbs heat from the surroundings
• Exergonic reaction


  A chemical reaction that releases energy
• Exothermic reaction


  A chemical reaction that releases heat to the surroundings
• Feedback inhibition


  A mechanism where the end product of a biochemical pathway inhibits an earlier step in the pathway, regulating its own production
• Induced-fit model


  A model that describes how the active site of an enzyme changes shape to better accommodate the substrate
• Loaded


  The state of an enzyme when it has a substrate bound to its active site
• Lock-and-key model


  A model that describes the active site of an enzyme as a rigid structure that perfectly fits the substrate