Chapter 5 - Microbial Metabolism

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  1. What is metabolism
    The sum of chemical reactions in an organism
  2. Can be described as an energy-balancing act
  3. Two types of Metabolic pathways
    • Catabolism- Provides energy and building blocks  for anabolism 
    • Anabolism- Uses energy and building block to build large molecules
  4. Catabolism
    • Provides energy and building blocks for anabolism
    • Releases energy
    • Breaks down organic compounds into smaller ones
    • Usually hydrolytic and exergonic reactions
    • AKA Degradative reaction
  5. Anabolism
    • Uses energy and building blocks from catabolism to build large molecules 
    • Requires energy
    • Building complex organic molecules
    • Requires dehydration synthesis
    • Endergonic reaction
    • AKA Biosynthetic Reaction 
  6. Exergonic reactions
    • Reaction that produce more energy then they use
    • Used during catabolism 

    Ex. When cell breaks sugar into COand H2O
  7. Hydrolytic Reactions
    • Reactions that uses water to break chemical bonds
    • Usually seen in catabolism
  8. Dehydration synthesis
    • Reactions that release water molecule
    • Seen in Anabolism
  9. Enderonic Reactions
    Reactions that consume more energy then it produces 

    Ex. Formation of proteins from amino acids, nucleic acids from nucleotides, and polysaccharides from simple sugars
  10. What is a metabolic pathway
    • A series of enzymatically catalyzed reactions that store and release E in organic molecules
    • Pathways are determined by enzymes
  11. What provides most cellular energy?
    Oxidation of carbohydrates
  12. Most common molecule in metabolism
  13. Advantages of cell metabolism
    Creates energy, breaks down more complex molecules, build more complex molecules, creates ATP
  14. Collision Theory
    Explain how chemical reactions occur and how certain factors affect the rate of those reactions (Activation energy and Reaction rate)

    All atoms, ions, and molecules are continuously moving colliding with one another to break and form new bonds
  15. Activation Energy
    The amount of energy needed to disrupt the stable electronic configuration of any specific molecule so the electrons can be rearranged.
  16. Reaction rate
    • The frequency of collisions containing sufficient energy to bring about a reaction
    • This depends on number of reactant molecules at or above activation energy
  17. How can you increase the reaction rate?
    By raising temperature or pressure
  18. Substances that can speed up a chemical reaction.
    Enzymes or biological catalysts
  19. Enzyme overview
    • 3D globular proteins 
    • Names end in -ase
    • Catalyze chemical reactions by lowering activation energy
    • Active sites are specific to substrate
    • Each enzyme catalyzes only one reaction
  20. Apoenzyme and Cofactor
    • Two parts that make up an enzyme (Holoenzyme)
    • Apoenzyme- Protein portion of the enzyme 
    • Cofactor- non protein component; inorganic (ions of Zn, Mg, Fe or Ca)
  21. True or False: The apoenzymes are not functional without the cofactor
    True; Without a cofactor, the apoenzyme will not function
  22. Holoenzyme
    The whole/active enzyme (Apoenzyme+Cofactor)
  23. Coenzyme
    • A organic cofactor (Vitamins) 
    • May help enzyme by accepting atoms removed from from the substrate or by donating atoms required by the substrate.
  24. Active and allosteric site
    • Active site: Location on an enzyme where substrate binds
    • Allosteric Site: "Other space"
  25. Important coenzymes
    • NAD+
    • NADP+
    • FAD
    • Coenzyme A
  26. Why are coenzymes important?
    • They assist by accepting pr donating atoms required by the substrate
    • Some act as electron carries and donate other molecules
  27. Normal Sequence of Enzymatic Action (4 steps)
    • 1. Substrate contacts active site of enzyme
    • 2. Form a temp cmpd (enzyme-substrate complex)
    • 3.Substrate transformed by rearrangement of atoms/the breakdown of substrate
    • 4.Transformed substrate molecule (prod of rxn) are released from enzyme because they no longer fit.
  28. Oxidoreductase
    Enzymes that perform Oxidation-reduction reactions
  29. Transferase
    Enzymes that transfer functional groups
  30. Hydrolase
    Enzymes that perform hydrolysis (using water to break down a compound)
  31. Lyase
    Enzymes the remove atoms without hydrolyses
  32. Isomerase
    Enzymes that rearrange atoms
  33. Ligase
    • Enzymes that join molecules
    • uses ATP
  34. What factos influence Enzyme activity
    • Temperature
    • pH
    • Substrate concentration
    • Inhibitors

    Too high or too low temp or pH slows down enzyme activity and causes denaturation
  35. Competitive Inhibition
    • Structure similar to normal substrate that competes the substrate for active site
    • Can be reversed by having higher [substrate]
  36. Noncompetitive Inhibition
    • Do not compete with the substrate for active site. Instead allosteric inhibition occurs where inhibitor binds to the allosteric site changing the shape of active site.
    • Enzyme is now non-functionable
    • In some instances allosteric inhibition may activate enzyme vs inhibit it
  37. Feedback or end-product inhibition
    • When the final product of the pathway inhibits an enzyme earlier in the "assembly line" to prevent making more substrate then it needs
    • It deforms active site
    • pathway shuts down
    • When [end-product] lowers, pathway resumes
    • This process is quick and short term
  38. Endoenzyme
    • Intracellular enzymes
    • Intake smaller substrates
    • Participate in Metabolic Pathways
  39. Exoenzyme
    • Extracellular enzyme (secreted)
    • Intake larger substrates
    • Neutralizes harmful chemicals
    • -IgA Protase, Urease
  40. Two Enzymes that are based on the site of action.
    • Endoenzyme (inside cell)
    • Exoenzymes (outside cell)
  41. Constitutive enzyme
    • Always present
    • But NOT always needed
    • They are essential to have
  42. Induced/Adaptive enzyme
    • Influenced by [substrate]
    • Conserves energy by only being produced when certain substrate is present/necessay
  43. Two type of enzymes that are based on when they are produced
    • Constitutive Enzymes
    • Induced/Adaptive Enzymes
  44. Ribozymes
    • RNA enzyme that function as catalysts
    • Contain an active site that binds with RNA
    • Cut and splices RNA
  45. What is Oxidation-Reduction and what are the two essential parts?
    • Aka Redox reaction, is an oxidation reaction paired with a reduction reaction
    • Oxidation is the removal of electrons 
    • Reduction is the gain of electrons
  46. During a Redox Reaction, reduced molecules are always _1______ and oxidized molecules are always _2_____
    • 1.Energy rich
    • 2.Energy poor
  47. During redox reaction, what acts as the electron carrier?
  48. Dehydrogenation Reaction
    Biological oxidization that involve loss of hydrogen atoms

    Usually 2 H+ atoms 
  49. ATP arises from ____
    • ADP
    • ADP is then given an inorganic phosphate group with input energy to form ATP
  50. Phosphorylation
    • When a phosphate attaches to a chemical cmpd  and breaks off its called phosphorylation 
    • Transfers ADP into ATP
  51. What are the 3 types of phosphorylation?
    • Substrate-Level 
    • Oxidative 
    • Photophosphorylation
  52. Substrate-Level Phosphorylation
    • When ATP is usually generated 
    • When high energy P is directly transferred from a phosphorylated cmpd (a substrate) to ADP

    C-C-C~P+ ADP -> C-C-C+ATP
  53. Oxidative Phosphorylation
    • Series of redox rxns using electron carriers (ETC)
    • Transferring of electrons releases energy, some going to produce ATP
    • Electrons passed in a series of carriers to molecules of 02 Or other oxidized organic or inorganic molecules
    • How the majority of ATP is made
  54. Where does oxidative phosphorylation take place in prokaryotes and eukaryotes?
    • Prokaryotes- Plasma Membrane 
    • Eukaryotes- Inner mitochondrial membrane
  55. Photophosphorylation
    • Occurs only in photosynthetic cells
    • Converts light into energy (ATP and NADPH)
  56. Cellular Respiration
    • Glucose is completely broken down
    • May be aerobic OR anaerobic
    • Results in inorganic cmpds (CO2, H2O)
  57. Aerobic Cellular Respiration (Final acceptor, ATP yield)
    • Oxygen is the final electron(H+) acceptor
    • Produces large amount of ATP

    1 Glucose = ~38 ATP
  58. Anaerobic Respiration (Final acceptor, ATP Yield)
    • Oxygen is NOT the final electron(H+) acceptor
    • Instead Nitrate, Sulfate or Carbonate are the final acceptors
    • Lower ATP yeild
    • 1 Glucose = ~32-34ATP
Card Set
Chapter 5 - Microbial Metabolism
Chapter 5/ Exam 2 Microbial metabolism
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