Microbial metabolism

• What is metabolism?

  The sum of all chemical reactions in an organism
• What is the role of catabolism in metabolism?

  It provides energy and building blocks for anabolism
• What does anabolism do in metabolism?

  It uses energy and building blocks to build large molecules
• What is a metabolic pathway?

  A sequence of enzymatically catalyzed chemical reactions in a cell
• What determines metabolic pathways?

  Enzymes, which are encoded by genes
• What does collision theory state?

  Chemical reactions can occur when atoms, ions, and molecules collide
• What is activation energy?

  Energy needed to disrupt electronic configurations
• How can reaction rate be increased?

  By enzymes or by increasing temperature or pressure
• What are enzymes?

  Biological catalysts that are specific and not used up in reactions
• What are the components of enzymes?

  Apoenzymes, cofactors, and holoenzymes
• What are coenzymes?

  Organic molecules like NAD+, NADP+, and FAD
• How are enzymes named?

  Based on their function, such as lactate dehydrogenase or cytochrome oxidase
• What can denature enzymes?

  Temperature and pH changes
• How does substrate concentration influence enzyme activity?

  Higher substrate concentration can increase enzyme activity until saturation
• What are competitive inhibitors?

  Inhibitors that compete with the substrate for the active site
• What are noncompetitive inhibitors?

  Inhibitors that bind to an allosteric site, changing enzyme shape
• What is feedback inhibition?

  A mechanism that controls the amount of substance produced by a cell
• What is oxidation in biochemical terms?

  The removal of electrons
• What is reduction in biochemical terms?

  The gain of electrons
• What is a redox reaction?

  An oxidation reaction paired with a reduction reaction
• How are biological oxidations often characterized?

  They are often dehydrogenations
• What are the two types of phosphorylation in ATP generation?

  1. Substrate level phosphorylation: transfer of a high-energy PO4 to ADP
  2. Oxidative phosphorylation: transfer of electrons to generate ATP by chemiosmosis
• What are the three steps of aerobic respiration?

  1. Glycolysis: oxidation of glucose to pyruvate
  2. Krebs cycle: oxidation of acetyl CoA
  3. Oxidative phosphorylation: electron transport chain
• What is glycolysis?

  A multi-step breakdown of glucose into pyruvate
• How much ATP is generated in glycolysis?

  A small amount of ATP
• What alternative pathways exist to glycolysis?

  Pentose phosphate and Entner-Doudoroff pathways
• What occurs during the transition step of the Krebs cycle?

  Acetyl-CoA is generated from pyruvate through decarboxylation
• What does the Krebs cycle generate?

  ATP, reducing power, and precursor metabolites
• What is the electron transport chain?

  A series of electron carriers that transfer electrons from glycolysis and TCA cycle
• What is the proton motive force (pmf)?

  A gradient generated by protons during electron transport
• How is ATP generated via chemiosmosis?

  By using the proton motive force to generate energy
• What is anaerobic respiration?

  A process where an inorganic molecule is the final electron acceptor
• What is the ATP yield in anaerobic respiration compared to aerobic respiration?

  Lower than in aerobic respiration
• What is fermentation?

  A process that uses an organic molecule as the final electron acceptor
• What is the scientific definition of fermentation?

  A process that does not use the Krebs cycle or ETC and has low energy yield
• What is the relationship of fermentation to glycolysis?

  Fermentation occurs after glycolysis and uses its products
• What is the ATP yield from complete oxidation of one glucose molecule using aerobic respiration?

  36 ATPs are produced in eukaryotes
• What enzymes are used for the digestion of polysaccharides?

  Amylases for starch and cellulase for cellulose
• What is protein catabolism?

  The breakdown of proteins into amino acids
• What are the steps involved in protein catabolism?

  Deamination, decarboxylation, dehydrogenation, and desulfurylation