Microbial Metabolism

• What is the ultimate function of metabolism?

  To reproduce the organism.
• What is the purpose of metabolism?

  Collection of controlled biochemical reactions within cells.
• How does energy for metabolism originate?

  From light or the catabolism of nutrients.
• Where is energy stored in cells?

  In adenosine triphosphate (ATP).
• What happens during catabolism?

  Nutrients are broken down to form precursor metabolites.
• What is the role of precursor metabolites?

  They, along with ATP and enzymes, are used in anabolic reactions.
• What are the six categories of enzymes based on action?

  Hydrolases, Isomerases, Ligases or Polymerases, Lyases, Oxidoreductases, Transferases.
• What are enzymes?

  Organic catalysts that increase the likelihood of a reaction.
• What are the three ways cells phosphorylate ADP to ATP?

  Substrate-level phosphorylation, Oxidative phosphorylation, Photophosphorylation.
• What is glycolysis?

  The splitting of a six-carbon glucose into two three-carbon sugar molecules.
• How many ATP molecules are gained from glycolysis?

  Two ATP molecules.
• What are the products of the Krebs cycle?

  Two ATP, two FADH2, six NADH, and four CO2 molecules.
• What is the role of the electron transport chain (ETC)?

  To pass electrons from one carrier molecule to another, releasing energy to form ATP.
• What are the electron carriers in cellular respiration?

  Flavoproteins, Ubiquinones, Metal-containing proteins, Cytochromes.
• What is chemiosmosis?

  The use of a proton gradient to generate ATP.
• What is the net ATP production from one glucose molecule?

  Approximately 34 molecules of ATP.
• What is fermentation?

  An anaerobic process that converts pyruvic acid into organic waste products.
• What are the two alternative pathways to glycolysis?

  Pentose phosphate pathway and Entner-Doudoroff pathway.
• What is the final electron acceptor in aerobic respiration?

  Oxygen, yielding water.
• What molecules serve as final electron acceptors in anaerobic respiration?

  Molecules other than oxygen.
• What is the role of feedback inhibition in metabolism?

  It slows or stops anabolic pathways when the product is abundant.
• What are the two major types of metabolic reactions?

  Catabolism and Anabolism.
• What is oxidation in biochemical reactions?

  The loss of electrons from a molecule.
• What is reduction in biochemical reactions?

  The gain of electrons by a molecule.
• What is ATP?

  Adenosine triphosphate, the main energy carrier in cells.
• What is substrate-level phosphorylation?

  The direct transfer of a phosphate group to ADP to form ATP.
• What is oxidative phosphorylation?

  ATP production driven by the electron transport chain and chemiosmosis.
• What is photophosphorylation?

  ATP formation using light energy in photosynthetic organisms.
• What are electron carrier molecules?

  Molecules that transport electrons during redox reactions.
• What are the three main electron carriers in cells?

  NAD+, NADP+, and FAD.
• How many ATP molecules are produced during aerobic respiration?

  About 34 molecules of ATP from one glucose molecule.
• What is the main product of glycolysis?

  Two molecules of pyruvic acid.
• What are the three stages of glycolysis?

  • Energy-Investment Stage
  • Lysis Stage
  • Energy-Conserving Stage
• What is the main purpose of the Krebs cycle?

  To transfer energy to coenzymes like NAD+ and FAD.
• Where does the Krebs cycle occur in prokaryotic and eukaryotic cells?

  In the cytoplasm of prokaryotes and the mitochondria of eukaryotes.
• What is fermentation?

  An anaerobic process that produces energy by converting pyruvate into waste products.
• What is an example of a waste product from fermentation?

  Lactic acid or ethanol.
• What is the Pentose Phosphate Pathway?

  An alternative to glycolysis that generates NADPH and precursor metabolites.
• What is the Entner-Doudoroff pathway?

  An alternative pathway that produces ATP and NADPH from glucose.
• What is the role of oxygen in aerobic respiration?

  It serves as the final electron acceptor in the electron transport chain.