micro lect 4a

• What are the sources of energy, electrons, and carbon for microbes?

  Microbes utilize diverse nutritional sources
• What are the five major nutritional types of microbes?

  1. Photoautotroph
  2. Photoheterotroph
  3. Chemoautotroph
  4. Chemoheterotroph
  5. Chemoorganotroph
• What is the role of ATP in microbial metabolism?

  ATP conserves energy from an energy source
• What do reducing power molecules provide in microbial metabolism?

  They supply electrons for chemical reactions
• What are precursor metabolites used for in microbes?

  They provide carbon skeletons for biosynthesis
• What are chemoorganotrophs also called?

  Chemoheterotrophs
• What processes are used by chemoorganotrophs to catabolize energy sources?

  • Respiration
  • Fermentation
• How do aerobic and anaerobic respiration differ in terms of electron acceptors?

  Aerobic uses O₂, anaerobic uses other acceptors
• What is the net reaction of the Embden–Meyerhof pathway?

  Glucose + 2 ADP + 2 NAD⁺ → 2 pyruvate + 2 ATP + 2 NADH
• What is the main function of the TCA cycle?

  Source of precursor metabolites for biosynthesis
• How many times must the TCA cycle turn to oxidize one glucose molecule?

  Twice
• What are the products generated from one acetyl-CoA molecule in the TCA cycle?

  2 CO₂, 3 NADH, 1 FADH₂, 1 GTP
• What is the role of the electron transport chain (ETC) in microbial metabolism?

  Transfers electrons to produce ATP
• What is the terminal electron acceptor in aerobic respiration?

  O₂
• What is the significance of the proton motive force (PMF) in ATP synthesis?

  Drives ATP synthesis by proton flow
• What type of bacteria is Paracoccus denitrificans?

  Gram-negative, facultative anaerobe
• How does Escherichia coli adapt to oxygen availability?

  Uses different cytochromes based on oxygen
• What is the difference between the two branches of E. coli's electron transport chain?

  One uses cytochrome bo, the other cytochrome bd
• How does ATP synthase utilize the proton motive force?

  It synthesizes ATP from ADP using PMF
• What is the role of reducing power in microbial metabolism?

  Provides electrons for biochemical reactions
• Why are precursor metabolites important in biosynthesis?

  They provide carbon skeletons for building blocks
• What are amphibolic pathways?

  • Pathways that function in both catabolic and anabolic directions
  • Key examples: TCA cycle and glycolytic pathways
• What enzymes are involved in glycolysis and gluconeogenesis?

  Hexokinase, phosphofructokinase, pyruvate kinase
• What are the differences between the Embden-Meyerhof pathway, Entner-Doudoroff pathway, and Pentose Phosphate pathway?

  • Embden-Meyerhof: Most common, generates NADH & ATP
  • Entner-Doudoroff: Used by some Gram-negative bacteria, yields 1 ATP, 1 NADPH, 1 NADH
  • Pentose Phosphate: Produces reducing power and carbon skeletons, key enzymes include transketolase and transaldolase
• What is the importance of NADH and FADH₂ in ATP production?

  They are oxidized in the electron transport chain
• What is the role of anaerobic respiration in microbial metabolism?

  Allows energy production without oxygen
• How do purple non-sulfur bacteria exhibit metabolic flexibility?

  They can grow under varying energy conditions
• Why is metabolic adaptability significant in changing environments?

  It allows survival under fluctuating conditions
• What are the unique features of bacterial and archaeal electron transport chains?

  They have distinct electron carriers and mechanisms
• What is the significance of the difference in reduction potentials between NADH and O₂?

  It results in a large energy release.
• What type of bacterium is Paracoccus denitrificans?

  Gram-negative, facultative anaerobe
• Under what conditions does Paracoccus denitrificans use aerobic respiration?

  Under oxic conditions
• How does the electron transport mechanism of Paracoccus denitrificans compare to mitochondria?

  It is similar in electron carriers and transport.
• What happens to protons in Paracoccus denitrificans during respiration?

  They are transported to the periplasmic space.
• What type of molecules can Paracoccus denitrificans use as a source of energy?

  One-carbon molecules like methanol
• What are the two branches of the electron transport chain in Escherichia coli based on oxygen availability?

  Cytochrome bo and cytochrome bd
• What is the advantage of cytochrome bd in Escherichia coli?

  It has a higher affinity for oxygen.
• What drives ATP synthesis in the Proton Motive Force (PMF)?

  Protons flow back across the membrane.
• How many protons are consumed per ATP synthesized by ATP synthase?

  4 H⁺
• What is the maximum ATP yield during aerobic respiration by eukaryotes?

  32 ATP