M3: Topic 1: nutrition and energy

• Typical cellular composition


  • 80-90% water
  • Macro, micro and trace elements
  • Main macro-element is carbon which is used to grow microbes!
• Nutritional requirements to grow organisms on medium

  • Carbon
  • Nitrogen
  • Sulfur
  • Phosphorus
  • Minor elements
  • Growth factors
  • Trace elements
• Metabolic reactions


  The sum of all chemical reactions
• Types of metabolic reactions

  • Catabolic "catabolism" – breakdown of chemicals and is energy production
  • Anabolic "anabolism" – biosynthesis of chemicals and requires energy
• Enzyme


  • Catalyses metabolic reactions
  • Lowers activation energy
  • Determine what organism are capable in environments
  • Gene expression regulates which determine what grows where
  • Enzyme binds to substrate = complex which breaks bonds
  • Factors of enzymes: vary on conditions
  • Further outside the conditions = slower growth
  • Optimal range: 35 degrees
• Cellular energy


  ATP which is from catabolic reaction that is generated by phospholyration of ADP
• Ways energy is generated

  • Substrate level phosphorylation – pathway
  • Oxidative phosphorylation -ETC
  • Photophosylation - light
• Conservation of ATP


  When energy is produced from catabolic process and used for anabolic reaction
• Energy production


  • Produce through series of oxidation and reduction reactions
  • Synthesis of energy rich compounds
• Oxidation


  Removal of electrons = donor – oxides (hydrogen)
• Reduction


  Gaining of electrons = acceptor (Oxygen)
• Reduction potential


  • More negative = less energy = more donation
  • More positive = more energy = less donation
• Energy sources


  • Light - Phototrophs use carbon dioxide as carbon source
  • Chemical - Chemotrophs

  A. Chemoorganotrophs: uses organic compounds like glucose

  B. Chemolitotrophs: uses inorganic compounds like carbon dioxide
• Biogeochemical cycles


  Process used by organisms to obtain energy and do chemical work
• Microbes based on carbon source

  • Autotrophs - inorganic carbon source – carbon dioxide - self-feeders - reducing

  A. Photoautotrophs – uses light

  B. Chemoautotrophs – uses inorganic source

  Heterotrophs - organic carbon source

  A. Photohertotrophs- uses light

  B. Chemohertotrophs – uses organic compounds