Respiration

• Respiration

  • Cellular respiration: Organic macromolecules oxidation to release energy
  • Photoautotrophs, producer: plants, some protoctists + some bacteria
  • Heterotrophs, consumers/decomposers: animals, fungi + most bacteria
  • All organisms respire
  • Transfer potential chemical energy of carbs, lipids + proteins to chemical (ATP) + thermal energy
  • Important to maintain cell temperature (for enzyme-controlled reactions)
  • Oxidation: Breakdown by O_2 or elecron/H+ removal
  • Reduction: Electron addition; metabolic pathway, can involve H+ addition
  • Oxidoreductases: Enzyme groups which catalyse oxidation-reduction (redox) reactions
  • Hydrolases: Enzyme groups which catalyse hydrolysis reactions
  • ATP (adenosine triphosphate)
  • Central metabolism molecule
  • Main respiratory product
  • Can't move around body
  • Continuously produced
  • ‘Universal energy carrier’
  • Has phosphate groups for metabolic pathways + enzyme activation
• Metabolism

  • Sum of all enzyme-controlled chemical reactions in a living organism
  • Metabolic pathway is reaction sequence resulting in formation of 1 substance (product) from different 1 (substrate)
  • Catabolic reaction: Breakdown of organic molecules; most exergonic - release chemical energy + involve oxidation or hydrolysis
  • Anabolic reactions: Synthesis of small molecules to form larger ones, are endergonic - absorb chemical energy + involve condensation
  • Metabolites converted to products in series of small reactions
  • Large catabolic reactions create unfavourable life conditions
  • Substances partially broken down for raw materials
  • Organic compounds complex
  • Synthesis impossible in 1 step w/ simple raw materials + small steps in anabolic pathway control product production