Respiration, Fermentation, Glycosis

• Catabolism


  Breaking down complex molecules into simpler ones
• Anabolism


  Building complex molecules from simpler ones
• Metabolism


  All chemical reactions that occur within an organism, both catabolic and anabolic reactions
• Catalyst


  Substance that speeds up chemical reactions
• Sources of energy for cells

  • Carbs
  • Fats
  • Proteins
• Exergonic reaction


  Releases energy to the environment, free energy of reactants is higher than product
• Endergonic reaction


  Requires energy to proceed, free energy of products is higher than reactants
• Building blocks for biosynthetic pathways (catabolism)


  • Carbon sources, like amino acids, purines, pyramids, lipids, sugars, enzyme cofactors
• Role of ATP in the cell


  Main carrier of energy within a cell, when energy is needed ATP is hydrolyzed to release energy
• Role of NAD+ in the cell

  Important in metabolism, Transfers molecules from one molecule to another
• Enzyme


  Biological catalysts that speed up chemical reactions without being consumed
• Active site


  Where enzymes bind to substrate molecules
• Optimum temperature for an enzyme

  37C or body temp, extreme temps cause denaturation
• Enzyme catalyzed reaction


  1. Binding: Substrates must bind to active site

  2. Catalysis: Enzyme facilitates reaction by lowering activation energy

  3. Release: Products are released from enzyme
• What an enzyme does to activation energy

  Lowers the activation energy of a reaction
• An enzyme can be used repeatedly
• An enzyme typically acts on a specific substrate or a group of closely related substrates
• Reason an enzyme reacts with a specific substrate

  Due to the lock and key model - the enzyme's active site has a unique shape and structure that fits the substrate
• Oxidation/Reduction (Redox) reaction


  Involves the transfer of electrons from one molecule to another
• What happens when a substance is oxidized

  It loses electrons
• What happens when a substance is reduced

  It gains electrons
• The atom nearly always involved in biological Redox reactions is hydrogen
• What controls Oxidation/Reduction reactions in the body


  Metabolic processes regulated by catabolic and anabolic hormones
• Glycolysis


  1. Location: Cytoplasm

  2. Inputs: Glucose, NAD+, ADP, Pi

  3. Outputs: Pyruvate, NADH, net gain of 2 ATP

  4. Process: Glucose is split into two 3-carbon pyruvate molecules
• Fermentation


  1. Location: Cytoplasm

  2. Inputs: 2 pyruvate, 2 NADH

  3. Outputs: Ethanol/CO2 or lactic acid

  4. Process: Pyruvate is converted into other forms like lactate or ethanol
• Aerobic Respiration


  1. Location: Mitochondria

  2. Inputs: 2 pyruvate, oxygen, ADP

  3. Outputs: CO2, H2O, ATP

  4. Process: Pyruvate Decarboxylation, Krebs Cycle, Electron Transport Chain and Oxidative Phosphorylation
• The most NADH is generated in the Krebs Cycle
• The final electron acceptor in aerobic respiration is oxygen
• Reactants and products of glycolysis

  • Reactants: Glucose, 2 NAD+, 2 ADP, 2 Pi

  Products: 2 pyruvate, 2 NADH, net gain of 2 ATP
• Glycolysis is an anaerobic process
• The total gain of ATP when anaerobic respiration (fermentation) follows glycolysis is 2 ATP
• The molecule produced by fermentation that is needed for glycolysis to continue is NAD+
• Final electron acceptors


  • Fermentation: Pyruvate or acetaldehyde

  Aerobic respiration: Oxygen (O2)
• If oxygen is present, the processes that follow glycolysis are the Krebs Cycle and the Electron Transport Chain
• Role of the Krebs Cycle

  Central role in the breakdown of organic fuel molecules in aerobic respiration
• Products of the Krebs Cycle

  • 2 CO2, 3 NADH, 1 FADH2, 1 ATP (or GTP)
• Each NADH that enters the electron transport chain gives rise to approximately 2.5 ATP
• The majority of ATP is formed during the Oxidative Phosphorylation phase of cellular respiration
• Location of electron transport chain

  • Bacterial cells: Plasma membrane

  Eukaryotic cells: Inner mitochondrial membrane
• What the energy in the flow of electrons is directly transferred into

  A proton gradient across a membrane, which drives the creation of ATP