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(GLYCOLYSIS) - Coggle Diagram

- - - - Enzyme: Hexokinase
      - ATP → ADP
      - Phosphorylation traps glucose inside the cell
    - - Enzyme: Phosphoglucose isomerase
      - Isomerisation rearranges the sugar
    - - Enzyme: Phosphofructokinase-1 (PFK-1)
      - ATP → ADP
      - Key regulatory and rate-limiting step
    - - Enzyme: Aldolase
      - Six-carbon sugar is split into two three-carbon molecules
    - - Enzyme: Triose phosphate isomerase
      - DHAP is converted to G3P
      - From this point, reactions occur twice per glucose
    - - Enzyme: G3P dehydrogenase
      - 2 NAD+ → 2 NADH + 2 H+
      - 2 Pi are added
      - Oxidation captures energy in NADH
    - - Enzyme: Phosphoglycerate kinase
      - 2 ADP → 2 ATP
      - Substrate-level phosphorylation
    - - Enzyme: Phosphoglycerate mutase
      - Phosphate group changes position
    - - Enzyme: Enolase
      - 2 H2O are removed
      - Creates a high-energy phosphate compound
    - - Enzyme: Pyruvate kinase
      - 2 ADP → 2 ATP
      - Substrate-level phosphorylation
  - - - Signals high cellular energy
      - → inhibits PFK-1
      - → decreases glycolysis
    - - Signal low cellular energy
      - → activate PFK-1
      - → increase glycolysis
    - - → strongly activates PFK-1
      - → increases glycolysis
    - - Signals abundant biosynthetic and energy intermediates
      - → inhibits PFK-1
    - - → inhibits PFK-1
      - Helps limit excessive glycolysis and acid accumulation
    - - Fed state
      - → promotes glycolysis in liver
      - → increases fructose-2,6-bisphosphate
    - - Fasting state in liver
      - → decreases glycolysis
      - → promotes glucose production
  - - - Amino acids
      - Lipids
      - Other cellular compounds
  - - - Dietary glucose
      - Glycogen breakdown
      - Gluconeogenesis
    - - → Glycolysis
      - → Pentose phosphate pathway
      - → Glycogen synthesis
    - - → Acetyl-CoA → Citric acid cycle
      - → Lactate → Fermentation
      - → Oxaloacetate → Gluconeogenesis
      - → Alanine → Amino acid metabolism
    - - Opposing pathways
      - Share several reversible reactions
      - Use different enzymes at irreversible control steps
    - - Share glucose-6-phosphate
      - PPP produces NADPH and ribose-5-phosphate
  - - - Steps 1–5
      - Uses 2 ATP
    - - Steps 6–10
      - Produces 4 ATP
      - Produces 2 NADH
    - - 2 ATP
      - 2 NADH
      - 2 Pyruvate
    - - Glucose + 2 ADP + 2 Pi + 2 NAD+
      - → 2 Pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O
  - - - Inhibited by glucose-6-phosphate
      - Feedback inhibition prevents unnecessary glucose phosphorylation
    - - Rate-limiting and major control point
      - Activated by AMP and ADP
      - Activated by fructose-2,6-bisphosphate
      - Inhibited by ATP
      - Inhibited by citrate
      - Inhibited by low pH / high H+
      - High ATP signals that energy is sufficient
      - Low energy signals increase glycolysis
    - - Activated by fructose-1,6-bisphosphate
      - Inhibited by ATP
      - Inhibited by alanine
      - In liver: glucagon promotes phosphorylation and inhibition
      - Insulin promotes dephosphorylation and activation
  - - - Pyruvate → Acetyl-CoA
        
        Enzyme complex: Pyruvate dehydrogenase
        
        → Citric acid cycle
        
        → further oxidation and energy production
    - - Pyruvate → Lactate
        
        Enzyme: Lactate dehydrogenase
        
        Regenerates NAD+
        
        Allows glycolysis to continue
      - Pyruvate → Ethanol + CO2
        
        Occurs in yeast and some microorganisms
        
        Regenerates NAD+
    - - Pyruvate → Oxaloacetate
        
        Supports gluconeogenesis and biosynthetic reactions
      - Pyruvate → Alanine
        
        Through transamination
      - Pyruvate → Acetyl-CoA
        
        Can support lipid synthesis when energy is abundant
  - - - Occurs in essentially all cells
      - Does not directly require oxygen
      - Can proceed during aerobic or anaerobic conditions