BIOL1040 Lecture Notes - Lecture 21: Inner Mitochondrial Membrane, Glucokinase, Citric Acid Cycle
GLYCOLYSIS
LEARNING GOALS
• Glycolysis
o Understanding of overall pathway
o What are the products of glycolysis – Control points
o Key reactions
• Where to after glycolysis (later lectures)
o Lactic acid fermentation
• Understanding of overall pathway
• What conditions does it occur
o TCA cycle
o Alcoholic fermentation
• Overall reaction of the breakdown of glucose
o C6H12O6 + 6O2 ® 6CO2 + 6H2O
o ΔG for this reatio is -2820 kJ mol-1
o Synthesis of more than 30 ATP molecules from ADP and Pi
• Glycolysis
o Glucose (6 carbon) ® pyruvate (3 carbon)
o 2 ATP and reduced 2NAD+ to 2NADH
o cytosol
• Citric acid cycle (TCA, Krebs cycle)
o Pyruvate converted to CO2
o ATP, NADH, FADH
o Mitochondria
• Electron transport chain (oxidative phosphorylation)
o Utilises NADH and FADH to produce ATP
o Generates the bulk of ATP
o Inner mitochondrial membrane
o Is where O2 is consumed
• Glycolysis is the central pathway of metabolism
o Found in almost all organisms
GLYCOLYSIS
• Generates
o 2 ATP
o 2 NADH
• NADH is oxidised in the mitochondria, generates NAD+ which returns to the cytosol for
glycolysis
• Pyruvate goes into the mitochondria
• Where does this glucose come from?
o Dietary uptake
o Glycogen (glycogenesis)
• Glycolysis can be broken down into energy investment stage and an energy recover stage
REACTION 1 - HEXOKINASE OR GLUCOKINASE
• Glucose + ATP ® Glucose-6-phosphate
• Catalysed by hexokinase or glucokinase
• Why invest energy in an energy generation process?
o Phosphorylation keeps glucose in the cell
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