ATP calculation for Oxidative Metabolism of a Glucose Molecule

Step 1: glycolysis

• glycolysis
  - produces NADH, ATP via substrate level phosphorylation, and pyruvate

• take a 6 carbon molecule, break it down into glyceralehyde through phosphate and we strip off energy

• products: NADH, ATP, and Pyruvate

• ATP value:
  - NADH: 2.5 ATP
  - ATP: 1.0
  - pyruvate: 0

• # of products per cycle:
  - NADH: 1
  - ATP: 2
  - pyruvate: 1

• # of cycles or paths:
  -NADH: 2
  - ATP: 2
  - pyruvate: 2

• ATP:
  - NADH: 2.5×1×2= 5.0
  - ATP: 1.0×2×2= 4.0
  - Pyruvate: since ATP value is equal to 0.0, pyruvate has no ATP

• Where did the NADH generate ATP?
  - the hydrogen and electrons from the NADH have to be shuttled into the mitochondria across the mitochondrial membrane where the electrons can then be used in the electron transport chain
  - this is specific to the complete oxidation of a glucose molecule

Step 2: Intermediate Step

• this involves pyruvate dehydrogenase and pyruvate dehydrogenase accepts pyruvate

• the pyruvate is shuttled into the mitochondria

• pyruvate strips off hydrogens and electrons

• Products:
  - NADH
  - CO2
  - Acetyle CoA

• ATP value:
  - NADH: 2.5
  - CO2: 0.0
  - Acetyle CoA: 0

• # of products per cycle
  - NADH: 1
  - CO2: 1
  - Acetyle CoA: 1

• # of cycles or paths
  - NADH: 2
  - CO2: 2
  - Acetyle CoA: 2

• ATP
  - NADH: 2.5×1.0×2= 5.0
  - CO2: 0×1×2= 0, since ATP value is 0
  - Acetyle CoA: 0×1×2= 0, since ATP value is 0

Kreb Cycle

• products
  - NADH
  - FADH
  - ATP (via substrate phosphorylation)

• ATP Value:
  - NADH: 2.5
  - FADH: 1.5
  - ATP: 1.0

• # of products per cycle
  - NADH: 3
  - FADH: 1
  - ATP: 1

• # of cycles or paths
  - NADH: 2
  - FADH:
  - ATP:

• ATP
  - NADH: 2.5×3×2= 15.0
  - FADH: 1.5×1×2= 3
  - ATP: 1.0×1×2= 2

recap

• glucose molecule, break it down in glycolysis producing NADH, producing ATP via substrate level phosphorylation, and pyruvate

• NADH are shuttled into the mitochondria via the electron transport chain, where they produce ATP

• the pyruvate shuttled into the mitochondria and in the intermediate step, we produce acetyle CoA which ends up in the Kreb cycle where we produce more NADH, FADH, and ATP via substrate level phosphorylation

• All of the electrons and hydrogens from the NADH and the FADH that entered the electron transport chain then allow us to produce ATP via substrate level phosphorylation

Gross ATP for glucose molecule via the oxidative metabolism

• 34.0 ATP

ATP net gain of a glucose molecule via the oxidative metabolism

• we spent two of our ATP during glycolysis so there are -2.0 there

• 34.0 ATP (gross ATP) - 2.0 (invest ATP)= 32.0 ATP