What is the role of ATP and ADP in cellular respiration?

1 Answer
Oct 9, 2015

ATP is consumed in glycolysis to convert glucose to pyruvate, and produced in electron transport chain.


Cellular respiration consists of three parts in order: glycolysis, Krebs cycle, and electron transport chain.

Glycolysis involves total of 10 steps. Out of those, step 1 and 3 use ATP.

  • In step 1, hexokinase (HK) take a phosphate from ATP and add the phosphate to glucose to create glucose-6-phosphate. Because a phosphate is taken out, ATP becomes ADP.

  • In step 3, phosphofructokinase (PFK) take a phosphate from ATP and add the phosphate to fructose-6-phosphate to create fructose-1,6-bisphosphate.

Electron transport chain consists of many steps as well. Out of those, the last step produces ATP.
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In last step, ATP synthase uses the difference in hydrogen ion concentration to make ATP.

  • NADH catalyzes a series of reactions with several proteins to move hydrogen cations from mitochondrial matrix to intermembrane space. This creates a difference in hydrogen cation concentration.
  • The higher concentration in intermembrane space means hydrogen cations prefer to go back to mitochondrial matrix.
  • ATP synthase use this force to drive reaction that adds a phosphate to ADP to create ATP.

More about phosphofructokinase (PFK)
More about electron transport chain