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Cellular Respiration

cellular respiration: a catabolic process that breaks apart glucose and strips it of its electrons

process of cellular respiration

equation: C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP

GOAL: take one glucose molecule and make 38 molecules of ATP (dismantle)

3 steps:

  1. glycolysis

    • no oxygen needed

    • occurs in cytoplasm

    • glucose broken down into 3-carbon molecules called pyruvate

    • produces 2 ATP, 2 NADH

  2. link

    • if oxygen is present, pyruvic acid broken down further into 2 acetyl COA (+2 NADH, releases CO2)

  3. krebs [citric acid] cycle

    • acetyl coa broken down

    • CO2 released

    • +2 ATP, 6 NADH, 2 FADH2

    • occurs in mitochondria

    • most of remaining energy is hydrogen attached to NADH + FADH2

  4. electron transport chain

    • occurs in inner membrane of the mitochondria

    • electrons from NAD(H) passed to carrier molecules embedded in inner membrane; allows H+ protons to diffuse from matrix → inner membrane space

    • forms steep proton gradient - H+ protons diffuse back down the gradient through ATP synthase; ATP is made as ADP picks up its third phosphate

    • hydrogen electrons land on oxygen - final electron acceptor, makes water

    • each hydrogen from NADH can make 3 ATP, each hydrogen from FADH2 makes 2 ATP

    • 10 moles of NADH = 30 ATP

    • 2 moles of FADH2 = 4 ATP

    • glycolysis/krebs cycle = 4 ATP
      → total: 38 ATP

Cellular Respiration

cellular respiration: a catabolic process that breaks apart glucose and strips it of its electrons

process of cellular respiration

equation: C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP

GOAL: take one glucose molecule and make 38 molecules of ATP (dismantle)

3 steps:

  1. glycolysis

    • no oxygen needed

    • occurs in cytoplasm

    • glucose broken down into 3-carbon molecules called pyruvate

    • produces 2 ATP, 2 NADH

  2. link

    • if oxygen is present, pyruvic acid broken down further into 2 acetyl COA (+2 NADH, releases CO2)

  3. krebs [citric acid] cycle

    • acetyl coa broken down

    • CO2 released

    • +2 ATP, 6 NADH, 2 FADH2

    • occurs in mitochondria

    • most of remaining energy is hydrogen attached to NADH + FADH2

  4. electron transport chain

    • occurs in inner membrane of the mitochondria

    • electrons from NAD(H) passed to carrier molecules embedded in inner membrane; allows H+ protons to diffuse from matrix → inner membrane space

    • forms steep proton gradient - H+ protons diffuse back down the gradient through ATP synthase; ATP is made as ADP picks up its third phosphate

    • hydrogen electrons land on oxygen - final electron acceptor, makes water

    • each hydrogen from NADH can make 3 ATP, each hydrogen from FADH2 makes 2 ATP

    • 10 moles of NADH = 30 ATP

    • 2 moles of FADH2 = 4 ATP

    • glycolysis/krebs cycle = 4 ATP
      → total: 38 ATP

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