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 \n → total: 38 ATP \n

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