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Natural Science - Year II

Unit 59: Krebs and Cellular Respiration

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Science Weblecture for Unit 59

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Science Lecture for Unit 59: Cell Respiration

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Cellular respiration is the process by which the mitochondria releases of stored energy so that the cell can do work—form other molecules, build proteins, move chemicals through its membrane. The cellular respiration reaction is also made of many steps, which are often broken down into two phases: the breakdown of glucose to pyruvic acid, followed by the Krebs cycle. The overall cellular respiration reaction is:

C 6 H 12 O 6   +   6   O 6     +   6   H 2 O      6   C O 2   + 6   H 2 O   +   energy    

Notice that this is just the photosynthetic reaction in reverse! As with the photosynthesis reaction, each step has its own enzyme.

Work through the process of glycolysis at John Kyrk's glycolysis site, then look at the Krebs cycle at the same site.

  • Find at least one step in glycolysis and one in the Krebs cycle where the only thing happening is rearrangement of the molecule.
  • Find at least one step in each process where the molecules gain atoms or atomic groups.
  • Find at least one step in each process where the molecules lose atoms or atomic groups.

Study/Discussion Questions:

Further Study On your Own (Optional)