Science Lecture for Unit 59: Cell Respiration
- Topic area: Biology: Cell Metabolism, Photosynthesis, Cell Respiration
- Terms and concepts to know: mitochondria, glycolysis, Krebs cycle, electron transport chain, fermentation
- See historical period(s): 20th Century Biology, Institutional Science
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:
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.
- How are cell respiration and photosynthesis similar? How do they differ?
- What do we mean by a "cycle" in the sense of the Krebs or Calvin cycles?
- Why are membranes important in both processes?
- In what part of the cell does each phase of the reaction take place?
Further Study On your Own (Optional)
- Check out Mitochondrial Mysteries Demystified, the website of the Biology Department at Taylor University. This is a fun site, but requires Shockwave software to see all the graphics.
© 2005 - 2019 This course is offered through Scholars Online, a non-profit organization supporting classical Christian education through online courses. Permission to copy course content (lessons and labs) for personal study is granted to students currently or formerly enrolled in the course through Scholars Online. Reproduction for any other purpose, without the express written consent of the author, is prohibited.