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BIO101A: Introduction to Molecular and Cellular Biology

Unit 6: Cellular Energy  

Metabolism is the set of chemical reactions that enable living things to produce the energy needed to maintain life. For plants, metabolism refers to the process of creating glucose through photosynthesis. For other organisms, however, metabolism means the conversion of food into energy. It might help you to think of metabolism as digestion at the molecular level, where the end product is ATP (which you learned about earlier). Living things rely upon a steady source of ATP in order to carry out all activities, from running after the bus to thinking about math problems. This process starts with glycolysis, which converts glucose to pyruvate. Pyruvate can then enter aerobic or anaerobic respiration, depending on the situation. The end result is still ATP. The biochemistry course (BIO401) will present metabolic reactions in greater detail.

Unit 6 Time Advisory
Completing this unit should take you approximately 10hours. 

☐    Unit 6: 2.5 hours

☐   Subunit 6.1: .75 hours

☐   Subunit 6.2: 5.25 hours

☐   Subunit 6.3: 1 hour

☐    Assessment: 0.5 hours

Unit6 Learning Outcomes
Upon successful completion of this unit, you will be able to:

  • describe aerobic respiration reactions in eukaryotic cells;
  • list aerobic respiration’s reactants and products in eukaryotic cells;
  • state the location of glycolysis, the Krebs cycle, and oxidative phosphorylation in eukaryotic cells;
  • compare and contrast aerobic and anaerobic respiration; and
  • name the high-energy molecules produced from aerobic and anaerobic respiration. 

  • Lecture: YouTube: University of California, Berkeley: Webcast.Berkeley: “Introduction to Bioenergetics,” “Cellular Energy Production and Anaerobic Processes I,” and “Cellular Energy Production and Anaerobic Processes II”

    Link: YouTube: University of California, Berkeley: Webcast.Berkeley: “Introduction to Bioenergetics,”“Cellular Energy Production and Anaerobic Processes I,” and “Cellular Energy Production and Anaerobic Processes II” (YouTube)

    Instructions: Watch these lectures to understand how the cell produces the energy it needs in the form of ATP. This can be a difficult unit, because it involves a bit of chemistry, so pay careful attention to the important molecules.

    Watching these videos and taking notes should take approximately 2 hours and 30 minutes.

    Terms of Use: The above video is reposted from the University of California, Berkeley’s Webcast.Berkeley. This video is released under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Unported License

6.1 Glycolysis   - Web Media: McGraw-Hill Higher Education: Seeley, Stephens, and Tate’s Anatomy & Physiology: “How Glycolysis Works”

Link: McGraw-Hill Higher Education: Seeley, Stephens, Tate’s
*Anatomy & Physiology: *[“How Glycolysis
Works”](http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html)
(Flash)  

 Instructions: Watch this animation to understand how glycolysis
works and then take the short quiz below the animation to see how
well you have learned the subject. The word *glycolysis* literally
means glucose breakdown. It is the name given to a series of
reactions that ultimately breaks down the 6 carbon glucose molecule
into two 3 carbon molecules of pyruvate and releases ATP as energy
in the process. But do note that while there is a net gain of ATP in
glycolysis, some reaction steps actually use up ATP.   

 Watching this animation should take approximately 15 minutes.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

6.2 Aerobic Respiration   - Lecture: Khan Academy’s “Introduction to Cellular Respiration”

Link: Khan Academy’s [“Introduction to Cellular
Respiration”](https://www.khanacademy.org/science/biology/cellular-respiration/v/introduction-to-cellular-respiration) (YouTube)  

 Instructions: Watch this lecture for an introduction to cellular
respiration.   

 Watching this video and taking notes should take approximately 30
minutes.  

 Terms of Use: This resource is licensed under a [Creative Commons
Attribution-NonCommercial-NoDerivatives 3.0 Unported
License](http://creativecommons.org/licenses/by-nc-nd/3.0/). It is
attributed to Khan Academy.

6.2.1 Citric Acid Cycle   - Lecture: Khan Academy’s “Krebs/Citric Acid Cycle”

Link: Khan Academy’s [“Krebs/Citric Acid
Cycle”](https://www.khanacademy.org/science/biology/cellular-respiration/v/krebs---citric-acid-cycle)
(YouTube)  

 Instructions: Watch this lecture for an introduction to the citric
acid cycle.   
    
 Watching this lecture and taking notes should take approximately 30
minutes.  

 Terms of Use: This resource is licensed under a [Creative Commons
Attribution-NonCommercial-NoDerivatives 3.0 Unported
License](http://creativecommons.org/licenses/by-nc-nd/3.0/). It is
attributed to Khan Academy.
  • Reading: National Center for Biotechnology Information’s Bookshelf: Harvey Lodish, Arnold Berk, et al.’s Molecular Cell Biology, 4e: “Oxidation of the Acetyl Group of Acetyl CoA in the Citric Acid Cycle Yields CO2 and Reduced Coenzymes” Link: National Center for Biotechnology Information’s Bookshelf: Harvey Lodish and Arnold Berk, et al.’s Molecular Cell Biology, 4e: “Oxidation of the Acetyl Group of Acetyl CoA in the Citric Acid Cycle Yields CO2 and Reduced Coenzymes” (HTML)

    Instructions: Read this section to understand how pyruvate, produced from glycolysis, becomes acetyl CoA before being oxidized in the citric acid cycle (also known as TCA cycle or Krebs cycle).

    Reading this section and taking notes should take approximately 30 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: McGraw-Hill Higher Education: Seeley, Stephens, and Tate’s Anatomy & Physiology: “How the Krebs Cycle Works”

    Link: McGraw-Hill Higher Education: Seeley, Stephens, and Tate’s Anatomy & Physiology: “How the Krebs Cycle Works” (Flash)

    Instructions: Watch this animation to visually observe the Krebs cycle’s pathways, and then take the short quiz below the animation to see how well you learned the material.

    Watching this animation and taking the quiz should take approximately 30 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

6.2.2 Oxidative Phosphorylation   - Reading: National Center for Biotechnology Information’s Bookshelf: Geoffrey Cooper’s The Cell: A Molecular Approach, 2e: “The Mechanism of Oxidative Phosphorylation”

Link: National Center for Biotechnology Information’s Bookshelf:
Geoffrey Cooper’s *The Cell: A Molecular Approach*, 2e: [“The
Mechanism of Oxidative
Phosphorylation”](http://www.ncbi.nlm.nih.gov/books/NBK9885/)
(HTML)  

 Instructions: Read the entire page to understand oxidative
phosphorylation and ATP generation. Aerobic respiration would not be
possible without the presence of oxygen, which serves as an electron
acceptor of electrons from the high-energy molecules NADH and
FADH<sub>2</sub>.  

 Reading this webpage and taking notes should take approximately 1
hour.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.
  • Web Media: McGraw-Hill Higher Education: Seeley, Stephens, and Tate’s Anatomy & Physiology: “Electron Transport System and ATP Synthesis”

    Link: McGraw-Hill Higher Education: Seeley, Stephens, and Tate’s Anatomy & Physiology: “Electron Transport System and ATP Synthesis” (Flash)

    Instructions: Watch this animation of how ATP is produced via oxidative phosphorylation, and then take the short quiz below the animation to see how well you learned the material.

    Watching this animation and taking the quiz should take approximately 30 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Lecture: Khan Academy’s “Oxidative Phosphorylation and Chemiosmosis”

    Link: Khan Academy’s “Oxidative Phosphorylation and Chemiosmosis” (YouTube)

    Instructions: Watch this lecture, which introduces oxidative phosphorylation and chemiosmosis. 
     
    Watching this lecture and taking notes should take approximately 15 minutes.

    Terms of Use: This resource is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 Unported License. It is attributed to Khan Academy.

  • Lecture: Khan Academy’s “Electron Transport Chain”

    Link: Khan Academy’s “Electron Transport Chain” (YouTube)

    Instructions: Watch this lecture, which introduces the electron transport chain. 
     
    Watching this lecture and taking notes should take approximately 30 minutes.

    Terms of Use: This resource is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 Unported License. It is attributed to Khan Academy.

6.2.3 ATP Produced   - Reading: Wikipedia: “Cellular Respiration: Theoretical Yields”

Link: Wikipedia: [“Cellular Respiration: Theoretical
Yields”](http://www.saylor.org/site/wp-content/uploads/2013/04/BIO101A-6.2.3-CellularRespiration.pdf) (PDF)  

 Instructions: Read the “Efficiency of ATP Production” section.
Understand when (i.e., during which stages) ATP is produced. Both
plants and animals use a similar proton-driven pump to produce ATP.
This pump literally forces ADP (adenosine diphosphate) and inorganic
phosphate together. Note that aerobic respiration produces much more
ATP than does anaerobic respiration.  

 Reading this article and taking notes should take approximately 1
hour.  

 Terms of Use: This article is licensed under a [Creative Commons
Attribution-ShareAlike 3.0
License](http://creativecommons.org/licenses/by-sa/3.0/). It is
attributed to Wikipedia, and the original version can be found
[here](http://en.wikipedia.org/wiki/Cellular_respiration).

6.3 Anaerobic Respiration   6.3.1 Alcoholic Fermentation   - Web Media: Pearson Education: “Alcoholic Fermentation”

Link: Pearson Education: [“Alcoholic
Fermentation”](http://www.phschool.com/science/biology_place/biocoach/cellresp/review5b.html) (HTML)  

 Instructions: Watch the four animations to understand how ethanol
(alcohol) is produced. Click on “Animate 1,” “Animate 2,” “Animate
3,” and “Animate 4” to view the steps of fermentation. Thanks to
alcoholic fermentation, we can enjoy beer, wine, and other alcoholic
beverages! Anaerobic respiration does not require the presence of
oxygen because it uses other molecules as electron acceptors for
electrons from high-energy NADH molecules.  

 Watching these four animations should take approximately 30
minutes.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

6.3.2 Lactic Acid Fermentation   - Web Media: Pearson Education: “Lactic Acid Fermentation”

Link: Pearson Education: [“Lactic Acid
Fermentation”](http://www.phschool.com/science/biology_place/biocoach/cellresp/review5a.html) (HTML)  

 Instructions: Watch the four animations to understand how lactic
acid is generated (you will notice it is similar to how ethanol is
created). When our bodies do not have enough oxygen to generate ATP,
or when we need more ATP than aerobic respiration is providing us
with, lactate fermentation steps up and enables us to produce the
ATP we need. Students should also compare the reactions of anaerobic
and aerobic metabolism to understand why the latter is more
efficient at producing energy-rich molecules necessary for life.
This difference also explains why most life forms on Earth utilize
aerobic metabolism.  

 Watching these four animations should take approximately 30
minutes.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

Unit 6 Quiz   - Assessment: The Saylor Foundation’s “BIO101 Unit 6 Quiz” Link: The Saylor Foundation’s “BIO101 Unit 6 Quiz” 

 Instructions: Complete this assessment to gauge your understanding
of the topics covered in this unit. The correct answers will be
displayed when you click the “Submit” button.  

 Completing this assessment should take approximately 30 minutes.