In this activity, students learn about the role of mitochondria in a cell's energy production. They compare the three metabolic pathways that produce ATP. They describe in detail the structure of mitochondria and how it relates to its function in energy production. As an option, they review the Krebs cycle and the electron transport chain to identify how ATP can be produced from glucose. They learn about the differences in structure of fast- and slow-twitch muscle fibers and the role of each in different types of physical activity. They explore how an understanding of aerobic and anaerobic metabolic pathways could affect the way athletes train. Finally, they learn about physiological research on the relationship between oxygen and performance at high altitudes.
- Learn about the role of mitochondria in a cell's energy production
- Compare the three metabolic pathways that produce ATP
- Identify the differences in structure and function of fast- and slow-twitch muscle fibers
- Explore how an understanding of aerobic and anaerobic metabolic pathways could affect athletic training regimes
- Learn about research on the relationship between oxygen and performance at high altitudes
- Two to three class periods
- Organelles in the Cytoplasm QuickTime Video
- The Powerhouse of the Cell QuickTime Video
- Mitochondrial Flyover QuickTime Video
- Mitochondria PDF Document
- Mitochondria Functions and Training PDF Document
- Is Lactic Acid a Four Letter Word? PDF Document
- Climbing without O's HTML Document
Optional Multimedia Resources
Before the Lesson
After the Lesson
- Follow up with a study of the structure and function of muscle cells and the muscular system.
- How do you think cells produce energy to live?
Show the Organelles in the Cytoplasm video and discuss the following:
- What is the role of the mitochondria?
- In what kind of cells would you expect to see the most mitochondria?
2. Show the The Powerhouse of the Cell video. Discuss the following:
- What three metabolic pathways produce ATP, the high-energy currency of the cell? Which pathway produces more, and why? Where do these processes occur in a cell?
- What is the difference between slow-twitch and fast-twitch muscle fibers?
- Which kinds of activities use mostly slow-twitch fibers? Which use mostly fast-twitch fibers?
- What increases the number of mitochondria in a cell?
- How do mitochondria replicate themselves?
- What is believed to be the evolutionary origin of mitochondria?
- Describe the mitochondrial DNA (mDNA) theory of aging.
3. Show the Mitochondrial Flyover video. Have students draw a mitochondrion in detail, labeling all the parts and writing a brief paragraph that answers the following questions:
- In what ways does the structure of the mitochondrion relate to its function?
- Where do the Krebs cycle and the electron transport chain specifically occur in the mitochondrion?
- Have students review the Mitochondria article to supplement their explanation.
- Where in these reactions does the ATP get produced?
- What is the role of oxygen?
- Up to 38 ATP are produced from one molecule of glucose. How can you account for this?
5. Ask teams of students to review either the Mitochondria Functions and Training article or the article Is Lactic Acid a Four Letter Word? and report back to the class on the relationship between mitochondria and exercise. Discuss the following:
- How is the ratio of fast-twitch to slow-twitch fibers in a person determined?
- How does the duration and intensity of training affect the muscle fibers? The concentration of mitochondria?
- When are anaerobic and aerobic energy pathways used during extended exercise such as distance running?
- How does aerobic endurance training affect muscles?
- How might an understanding of anaerobic and aerobic energy pathways affect the way athletes train for different sports?
6. Ask students:
- How do you think the low concentration of oxygen in the air at high altitudes would affect muscle performance?
Have students read the Climbing without O's article and discuss the following:
- How did physiologists test their hypothesis that climbers would be able to reach high altitudes without supplemental oxygen? What did they measure?
- What questions about exercise at high altitudes still remain unanswered?
- What do you think would happen to the concentration of mitochondria in muscle cells if a person lived in a high-altitude environment for a long time?