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.
1.
Ask:
- 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.
4.
Optional: Have students review the
Krebs Cycle
and Electron Transport Chain diagrams.
Tell them to work in pairs to answer the following:
- 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?
