How Muscle Cells Work During Exercise Animation

NOVA scienceNOW: Marathon Mouse

Classroom Action

Activeness Summary
Student teams analyze pictures of magnified muscle cells from a hypothetical experiment to decide the effects of exercise and functioning-enhancing drugs.

Learning Objectives
Students volition exist able to:

describe the role of mitochondria
describe cellular changes acquired by exercise
clarify a cause-and-effect human relationship between behavior and physiology
make predictions based on information
explicate the importance of a control grouping in an experiment
argue the pros and cons of functioning-enhancing substances

Suggested Time
One course period

Multimedia Resources

Marathon Mouse QuickTime or Windows Media Video
The Fate of Fat QuickTime or Windows Media Video
Where Do You Get Your Energy? Flash Interactive
Marathon Mouse QuickTime or Windows Media Video
How the Torso Responds to Exercise QuickTime Video

Additional Materials

Marathon Mouse Student Handout (PDF), one per pupil
Marathon Mouse teacher blackline master (PDF)
Envelopers, ane per educatee pair

Background

Many furnishings of regular exercise are obvious, such also-divers muscles, weight loss, and less huffing and puffing through workouts. But few people consider the cellular changes underlying noticeable physical results. Improved endurance is ane aspect of practice preparation that has been studied at the cellular level.

Eukaryotic cells get energy thorugh respiration
All cells require energy to only survive, and cells obtain that energy from nutrient molecules, such as glucose. Nutrient molecules are broken down in several chemic reactions that release usable energy, which is stored in loftier-energy adenosine triphosphate molecules (ATP). ATP is then used by cells to carry out life processes. One method eukaryotic cells use to make ATP from glucose is known every bit aerobic respiration , which occurs in the mitochondria. Overall, the process tin can exist summarized in the following reaction:

Glucose + Oxygen → H2o + Carbon Dioxide + ATP

Practise changes cells
The prove describes 2 types of muscle cells, slow twitch and fast twitch. Deadening-twitch muscles are of import for endurance. They accept lots of mitochondria and efficiently fire both fat and glucose. Fast-twitch muscles, which are used in quick bursts of activeness, have fewer mitochondria and primarily burn glucose. The number of slow- and fast-twitch fibers in any particular muscle appears to be genetically determined. However, athletes can gear their training to especially develop one kind of muscle. For example, endurance training will develop more than irksome-twitch muscle, on a percent-total-mass basis. These tedious-twitch muscles will incorporate more and larger mitochondria and have an improved ability to catechumen fats into usable energy.

Endurance in a pill
The testify describes a genetically engineered mouse that could run longer and further than normal mice. How? Researchers turned a factor, chosen PPAR delta, on overdrive. From birth, the mouse'due south musculus cells made more mitochondria and burned more than fat than the muscle cells of normal mice would.

Boosted research on mice showed that a drug known equally AICAR had the same influence equally endurance training. The drug works by triggering the jail cell's fuel guess, making it carry as if energy is deficient, fifty-fifty when it's non. The prison cell responds by increasing the amount of slow-twitch muscle, on a pct-total-mass basis. The cells even burn fat better. Could the drug work in humans? No one knows—yet.

In this activity
In this activity, students volition analyze pictures of magnified muscle cells from a hypothetical experiment to decide the effects of exercise and functioning-enhancing drugs.

Earlier the Lesson

Make copies of the Marathon Mouse handout (i per student).
Obtain envelopes (one envelope per educatee pair).
Make copies of the Teacher Black Master, cut out the images, and place the images from ii dissimilar mice in each envelope. If you programme to reuse the materials, consider laminating the images.
If possible, provide computer access for each pair of students. Alternatively, as a grade, watch the ii videos mentioned in the student handout.
Bookmark the following Spider web sites:
- Marathon Mouse Quick Time or Windows Media Video
- The Fate of Fat QuickTime or Windows Media Video
- Where Do You Go Your Energy? Wink Interactive
- Marathon Mouse QuickTime or Windows Media Video
- How the Trunk Responds to Exercise QuickTime Video

The Lesson

As a form, watch the NOVA scienceNOW segment Marathon Mouse (11 minutes). You can stream it from the NOVA scienceNOW Web site at http://www.pbs.org/wgbh/nova/sciencenow/0403/03.html. Discuss any questions students take about the segment.
Ask students where people get their energy. (Food) To illustrate how food is digested and distributed to various tissues for storage or energy, prove the course the two-minute video titled "The Fate of Fatty" (scroll downward to find information technology): http://www.hhmi.org/biointeractive/obesity/animations.html.
Discuss the video and tell students that the fatty entering musculus cells volition be broken downwards and used by the mitochondria. Remind them that mitochondria convert food molecules into usable energy and that a simplified reaction for aerobic respiration is:

Glucose + Oxygen → H2o + Carbon Dioxide + ATP
Tell students that they will analyze data from a hypothetical experiment similar to the ones presented in the segment. Divide the grade into pairs, and give each pair a copy of the handout. Also give each pair an envelope containing data from two of the four experimental mice. Tell students that the darker areas in the images are the mitochondria-rich muscle cells.
Have each pair read the handout's opening statement and consummate the procedure for analyzing their cell samples, including viewing the Flash blitheness Where practise you get your energy? and the How the Torso Responds to Exercise video.

Write a chart on the board to organize the course data, and have students fill up in their responses once pairs accept completed Step 3 of the handout. Here is an example: (Annotation: The numbers in the chart are hypothetical numbers.)

Mouse	Educatee Pair	Number of mitochondria-rich cells at the beginning of the experiement	Number of mitochondria-rich cells at the end of the experiement
i	Bob and Sue	4	5
i	Maria and Olivia	5	5
2	Carlos and Andre	4	seven

Ask students to look at the class data and predict which mouse received which treatment. Then, reveal the answers:
- Mouse one is the control mouse (no exercise, no drugs, mitochondria/cells stayed the same).
- Mouse 2 exercised daily (increased number of mitochondria-rich cells).
- Mouse 3 received Drug x (same consequence as practise).
- Mouse 4 received Drug y (no event).
Ask students to compare the effects of each handling. For instance, both Drug Ten and Exercise created more mitochondria. On the other mitt, "no treatment" led to no alter in the number of mitochondria-rich cells, but like the ineffective Drug Y. Ask students to explain any incorrect predictions. For example, they didn't know which drugs were effective in this hypothetical experiment until all the available data was compared.
Take students fence the pros and cons of a pill that simulates exercise. For example, such a pill could do good the elderly, hospital patients, and people with muscular conditions. On the other hand, a pill that simulates exercise could be abused in sports and might have adverse side effects. Also, remind students that, currently, the but guaranteed way for people to increase their fitness is to exercise.

Extensions

Examine and discuss the differences between light and night meat in craven. Nighttime meat contains more fat, has a richer claret supply, and is composed primarily of slow-twitch muscle fibers, which are full of cells rich in mitochondria. This muscle is well adapted to low-intensity, long- duration activities. Ask students to consider why dark meat is concentrated in specific locations in the chicken. (Dark meat is full of mitochondria-rich cells and is constitute in muscles used in activities requiring endurance, such as flying and walking.) Ask students to hypothesize where dark meat might exist found in other animals, such as those that travel long distances (east.g., ducks, caribou, and certain turtles and fish).
For avant-garde students, testify the animation PPAR-delta Activation in the Muscle Cell at: http://www.hhmi.org/biointeractive/obesity/animations.html (whorl down to find it). It illustrates how the PPAR-delta receptor activates certain genes in a muscle cell, resulting in the burning of fat. Prove the animation several times and have students summarize what is happening: PPAR-delta is a type of receptor related to the metabolism and storing of fat. Information technology activates certain genes that signal the musculus cell to burn down fatty for free energy. Also, relate this blitheness to the original NOVA scienceNOW segment: the Marathon Mouse was genetically engineered to have PPAR-delta in overdrive, allowing information technology to run significantly longer distances than regular mice could.

Assessment

Educatee Handout

Summarize the office of mitochondria. (Mitochondria catechumen food energy, such as glucose, into usable energy known as ATP. Because of this, mitochondria are oft referred to every bit the "powerhouses" of the cell.)
Predict how the number of mitochondria-rich muscle cells would change in each of the situations below. (Answers will vary.)

In the tabular array beneath, enter the number of mitochondria-rich muscle cells shown in each of your images. (Answers volition vary slightly, but should reflect the gauge numbers beneath:)

Mouse Number	Number of mitochondria-rich cells at showtime of experiment	Number of mitochondria-rich cells at end of experiment
1	four	iv
two	four	10
3	4	8
4	5	five

Student Handout Questions

Explain your conclusions about how and why each treatment affected the number of mitochondria-rich cells for each of the iv mice. (The number of mitochondria-rich cells in Mouse 1 and four did non change, whereas the number of mitochondria-rich cells in Mouse 2 and 3 increased. No treatment resulted in no alter in the number of mitochondria-rich cells. Practise acquired the number of mitochondria-rich cells to increase because mitochondria supply energy required for activity. Drug Ten appears to mimic do, since Drug X caused an increase in mitochondria-rich cells too. Drug Y, however, appears to have no upshot on the number of mitochondria-rich cells.)
In both the Marathon Mouse experiment and the hypothetical experiment above, one mouse received no special treatment. What was the purpose of having this mouse in the experiment? (The mouse that was left in its cage served as the experimental control. The mouse was included in the experiment as a standard for comparison, to provide a baseline against which to compare the other mice.)
List some pros and cons of a drug that can produce the same effects as do. (Pros: maintain muscle mass of chronically sick or hospitalized patients and people unable to become sufficient practice. Cons: potential for abuse by athletes; side effects; potential for addiction; potential for entering the homo nutrient chain through animals treated with the drug.)
Imagine that you could design an animal with peachy endurance, either flying, running, or swimming. Draw the animal and characterization its endurance characteristics. (If possible, picket the video How the Body Responds to Practice at: http://world wide web.teachersdomain.org/resource/oer08.sci.life.reg.exercise/.) (Answers will vary. Endurance characteristics could include: more than irksome-twitch muscle, increased number of mitochondria in each musculus cell, increased blood flow to the muscles, and increased ability to use oxygen efficiently.)

Use the following rubric to assess each squad's work.

	Fantabulous	Satisfactory	Needs improvement
Complete the Marathon Muscles student handout and graph the hypothetical data.	Students utilise Web resources effectively to answer questions. Students prove ability to obtain, graph, and translate information. Students use data effectively to justify predictions.	Students need aid while using resources. Students have difficulty obtaining, graphing, and interpreting information. Students make predictions but cannot justify their reasoning.	Students take difficulty using Web resources to answer questions. Students cannot obtain, graph, or translate the experimental data. Students cannot make predictions based on information.

The Marathon Mouse activeness aligns with the following National Science Education Standards (see books.nap.edu/html/nses).

Grades 9-12
Life Science Standard C

The Prison cell
Matter, energy, and organization in living systems

Life Science Standard F

Science in Personal and Social Perspectives

Life Scientific discipline Standard G

Science every bit a human endeavor
Nature of scientific cognition

Classroom Action Writer

Alison Fromme and WGBH Educational Outreach staff

Funding for NOVA scienceNOW is provided by the National Science Foundation, the Howard Hughes Medical Institute, the Alfred P. Sloan Foundation, and public television viewers.

A private corporation funded by the American people

This material is based upon work supported by the National Science Foundation nether Grant no. 0638931. Whatsoever opinions, findings, and conclusions or recommendations expressed in this material are those of the writer(south) and do non necessarily reverberate the views of the National Science Foundation.

Source: https://www.pbs.org/wgbh/nova/teachers/activities/0403_03_nsn.html

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