MARATHON MOUSEA Study of Mitochondria Activity

Mrs. MacWilliams

Academic Biology

BACKGROUND• Effects of exercise

• well-defined muscles, weight loss, and less huffing and puffing through workouts.

• There are also CELLULAR changes underlying noticeable physical results.

• Example: Improved endurance

Eukaryotic cells get energy thorugh respiration

• All cells require energy to simply survive• Cells obtain energy from food, such as glucose.• Food is broken down into chemical reactions that

release usable energy, which is stored in high-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 as aerobic respiration , which occurs in the mitochondria

• Glucose + O2→ H2O+ CO2 + ATP

WATCH THE FATE OF FAT

Exercise Changes Cells Slow-twitch muscles - important for endurance. They

have lots of mitochondria and efficiently burn both fat and glucose.

Fast-twitch muscles- used in quick bursts of activity, have fewer mitochondria and primarily burn glucose.

Number of slow- and fast-twitch fibers in any particular muscle appears to be genetically determined.

Athletes can gear their training to especially develop one kind of muscle (endurance training will develop more slow-twitch)

Slow-twitch muscles will contain more and larger mitochondria and have an improved ability to convert fats into usable energy.

Endurance in a Pill• This activity describes a genetically engineered mouse

that could run longer and farther than normal mice.• Researchers turned a gene, called PPAR delta, on

overdrive. From birth, the mouse's muscle cells made more mitochondria and burned more fat than the muscle cells of normal mice would.

• Additional research on mice showed that a drug known as AICAR had the same influence as endurance training. The drug works by triggering the cell's fuel gauge, making it behave as if energy is scarce, even when it's not. The cell responds by increasing the amount of slow-twitch muscle, on a percent-total-mass basis. The cells even burn fat better.

• Could the drug work in humans? No one knows—yet.

YOUR TASK!

• In this activity, you will analyze pictures of magnified muscle cells from a hypothetical experiment to determine the effects of exercise and performance-enhancing drugs.

• WATCH MARATHON MOUSE

1. Where do you get energy?

GO THROUGH ANIMATION

WHERE DO YOU GET YOUR ENERGY?

Now summarize the function of mitochondria on your paper. INCLUDE EVERYTHING IN THE ANIMATION!

TABLE 1

PREDICT (Make a hypothesis) how the number of mitochondria rich cells would change. FILL IN TABLE 1.

TABLE 2

REVIEW THE PICTURES ON THE NEXT FOUR SLIDES. COUNT HOW MANY DARK CELLS ARE AT THE BEGINNING AND AT THE END OF THE EXPERIMENT. WHEN COUNTING CELLS COUNT ALL CELLS THAT ARE DARKER THAN THE ORIGINAL (Does not matter if they are a little or a lot darker… count it)

FILL IN TABLE 2.

TABLE 2

TABLE 2

TABLE 2

TABLE 2

TABLE 3PREDICT WHAT TREATMENTS EACH MOUSE RECEIVED. FILL IN TABLE 3.

DO NOT PROCEDE TO NEXT SLIDE UNTIL YOU HAVE MADE YOUR

PREDICTION FOR EACH OF THE 4 MICE!!!!!!!!!!!!!!!!

ACTUAL RESULTS (WRITE ALL IN TABLE 3)

• Mouse 1• control mouse (no exercise/drugs, mitochondria

same).• Mouse 2

• exercised daily (increased mitochondria).• Mouse 3

• received Drug x (same effect as exercise-AICAR).• Mouse 4

• received Drug y (no effect).• PLACEBO!!!!

QUESTIONS:

WATCH HOW THE BODY RESPONDS TO EXERCISE

*COMPLETE QUESTIONS 1-4 THEN TURN IN ASSIGNMENT