Period
Date
Background: Muscle cells rely on aerobic cellular respiration for their energy needs. When
muscles are deprived of their customary oxygen, they are capable of
functioning but for only a short period of time. During intense activity,
oxygen is often being used by the body faster than it can be supplied to the
muscle. The muscle cells will continue to function. However, they begin to
obtain the necessary energy through anaerobic lactic acid fermentation.
ln lactic acid fermentation, your body builds up lactic acid causing your
muscles to experience a burning sensation. Following a period of the rest,
allowing the lactic acid to be flushed out of your muscles, the muscle cells
regain their normal condition.
Materials: Springtype clothespin, stopwatch or second hand on wall clock, graph paper, ruler,
dishpan of ice watbr
Procedure:
PART ONE: EFFECT OF TEMPERATURE ON MUSCLE CONTRACTION
1. Prediction:
Read through the procedure for part one. How do you expect your baseline
data to differ from your cold data? Explain your reasoning.
2. Using your "off' hand, count the number of times you can open and close a clothespin in
30 seconds. Hold the clothespin between your thumb and index finger and hold your
other fingers out straight. Try to do so as many times as you can in 30 seconds. Be
sure to open and close the clothespin completely each time. Record your data in
the following table as the first baseline trial.
your hand and allow your fingers to rest for a few seconds. Then repeat the
30 second operation with the same hand and same technique. Record your data.
3. Shake out
4. Calculate the average of the two baseline trials. Record the average in the table.
5. Now submerge
your hand in an ice water bath for one full minute.
6. After one minute, remove your hand from the ice water bath and immediately count the
number of times you can open and close the clothespin in 30 seconds. Be sure to use
the same technique throughout this exercise. Record your data in the following table as
the first cold trial.
7, Shake out your hand and allow your fingers to rest for a few seconds. Then repeat the
30 second operation with the same hand and same technique. Record your data.
8. Calculate
the average of the two cold trials. Record the average in the table.
PART TWO: EFFECT OF SUSTAINED EXERCISE
9. Prediction:
Read through the procedure for part two. How do you expect your data to
change over time (through all ten trials)? Explain your reasoning.
10. Now using your dominant hand, count the number of times you can open and close a
clothespin in 30 seconds. Hold the clothespin between your thumb and index finger and
hold your other fingers out straight. Try to do so as many times as you can in 30
seconds. Be sure to open and close the clothespin completely each time. Record
your data in the following table as the first dominant hand trial.
the 30 second operation again 9 more times with the same hand and record
your data with each successive trial. DO NOT STOP TO REST any longer than it takes
to record your data. Again, be sure to use the same technique (fingers) throughout this
exercise.
11. Repeat
line graph of your results for part two with the vertical axis being labeled
"number of contractions" and the horizontal axis being labeled "number of trials".
12. Construct a
13.Answer the questions on your graph paper, using complete senfences.
Data:
PART ONE
hand
Number of
"Off"
baseline trial #
contractions
PART TWO
Dominant
Number of
hand trial #
contractions
1
1
2
2
Total:
Baseline average:
4
"Off" hand cold trial #
8
3
1
I
2
10
Total:
Cold average:
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Questions: (Answer on a
rate sheet of
1.
What effect did the cold temperature have on the action of your hand muscles? Explain
why. Was your prediction supported by the data?
2.
Describe the shape (no need to explain why) of your line graph in as much detail as
possible.
3.
Examine your graph. Explain why the number of contractions changed over time
(through all ten trials). Was your prediction supported by the data?
4.
Did your hand/finger muscles experience a burning sensation during any parts of this
lab? Explain why this occurred when it did and why it didn't occur when it didn't.
5.
Explain why muscles must use lactic acid fermentation instead of cellular respiration
during intense physical activity.
6. For how long can muscles rely solely on lactic acid fermentation to generate ATP?
7. Explain why muscles require a period of rest after intense physical activity.
8. What is meant by the phrase "feel the burn", What are you feeling?
9. While working out with a friend, he mentioned blood doping as a way to improve athletic
performance. This friend was thinking of doing this for next weeks big game. Do some
research and write a paragraph (at least 5 sentences) about what blood doping is.
lnclude in your paragraph how it is related to cellular respiration and your advice to this
friend. Would you recommend it? Why or why not?