Clothespin Lab Assignment - Student Copy - NS 2020 PDF

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Summary

This assignment is an individual experiment conducted in order to scrutinize muscle fatigue and corresponding cell purposes....

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SBI 4U

Investigating Muscle Fatigue Lab

Due: Sun, Apr 12

Muscle cells provide a good example of how cells in the human body perform the process of cell respiration, under both aerobic and anaerobic conditions. All cells, including muscle cells, need glucose and oxygen in order for their mitochondria to perform aerobic cell respiration. When the oxygen supply to cells is reduced, anaerobic respiration takes over. Ultimately, both processes provide cells with their needed ATP, which in turn supplies the cell with energy to function properly. When muscle activity is continuous and excessive, muscle cells will switch from aerobic respiration to anaerobic respiration as the availability of oxygen decreases. Overworked muscle cells in a state of anaerobic respiration can become tired or fatigued. A fatigued muscle cannot function efficiently. The symptoms of excessive anaerobic respiration are sore muscles and muscle “cramps”. These cramps are largely due to a buildup of lactic acid among the muscle tissue. Fortunately, this condition is not permanent. When the overworked muscle cells are given a rest to allow the body to “catch up” its oxygen supply, the lactic acid will recycle back through the system and the cells will revert once again to aerobic respiration. PURPOSE OF INVESTIGATION: 1. To experience the reduction in muscle efficiency from continuous muscle contractions due to muscle fatigue. 2. To explain the observed pattern of muscle fatigue in terms of aerobic and anaerobic respiration pathways, oxygen availability, and waste buildup. MATERIALS: Clothespin*, timer (*you can also use a kitchen clip or hair clip to do this activity) PROCEDURE: Choose one of the following options for this assignment Option A: If you have a clothespin or similar object at home 1. Hold the clothespin between the thumb and pointer finger of your non-writing hand. The rest of your fingers should be closed like a fist. 2. Open and close the pin AS FAST AS YOU CAN for 20 seconds, and count the number of closures you can do in 20 seconds. You get a 5 second break in-between trials. 3. Count the number of times you closed the clothespin for every trial and record the number in the following data table. Repeat this procedure for 5 trials. DATA TABLE # of Squeezes

Trial 1 2 3 4 5

4. Graph your data. Then answer analysis questions 1-7, and discussion questions 1-5.

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Option B: If you DO NOT have a clothespin or similar object at home 1. IMAGINE you are holding clothespin between the thumb and pointer finger of your nonwriting hand. The rest of your fingers should be closed like a fist. 2. AS FAST AS YOU CAN for 30 seconds, count the number of times you can open and close your thumb and pointer finger. Make sure that you “close” your fingers by touching them together. Take a 5 second break in-between trials. 3. Record the number of times you open and closed your fingers together for every trial in the following data table. Repeat this procedure for 5 trials. DATA TABLE # of Squeezes

Trial

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1 2 3 4 5

4. Graph your data. Then answer analysis questions 1-7, and discussion questions 1-5. --------------------------------------------------------------------------------------------------------------------------RESULTS: Make a rough graph of your data from the table. Make sure to label your axis.

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ANALYSIS QUESTIONS:

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1. What do all cells need in order to perform cell respiration? /2

2. What type of respiration occurs when the oxygen supply is reduced? /1

3. What does the process of cell respiration provide for cells? /1

4. True or False - If anaerobic respiration is occurring, no ATP will be produced. /1

5. What are some characteristics of a fatigued muscle cell? /2

6. Under what circumstances would a muscle cell become fatigued? /2

7. Once anaerobic respiration takes place, are the effects permanent? Why or why not? /2

/13 DISCUSSION QUESTIONS: (Using full sentences, write your response in the box below each question. There is no word limit for the boxes, so you can write as much as you need to. Click SAVE often.)

1. Observe the pattern of your “fatigue graph”. Describe how the number of closures changed over time, and the trend line of your graph (does it show a regular and consistent change over the trials, or were there any major irregularities). /3

2. Given what you know about muscle fatigue, did the results turn out the way you expected? Why or why not? /2

3. Review the process of muscle fatigue. Can you determine from your graph when fatigue occurred? Was fatigue a continuous process? Why or why not? /3

4. Based on the data table and/or graph, explain the body’s transition from aerobic to anaerobic respiration during cellular work? /3

5. Unfortunately, no experiment is ever perfect! List 2 examples of experimental errors that could have occurred during the procedure? Be specific. /2...