Name: ______Date: ______Block: ______

Cellular Respiration Activity

Purpose: We can measure cellular respiration utilizing an indicator known as Bromothymol blue (BTB). When CO2 is bubbled through water, carbonic acid is formed. CO2 + H2O  H2CO3. BTB changes color toward yellow in the presence of an acid. The more yellow the BTB is, the more carbon dioxide is present.

Problem: How does exercise affect disposal of waste (CO2) from cellular respiration.

Hypothesis: ______

______

______
Null Hypothesis: ______

______

Materials:

  • 1flask
/
  • 10 ml graduated cylinders

  • 200 ml beaker
/
  • 2 straws

  • 10 ml of bromothymol blue (5 ml per trial)
/
  • clock or stopwatch

Procedure:

  1. You will complete this lab with a partner. One person will be the recorder the other person will perform the exercise.
  2. Record your hypothesis above, as to how exercise will affect your body’s production of CO2
  3. Put 50 ml of water and 5 ml of bromothymol blue in the flask.
  4. When your partner says ‘go’, gently blow air through the straw into the bottom of flask.

CAUTION: Do not inhale through the straw!

  1. Your partner will record the time it takes for the color to change.
  2. Repeat experiment but now jog in place for 1 minute

CAUTION: If you feel dizzy or weak while exercising, stop immediately and sit down.

  1. Also collect the data from other individuals and complete the class data chart.
  2. Find the class statistical analysis data.

Individual Data Collection:

Individual: / Before Exercise (seconds) / After Exercise (seconds)
1.

Table 1: The amount of time (seconds) it takes for Bromothymol blue (BTB) to change color before and after exercise.

Trial / Before Exercise (seconds) / After Exercise (seconds)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Overall Average

Table:

Use Excel to create a data table that includes: Mean, Mode, Median, Range, Standard Deviation, and a T-test.

Graph:

Use Excelto graph the class average (in seconds) before and after exercise. Make sure to include the following in your data table: title, labeled axis, key, and standard deviation error bars.

Conclusion:

  • What was the purpose/significance of the experiment?
  • What process in your body produces carbon dioxide? How does exercise affect this process?
  • Explain if your hypothesis (s) was accepted or rejected with supportive evidence and explain if your null hypothesis (s) is failed to reject or rejected with supportive evidence (remember the null hypothesis is failed to reject or rejected based on the T-test only).
  • Give Evidence for the claim (refer to the data and statistical tests). This is an important explanation and the main purpose of the conclusion. Explain howthe data supports the claim. Never leave it up to your reader to draw connections.
  • Explain unusual results and/or possible errors in procedures and/or limitations of the experiment.
  • Future Directions: Improvements to the procedure, sample size, etc. (be realistic)
  • Further research questions raised and relationship to content material.

Turnitin.com:You will need to post a copy of your data table, graph, and conclusion (which will need to all be cut and pasted onto one word document). Make sure to print off a hard copy of this assignment and bring it with you to class. See me with questions.