Name __________________________
Ms. Smith
Regents Biology
Respiration Lab
Background information: During the process of cellular respiration, energy
is released from our obtained nutrients in the form of ATP (adenosine triphosphate). Two types of respiration exist. During anaerobic respiration,
which occurs in the cytoplasm of the cell, nutrients are partially broken
down in the absence of oxygen to give us small quantities of ATP. During
aerobic respiration, which occurs in the mitochondria of the cell, nutrients
are fully broken down in the presence of oxygen, resulting in a high yield of
energy. Therefore, the preferable respiratory pathway is aerobic.
The overall formula for aerobic respiration is:
O2 + C6H12O6  CO2 + H2O + ATP
OR
oxygen + sugar (glucose)  carbon dioxide + water + energy
In order to obtain increased amounts of energy for normal metabolic
processes and physical activity, we also produce more CO2 and H2O. These
by-product wastes are released through our respiratory and excretory
systems.
In this lab, you will investigate the affect that exercise has on the body’s
production of CO2 as a result of cellular respiration.
Hypothesis and Prediction:
Record your hypothesis and prediction about how exercise will affect the
body’s production of CO2.
Materials:
2 small test tubes (per person)
Graduated cylinder
Bromthymol Blue Solution
tape
straws
Stop watch
Procedure:
1. Gather and label 2 test tubes, A and B. Fill each test tube with 10 ml. of
water and add 10 drops of bromthymol blue solution.
**** The presence of CO2 turns bromthymol blue to yellow or
green.****
2. Your partner will time as you blow air through the straw into the bottom
of test tube A.
****DO NOT INHALE OR SUCK IN THROUGH THE
STRAW ****
3. When the solution has changed color, your partner should tell you to
stop. Record how long the color change took. This is your normal
aerobic respiratory capacity.
4. Exercise for three minutes by running in place or performing jumping
jacks.
5. Repeat steps 3 and 4 using test tube B.
6. Perform 2 more trials for test tubes A and B. Average your times for
each.
7. Trade roles with your partner and repeat steps 3-6.
Table 1
Test Tube A
Average =
Test Tube B
Average =
Analysis and Conclusions:
1. How did exercise affect the time for the solution to change color? What
was the difference in the average time it took for bromthymol blue to
change color before and after exercise?
2. What process in your body produces CO2? How does exercise affect this
process?
3. Was your prediction correct? Explain your answer.
4. What are some possible reasons it may have taken longer for some of
your classmates’ solutions to change color even after exercise?
5. What is the reason for heavier breathing during exercise? (Hint: Look
back at the equation for cellular respiration.)