 Bromothymol blue is a chemical indicator that
changes color as the pH of a solution changes. It is
yellow in acidic solutions and blue in basic and
neutral solutions.
 When CO2 is dissolved in water, it creates carbonic
acid, pH 5.7.
 In the body, carbonic acid is neutralized by
bicarbonate.
 One of the products of Cellular Respiration is CO2.
As cells produce CO2, it is carried by blood cells to
our lungs where it is exhaled.
1. How is breathing related to cellular
respiration?
2. Hypothesis: How will exercise affect the
rate of cellular respiration?
3. How can Bromothymol blue help you
measure your rate of cellular respiration?
 Materials
 Stopwatch
Use your cell phone if necessary.
 Drinking Straws
 Found on the side of the room.
 Bromothymol blue solution
 You need 5 mL.
 Beaker
 Graduated cylinder
 SAFETY GOGGLES FOR PERSON WHO IS
HANDELING BROMOTHYMOL BLUE

 Safety Note
 Do NOT inhale bromothymol blue.
 If you do, the nurse/I have to induce vomiting.
 No fun.
 If you think you may laugh or inhale or
something, don’t be directly part of this
experiment.
 Do NOT leave the bottles of BTB open –
they’re air sensitive.

Obviously…
1. Assign one person to be the timer, and one
2.
3.
4.
5.
person to perform the experiment.
Fill the beaker with approximately 40 mL water
and 5 mL bromothymol blue solution.
When the timer says “START”, the experimenter
will exhale FROM THE LUNGS through the
straw into the bromothymol blue solution until
the color changes from blue to green.
Your partner will stop the time as soon as the
color changes.
Record the time it took for the color change in
the observation table below. This is the control
group.
6. Now have the experimenter do jumping jacks or a
similar exercise for 1 minute. You should feel a little
winded when you are finished!
7. Rinse out the beaker, and refill with 40 mL water and
5 mL bromothymol blue solution.
8. Using the same straw, exhale into the solution the
same way as in the control group and record how
long it takes for the solution to change color.
9. Write down the time it took for the color change in
the observation table below. This is the variable
group.
 Throw away used straws.
 Pour used Bromothymol blue down the sink
with the water running.
 Rinse out and dry beakers and graduated
cylinders.
 Wipe down area.
 Graph, analyze and answer the questions.
Definition:
 The process of breaking down glucose to release
energy and form molecules of ATP
 Need to change the “currency” of energy from
chemical bonds of glucose into ATP currency.
II. Equation:
I.
C6H12O6 + 6 O2
6 CO2 + 6 H2O + ATP
Basically the reverse of
Photosynthesis!
 Occurs in cytoplasm
 (Does not need oxygen = Anaerobic)
Glucose
2 ATP
4 ATP
in
out
NAD+
NADH
2 Pyruvic Acids
C
C
C
C
C
C
Glucose
2 ATP
4 ATP
in
out
NAD+
2 Pyruvic Acids
C
C
C
C
C
C
NADH
• 2 NET ATP
• NAD+ picks up Hydrogen/electrons for
later! (ETC)
If oxygen is present…
Krebs Cycle
aka: Citric Acid Cycle
 Occurs in mitochondria
 Needs oxygen = Aerobic
If oxygen is NOT present…
Fermentation
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
Krebs Cycle
aka: Citric Acid Cycle
Continued
 2 NET ATP
produced (remember
there are 2 pyruvates!)
 NAD+ and FAD+
pick up
hydrogen/electrons
for later (ETC)
 CO2 is given off!
Fermentation
Electron Transport Chain
 Occurs in
mitochondria
 Needs oxygen =
Aerobic
Fermentation
Electron Transport Chain
 NAD/FAD pass
electrons from carrier to
carrier until it reaches
the final electron
acceptor (oxygen)
 Hydrogen’s dropped off
by NAD and FAD create
concentration gradient
 H2O is released
 34 ATP produced
(about)
Fermentation
If oxygen is present…
If oxygen is NOT present…
Krebs Cycle
Fermentation
aka: Citric Acid Cycle
 Def. - releases energy
from glucose
molecules by
producing ATP in the
absence of oxygen
 Occurs in mitochondria
 Needs oxygen = Aerobic
 Does not need oxygen =
anaerobic
Krebs Cycle
aka: Citric Acid Cycle
Continued
Fermentation
Continued
 Two types:
1. Alcoholic Fermentation
 2 NET ATP
produced (remember
there are 2 pyruvates!)
 NAD+ and FAD+
pick up
hydrogen/electrons
for later (ETC)
 CO2 is off!
 Example: Yeast causes
bread to rise. Wine, root
beer, ginger ale can also be
made.
Electron Transport Chain
Fermentation
2. Lactic Acid
Fermentation
 NAD/FAD pass electrons
from carrier to carrier
until it reaches the final
electron acceptor
(oxygen)
 Hydrogen’s dropped off
by NAD and FAD create
concentration gradient
 H2O is released
 34 ATP produced
(about)
 Example: Overworked
muscles produce lactic acid
which causes muscle
cramps, cheese and kimchi
also can be produced by
fermentation.
 Pick 3
 Root beer
 Cream Soda
 Cola
 Cherry
 Birch beer
 Raspberry









Clean 2 Liter plastic soft drink bottle
1 cup measuring cup
¼ tsp measuring spoon
1Tbl measuring spoon
Funnel
1 cup table sugar
Flavor extract (1Tbl spoon)
Champagne yeast (1/4 tsp)
Water
 Background Information
 Pre-Lab Questions
1. What is the equation for cellular respiration?
2. What do you think the reactants of the soda
reaction are (Make sure you read carefully, it
may not be identical to the question above)?
3. What do you think the products of the soda
will be?
4. Are we performing aerobic or anaerobic
respiration in this experiment? Explain why.
__________ + ________  _________ + __________ +________
Remember… If you
know the
photosynthesis
equation, you know
this one!
 Read each clue and try to answer! If you need an extra
clue, Miss L will give you the word scrambled.
1. During cellular respiration, the cell releases energy
from this material.
(LCUOSEG)
2. The energy molecule created during cellular
respiration.
(TAP)
3. The type of cellular respiration that requires
oxygen.
(RBIAOCE)
4. The cell structure in which most of the reactions
of cellular respiration occur.
(OTMIDOHCRNIA)
5. In addition to energy, the other two products of
cellular respiration.
(RBAONC) (XIDIODE)
(AWTRE)
6. The type of cellular respiration that does not
require oxygen.
(NAEBACORI)
7. The first stage of cellular respiration.
(LCYOGLYISS)
8. When oxygen is present; the second stage of
cellular respiration.
(TICIRC) (CDAI) (YCLCE)
9. What ATP is (the primary ________ source of for
the cell).
(NEREGY)
10. Cells in the human body that are capable of
anaerobic respiration.
(USMLCE)
11. Another name for the citric acid cycle.
(REKBS) (YLCCE)
12. As the energy of ATP is used by the body, the
ATP becomes what compound?
(DAP)
What
A. Glycolysis
B. Krebs Cycle
C. ETC
(Electron Transport
Chain)
Where
Glycolysis
Oxygen present
(aerobic)
Krebs Cycle
Electron
Transport Chain
No oxygen
(anaerobic)
Alcoholic
Fermentation
Lactic Acid
Fermentation
__________ + ________  _________ + __________ +________
Remember… If you
know the
photosynthesis
equation, you know
this one!
Warm-up
• Finish Cell Respiration Fairy Tale
Objectives 
• Cellular Respiration Fairy Tale
• Quiz
Homework 
• Honors: None
• Academic: None
 Read article.
 After reading:
 Write a 3 paragraph response:
 1st


¶ – Summary of article
2nd ¶ – How does this article relate to biology
class?
3rd ¶ – Personal opinion (what did you think
about the article? Did this information surprise
you? If scientists studied mitochondria in more
detail, could we help cure diseases?)