Our goal is to find out the inputs
and outputs of cellular respiration
INPUTS
OUTPUTS
Please read pp. 288-289, “A
Matter of Explosions” and
answer the questions on
your activity sheet.
Questions:
 Where did the energy for the grain explosion come
from?
 How can energy be stored in grain?
 What started the explosion that released the
energy?
 How do you explain the fact that you do not
explode when you eat grain products such as cereal
or bread?
So, what is our first IMPUT of
cellular respiration:
 FOOD! But not just food, GLUCOSE!
 It’s chemical composition looks like this: C6H12O2
 Glucose is a sugar (and a carbohydrate).
 Remember: Carbo=carbon, Hydrate=hydrogen+oxygen
 Chemical energy is stored in food. Our digestive
system is able to break down food into smaller parts
like lipids, proteins, and carbohydrates that our cells
can use to create energy.
Glycolysis
 Glycolysis is the first step of cellular respiration. It
releases some energy, but also creates the
ingredients for the later steps to use.
 Glycolysis means SUGAR SPLITTING
 Glyco = sugar
 -lysis = splitting
So far…
GLUCOSE
C6H12O2
?
OUTPUTS
Candle Demonstration
http://www.youtube.com/watch?v=x-stLxqPt6E
 What made the candles go out? Why did the top
candle go out first?
 How can you explain the change in water level inside
the beaker?
 What does this tell you about the requirements for
burning (releasing) energy?
 Can you guess what our next input will be?
Oxygen is needed for
cellular respiration
 You can not light a fire without enough oxygen
 Similarly, if you don’t have enough oxygen (O2)
during cellular respiration than FERMENTATION
occurs.
 This creates Lactic Acid in your muscles
 This is also the process that creates alcohol in beer and
wine.
 This process is called Anaerobic respiration.
 When there is Oxygen present, we say it is
AEROBIC RESPIRATION
Now, we have our inputs…
GLUCOSE
OXYGEN
C6H12O2
6 O2
?
Bromothymol Blue Demo
 Why did the water turn clear?
 What does this tell us about the gasses that come
out when we breathe?
 If you were to exercise heavily first and then exhale
through the solution, would it change color faster or
slower? Why?
 Can you guess what our next output will be?
Carbon Dioxide
 Carbon Dioxide is one byproduct of cellular
respiration
 It’s chemical composition looks like this: CO2
 CO2 is also emitted into the atmosphere by cars,
boats, factories, and power plants when they burn
fuel for energy (in MUCH bigger amounts).
Now we have this…
What goes last?
GLUCOSE
OXYGEN
C6H12O2
6 O2
6 CO2
?
And, there we have it!
GLUCOSE
OXYGEN
C6H12O2
6 O2
6
CO2
6 H2O
Final reflection questions:
 What form does the water produced by cellular
respiration take?
 Explain why when you exercise you breathe harder
and sweat more (at least 3 sentences).
 Draw your own diagram representing cellular
respiration. Be as creative as you like.