1. Chapter 9
Cellular Respiration

2. Overview of Cellular Respiration
6 O2 + C6H12O6 → 6 CO2 + 6 H2O + energy

3. Glucose is broken down into two molecules of pyruvic acid
Step 1: Glycolysis
Glucose is broken down into two molecules of pyruvic acid
Where does glycolysis take place in the cell?
In the cytoplasm
Where in the figure does it show that the cell is using energy to start glycolysis?
During the breakdown of glucose
NAD+ is an electron carrier in this process. What is an electron carrier?
A compound that can carry hight energy electrons and transfer them with most of their energy to another molecule
Glycolysis is an energy releasing process. Where in this figure does it show energy being released?
At the bottom, 4 ATP molecules are produced when glucose is broken down
Glucose
ATP
ADP
ATP
ADP
Pyruvic acid
Pyruvic acid
2 ATP NADPH
2 ATP NADPH

4. Alcoholic Fermentation Lactic Acid Fermentation
Cells convert NADH to NAD+ and produces alcohol and carbon dioxide when oxygen is not present after glycolysis
Pyruvic acid + NADH → alcohol + CO2 + NAD+
This type of fermentation causes bread dough to rise
Cells convert NADH to NAD+ and produces lactic acid when oxygen is not present after glycolysis
Pyruvic acid + NADH → lactic acid + NAD+
This type of fermentation causes sore muscles

5. Step 2: The Krebs Cycle
During the Krebs cycle, the pyruvic acid formed during glycolysis is broken down into carbon dioxide.
Where does this cycle take place in the cell?
In the mitochondria
How many ATP molecules are generated for every one turn of the Krebs cycle?
One
Where is most of the chemical energy in pyruvic acid transferred as a result of the cycle?
Most of it is transferred into electron carriers such as NADPH
Why is the Krebs cycle also known as the citric acid cycle?
Because citric acid is the first compound formed in this series of reactions

6. Step 3: Electron Transport Chain
The electron carriers NADPH and FADH2 carry the electrons to the electron transport chain where the electrons are used to turn ADP into ATP
Where does the third stage of respiration take place?
In the inner membrane of the mitochondria
What happens that causes NADPH to change into NAD+ and FADH2 to change to FAD?
They transfer the electrons to the carriers along the transport chain
What happens to those electrons?
They are passed from one carrier to the next
Where does the energy come from that moves hydrogen ions into the intermembrane space?
The energy comes from the electrons moving down the electron transport chain
What is the role of ATP synthase?
ATP synthase uses energy from H+ ions to convert ADP to ATP

7. The Totals?
How many molecules of ATP are produced during cellular respiration?

8. Comparing Photosynthesis and Cellular Respiration
Stores energy
Takes place inside chloroplasts
Reactants are: CO2 and H2O
Products are: O2 and C6H12O6
Equation: 6 CO2 + 6 H2O → C6H12O6 + 6 O2
Releases energy
Takes place inside mitochondria
Reactants are: O2 and C6H12O6
Products are: CO2 and H2O
Equation: 6 O2 + C6H12O6 → 6 H2O + 6 CO2

9. Homework!
P. 225 #1-6
P. 232 #1-5
Don’t forget flashcards for chapter 9 are due Friday and vocabulary chapter 9 quiz is Friday