Chapter 9 Cellular Respiration Overview of Cellular Respiration

Chapter 9 Cellular Respiration

Overview of Cellular Respiration 6 O 2 + C 6 H 12 O 6 → 6 CO 2 + 6 H 2 O + energy

Step 1: Glycolysis 1. Where does glycolysis take place in the cell? • 2. Glucose During the breakdown of glucose NAD+ is an electron carrier in this process. What is an electron carrier? • 4. In the cytoplasm Where in the figure does it show that the cell is using energy to start glycolysis? • 3. Glucose is broken down into two molecules of pyruvic acid 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? • ATP ADP Pyruvic acid At the bottom, 4 ATP molecules are produced when glucose is broken down 2 ATP NADPH

FERMENTATION Alcoholic Fermentation Cells convert NADH to NAD+ and produces alcohol and carbon dioxide when oxygen is not present after glycolysis Ø Pyruvic acid + NADH → alcohol + CO 2 + NAD+ This type of fermentation causes bread dough to rise Lactic Acid Fermentation Cells convert NADH to NAD+ and produces lactic acid when oxygen is not present after glycolysis Ø Pyruvic acid + NADH → lactic acid + NAD+ This type of fermentation causes sore muscles

Step 2: The Krebs Cycle During the Krebs cycle, the pyruvic acid formed during glycolysis is broken down into carbon dioxide. 1. Where does this cycle take place in the cell? • 2. How many ATP molecules are generated for every one turn of the Krebs cycle? • 3. One Where is most of the chemical energy in pyruvic acid transferred as a result of the cycle? • 4. In the mitochondria 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

Step 3: Electron Transport Chain The electron carriers NADPH and FADH 2 carry the electrons to the electron transport chain where the electrons are used to turn ADP into ATP 1. Where does the third stage of respiration take place? • 2. What happens that causes NADPH to change into NAD+ and FADH 2 to change to FAD? • 3. They are passed from one carrier to the next Where does the energy come from that moves hydrogen ions into the intermembrane space? • 5. They transfer the electrons to the carriers along the transport chain What happens to those electrons? • 4. In the inner membrane of the mitochondria 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

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

Comparing Photosynthesis and Cellular Respiration Photosynthesis Cellular Respiration • Stores energy • Takes place inside chloroplasts • Reactants are: CO 2 and H 2 O • Products are: O 2 and C 6 H 12 O 6 • Equation: • Releases energy • Takes place inside mitochondria • Reactants are: O 2 and C 6 H 12 O 6 • Products are: CO 2 and H 2 O • Equation: 6 CO 2 + 6 H 2 O → C 6 H 12 O 6 + 6 O 2 + C 6 H 12 O 6 → 6 H 2 O + 6 CO 2

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