Chapter 9 Cellular Respiration

1. Chapter 9 Cellular Respiration

2. 9-1 Chemical Pathways Food provides living things with the chemical building blocks they need to grow and reproduce. Chemical Energy and Food - One gram of Glucose – 3811 calories of heat energy when burned Calorie – energy needed to raise one gram of water one degree C◦ Glycolysis releases only a small amount of energy.

3. Flow of Cellular Respiration

4. A. Overview of Cellular Respiration 1. In the presence of oxygen Glycolysis is followed by the Krebs cycle and the Electron Transport Chain 2. Cellular Respiration – process that releases energy by breaking down glucose and other food molecules in the presence of Oxygen. 6O2 + C6H12O6 --> 6CO2 + 6H2O + energy

5. 3. CR cannot take place in one step, because it would release all the energy at once, mostly in the form of light and heat. 4. There are three main stages of CR A. Glycolysis- occurs in cytoplasm B. Krebs Cycle- occurs in the mitochondrial matrix C. ETC – Electron Transport Chain- occurs in the inner membrane of the mitochondria

6. Checkpoint! 1. How is a Calorie of energy measured? • 1 Cal can raise one ounce of water one degree C◦ • 1 Cal can raise ten grams of water one degree C◦ • 1 Cal can raise one gram of water one degree C◦ • 1 Cal can raise one gram of water ten degree C◦ 2. What is the first step in CR? • Krebs Cycles • Glycolysis • Electron Transport Chain • Fermentation

7. B. Glycolysis 1. Glycolysis- breaking down of one molecule of glucose into two molecules of pyruvic acid 2. ATP production – a. 2 molecules of ATP must be used to get reaction started b. By the end of the process 4 ATP molecules have been produced Net Gain -+ 2 ATP molecules

8. Draw out Glycolysis

9. 3. NADH Production a. NAD+ - electron carrier b. becomes NADH when the molecule is full of high energy electrons and H+ 4. Advantages of Glycolysis - fast and can produce thousands of ATP in milliseconds - Does not require O2 5. Disadvantages of Glycolysis - Uses up NAD+ - they are all filled - ATP Production stops

10. C. Fermentation 1. Fermentation – process that follows glycolysis if O2 is not present 2. Anaerobic – does not require oxygen a. NADH passes high energy electrons to back to pyruvic acid b. this allows glycolysis to keep happening

11. Checkpoint! • What is the starting molecule for glycolysis? a. oxygen b. glucose c. carbohydrate d. CO2 2. What is the electron acceptor for glycolysis? a. NADP b. NAPD c. NAD d. NADPH 3. Fermentation occurs in the absent of O2… it is called a. aerobic b. anaerobic c. oxygenic d. non-oxygenic

12. D. 2 Types of Fermentation 1. Alcoholic Fermentation – Pyruvic acid + NADH --> alcohol +CO2 +NAD+ (Produces CO2 as well as alcohol)

13. 2. Lactic Acid Fermentation a. pyruvic acid can accumulate and convert to lactic acid b. regenerates NAD+ so that glycolysis can continue pyruvic acid + NADH --> lactic acid + NAD+

14. 9-2 The Krebs Cycle and Electron Transport Chain • 90 % of the energy from glucose is still unused in pyruvic acid – in the electrons • Aerobic – with oxygen - world’s best electron receptor - Energy releasing pathways require oxygen – therefore this is why we breathe

15. A. Krebs Cycle

16. B. ETC