1. Chapter 7 Cellular Respiration

2. Chemical Energy and food. One gram of the sugar glucose releases 3811calories of heat energy. Calorie – the amount of energy needed to raise the temp. of 1g of water 1 degrees C. A kilocalorie (big C) = 1000 calories (small c)

3. Mitochondrion

4. Overview of Cellular Respiration Cellular Respiration is the process of releasing energy by breaking down food molecules in the presence of oxygen (aerobic). The three main processes of cellular respiration are: –Glycolysis –Krebs Cycle –Electron Transport Chain

5. Cellular Respiration

6. Glycolysis Occurs in cytoplasm The first stage in cellular respiration During glycolysis, glucose in broken down into two molecules of pryuvic acid

7. Glycolysis 2 ATP’s used to start glycolysis. 4 ATP’s Produced Net gain of 2 ATP’s and two Pyruvic Acid molecules (Aerobic)If O 2 is present pyruvic acid  Krebs Cycle inside the mitochondria (Anaerobic) If no O 2 is present pyruvic acid  lactic acid fermentation Glyceraldehyde-3- Phosphate (PGAL, G3P)

8. Quick Review What is cellular respiration? What are the three steps to cellular respiration? Where does glycolysis take place? How many ATP’s start glycolysis? How many ATP’s and NADH’s are produced in glycolysis? (Letter Ea and Eb) How many pyruvic acid molecules and ATP’s are produced at the end of glycolysis? When oxygen is present, what cycle does the pyruvic acid move into? When oxygen is not present, where does the pyruvic acid move into?

9. Fermentation – What happens if there’s no oxygen? When no oxygen in present, which is called anaerobic, the two pyruvic acid molecules moves in fermentation. There are two types of fermentation: –Alcoholic Fermentation: produce ethyl alcohol and carbon dioxide, it’s carries out by some yeast and some bacteria, used in brewing beer, making wine and baking bread and cakes. –Lactic Acid Fermentation: carried out by your muscles when you’re exercising hard (need ATP) and can’t get enough oxygen, causes muscle cramps and soreness.

10. The Krebs cycle (background) Occurs in the matrix of the mitochond ria Begins after acetyl-CoA formation

11. The Krebs Cycle & Acetyl CoA formation (overview) 1 Pyruvic Acid enters the mitochondria Acety-CoA formation –1NADH Kreb Cycle –3 NADH 1 –1 FADH 2 –1 ATP (SLP) Electron Carriers are sent to the ETC

12. Acetyl CoA formation Begins when 1 pyruvic acid enters the cycle One carbon from pyruvic acid breaks off to form a CO 2 molecule The 2 remaining carbons (acetyl group) bind with Coenzyme A to form acetyl-CoA Acetyl-CoA then adds the acetyl group (2 carbon molecule) to a 4 carbon molecule in the cycle to form a 6 carbon molecule called citric acid – this starts the beginning of the KREB cycle

13. Krebs Cycle (1) Citric Acid has been formed. 1 CO 2 molecule breaks off and 1 NADH is formed in the process. A 5 carbon molecule is left behind. A second CO 2 molecule breaks off. 1 NADH and 1ATP is formed. A 4 carbon molecule is left behind. The remaining 4 carbon molecule is rearranged. 1FADH 2 and 1 NADH is formed in the process at the end of the citric acid.

14. Electron Transport Chain The ETC uses the high-energy electrons from the Krebs cycle to convert ADP into ATP There are 1000’s of ETC embedded in the cristae membrane of mitochondria

15. Comparison Photophosphorylation is the process of creating ATP using a Proton gradient created by the Energy gathered from sunlight. Oxydative Phosphorylation is the process of creating ATP using a Proton gradient created by the Energy gathered from the oxidation of glucose.

16. Mitochondrion

17. Electron Transport Chain (overview) Eukaryotes – Carrier proteins that form ETC are located in the cristae membrane of the mitochondrion Prokaryotes – Carrier proteins of ETC are located in the cell membrane On average 3 ATP’s are formed from each pair of electrons.

18. Electron Transport Chain (A) High-energy electrons from NADH and FADH2 are passed into and along the electron transport chain. (Oxidation) Energy from the high-energy electrons is used to push protons (H+) from the matrix, through the cristae membrane, into the intermembrane space.

19. Electron Transport Chain (B) Hydrogen Ion Movement) H+ ions build up in the intermembrane space – (high concentration and positively charged) The matrix has a low concentration of H+ and a large – charge The H+ gradient powers the phosphorylation of ADP  ATP. Oxygen is the final hydrogen acceptor and pulls electron through the ETC to form H 2 O. (Reduction) 32 ATP’s are formed at the end of this process.

20. Oxidative Phosphorylation The general name for the processes occurring between NADH, FADH2, ETC, and ATPsynthase is oxidative phosphorylation.

21. The Totals Results Glycolysis  2 ATP Krebs  2 ATP ETC  32 ATP Total of 36 net ATP’s formed

22. Energy and Exercise Long-term Energy Short-term Energy

23. Energy and Exercise Intake and Distribution of O2 is able to keep up with ETC demands. Glycolysis  Krebs  ETC Intake and Distribution of O 2 can not keep up with ETC demands Glycolysis  Lactic Acid Fermentation Muscle Burn = Lactic Acid Build Up –Can Lead to Muscle Failure –Take energy and time to break down and dispose of lactic acid. –Long recovery time Long Term Energy Quick Energy