1. Bio 601: CELLULAR RESPIRATION Chapter 9 Notes 1

2. Humans inhale air that contains approximately 21% oxygen. Oxygen diffuses INTO the blood stream from the alveoli and is picked up by red blood cells. Meanwhile, carbon dioxide diffuses OUT of the blood stream and into the alveoli of the lungs to be exhaled from the body.

3. Blood that is rich in CO 2 will return to the right side of the heart from the body. The right side of the heart will pump the blood to the lungs, where it will drop off CO 2 and pick up O 2. Blood that is rich in O 2 will return to the left side of the heart from the lungs. The left side of the heart will pump the blood that is rich in O 2 to the cells of the body, where it will drop off O 2 and pick up CO 2. The Pathway of Blood Through the Human Body Why is oxygen essential to the survival of our cells?

4. How is a marathoner different from a sprinter? It is unusual to find a runner who competes equally well in both 100-m and 10,000-m races. Why? Could it be that runners’ bodies “tell” them which races are best for them? 4

5. Slow vs. Fast Twitch Muscle Fibers All human muscles contain both slow and fast fibers, but muscles differ in the percentage of each “Slow twitch” can sustain repeated, long contractions but don’t generate a lot of quick power for the body. “Fast twitch” can contract more quickly and powerfully but fatigue much more easily. 5

6. What makes these two types of muscle fibers perform so differently? Slow Fibers –Aerobic (use oxygen to breakdown glucose into ATP) –Many mitochondria –Many molecules of myoglobin (carrier of O 2 ) –the “dark meat.” Fast Fibers –Anaerobic (does not use oxygen to breakdown glucose into ATP) –Thicker, myoglobin-poor –fewer mitochondria –the “white meat. ” Think Poultry… What type of meat are chicken legs and thighs? vs. chicken breasts? Why? 6

7. Oxygen is needed for cells to undergo cellular respiration. Cellular respiration is the harvesting of energy from food molecules. It is considered an aerobic process, because it requires oxygen. Glucose ATP Glucose molecules are great for the storage of energy, but not for the transfer of energy. Vs.

8. Remember: Cells use ATP for Energy Adenosine triphosphate (ATP) Energy Inorganic phosphate Adenosine diphosphate (ADP)

9. Where is ATP made in cells? Video Link: https://youtu.be/RrS2uROUjK4 https://youtu.be/RrS2uROUjK4 9

10. 10 Electron Transport Chain Overview: AEROBIC Cellular respiration occurs in three main stages. ANAEROBIC: FERMENTATION

11. What happens after Glycolysis Depends on cellular conditions… Anaerobic Conditions: NO OXYGEN PRESENT Fermentation occurs in 2 steps: –Glycolysis –Fermentation –TWO TYPES: Lactic acid fermentation Alcohol fermentation Aerobic Conditions: OXYGEN PRESENT Cellular Respiration can occur. –Cellular Respiration has 3 steps: Glycolysis Kreb’s Cycle Electron Transport Chain

12. Step 1: Glycolysis Glycolysis means “splitting sugar.” In cytoplasm 1 glucose molecule is split into 2 pyruvic acid molecules 2 ATP are gained

13. Step 2: Krebs Cycle If O 2 is present, pyruvate molecules enter mitochondrial matrix CO 2 released Energy captured as ATP, NADH, FADH 2 Aerobic

14. Step 3:Electron transport chain (ETC) Along inner mitochondrial membrane Oxygen combines with hydrogen to form water Hydrogen ions pumped across membrane  create a concentration gradient that drives production of ATP Aerobic! – why we need to breathe in O 2

15. Electron Transport Chain

16. Certain poisons interrupt critical events in cellular respiration. 16

17. Fermentation When oxygen is NOT present (anaerobic) 1.Glycolysis(2 ATP gained) 2.Fermentation (allows glycolysis to repeat) –Alcoholic fermentation –Lactic acid fermentation

18. Step 1: Glycolysis Glycolysis means “splitting sugar.” In cytoplasm 1 glucose molecule is split into 2 pyruvate molecules 2 ATP are gained Anaerobic

19. Lactic Acid Fermentation Pyruvic acid builds up in cells as a result of glycolysis All of the NAD + molecules become NADH meaning…. – there are no electron carriers left  … so your cell must free some up to allow glycolysis to continue. Pyruvic Acid + NADH  Lactic Acid + NAD + Lactic acid builds up in muscle cells causing fatigue and soreness. Lactic acid is eventually carried in the blood to the liver, where it is converted back to pyruvic acid. 19

20. Alcoholic Fermentation

21. Energy Totals Glycolysis – 2 ATP –If no O 2 available, this is all you get –Remember Fermentation occurs to free up electron carriers. Krebs cycle and ETC – 32-34 ATP Total = 36-38 ATP! 38% of energy in glucose is captured this way – way more efficient than your car!