1. Agenda Collect Homework #2 Go over Cellular Respiration Fill-in Lecture: – Finish Cellular Respiration, etc – DNA Structure and Function Lab – Cellular Respiration Lecture Quiz #4 this afternoon Lecture – Protein Synthesis and Gene Expression

2. Cellular Respiration Review Occurs in all eukaryotes Generates ATP Involves oxidation – reduction reactions – Oxidation = loss of electron / H atom; gain of charge – Reduction = gain of electron / H atom; loss of charge

3. Glycolosis Takes place in cytoplasm Starts with glucose Uses 2 ATP to prepare glucose Generates 2 NADH – Is this oxidation or reduction? Generates 4 ATP NET YIELD: 2 NADH (goes to ETC) and 2 ATP

4. The Citric Acid (Krebs) Cycle Takes place in mitochondrial matrix Uses Coenzyme A to prepare pyruvate Completes breakdown of glucose to CO 2 Each molecule of pyruvate processed generates – 4 NADH – 1 FADH 2 – 1 ATP

5. So far… 5

6. Oxidative Phosphorylation ETC: Takes place on inner mitochondrial membrane Electrons from NADH and FADH 2 pass electrons down ETC O 2 is the final oxygen acceptor Generates a H+ gradient

7. Oxidative Phosphorylation Chemiosmosis: H+ gradient powers ATP Synthase enzyme to phosphorylate ADP to make ATP ADP + P  ATP Yield = 32-34 ATP molecules

8. So far… 8

9. What if there’s no Oxygen? O 2 can’t act as final electron acceptor ETC can’t happen Can still get 2 ATP from glycolysis (doesn’t require O 2 )

10. What if there’s no Oxygen? Can generate 2 ATP Makes 2 NADH

11. What if there’s no Oxygen? PRESENCE OF O 2 NADH goes to ETC ABSENCE OF O 2 ETC can’t function NADH must be oxidized back to NAD+

12. Anaerobic Respiration Cellular respiration in the absence of oxygen Oxidizes NADH to replenish NAD+ Lactic Acid Fermentation Ethanol Fermentation

13. Anaerobic Respiration LACTIC ACID FERMENTATION Occurs in muscle cells Oxidizes NADH to NAD+ by reducing pyruvate to lactate (lactic acid)

14. Anaerobic Respiration AlCOHOL FERMENTATION Occurs in yeast Oxidizes NADH to NAD+ by reducing pyruvate to ethanol (ethyl alcohol)

15. Anaerobic Respiration Lactic Acid FermentationAlcohol Fermentation

16. Why we like fermentation Often used by bacteria to make tasty foodies Used for thousands of years Method of preserving food

17. Other Organic Molecules as Fuel for Cellular Respiration Carbohydrates: Enter at beginning of glycolysis Examples: Starch, Glycogen

18. Other Organic Molecules as Fuel for Cellular Respiration Fats: Hydrolyze fatty acids off of glycerol Glycerol  glycolysis Fatty Acids  broken into 2-C pieces and sent to TCA 1 g fat yields 2x ATP as 1g starch

19. Other Organic Molecules as Fuel for Cellular Respiration Proteins: Hydrolyze to amino acids, build more proteins Can be used in glycolysis or TCA

20. Biosynthesis of Molecules ATP provides power for biosynthetic reactions Some are reverse of break-down pathways, some are not