Chapter 9: Cellular Respiration and Fermentation

1. Chapter 9: Cellular Respiration and Fermentation Section 1: Cellular Respiration: An Overview

2. A. Chemical Energy and Food • Respiration- Opposite of Photosynthesis • Breaks down the food we eat into ATP for cellular activity and maintenance of homeostasis • Energy conversion: • Sun Photosynthesis Glucose-RespirationEnergy for Activity

4. Therefore- Photosynthesis: Sunlight + CO2+ H2O---------- C6H12O6 + 6O2 And…………….. Respiration: C6H12O6 + 6O2------6CO2 + 6H20 + ATP Are energy conversions responsible for converting……..(Finish this statement )

5. B. Aerobic v Anaerobic Respiration • Respiration is responsible for producing energy for cellular activity • It is much more efficient to break down food in order to liberate energy in the presence of OXYGEN This means it is AEROBIC- with O2 • Some organisms live in ANOXIC environments (Without Oxygen) These bacteria are known as OBLIGATE ANAEROBES-oxygen is harmful to them

6. Some anaerobes can survive for short periods of time in the presence of oxygen- They are called Facultative Anaerobes ex- Brewer’s Yeast Most Aerobes can survive for very short periods of time in low oxygen conditions

7. People/Humans prefer to respire aerobically- This is why we breathe!! • From time to time we respire anaerobically- like after intense exercise, like weight lifting and sprinting- (This is why we are often out of breathe afterwards) • When our bodies anaerobically respire for too long we get cramps due to build up of lactic acid • This does damage to tissue and will not sustain us for long

8. C. Glycolysis! • Both Aerobic and Anaerobic Respiration begin with Glycolysis!! • Glycolysis- breakdown of Glucose When Glucose is broken down it becomes a three Carbon molecule called Pyruvate a.k.a Pyruvic Acid • This takes place in the cytoplasm (outside the Mitochondria)

9. Glycolysis 2 Phases: Energy Investment (It takes money to make money) Initial Cost of 2 ATP in order to break apart glucose Energy Payoff- By breaking down glucose we form 4 ATP Net Gain of 2 ATP

10. Glycolysis • Inputs of Glycolysis: Glucose- all food is broken down through digestion into simple sugars such as glucose ATP- Initial Energyto break apart glucose into PGAL- Two 3 Carbon Intermediates • Outputs of Glycolysis ATP- 2 ATP Molecules are produced Two molecules of Pyruvate- Pyruvic Acid 2 Molecules of NADH- Electron carriers

11. Glycolysis

12. Glycolysis • The Fate of Pyruvic Acid depends on the presence of Oxygen • If O2 is present Aerobic Respiration occurs aka Respiration • If O2 absent- Anaerobic Repiration occurs- aka Fermentation

13. D. Aerobic Cellular Repiration • Happens in the Presence of Oxygen • Begins with the products of Glycolysis: two molecules of Pyruvic Acid (C-C-C) • The Pyruvic Acid diffuses into the Mitochondrial Matrix and enters the Citric Acid Cycle- aka Kreb’s Cycle - In the CAC Pyruvic Acid is broken apart, one Carbon at a time and released as CO2 - As it is broken energy is converted (2ADP- 2ATP) and electron energy is stored (4NAD+--- 4NADH and FAD+ ----FADH) - This happens twice ( 8 NADH and 2 FADH Total- that is 20 Electrons)

14. 1. Citric Acid Cycle a. Begins with Pyruvic Acid (C-C-C) b. Enzymes remove 1 Carbon- leaving behind a two carbon compound called Acetyl/Acetic Acid • This joins with another enzyme (Co A) which is 4 Carbons Long! Becomes Acetyl Co A (6 Carbons) This makes it easier to separate the last two carbons from Pyruvic Acid and expel them as CO2 while stealing their energy in the form of electrons- Lots of NADH and FADH

15. Citric Acid Cycle Every time a Carbon is removed- 2 High Energy Electrons are Freed and stored by NAD and FAD Total ATP= 2 Total electron Pairs= 10 Remember- this happens twice!!! Glucose was broken down into two mols of Pyruvic Acid!

16. Citric Acid Cycle Inputs: 2 Pyruvic Acids (Glycolysis) Outputs: CO2 (Expelled as waste) 2 ATP (very little energy- used for cellular activity) NADH and FADH (To be used later in order to make a lot of ATP) All of these electrons are going to be used during the next phase (Electron Transport) to synthesize ATP

17. Electron Transport Chain (ETC) • Electrons carried to the inner membrane by NADH and FADH are dropped off at the beginning • As the electrons are passed along, their energy is used to pump H+ ions out of the matrix and into the intermembrane space creating a Conc. Gradient • The only way back into the matrix for H+ ions is through a protein called ATP Synthase. • As H+ move through ATP Synthase like water through a dam, energy is used to convert ADP to ATP. • Each pair of electrons can produce between two and three ATPs (Depends on if they came from NADH or FADH) • 9NADH= 28 ATP 2FADH= 4 ATP Total of 32 ATPs created during ETC!!!!

18. Electron Transport Chain and ATP Synthase

19. Total ATP Production • Glycolysis- 2 ATP • Citric Acid Cycle- 2ATP • Electron Transport-32 ATP TOTAL= 36 ATP Not bad for one molecule of glucose!!

20. D. Anaerobic Respiration • Occurs without Oxygen Present • Also known as “Fermentation” Tequila Beer Whiskey Cramping What do they all have in common? (Three Things) Fermentation

21. Fermentation 1. Alcoholic Fermentation: • Occurs in Yeast when Oxygen is not present to clear the ETC and CAC Cycle • Electrons cannot be passed into Kreb’s cycle so they get passed back to Pyruvic Acid • Forms new products Ethyl Alcohol and Carbon Dioxide

22. Alcoholic Fermentation = Ethyl Alcohol Pyruvic Acid Count the Atoms- What goes in should come out!!!! Carbon Dioxide

23. 2. Lactic Acid Fermentation a. Occurs in all animal species b. When Oxygen is not present- electrons get passed back to Pyruvic acid and attach in a different location (Look at H’s)- Forms Lactic Acid c. Responsible for muscle soreness and cramping

24. Lactic Acid Fermentation = Pyruvic Acid