1. Cellular Respiration Chapter 4.4
Dr. Bill Stafford
2014

2. converts sugar into ATP using oxygen.
KEY CONCEPT The overall process of cellular respiration
converts sugar into ATP using oxygen.

3. Cellular Respiration – Chap. 4.4
Definition – the process by which the cell breaks down food molecules to release the energy stored in them and use that energy to form ATP
Chemical reaction C6H12O6 + 6O2  6CO2 + H2O + energy (ATP)
sugar + oxygen carbon + water
dioxide

4. Cellular Respiration – Chap. 4.4
Four stages of cellular respiration
Glycolysis – anaerobic – does not require oxygen
Intermediate stage – where the products of glycolysis enter the mitochondria - aerobic
Citric acid cycle (Krebs cycle) – aerobic – requires oxygen
Electron transport chain (ETC) - aerobic

5. Cellular Respiration
Mitochondria – organelle where citric acid cycle and ETC are located – site of cellular respiration
Double membraned structure with the inner membrane highly folded
The citric acid cycle occurs in the inner membrane spaces
The ETC takes place in the inner membrane

6. Cellular Respiration – Chap. 4.4
Glycolysis – first stage of the breakdown of glucose
Takes place in the cytoplasm
Anaerobic – does not require oxygen
Gives a net of 2 ATP for each glucose molecule

9. Cellular Respiration – Chap. 9.3
Intermediate step – where the two pyruvate molecules produced from one glucose molecule during glycolysis enter the mitochondria – requires oxygen (aerobic)
Produces 1 NADH for each pyruvate molecule or 2 NADH for each glucose molecule
Ends up as a 2-carbon molecule Acetyl-CoA and 2 CO2 molecules
Also gives 1 NADH per pyruvate molecule and 2 NADH per glucose molecule

10. Cellular Respiration – Chap. 4.4
Intermediate step (cont.)
2 pyruvate  2 acetyl-CoA + 2CO2 + 2NADH

11. Cellular Respiration

12. Cellular Respiration – Chap. 4.4
Citric acid cycle (Krebs cycle) – series of chemical reactions that breaks down acetyl-CoA into 2 CO2 molecules and releases more energy that was stored in the chemical bonds of acetyl-CoA
Takes place in the space inside the inner membrane of the mitochondria called the matrix
Requires oxygen – aerobic
Produces 2 ATP

13. Cellular Respiration – Chap. 4.4
Citric acid cycle (cont.)
For each citric acid cycle
Acetyl-CoA  2CO2 + 3NADH + 1FADH2 + 1ATP
For each glucose molecule
2acetyl-CoA  4CO2 + 6NADH + 2FADH2 + 2ATP

15. Cellular Respiration – Chap. 9.3
Electron transport chain (ETC) – takes the energy from the energized electron carried by NADH and FADH2 and uses that energy to produce ATP
Requires oxygen – aerobic
Located in the inner membrane
Electron is passed from step to step to release the energy in the electron slowly and capture the energy
Makes 34 ATP

16. Cellular Respiration – Chap. 4.4
ETC (cont.)
1 NADH gives 3 ATP
1 FADH2 gives 2 ATP
2 NADH come from glycolysis, 2NADH comes from intermediate step, and 6 NADH comes from citric acid cycle for each glucose – this gives 10 NADH for each glucose molecule which gives 30 ATP from the ETC from NADH
2 FADH2 comes from citric acid cycle and gives 4 ATP from the ETC

17. Cellular Respiration – Chap. 4.4
The final electron acceptor at the end of the ETC is oxygen
The ETC will shut down if no oxygen is available because there is no place for the electrons to go
2e- + 2H+ + O  H2O

19. Fermentation – Chap. 4.5
Definition - Anaerobic process that allows for the net production of 2 ATP if no oxygen is available
Happens in the cytoplasm
2 major types of fermentation
Lactic acid fermentation – this process allows the NADH molecules produced by glycolysis to give up their electrons and produce NAD+ so that glycolysis can continue to produce 2 ATP
Pyruvate + NADH  lactic acid + NAD+
Occurs in us and other animals if we run out of oxygen

21. Fermentation – Chap. 4.5 2 major types – (cont.)
Alcoholic fermentation – produces CO2 and ethyl alcohol from pyruvate and NADH and produces NAD+ to allow glycolysis to continue and produce 2 ATP
CO2 production by yeast is what causes bread to rise
Alcohol is used by the beer and wine industry
Pyruvate + NADH  ethyl alcohol + NAD+ + 2CO2

23. Fermentation
Lactic acid fermentation takes place in our muscles when we over exercise and use up our oxygen – the lactic acid makes our muscles sore
Yeast does alcoholic fermentation and this process is used to make beer and wine and the CO2 produced by yeast is what makes bread rise

27. Fermentation Comparison of fermentation and cellular respiration
Cellular respiration produces 38 ATP aerobically from each glucose molecule using the mitochondria while fermentation produces 2 ATP anaerobically from each glucose molecule
Fermentation takes place only in the cytoplasm
Make a Venn Diagram

28. Interactions Autotrophs and producers
Mostly photosynthesis – can make their own food and energy from sunlight and CO2
Could be chemosynthesis

29. Interactions Heterotrophs and consumers
Must eat food produced by autotrophs for energy to produce ATP
Most do cellular respiration
Some live off fermentation

30. Interactions
Cycle in nature between O2 and CO2
Oxygen carbon dioxide

31. Interactions
Photosynthetic organisms produce 2 things needed by heterotrophs – food and oxygen

32. Interactions Flow of energy through an ecosystem
Photosynthesis cellular respiration
chloroplast mitochondria