1. By: Lindsay Koenig, Hannah Watson, and Kayleen Smith
Cellular Respiration
By: Lindsay Koenig, Hannah Watson, and Kayleen Smith

2. Prior Knowledge What is the basic energy used in cellular respiration?
ATP
How is energy released from ATP?
Phosphate removed = release of energy from the molecule
Adenine
Sugar
Triphosphate Group

3. First let’s examine the equation
Reactants
Products 6 6 6
Reduced:
Gains electrons
Oxidized:
Loses electrons

4. So, What is cellular respiration?
It is a set of three metabolic reactions and processes that occurs in a cell's mitochondria, in which it converts biochemical energy into adenosine triphosphate (ATP), to do used as energy
What are the THREE processes?
Glycolysis
Citric Acid Cycle
Electron Transport Chain (oxidative phosphorylation)

5. General Overview of Cellular Respiration

6. Elementary Glycolysis/AP Glycolysis
Elementary definition
The breakdown of pyruvates into two molecules of pyruvate to be used in future processes
AP glycolysis:
AP definition
Rearrangement of bonds in glucose molecules to release free energy, converting ADP to ATP and inorganic phosphate, resulting in a pyruvate

7. Glycolysis
Glycolysis literally means the “splitting of sugar”, aka breaking down glucose into two molecules of pyruvate
Uses substrate-level phosphorylation
Where does it occur?
It occurs in the CYTOPLASM
Two major phases
Energy investment phase
Energy payoff phase
Why substrate-level phosphorylation?
ATP is directly coupled with the degradation of glucose without the participation of an intermediate molecule such as NAD+.

8. Breaking it Down PGAL PGAL
Glycolysis is a series of reactions that lead to the oxidative breakdown of glucose into two molecules of pyruvate (the ionized form of pyruvic acid), the production of ATP, and the reduction of NAD+ into NADH.
•occur in cytoplasm
•mediated by specific enzymes
•2 ATP USED
•4 ATP PRODUCED
•NET PRODUCTION= 2 ATP

9. Energy Investment Phase

10. Energy Payoff Phase

11. Net totals

12. What happens with the pyruvate?
The pyruvates go to the citric acid cycle, but must be converted into ACETYL COENZYME A (Acetyl CoA)
What does this do?
It is a connector between glycolysis and the citric acid cycle

13. Connection, I can’t see it...

14. Citric Acid Cycle (KREBS CYCLE)
What is the Krebs cycle?
Elementary Definition: series of reactions in the mitochondria that use acetyl compounds to produce phosphate compounds, the source of cellular energy
AP Definition: carbon dioxide is released, while ATP is synthesized from ADP and inorganic phosphate due to substrate level phosphorylation, with electrons being extracted and carried away by NADH and FADH2

15. Basis of the Krebs Cycle
Where does it occur?
Mitochondrial matrix
What does it result in?
NAD, FAD, and ADP
What type of phosphorylation does it enact?
Oxidative Phosphorylation

16. Overall Picture

17. Steps of the Krebs Cycle
Step 1: Acetyl Coa joins with a four-carbon molecule, oxaloacetate, releasing CoA, forming citrate
Step 2: Citrate removed and added a water molecule, forming isocitrate (its isomer)
Step 3: Carbon dioxide is released, NAD+ is reduced to NADH, a five-carbon molecule is formed (a-ketoglutarate)

18. Steps of the Krebs Cycle
Step 4: NAD+ is reduced to NADH, releasing carbon dioxide, with a four-carbon molecule picking up Coenzyme A to form succinyl CoA
Step 5: CoA of succinyl CoA is replaced by a phosphate group, ADP makes ATP, four-carbon molecule produced called succinate

19. Steps of the Krebs Cycle
Step 6: Succinate is oxidized forming fumarate, FAD is transformed into FADH2
Step 7: water is added making fumarate into another four-carbon molecule called malate
Step 8: oxaloacetate is regenerated by oxidation of malate, NAD+ is reduced to NADH

20. Products of the Krebs Cycle
In one single rotation of the cycle (*remember it goes through 2 cycles, one for each pyruvate)
NADH- three molecules
FADH2- one molecule
ATP/GTP- one molecule
These products will then travel to the Electron Transport Chain to drive the synthesis of ATP molecules through oxidative phosphorylation

21. Electron Transport Chain (ETC)
NADH and FADH2 are passed through electron acceptors as they move towards the final acceptor, oxygen
Proton gradient- located across the inner mitochondrial membrane separating high and low proton concentrations
Location: INNER MITOCHONDRIAL MEMBRANE
•oxidative phosphorylation
•as electrons are transferred, free energy is produced, forming ATP

22. Chemiosmosis
Proteins pump H+ from the mitochondrial matrix to the intermembrane space
H+ moves back through ATP synthase
Uses exergonic flow to drive phosphorylation of ATP
THIS IS CHEMIOSMOSIS,
Using energy in a H+ gradient to drive cellular work
This energy aids in redox reactions
The gradient is responsible for a proton-motive force

23. Electron Transport Chain

24. Anaerobic vs Aerobic Respiration
Anaerobic= producing cellular energy WITHOUT oxygen
Aerobic= producing cellular energy INVOLVING oxygen

25. Aerobic Respiration

26. Anaerobic Respiration
Cellular respiration requires O2 to produce ATP
No oxygen means anaerobic respiration, or it uses fermentation to produce ATP
Anaerobic respiration still uses the ETC, but the final acceptor is not oxygen, instead it may be sulfate, etc.
Fermentation uses substrate-level phosphorylation, not the ETC

27. Anaerobic Respiration

28. What are the types of Fermentation?
Alcohol fermentation= pyruvate releases CO2 to form ethanol in two steps
Lactic acid fermentation= pyruvate forms lactate, allowing no CO2 to be released, yet a reduction of NADH

29. Everyday Uses Fermentation
Alcoholic Fermentation
Brewing
Winemaking
Baking
Lactic Acid Fermentation
Cheese
Yogurt
Muscle cells (cramps)

30. Lactic Acid Fermentation

31. Alcoholic Fermentation

32. Similarities vs Differences
Fermentation
Anaerobic/Aerobic Respiration
Net ATP= 2
NAD+ is the oxidizing agent
Final electron acceptor: organic molecules
Final electron acceptor: O2
2 ATP per glucose molecule
32 ATP per glucose molecule

33. Evolution of Glycolysis?
Prokaryotes thought to used glycolysis due to the absence of O2

34. Respiration Control Feedback inhibition
Drop in ATP= speed up in respiration
Increase in ATP= slow down in respiration
Control is based on enzymes throughout the catabolic pathway