1. Breaking down food to release energy
Cellular Respiration
Breaking down food to release energy

2. Cellular Respiration
Cellular respiration is the controlled release of energy from organic compounds in cells to form ATP.
What do the parts of this definition mean?
Controlled release:
Organic compounds:
ATP:

3. Cellular Respiration All cells do cellular respiration
It’s one of the characteristics of living organisms
But they don’t all do it in the same way:
Aerobic respiration
Anaerobic respiration

4. Relationship of the Types of Cellular Respiration
Cellular Respiration Step 1: Glycolysis
Anaerobic
Fermentation by Yeast
Lactic Acid Production in Human Muscle Cells
Aerobic
Link reaction, Kreb’s Cycle, Electron Transport Chain

5. Overview
Today I’ll give you an overview of aerobic respiration, and we’ll discuss glycolysis.
Essential Questions:
What is a redox reaction?
How are the phases of cellular respiration linked?
What are the overall inputs and outputs of glycolysis?

6. Redox Cellular Respiration is an example of a redox reaction.
What is redox?
Redox stands for reduction oxidation.
Reduction oxidation reactions involve the transfer of electrons from one molecule to another.

7. Electron transfer? Electrons have energy, and they move.
Therefore, they can transfer energy around.
The energy can be used to drive cellular processes.
Electron transfer is essential in many cellular processes, including:
Cellular Respiration
Photosynthesis

8. Redox and Electron Transfer
In redox reactions, some substances are reduced, and some substances are oxidized.
Substances are oxidized when they lose electrons.
Substances are reduced when they receive electrons.

9. Redox, an Example

10. Cellular Respiration

11. Cellular Respiration Phases of aerobic cellular respiration
Glycolysis (the beginning of all cellular respiration)
Transition / Link / Acetyl-CoA reaction
Krebs cycle
Electron transport system
These phases are nothing more than metabolic reactions involving the conversion of glucose & other molecules into carbon dioxide & water
The resulting energy released from this conversion is used to produce ATP

12. Cellular Respiration
Act it out!

13. Relationship of the Types of Cellular Respiration
Cellular Respiration Step 1: Glycolysis
Anaerobic
Fermentation by Yeast
Lactic Acid Production in Human Muscle Cells
Aerobic
Link reaction, Kreb’s Cycle, Electron Transport Chain

14. Glycolysis
Although cellular respiration ends differently depending on if it is aerobic or anaerobic, it starts out the same way.
The process that begins both aerobic and anaerobic respiration is glycolysis.

15. Glycolysis In glycolysis, glucose is broken down into pyruvate.
Glucose  2 Pyruvate
2 ATP
Then energy from this hydrolysis releases a small amount of energy that is used to make 2 molecules of ATP.
We will think about glycolysis in three basic steps.

16. Glycolysis Step 1: Energy investment
Two ATPs are used to phosphorylate glucose
The resulting molecule is unstable.
Why is this step called the “energy investment phase”?

17. Glycolysis Step 1: Energy investment

18. Glycolysis Step 2: Lysis
The unstable molecule formed from phosphorylation splits in half

19. Glycolysis Step 3: Energy return
4 ATP will be made by Substrate Level Phosphorylation (SLP)
SLP is an enzyme-facilitated transfer of a phospate group to ADP to form ATP.
Electrons will also be transferred to 2NAD+ to create 2NADH.
At the end two 3-carbon molecules of pyruvate are remaining from the original 6-carbon glucose.

20. Glycolysis Step 3: Energy Return

21. Glycolysis Overall inputs & outputs
Glucose + 2 ATP  2NADH + 4ATP + 2 pyruvate Total Energy Gain?

22. Relationship of the Types of Cellular Respiration
Cellular Respiration Step 1: Glycolysis
Anaerobic
Fermentation by Yeast
Lactic Acid Production in Human Muscle Cells
Aerobic
Link reaction, Kreb’s Cycle, Electron Transport Chain

23. Glycolysis Aerobic Anaerobic Respiration Respiration
Beyond Glycolysis
From glycolysis, cellular respiration can either proceed aerobically or anaerobically.
Some organisms can do both of these processes (i.e. yeast, human muscle cells)
Some organisms can either do one or the other, but not both.
Glycolysis Aerobic Anaerobic Respiration Respiration
pyruvate
pyruvate

24. Relationship of the Types of Cellular Respiration
Cellular Respiration Step 1: Glycolysis
Anaerobic
Fermentation by Yeast
Lactic Acid Production in Human Muscle Cells
Aerobic
Link reaction, Kreb’s Cycle, Electron Transport Chain

25. Aerobic Respiration
If oxygen is available after glycolysis, organisms are able to do aerobic respiration.
In this case, pyruvate is transported from the cytoplasm into the mitochondrion
pyruvate
mitochondrion

26. Aerobic Respiration
In the mitochondrion, the next three steps of aerobic cellular respiration occur.
Link/transition reaction
Inputs:
Outputs:
Kreb’s Cycle
Electron Transport