1. Cellular Respiration
8.3

2. Main Idea: Living organisms break down organic molecules (food) in the presence of oxygen during cellular respiration to get energy.
C6H12O6 + 6O2 -> 6CO2 +6H2O + Energy
Know this equation! What are the reactants and what are the products?

3. 2 Main Parts: Anaerobic (without oxygen) Glycolysis
Lactic Acid Fermentation
Alcohol Fermentation
Aerobic (with oxygen)
Krebs Cycle
Electron Transport

4. Let’s start with Glycolysis
What is glycolysis?
Breakdown of glucose in the cell’s cytoplasm
Page 229 in your book- Figure 8.12
Glucose is broken down into 2 three-carbon molecules. (2 ATP are used)
NAD+ becomes NADH (electron carrier)
2 three-carbon molecules become 2 pyruvate and 4 ATP are produced.

5. What are the net products of glycolysis?
2 Pyruvate
2 ATP
Why not 4 ATP?
Because 2 ATP are used to start the reaction so only a net of 2 ATP are produced.

6. Krebs Cycle
Pyruvate converted to CO2 in the mitochondrial matrix. ATP, NADH, and FADH2 are produced.
Page 230 Figure 8.13
Acetyl CoA formed
Acetyl CoA moves to mitochondrial matrix and combines with a 4-carbon compound: Citric Acid made
Citric Acid Broken down
Acetyl CoA and citric acid are generated and the cycle begins again.

9. Remember
For every glucose molecule there is 2 turns of the Krebs cycle.
What is the net yield of products of the Krebs cycle?
6 CO2
2 ATP
8 NADH
2 FADH2

10. Electron Transport Final Step in breakdown of glucose
Happens in the mitochondrial membrane
Page 230 figure 8.14
NADH and FADH2 release electrons & H+ becoming NAD+ and FAD
H+ is pumped into the intermembrane space across the inner membrane
H+ diffuses back across membrane into matrix (chemiosmosis)
O2 is the final electron receptor
Protons and e- are transferred to oxygen to form H2O

11. In Eukaryotes 1 molecule of glucose gives us 36 ATP
From what cycles are these ATP produced and how many are produced in each cycle?
Glycolysis 2 ATP
Krebs 2 ATP
Electron Transport 32 ATP
ATP is used to provide energy for the cell

12. In Prokaryotes cellular respiration
No Mitochondria so there are differences
Electron transport happens in the cellular membrane
Because we don’t have to move pyruvate to the mitochondria in prokaryotes 2 ATP are “saved”.
Net total ATP = 38
Why are 2 more ATP produced in prokaryotic cellular respiration than in eukaryotic cellular respiration?

13. Anaerobic Respiration
Without oxygen
Glycolysis
Lactic Acid Fermentation
Alcohol Fermentation

14. Fermentation Occurs in the cell’s cytoplasm
It regenerates ATP and produces small amount of ATP
Lactic Acid Fermentation
Pyruvate converted to lactic acid with help of enzymes
Skeletal muscles produce lactic acid when O2 supply is low
Some microorganisms produce lactic acid -> used in cheese, yogurt, sour cream
Alcohol Fermentation: pyruvate converted to ethyl alcohol and CO2

15. Moonshining