1. Cellular Respiration Overview
By Sarah Lanoie; 12/5/08

2. Cellular Respiration Formulas
Word Equation:
Glucose + Oxygen → Energy + Carbon Dioxide + Water
Symbol Equation:
C6H12O6 + 6O2 → Energy (ATP) + 6CO2 + 6H2O

3. Cellular Respiration Step-wise release of energy from food
Allows for efficient energy use
Removal and transfer of electrons from simple food molecules to carriers to release energy for ATP synthesis

4. Redox Reactions
Involve the transfer of electrons from one reactant to another
Oxidation = loss of electrons from a substance
Reduction = addition of electrons to a substance (reducing the positive charge)
Electron donor = reducing agent
Electron accepter = oxidizing agent

5. A Quick Overview of the main Stages
1. Glycolysis
In cytosol
Glucose is split into pyruvate
Creates ATP and NADH

6. 2. Krebs Cycle / Citric Acid cycle
In mitochondrial matrix
Pyruvate is broken down
Creates ATP, NADH, and FADH2
Releases CO2

7. 3. Oxidative Phosphorylation (Electron Transport Chain)
In inner mitochondrial membrane
NADH and FADH2 release hydrogen (results: NAD+ and FAD)
Creates lots of ATP
Releases H₂O

8. Summary

9. Phosphorylation of ATP
Substrate level- when an enzyme transfers a phosphate from a substrate (organic molecule) to ADP
Oxidative phosphorylation – powered by electron transport chain and results in an inorganic phosphate is added to ADP to make ATP

10. Glycolysis

11. The splitting of glucose
Energy is harvested by oxidizing glucose to pyruvate
Requires an initial input of energy to get energy out

12. Glycolysis I (energy in)
Glucose enters the cell and gains a phosphate from ATP
Glucose is rearranged by enzymes and gains another phosphate from ATP molecule (6 carbon sugar biphosphate)
Enzymes split 6 carbon sugar biphosphate into two 3- carbon sugar phosphates

13. Glycolysis II (energy out)
3-carbon sugar phosphates gain 2 phosphates and during the reaction energy is give off to cause 2 NAD+  2NADH
One phosphate from each 3 carbon sugar biphosphate is given to 2 ADP  2 ATP
Phosphate groups get re-arranged  release 2 H2O
Phosphate from 3 carbon sugars given to 2ADP  2ATP
Results in 2 molecules of pyruvate
Net release of 2NADH and 2ATP

15. Aerobic Respiration Aerobic = O₂ present
If O₂ present pyruvate goes to mitochondria for Krebs cycle
Net ATP production = 36

16. Anaerobic Respiration
Anaerobic = no O₂ present
Prokaryotes that live in oxygen free environments
Electron transport chain present- oxygen is not final electron acceptor

17. Fermentation
No Oxygen or electron transport chain present (can be used by prokaryotes and eukaryotes)
Glycolysis products are fermented for energy
Lactic Acid Fermentation
Pyruvate takes energy from NADH (goes back to NAD+) and is converted to lactate (a 3 carbon acid)
Net ATP production = 2