1. Bellwork question: Why do macromolecules differ in the amount of energy they contain?

2. Cellular Respiration – an overview
Section 9.1

3. Where do organisms get their energy?
Unit – calories
1 calorie = amount of energy required to increase 1 gram of water by 1 degrees Celsius
1000 calories – 1 Calorie
Cells can use all sorts of food as energy

4. Examples 1 gram of sugar = 3811 calories (3.8 Calories)
1 gram of beef fat = 8893 calories (8.9 Calories)
Carbohydrates and proteins – approximately 4000 (4 Calories) calories per gram
Fats- approximately 9000 calories (9 Calories) per gram

5. Cellular respiration overview
It does not happen instantaneously!

6. Stages of cellular respiration
Cells can use variety of food sources
Glucose most important
Only a small amount of energy is ‘liberated’ during glycolysis
Pyruvic acid enters in Krebs cycle
Most energy generated in electron transport chain

7. Role of oxygen
Oxygen required at the end of the electron transport chain
If cell needs energy it needs oxygen
We need to breather to respire
Cellular respiration with oxygen is aerobic
Krebs cycle
Electron transport chain
Occur in mitochondria
Glycolysis is anaerobic
Occurs in cell cytoplasm
Can continue without oxygen – fermentation
Keeps glycolysis running

8. Photosynthesis vs Repsiration
Photosynthesis removes CO2
Respiration replaces CO2
Photosynthesis releases oxygen
Respiration requires oxygen
Virtually all living things respire, but only plants and some bacteria can photosynthesize

9. Bellwork: Why does glycolysis have to occur before the Krebs cycle?

10. The process of cellular respiration
Section 9.2