1. 9.1 Cellular Respiration: An Overview
Lesson Overview
9.1 Cellular Respiration: An Overview

2. Chemical Energy and Food
Where do organisms get energy?
Organisms get the energy they need from food.

3. Chemical Energy and Food
Food provides things with the chemical building blocks they need to grow and reproduce.
Calorie- is the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius.
1000 calories = 1 kilocalorie, or Calorie.
Energy stored in food
including fats, proteins, and carbohydrates
energy stored in each of these molecules varies because their chemical structures (energy-storing bonds) differ.
Cells break down food and produce ATP and other compounds

4. Overview of Cellular Respiration
What is cellular respiration?
Cellular respiration is the process that releases energy from food in the presence of oxygen.

5. Overview of Cellular Respiration
Cellular respiration is the process that releases energy from food in the presence of oxygen.
Only if Oxygen is available.
Involves many separate reactions
Cells release energy in food gradually, or energy would be lost as heat or light
In symbols:
6 O2 + C6H12O6  6 CO2 + 6 H2O + Energy
In words:
Oxygen + Glucose  Carbon dioxide + Water + Energy

6. Stages of Cellular Respiration
3 Main Stages-
Glycolysis
Krebs Cycle
Electron Transport Chain

7. Stages of Cellular Respiration
Glycolysis-
produces a small amount of energy.
90% of glucose energy remains locked in chemical bonds of pyruvic acid at end of

8. Stages of Cellular Respiration
Krebs cycle
a little more energy is generated from pyruvic acid.

9. Stages of Cellular Respiration
electron transport chain-
produces the bulk of the energy by using oxygen, a powerful electron acceptor.

10. Oxygen and Energy Aerobic- require oxygen
The Krebs cycle and electron transport chain
Both take place inside the mitochondria.

11. Oxygen and Energy Anaerobic-
does not directly require oxygen, nor does it rely on an oxygen-requiring process to run
Gylcolysis
takes place in the cytoplasm of a cell.

12. Comparing Photosynthesis and Cellular Respiration
What is the relationship between photosynthesis and cellular respiration?
Photosynthesis removes carbon dioxide from the atmosphere-- cellular respiration puts it back.
Photosynthesis releases oxygen into the atmosphere--cellular respiration uses that oxygen to release energy from food.

13. Comparing Photosynthesis and Cellular Respiration
Photosynthesis and cellular respiration are opposite processes.
The energy flows in opposite directions. Photosynthesis “deposits” energy, and cellular respiration “withdraws” energy.
The reactants of cellular respiration are the products of photosynthesis and vice versa.