1. Cellular Respiration

2. Where do organisms get energy?
Organisms get energy from food molecules which contain energy that is released when their chemical bonds are broken.

3. What is a calorie?
The amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius.
The Calorie (capital C) that is used on food labels is a kilocalorie, or calories.

4. Calories
The energy stored in each of the macromolecules varies because of their chemical structures, therefore their energy-storing bonds, differ.

5. Calories Cells don’t burn food and release energy as heat.
They break down food molecules gradually, capturing a little bit of chemical energy at key steps to produce ATP.
Remember: ATP is cell energy

7. Oxygen Requirements Aerobic- require oxygen
Anaerobic- does not require oxygen

8. What is cellular respiration?
The process that releases energy from food in the presence of oxygen
6 O2+C6H12O66 CO2+ 6 H2O+ Energy
Oxygen+Glucose Carbon Dioxide+Water+Energy

9. Cellular Respiration
Involves a series of controlled reactions that slowly release energy. If the energy were to be released too suddenly, most of it would be lost in the forms of light and heat

10. The Steps of Cellular Respiration

11. Glycolysis
During glycolysis, one molecule of glucose is transformed into two molecules of pyruvic acid and energy is released

12. Glycolysis
In the process of glycolysis, 2 ATP molecules are used and 4 are made, for a net increase of 2 molecules.
Although the energy yield is small, the process is so fast that cells can produce thousands of ATP molecules in just a few milliseconds

13. Glycolysis
Glycolysis does not require oxygen. This means that it can quickly supply chemical energy to cells when oxygen is not available.

14. The Krebs cycle
During the Krebs cycle, pyruvic acid is broken down into carbon dioxide (requires oxygen)
The Krebs cycle begins when pyruvic acid passes through the two membranes of the mitochondria and into the matrix (the innermost compartment of the mitochondria)

15. The Krebs cycle
The Krebs cycle results in 1 ATP molecule for every 1 molecule of pyruvic acid.
The carbon dioxide that is produced is expelled in every exhalation.

16. The Electron Transport Chain
The electron transport chain uses high- energy electrons from glycolysis and the Krebs cycle to create ATP (requires oxygen)
For every 1 molecule of glucose, 32 molecules of ATP are created.

17. Cellular Respiration Totals
Together, glycolysis, the Krebs cycle, and the electron transport chain release about 36 molecules of ATP per molecule of glucose.
Aerobic conditions enable the cell to produce 18 times as much energy than anaerobic alone.
The 36 ATP molecules generated represent about 36% of the total energy of glucose. The remaining 64% is released as heat.

18. Cellular Respiration vs. Photosynthesis
Photosynthesis removes carbon dioxide from the atmosphere, and cellular respiration puts it back. Photosynthesis releases oxygen into the atmosphere, and cellular respiration uses that oxygen to release energy from food.

20. What is fermentation?
An anaerobic process that occurs in the cytoplasm of cells that releases ATP from food molecules.
Takes place after glycolysis

21. Alcoholic Fermentation
Produces alcohol and carbon dioxide from pyruvic acid
Performed by yeasts and other microorganisms
Used to make alcoholic beverages and causes bread to rise

22. Lactic Acid Fermentation
Produces lactic acid from pyruvic acid
Performed by most organisms, including us
Prokaryotes are used to make cheese, yogurt, buttermilk, and sour cream