1. Cellular Respiration

2. How do living things get the energy they need to survive?
From the food they eat!
Remember the gummy bear?!?

3. Chemical Energy and Food
One gram of glucose (C6H12O6), when burned in the presence of O2, releases 3811 calories of heat E.
A calorie is a measure of energy.
In respiration, Cells release the energy from glucose, which is stored in chemical bonds, beginning with GLYCOLYSIS!

4. Overview of Cellular Respiration
Cellular respiration is the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.
Equation:
6O2 + C6H12O6 → 6CO2 + 6H2O + energy
oxygen + glucose → carbon dioxide + water + energy
MEMORIZE THIS!
(Psst - Look familiar?!)

5. Photosynthesis and Respiration make a cycle called the Carbon cycle.
YES!
The equation for cellular respiration is the exact opposite of that of photosynthesis!
Photosynthesis:
6CO2 + 6H2O + energy → 6O2 + C6H12O6
Respiration:
6O2 + C6H12O6 → 6CO2 + 6H2O + energy
Photosynthesis and Respiration make a cycle called the Carbon cycle.

7. Overview of Cellular Respiration

8. Overview of Cellular Respiration
Two main stages:
1. glycolysis (in the cytoplasm)
2. Aerobic Respiration (in the mitochondria)

9. The First Step: Glycolysis
Glycolysis is the process in which one molecule of glucose is broken in half, producing two molecules of ATP

10. The First Step: Glycolysis
cells have to put in (use) 2 ATP’s to get glycolysis started, but 4 ATP’s are produced at the end of glycolysis, for a net gain of 2 ATP’s

11. The First Step: Glycolysis
this process is so fast that thousands of ATPs can be produced in a few milliseconds!
Glycolysis does NOT require oxygen!

12. The First Step: Glycolysis
ATP goes off to the other parts of the cell to do work
The other products of glycolysis are sent off to the mitochondria to be further broken down to produce much more energy rich ATP!

13. What if oxygen is NOT present?
if there is no oxygen present, glycolysis is followed by another pathway, Anaerobic Fermentation. (Anareobic means “no air”)

14. Two types of fermentation
1. Alcoholic Fermentation
2. Lactic Acid Fermentation

15. Alcoholic Fermentation
used by yeasts (& other microorganisms)
equation:
pyruvic acid + NADH  alcohol + CO2 + NAD+
Creates CO2 and alcohol

16. Lactic Acid Fermentation
equation:
pyruvic acid + NADH  lactic acid + NAD+
LAF is a back up fermentation for your cells when they don’t get enough Oxygen. This is why your muscles burn when you work out.
lactic acid is also a waste product for some organisms to make food and beverages such as cheese, yogurt, buttermilk, and sour cream

17. What if there is Oxygen?…
If there IS oxygen present, Aerobic Respiration follows Glycolysis.

18. The Krebs Cycle
The second part of respiration occurs in the mitochondria
It can produce a LOT more ATP than glycolysis.

19. The Totals Glycolysis only produces 2 ATP molecules per one glucose
With O2, glycolysis and Aerobic Respiration produce 36 ATP molecules per one glucose!

20. Energy and Exercise
At the start of a race, your body has access to 3 ATP sources: 1. stored ATP already in muscles 2. new ATP made by lactic acid fermentation 3. new ATP made by cellular respiration

21. Energy and Exercise: Quick Energy
stored ATP can provide E for a few seconds (50 meters)
new ATP made by lactic acid fermentation provides energy for about 90 sec ( meters)
lactic acid fermentation produces lactic acid, which can only be rid of with extra oxygen – where does this come from? heavy breathing after the race!

22. Energy and Exercise: Long-Term Energy
your body uses ATP from cellular respiration for endurance races
cellular respiration releases energy more slowly than fermentation, which is why athletes have to pace themselves
after min of activity, your body uses energy from other stored molecules (such as fats) for energy, which is why aerobic forms of exercise are good for weight loss

23. Comparing Photosynthesis & Cellular Respiration
function
energy capture
energy releases
location
chloroplasts
mitochondria
reactants
CO2 and H2O
C6H12O6 and O2
products
equation
6CO2 + 6H2O → C6H12O6 + 6O2
C6H12O6 + 6O2 → 6CO2 + 6H2O
energy
energy