1. Cellular Respiration

2. Chemical Energy & Food One gram of glucose = 3811 calories
1 calorie = amount of energy needed to heat 1 gram of water 1 degree Celsius
Food calories are measured in Calories where 1 Calorie = 1000 calories.
What is the difference?

3. Calories

4. Cellular Respiration
Cellular Respiration is the process that releases energy by breaking down food molecules in the presence of oxygen.
6O2 + C6H12O6  6CO2 + 6H2O + Energy
Oxygen + Glucose  Carbon Dioxide + Water + Energy

5. ATP Adenosine Triphosphate (ATP)—usuable energy form in living things
ATP is the important product of cellular respiration.

6. 3 Steps in Cellular Respiration
Glycolysis—happens in cytoplasm
Krebs Cycle—happens in mitochondria
Electron Transport Chain—happens in mitochondria

7. Glycolysis--Step 1
Glycolysis is the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid (a 3 carbon compound).
2 ATP needed to start reaction, 4 ATP are produced thus the net gain is 2 ATP.
Does NOT require oxygen

8. Electron Carriers
NAD+ (nicotinamide adenine dinucleotide) is an electron carrier used during glycolysis
When electrons are added to NAD+ it turns into NADH (which holds the electrons until they are needed later on in cellular respiration

9. The Krebs Cycle—Step 2 NEEDS OXYGEN
During the Krebs Cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.
Citric Acid is created during the first step of this cycle thus giving it the nickname Citric Acid cycle.
Net ATP Production is 2 ATP.

10. Electron Carriers in Kreb’s Cycle
NAD+
FAD (flavin adenine dinucleotide)
When electrons are added to FAD it turns into FADH2
Both NADH and FADH2 carry high energy electrons to the electron transport chain

11. Electron Transport Chain—3rd Step
The electron transport chain uses the high-energy electrons from the glycolysis and Kreb’s Cycle to convert ADP to ATP.
In eukaryotes, high energy electrons are passed along the electron transport chain over a series of carrier proteins on the mitochondrial inner membrane
In prokaryotes this occurs on the cell membrane
Total ATP 32.

12. Fermentation
Releases energy from glucose without the presence of oxygen.
There are two types of fermentation: alcoholic and lactic acid.
Alcoholic fermentation is done by yeasts and some microorganisms. It produces alcohol & Carbon Dioxide
Lactic Acid is produced by muscles during rapid exercise when the body cannot supply enough oxygen.

13. Totals Gycolysis 2 ATP Krebs Cycle 2 ATP
Electron Transport Chain 32 ATP
Total = 36 ATP

14. Energy & Exercise
Quick energy – Lactic Acid fermentation is used to get quick energy and gives off lactic acid as a by product, thus the muscle pain.

15. Respiration Odds and Ends
Fermentation is less efficient than aerobic respiration, but it is faster
Fermentation alone cannot keep you alive for long.
All fermentation (ethyl alcohol and lactic acid) occurs in the cytoplasm
Glycolysis is done by all organisms on Earth

16. Odds and Ends Cont.
CO2 is the by-product of respiration. Not all energy in glucose is conereted to ATP, some is lost as heat.
Not all cells have the same number of mitochondria. Cells with high energy needs have more. Cells with less don’t do much work.
Muscles = lots (100’s or 1000’s)
Skin cells = few

17. Odds and Ends Cont
Most of the energy produced by aerobic respiration is produced by the Electron Transport Chain step.
2 ATP’s are needed to start respiration. These are called the activiation energy.

18. Comparing Photosynthesis & Respiration
Cellular Respiration
Function
Energy Storage
Energy Release
Location
Chloroplasts
Mitochondria
Reactants
CO2 and H2O
C6H12O6 and O2
Products
Equation
6CO2 + 6H2O  C6H12O6 + 6O2
C6H12O6 + 6O2
6CO2 + 6H2O