Chapter 9 – Cellular Respiration
1. Equation for Aerobic Respiration:
C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy
2. Glycolysis - the breakdown of glucose to make 2 ATP and 2 pyruvic acid
- occurs in the cytoplasm of all cells.
3. Structure of the Mitochondria:
cristae - folds of the inner membrane
matrix- spaces between the cristae
*mitochondria and chloroplasts both:
· Have double membranes
· Have their own DNA
· Can reproduce independently of the cell
4. Aerobic Respiration – after glycolysis, the 2 pyruvic acids go into the mitochondria
A) Krebs Cycle – occurs in the matrix
Two turns of the cycle makes: 2ATP
4CO2 (which we exhale)
6NADH and 2FADH2 (which go to the cristae)
B) Electron Transport - occurs in the cristae
- NADH and FADH2 give off electrons, which move down the electron transport chain until trapped by oxygen
- Makes ATP and H2O
5. ATP totals: glycolysis – 2 ATP
Aerobic Respiration – 34 ATP
36 ATP from one glucose
6. Fermentation – Anaerobic Respiration (2 types)
- occurs in the cytoplasm
7. Alcoholic Fermentation - occurs in yeast
2 pyruvic acid + 2NADH → ethyl alcohol + NAD+ + CO2
(NAD+ goes back to glycolysis to make 2ATP)
Yeast - need warmth, glucose, moisture and prefer the dark
Baking: CO2 makes the dough rise, alcohol evaporates
Brewing: alcohol kills the yeast, wine and beer have a low alcohol content
8. Lactic Acid Fermentation –occurs in the cytoplasm
2 pyruvic acid + 2NADH → lactic acid + NAD+
(NAD+ goes back to glycolysis to make 2ATP)
A) Occurs in some bacteria and fungi
Useful: causes milk to spoil, used to make yogurt, cheese,
buttermilk, sour cream
B) Occurs in your muscles when they are oxygen starved
- Lactic acid builds up, causing muscle fatigue, pain, cramps
- Eventually it is converted back to pyruvic acid by the glycogen
in your liver
*For Athletes:
· Intense exercise uses up oxygen, the body switches to lactic acid fermentation
· This works for a short time (less than 2 minutes) because you quickly run out of NADH
· Training increases the amount of glycogen which increases tolerance for lactic acid and increases the number of mitochondria in the muscles