1. 9-1 Making ATP Without Oxygen

2. Chemical Energy and Food
calorie: the amount of energy needed to raise the temperature of 1 gram of water 1ºC
energy from food (glucose) is released by cellular respiration
3 steps in cellular respiration
glycolysis
Krebs cycle
electron transport chain

3. Overview of Cellular Respiration
cellular respiration: the process that releases energy by breaking down molecules in food in the presence of O2
aerobic: processes that require oxygen
6O2 + C6H12O6  6CO2 + 6H2O + Energy (heat)
oxygen + glucose  carbon dioxide + water
pyruvic acid produced in cytoplasm goes into mitochondria where further energy is released for ATP

4. Glycolysis
one 6-carbon glucose molecule is broken in half to form two 3-carbon molecules of pyruvic acid
Takes place in the cytoplasm
ATP production
two ATP molecules used between glucose and pyruvate while 4 ATP is made with pyruvic acid
net gain of 2 ATP

5. NADH Production
4 high-energy electrons from pyruvate molecules and passed to 2 NAD+ (nicotinamide adenine dinucleotide) to form 2 NADH
NADH used in other energy pathways in the cell to make ATP
Glycolysis DOES NOT require O2

6. Glycolysis

7. Fermentation
fermentation: a process in which cells release energy in the absence of oxygen
converts NADH back to NAD+ by passing high-energy electrons back to pyruvic acid
anaerobic: process does not require oxygen

8. Alcoholic Fermentation
process used by yeast and a few other organisms to produce ethyl alcohol and CO2
pyruvic acid + NADH  alcohol + CO2 + NAD+
This process is used to make bread
Bubbles of CO2 makes bread rise
Small amount of alcohol evaporates during baking

9. Lactic Acid Fermentation
Many cells convert accumulated pyruvic acid into lactic acid
pyruvic acid + NADH  lactic acid + NAD+
Lactic acid produced in muscles during strenuous exercise when body cannot supply enough O2. This makes muscles sore.