Cell Processes & Energy

Respiration

Chapter 2

Section 2

Respiration

• Cells break down simple food molecules, such as glucose, and release the energy they contain– Requires oxygen, O2

Respiration Equation

• C6H12O6 + 6 O2 6 CO2 + 6 H2O + energy

Respiration (Step 1)

• Glucose is broken down into small molecules in the cytoplasm– Only a little bit of energy is released

Respiration (Step 2)

• The mitochondria break down the small molecules in the presence of oxygen, O2

– Lots of energy is released!!!

Photosynthesis vs. Respiration

• Can be thought of as opposite processes

Fermentation

• Allows cells to break down sugars without oxygen– Produces either…

• Alcohol• Lactic Acid

Alcoholic Fermentation

• When yeast breaks down sugars without oxygen– Beer– Wine

• Gives off Carbon dioxide, CO2

– Produces bubbles

Lactic Acid Fermentation

• Produced by muscle cells when they do not have enough O2

– 100m sprint• Sore, wobbly legs