Photosynthesis and Cell Respiration
• Cell Respiration is the opposite of
photosynthesis.
– What is the equation for
photosynthesis?
– What is the equation for
respiration.
– Respiration breaks down
carbohydrates into ATP.
Photosynthesis and Cell Respiration
• Plants perform both
photosynthesis and respiration.
– Think: It would be pointless to
make carbohydrates if you did
not break them down into
energy.
Cellular Respiration
Chapter 9 in the textbook
Chemical Energy and Food
The equation for cellular respiration is catabolic.
• Catabolic Reactions: a chemical reaction that breaks
down larger molecules into smaller units.
– Catabolic reactions are exergonic: energy is released.
• Anabolic reaction: an endergonic reaction that builds
molecules from smaller units.
– Photosynthesis is an anabolic reaction.
Chemical Energy and Food
Oxidation: Glucose loses electrons (and hydrogens)
Reduction: Oxygen gains electrons (and hydrogens)
Cellular Respiration is an oxidation/reduction reaction
• Oxidation: The loss of electrons
• Reduction: The gain of electrons
In cellular respiration glucose is oxidized and oxygen is reduced
• Hydrogen is a source of electrons