Aerobic respiration: the Krebs
cycle & electron transport system
What happens in the mitochondria
does not stay in the mitochondria
Aerobic
Respiration
• Occurs in the
mitochondria.
• Composed of two
processes:
– Citric acid cycle (Krebs).
– Electron Transport
System (ETS)
Mitochonodria located in a muscle cell
Krebs cycle: aka Citric acid cycle
• Occurs in the
matrix.
• Uses pyruvic acid
as a raw material
• uses Oxygen
• Produces: 2 ATP,
NADH & FADH2
• Waste product is
carbon dioxide.
Pair share: why is it called
a cycle?
Electron Transport System
• Occurs in the
cristae
• Produces 34 ATP
• Uses NADH &
FADH2 in order to
store Hydrogen.
• Uses Oxygen
• Waste product is
water.
Pair share: what is being
pumped out of the matrix?
ATP Production Summary
• Glycolysis.
– 4 ATP produced - 2 ATP used = 2ATP Gained
• Citric Acid Cycle (Krebs)
– 2 ATP Produced.
• Electron Transport System
– 34 ATP Produced
• Total ATP Produced from each glucose
molecule = 38 ATP
Efficiency Comparison
Anaerobic respiration ------ 2%
Aerobic respiration --------- 66%
More energy from
the same food! =
More bang for
your buck!
Whole foods
= anaerobic
the dollar store = aerobic
Reactants and Products
Process
Reactants
Products
• Glycolysis
Glucose
Pyruvic acid & NADH
• Citric Acid
Cycle
Pyruvic acid
(Acetyl CoA)
NADH & FADH2
Carbon dioxide
NADH & FADH2
Water
• ETS
Start with glucose in glycolysis, add O2 during Krebs cycle &
CO2 is produced, during ETS water is produced.
White board Review
1. Where does the Krebs cycle take place and how
much ATP is produced?
2. In ETS where are the electrons being transported?
3. Why do you think there are not any multicellular
prokaryotes?