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Respiration
Chapter 7
p. 132-147
ATP Reminders
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Main energy molecule
Energy stored in bonds between phosphate
molecules
Energy comes from food we eat
The Importance of Electrons
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Energy to make ATP
from ADP comes from
movement of electrons
Where do these
electrons come from?
We breathe so that
oxygen can be the final
electron acceptor from
this process
Redox Reactions
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Oxidation- loss of electrons
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Ex:
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Reduction- gain of electrons
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Redox = Oxidation + Reduction
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The process by which electrons are transferred
from one molecule to another
Electron Carriers
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Help with ATP formation
Molecules that transfer electrons from one
molecule to another
Ex: NAD+
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NAD+ is the oxidized form
NADH is the reduced form
An Overview of the 3 Stages of
Respiration
2 ATP
Where does each step occur?
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Glycolysis
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Krebs Cycle
Electron Transport
Chain
Cellular Respiration
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Produces 36 ATP molecules
Aerobic- process that requires oxygen
Releases carbon dioxide
Uses electron carriers to transfer energy
Enzymes enable electron transfers
Glycolysis
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Occurs in cytosol
Requires energy input: 2
ATP
Makes 4 ATP
Begin with glucose (6C),
end with 2 pyruvic acid
molecules (3C) that go
on to the Krebs cycle
NET GAIN =
TOTAL ATP =
Krebs Cycle
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Occurs in mitochondria
Begins with pyruvic
acid from glycolysis
Cycle occurs 2 times
for each molecule of
glucose
Makes 2 ATP
Readies electron
carriers for the electron
transport chain
TOTAL ATP =
Electron Transport Chain
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Occurs in mitochondria
Makes remaining ATP
using energy from the
electron carriers
TOTAL ATP =
What happens if no oxygen is present?
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Fermentation- anaerobic process (no oxygen)
occurring when energy harvesting ends with
glycolysis
Way to recycle electron carriers since the
energy is not used in the Krebs Cycle and
Electron Transport Chain
Causes cramps in muscles during exercise
Yeast produce alcohol