Chapter 9 Cellular Respiration

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• Chapter 9 Cellular Respiration
• Objectives
• Cellular respiration is a catabolic pathway
  fueled by oxidizing organic compounds like sugar
• Glycolysis oxidizes glucose to pyruvate
• The Citric Acid Cycle completes energy harvest of
  the organic fuels
• During Oxidative Phosphorylation, chemiosmosis
  couples electron transport to make ATP
• Anaerobic Respiration produces ATP without Oxygen
• Glycolysis and the Krebs cycle connect to other
  metabolic pathways

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• Catabolism
• The break down of C6H12O6 is highly exergonic
  with a
• Change in G -686 kcal/mol energy release
• Energy is transferred to ATP, which can be used
  for Cellular Work

Redox Reactions -Energy is release through a
series of electron transfers. -Electrons are
transferred from one reactant to
another -Oxidation Loss of electrons
(LEO) -Reduction Gain of electrons
(GER) (net reduction in oxidation number)
-Oxygen is one of the greatest oxidizers -Oxygen
pulls electrons from sugar -Electrons travel with
hydrogens -The more hydrogen atoms the more
electrons that can be transfered the more
energy can be captured
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Electrons are released to Oxygen slowly -Use of
NAD which is reduced to NADH (High potential
energy) -Travels to Electron Transport Chain
where ATP is produced
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Cellular Respiration Overview -Think
Mitochondria -Think Plant and Animal Cells -Think
Production of ATP
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Glycolysis Overview
Goal is to split one glucose in half See page 168
-169 for details
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The Citric Acid Cycle Krebs Cycle

• Pyruvate enters and converts to Acetyl CoA, which
  is a co enzyme
• -Cycle goes twice per glucose molecule
• p. 171
• -Produces/cycle
• 4 NADH
• 2 FADH2
• 3 CO2

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Oxidative Phosphorylation -Differs from
Substrate level phosphorylation -Protein
complexes are in the inner membrane of the
mitochondria -Electron carriers alternate
between oxidized and reduced forms -Each form is
oxidized by a more electronegative
neighbor -Oxygen is the final oxidizer
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Electron Transport Powers Chemiosmosis -When
electron carrier is oxidized a proton is
tranfered to intermembrane space -Proton
gradient is used to run the ATP Synthase to
produce ATP
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Most Energy Flows through Glucose -- NADH --
Electron Transport Chain -- Proton Motive Force
-- ATP
-Total ATP is not exact -About 40 efficient
based on energy available and energy released in
ATP
NADH 3 ATP FADH2 2 ATP
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Fermentation -Most of the ATP is dependent on
Oxygen to pull electrons down the electron
Transport Chain -Fermentation is a way to harvest
chemical energy without an electron transport
chain -Glycolysis is the most wide spread
metabolic pathway in all species producing
Pyruvate --- is a juncture between aerobic
and anaerobic activity
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Carbs, Proteins, and Lipids can enter the
Respiration cycle at various points
Respiration is governed by supply and demand