Download Oxygen pulls electrons from sugar

Chapter 9 Cellular Respiration
Objectives:
1.
Cellular respiration is a catabolic pathway fueled by
oxidizing organic compounds like sugar
2.
Glycolysis oxidizes glucose to pyruvate
3.
The Citric Acid Cycle completes energy harvest of the
organic fuels
4.
During Oxidative Phosphorylation, chemiosmosis
couples electron transport to make ATP
5.
Anaerobic Respiration produces ATP without Oxygen
6.
Glycolysis and the Krebs cycle connect to other
metabolic pathways
Catabolism
-The break down of C6H12O6
is highly exergonic with a
Change in G = -686 kcal/mol
energy release
Redox Reactions
-Energy is release through a series of electron transfers.
-Electrons are transferred from one reactant to another
-Energy is transferred to ATP,
which can be used for Cellular
Work
-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
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
Cellular Respiration Overview
-Think Mitochondria
-Think Plant and Animal Cells
-Think Production of ATP
Glycolysis Overview
Goal is to split one glucose in half
See page 168 -169 for details
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
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
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
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
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
Carbs, Proteins, and Lipids can enter
the Respiration cycle at various points
Respiration is governed by supply and
demand