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 C 6 H 12 O 6 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

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 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 Produces/cycle: 4 NADH 2 FADH 2 3 CO 2

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 NADH = 3 ATP FADH 2 = 2 ATP -Total ATP is not exact -About 40% efficient based on energy available and energy released in 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