Respiration What to know Differences between fermentation and respiration Role of glycolysis in oxidizing glucose to two molecules of pyruvate Process that brings pyruvate from cytosol to mitochondria into citric acid cycle How chemiosmosis utilizes e’s from NADH and FADH2 to produce ATP

Respiration and Fermentation are Catabolic Pathways Release energy by oxidizing organic fuels Catabolic Pathways: occur when molecules are broken down and energy is released Two types are… Fermentation: partial degredation of sugars w/o O2 Cellular Respiration: Most efficient O2 and organic fuel consumed Aka aeorbic respiration Purpose is to recharge ATP

Photosynthesis in chloroplasts Cellular respiration in mitochondria Figure 9.2 Light energy ECOSYSTEM Photosynthesis in chloroplasts  O2 Organic molecules CO2  H2O Cellular respiration in mitochondria Figure 9.2 Energy flow and chemical recycling in ecosystems. ATP powers most cellular work ATP Heat energy

Respiration Overview

Cellular Respiration Reactants Standard equation Carbs, fats, proteins Glucose is most common Standard equation C6H12O6 + 6O2  6CO2 + 6H2O + Energy (686kcal/mole glucose) Energy used to make ATP from ADP This is an oxidation reduction reaction

Cellular Respiration Three main phases Glycolysis Citric acid cycle Oxidative phosphorylation and e- transport chain

Electrons carried via NADH Substrate-level phosphorylation Figure 9.6-1 Electrons carried via NADH Glycolysis Glucose Pyruvate CYTOSOL MITOCHONDRION Figure 9.6 An overview of cellular respiration. ATP Substrate-level phosphorylation

Electrons carried via NADH Electrons carried via NADH and FADH2 Figure 9.6-2 Electrons carried via NADH Electrons carried via NADH and FADH2 Pyruvate oxidation Glycolysis Citric acid cycle Glucose Pyruvate Acetyl CoA CYTOSOL MITOCHONDRION Figure 9.6 An overview of cellular respiration. ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation

Electrons carried via NADH Electrons carried via NADH and FADH2 Figure 9.6-3 Electrons carried via NADH Electrons carried via NADH and FADH2 Oxidative phosphorylation: electron transport and chemiosmosis Pyruvate oxidation Glycolysis Citric acid cycle Glucose Pyruvate Acetyl CoA CYTOSOL MITOCHONDRION Figure 9.6 An overview of cellular respiration. ATP ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation Oxidative phosphorylation

Oxidation & Reduction Oxidized = loss of electrons Reduced = gain of electrons LEO goes GER Major concept is electrons striped from glucose 2 electrons hitch a ride on NAD+ along with H+ Is NAD+ oxidized or reduced when it gains electrons?

becomes oxidized (loses electron) becomes reduced (gains electron) Figure 9.UN01 becomes oxidized (loses electron) becomes reduced (gains electron) Figure 9.UN01 In-text figure, p. 164

Oxidation Reduction

becomes oxidized becomes reduced Figure 9.UN03 becomes oxidized becomes reduced Figure 9.UN03 In-text figure, p. 165

Glycolysis Harvests chemical energy by oxidizing glucose to pyruvate Occurs in cytosol One glucose = 2 pyruvate 2 phases Investment phase Payoff phase

Glycolysis ATP Consuming Phase 2 ATPs consumed destabolize glucose Glucose now more reactive Later 4 ATPs are produced for net gain of 2 2 NADH’s also produced Destined for electron transport system 2 pyruvate molecules produced Retain most of the potential energy

Glycolysis to Citric Acid Cycle

Glycolysis to Citric Acid Cycle Note… Pyruvate enters mito matrix via transport protein CO2 enzymatically removed e- removed Coenzyme A added, makes acetyl CoA Acetyl CoA enters the citric acid cycle

The Citric Acid Cycle

Citric Acid Cycle Glucose broken down CO2 released Takes 2 turns of cycle to break down a glucose ONE turn of citric acid cycle results in… 2 CO2 3 NADH 1 FADH2 1 ATP Now all carbons from glucose released in CO2 Energy resides in electrons headed for electron transport chain