1 1 11/3/2015 Cellular Respiration Filename: Respire.ppt

2 2 11/3/2015 Lecture Outline Using Chemical energy to drive metabolism Production of ATP Cellular respiration –Clycolysis –Krebs cycle –Electron transport –Chemiosmosis

3 3 11/3/2015 Lecture Overview All organisms drive their metabolism with ATP generated from Rearrangement of chemical bonds Energetic electrons from proton pumps Electrons from photosynthesis Electrons from oxidation of sugars and fats

4 4 11/3/2015 Background Terms & Concepts Glucose Chemiosmosis Oxidation- reduction ATP Exergonic vs endergonic reactions

5 5 11/3/2015 Concepts from OAC Synthesis of ATP Glycolysis: Krebs cycle anaerobic vs aerobic glucose catabolism Energy from fats & proteins

6 6 11/3/2015 Energy Flow & Recyling Energy Poor Energy Rich

7 7 11/3/2015 Cellular Respiration Release of energy stored in organic compounds –Carbohydrate –Fats –Proteins (net energy loss) Oxygen is consumed as a reactant Carbon dioxide and water are byproducts Energy is used indirectly –trapped as ATP

8 8 11/3/2015 Pathways in Cellular Respiration Glycolysis Krebs cycle Electron transport chain Cellular Respiration Cumulative function of three metabolic pathways and chemiosmosis

9 9 11/3/2015 Catabolism of various foods

10 11/3/2015 Overview of Cellular Respiration A room of your own... ATP

Glycolysis occurs whether or not oxygen is present

12 11/3/2015 Glycolysis OCCURS in the CYTOPLASM Glucose (6 carbon sugar) >>> 2 pyruvate (3 carbon sugar) Energy investment phase Energy yielding phase Net yield of energy No Carbon dioxide is released during glycolysis

13 11/3/2015 Electron Transport System

14 11/3/2015 Glycolysis

15 11/3/2015 Glycolysis: Energy Investment Glucose + ATP-> glucose-6-P + ADP – hexokinase Glucose-6-P -> Fructose-6-P –phosphoglucoisomerase Fructose-6-P + ATP -> Fructose 1,6, diphosphate + ADP –phosophofructokinase Fructose 1,6,diphosphate -> glyceraldehyde phosphate + dihydroxyacetone phosphate –aldolase

16 11/3/2015 Energy Investment Phase

17 11/3/2015 More ATP investment ATP Investment

18 11/3/2015 Isomerization glyceraldehyde phosphate & dihydroxyacetone phosphate are isomers –Isomerase interconverts –glyceraldehyde phosphate removed next as next step THUS Equilibrium between the two sugars is in direction of glyceraldehyde phosphate

19 11/3/2015 Glycolysis: Energy Yield Phase Glyceraldehyde-P + 2NAD+ +2Pi -> 1,3 glycerophosphate + 2 NADH + 2 H+ !,3 glycerophosphate + 2ADP -> 3 phosphoglycerate + 2 ATP Relocate phosphate group Remove water to create phosphoenolpyruvate Remove phosphate from PEP PEP + 2ADP -> pyruvate + 2ATP

20 11/3/2015 The first payoff (substrate-level phosphorylation) Substrate level Phosphorylation

21 11/3/2015 More dividends (substrate-level phosphorylation) More Energy Payoff

22 11/3/2015 Glycolysis: Net Energy Yield Glucose >>> 2 pyruvate 2 ADP >>> 2 ATP 2 NAD+ >>> 2NADH NADH>>> electron transport chain if oxygen is present

23 11/3/2015 Alternate Glycolytic Pathway Glycolysis Embden-Meyerhof Glucose>> glucose-6 phosphate Fructose-6 phosphate Fructose 1,6 diphosphate ISOMERS –dihydroxyacetone phosphate –Glyceraldehyde 3 P Alternate Enter-Doudoroff Glucose>> glucose-6 phosphate 6 phosphogluconic acid Keto deoxy 6 phoshogluconic acid pyruvic acid + Glyceraldehyde 3 P

24 11/3/2015 Pyruvate Fermentation Oxidative phosphorylation

25 11/3/2015 Role of Pyruvate

26 11/3/2015 Formation of Acetyl CoA Pyruvate translocated from cytoplasm to mitochrondial matrix Pyruvate + NAD+ -> Acetate + NADH + CO2 Acetyl group attached to Coenzyme A Acetyl CoA links glycolysis to the Krebs cycle

27 11/3/2015 Formation of Acetyl CoA

28 11/3/2015 Krebs cycle oxidation of pyruvate generated by glycolysis –glucose->2 pyruvate Generates 1 molecule of ATP/ pyruvate –substrate level phosphorylation Generates 4 molecules of NADH / pyruvate Generates 1 molecule of FADH2/ pyruvate Generate 3 molecules of carbon dioxide OCCURS in MITOCHONDRIAL MATRIX occurs in prokaryotic cytoplasm

29 11/3/2015 Krebs cycle

30 11/3/2015 Summary of Krebs Cycle IN Out

31 11/3/2015 Krebs Cycle Balance Sheet Input Water ADP NAD+ FAD+ Acetyl CoA Output Carbon Dioxide ATP NADH FADH