Copyright © 2010 Pearson Education, Inc. Figure 5.7a–b Enzyme Inhibitors: Competitive Inhibition

Copyright © 2010 Pearson Education, Inc. Enzyme Inhibitors: Competitive Inhibition Example-Sulfa drugs (sulfonamides) Discovered in the 1930s

Copyright © 2010 Pearson Education, Inc. Figure 5.9 Oxidation-Reduction

Copyright © 2010 Pearson Education, Inc. Figure 5.10 Representative Biological Oxidation

Copyright © 2010 Pearson Education, Inc. The Generation of ATP  ATP is generated by the phosphorylation of ADP 1.Substrate-level Phosphorylation 2.Oxidative Phosphorylation 3.Photophosphorylation

Copyright © 2010 Pearson Education, Inc. Substrate-Level Phosphorylation  A chemical reaction where a phosphate group is transferred from one molecule to ADP. This requires a specific enzyme that can transfer the phosphate from this specific molecule to ADP.  ATP is produced this way during  FERMENTATION  Glycolysis (or alternative pathways)  Krebs cycle

Copyright © 2010 Pearson Education, Inc. Oxidative Phosphorylation  Energy released from transfer of electrons (oxidation) from one compound to another (reduction) is used to generate ATP in the electron transport chain  An electron transport chain(ETC) couples a chemical reaction between an electron donor (such as NADH) and an electron acceptor (such as O 2 ) to the transfer of H + ions across a membrane, through a set of mediating biochemical reactions. 2H + ionsmembrane

Copyright © 2010 Pearson Education, Inc. Photophosphorylation  Light causes chlorophyll to give up electrons. The electrons go through a process similar to what happens during respiration (an electron transport chain and chemiosmosis occur). This process releases energy used to bond a phosphate to ADP producing ATP.  The ATP produced is used to produce food molecules (sugars-glucose).

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Figure 5.11 Glycolysis  The oxidation of glucose to pyruvic acid produces ATP (Substrate level phosphorylation)and NADH 2 Stages: See next 2 slides

Copyright © 2010 Pearson Education, Inc. Figure 5.12, steps 1–5 Energy Using Stage of Glycolysis  2 ATP are used  Glucose is split to form 2 glucose-3-phosphate

Copyright © 2010 Pearson Education, Inc. Figure 5.12, steps 6–10 ATP Creating Stage of Glycolysis  2 glucose-3-phosphate oxidized to 2 pyruvic acid  4 ATP produced  Substrate-level phosphorylation  2 NADH produced

Copyright © 2010 Pearson Education, Inc. Figure 5.13 Preparatory Step Intermediate between Glycolysis and Krebs Cycle  Pyruvic acid (from glycolysis) is oxidized and decarboyxlated

Copyright © 2010 Pearson Education, Inc. Figure 5.13 The Krebs Cycle

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Figure 5.16 Chemiosmotic Generation of ATP

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PathwayEukaryoteProkaryote GlycolysisCytoplasm Intermediate stepCytoplasm Krebs cycleMitochondrial matrixCytoplasm ETCMitochondrial inner membranePlasma membrane Comparing Eukaryotic and Prokaryotic Cellular Location of Catabolic Processes

Copyright © 2010 Pearson Education, Inc. Aerobic and Anaerobic Respiration  Aerobic respiration: The final electron acceptor in the electron transport chain is molecular oxygen (O 2 ).  Anaerobic respiration: The final electron acceptor in the electron transport chain is not O 2. Yields less energy than aerobic respiration because only part of the Krebs cycles operates under anaerobic conditions.

Copyright © 2010 Pearson Education, Inc. Electron AcceptorProducts NO 3 – NO 2 –, N 2 + H 2 O SO 4 – H 2 S + H 2 O CO 3 2 – CH 4 + H 2 O Anaerobic Respiration

Copyright © 2010 Pearson Education, Inc. Fermentation  FERMENTATION Scientific definition:  Releases energy from oxidation of organic molecules  Does not use oxygen  Does not use the Krebs cycle or ETC  Uses an organic molecule (pyruvic acid) as the final electron acceptor to form ‘end-products’ (acids and alcohols)  2 ATPs netted

Copyright © 2010 Pearson Education, Inc. Figure 5.19 Types of Fermentation

Copyright © 2010 Pearson Education, Inc. Figure 5.21 Catabolism of Organic Food Molecules

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Photosynthesis  Conversion of light energy into chemical energy (ATP) which is used to synthsize nutrients (glucose)  Overall Summary Reaction?  Compare and Contrast: Oxidative Phosphorylation and Photophosphorylation.

Copyright © 2010 Pearson Education, Inc. Photosynthesis  Oxygenic:  Anoxygenic:

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Figure 5.33 Amphibolic Pathways

Copyright © 2010 Pearson Education, Inc. Figure 5.33 Amphibolic Pathways

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Nutritional TypeEnergy SourceCarbon SourceExample PhotoautotrophLightCO 2 Oxygenic: Cyanobacteria plants Anoxygenic: Green, purple bacteria PhotoheterotrophLightOrganic compounds Green, purple nonsulfur bacteria ChemoautotrophChemicalCO 2 Iron-oxidizing bacteria ChemoheterotrophChemicalOrganic compounds Fermentative bacteria Animals, protozoa, fungi, bacteria. Metabolic Diversity among Organisms