Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition Solomon Berg Martin Chapter 7 How Cells Make ATP: Energy-Releasing Pathways
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Cellular respiration Aerobic respiration –Requires molecular oxygen –Includes redox reactions Anaerobic –Anaerobic respiration –Fermentation –Do not require oxygen All exergonic
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Four stages of aerobic respiration Takes place in the cytosol –Glycolysis Takes place in the mitochondrion –Formation of acetyl CoA –Citric acid cycle –Electron transport chain/chemiosmosis
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Four stages of aerobic respiration
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Summary of aerobic respiration
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Glycolysis “Sugar splitting” Does not require oxygen Divided into two major phases –Energy investment phase –Energy capture phase Each glucose molecule produces net yield of two NADH molecules and two ATP molecules
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Glycolysis
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Glycolysis: energy investment phase
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Glycolysis: energy capture phase
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Formation of acetyl CoA Catalyzed by enzyme pyruvate dehydrogenase –First carboxyl group is split off as carbon dioxide –Then remaining two-carbon fragment is oxidized and electrons transferred to NAD + –Finally, oxidized two-carbon group is attached to coenzyme A
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Formation of acetyl CoA
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Citric acid cycle For every glucose, two acetyl groups enter the citric acid cycle Each two-carbon acetyl group combines with a four-carbon compound Two CO 2 molecules are removed Energy captured as one ATP, three NADH, and one FADH 2 per acetyl group
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Citric acid cycle
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Detail of citric acid cycle
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Electron transport chain Series of electron carriers Each carrier exists in oxidized or reduced form Electrons pass down the electron transport chain in series of redox reactions Lose energy as pass along the chain
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Electron transport chain
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Accumulation of protons within the inter-membrane space
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Electron transport and chemiosmosis
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Energy yield from complete oxidation of glucose by aerobic respiration
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Many organisms depend on nutrients other than glucose Products of protein and lipid catabolism enter same metabolic pathways as glucose Amino acids are deaminated
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Energy from carbohydrates, proteins, and fats
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Anaerobic respiration versus fermentation Anaerobic respiration –Electrons transferred from fuel molecules to electron transport chain –Final electron acceptor is inorganic substance Fermentation –Anaerobic process that does not use electron transport chain
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Comparison of aerobic respiration, anaerobic respiration, and fermentation
Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 7 How Cells Make ATP: Energy-Releasing Pathways Fermentation