Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. BIOLOGY A GUIDE TO THE NATURAL WORLD FOURTH EDITION DAVID KROGH Life’s Mainspring: An Introduction to Energy

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 6.1 Energy is Central to Life

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Energy is Central to Life All living things require energy. Sunlight - ultimate source of energy for most living things.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Energy is Central to Life Sun’s energy is captured by photosynthesizing organisms (such as plants and algae), Which then pass this energy on to other organisms in the form of food.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 6.4 The Energy Dispenser: ATP

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Energy Dispenser: ATP Adenosine triphosphate (ATP) - most important energy transfer molecule in living things.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. ATP Energy extracted from food is transferred to ATP Energy in ATP is used to drive metabolic processes. Examples: to power muscle contraction and nerve signal transmission.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The ATP/ADP Cycle Figure 6.6 phosphate groups adenosine ATP ADP H2OH2O+ energy out energy in endergonic reaction exergonic reaction adenine ribose

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Energy and Biology PLAY Animation 6.1: Energy and Biology

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 6.5 Efficient Energy Use in Living Things: Enzymes

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Efficient Energy Use in Living Things: Enzymes Enzyme - type of protein that speeds up a chemical reaction Nearly every chemical process in living things is facilitated by an enzyme Example: hemoglobin – a protein in blood cells –Transfers oxygen from lungs to body cells –Transfers carbon dioxide from body cells to lungs

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Enzyme Action Figure 6.8 substrates enzyme A enzyme B enzyme C product

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Metabolism and Enzymes metabolism - sum of all chemical reactions that a cell or organism carries out

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 6.6 Lowering the Activation Barrier through Enzymes

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Enzymes Accelerate Chemical Reactions Figure 6.9 lactoseglucose + galactose activation energy without enzyme activation energy with enzyme net energy released from splitting of lactose net energy released lactose lactase glucose + galactose (a)Without enzyme (b)With enzyme

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Substrate Binding Figure 6.10

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Enzymes Overview PLAY Animation 6.2: Enzymes

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Ch. 7-Vital Harvest: Deriving Energy from Food

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 7.1 Energizing ATP: Adding a Phosphate Group to ADP

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Storing and Releasing Energy Figure 7.1 Energy from food is required to push a third phosphate group onto ADP Energy from food is then stored as a phosphate bond in ATP. Energy is then released when the phosphate bond is broken, and can be used to fuel our everyday activities. ADPP+ energy hill P+ energy out energy in ATP

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Electron Carrier NAD + Figure 7.3 empty loaded proton (oxidized) used in later stage of respiration used in later stage of respiration goes to pick up more electrons (reduced) NAD + within a cell, along with two hydrogen atoms that are part of the food that is supplying energy for the body. NAD + is reduced to NAD by accepting an electron from a hydrogen atom. It also picks up another hydrogen atom to become NADH. NADH carries the electrons to a later stage of respiration then drops them off, becoming oxidized to its original form, NAD +.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Oxidation and Reduction PLAY Animation 7.1: Oxidation and Reduction

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 7.3 The Three Stages of Cellular Respiration: Glycolysis, the Krebs Cycle, and the Electron Transport Chain

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Three Stages of Cellular Respiration: Glycolysis, the Krebs Cycle, and the Electron Transport Chain In most organisms, the harvesting of energy from food takes place in three principal stages.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Cellular Respiration Cellular respiration is making energy (ATP) from food (glucose). It has three stages: 1.Glycolysis 2.Krebs Cycle (Citric Acid Cycle) 3.Electron Transport Chain (ETC)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Cellular Respiration Glycolysis takes place in the cell’s cytosol, Krebs cycle and ETC take place in mitochondria

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Cellular Respiration Glycolysis yields two net molecules of ATP per molecule of glucose, as does the Krebs cycle.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Cellular Respiration Suggested Media Enhancement: Cellular Respiration To access this animation go to folder C_Animations_and_Video_Files and open the BioFlix folder.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Cellular Respiration The net yield in the ETC is a maximum of about 32 ATP molecules per molecule of glucose.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Cellular Respiration Glycolysis and the Krebs cycle are critical in that they yield electrons that are carried to the ETC for the final high-yield stage of energy harvesting.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Energy Harvesting Figure ATP 32 ATP glycolysis 36 ATP maximum per glucose molecule Krebs cycle electron transport chain glucose (b)In schematic terms (a)In metaphorical terms mitochondrion H2OH2O O2O2 2 FADH 2 2 NADH 6 NADH CO 2 glucose derivatives cytosol glycolysis Krebs cycle electron transport chain insert 1 glucose 2 energy tokens 2 energy tokens 32 energy tokens reactantsproducts

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 7.4 First Stage of Respiration: Glycolysis

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Glycolysis Figure 7.5 molecules in molecules out 1,3-diphosphoglyceric acid Red balls are carbons and gold ovals are phosphate groups glucose glyceraldehyde-3-phosphate 3-phosphoglyceric acid pyruvic acid glucose-6-phosphate fructose-6-phosphate fructose-1,6-diphosphate glycolysis glucose Krebs cycle electron transport system

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 7.5 Second Stage of Respiration: The Krebs Cycle

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Transition Between Glycolysis and the Krebs Cycle Figure 7.7 glycolysis Krebs cycle Krebs cycle 2 NADH to electron transport chain electron transport chain mitochondrion CO 2 NAD + NADH inner compartment cytosol pyruvic acid acetyl coenzyme A CoA glucose derivatives coenzyme A A

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Krebs Cycle The net energy yield of the Krebs cycle per molecule of glucose is: –six molecules of NADH –two molecules of FADH 2 –two molecules of ATP

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Krebs Cycle Figure 7.8 malic acid succinic acid oxaloacetic acidcitric acid  -ketoglutaric acid  -ketoglutaric acid derivative acetyl coenzyme A glycolysis Krebs cycle electron transport chain

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 7.6 Third Stage of Respiration: The Electron Transport Chain

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Electron Transport Chain Figure 7.9 glycolysis Krebs cycle electron transport chain H2OH2O O2O2 outer compartment inner membrane Mitochondrion inner compartment outer compartment inner membrane Electron transport chainATP synthesis inner compartment ADP + P ATP synthase NAD + H2OH2O2 H + + — O 2 1 2

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 7.7 Other Foods, Other Respiratory Pathways

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Many Respiratory Pathways Figure 7.10 food sugarsglycerolfatty acids glycolysis glucose pyruvic acid acetyl CoA Krebs cycle electron transport chain NH 3 (ammonia) amino acids proteinscarbohydratesfats