Presentation is loading. Please wait.

Presentation is loading. Please wait.

Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential.

Similar presentations


Presentation on theme: "Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential."— Presentation transcript:

1 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential Biology with Physiology Neil Campbell, Jane Reece, and Eric Simon Presentation prepared by Chris C. Romero CHAPTER 6 Cellular Respiration: Harvesting Chemical Energy Figures 6.6 – 6.16

2 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The path that electrons take on their way down from glucose to oxygen involves many stops NADH and Electron Transport Chains Figure 6.6 1/21/2 (from food via NADH) 2 H 2 e Energy for synthesis of Electron transport chain 2 e 2 H 1/21/2

3 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The first stop is an electron acceptor called NAD + –The transfer of electrons from organic fuel to NAD + reduces it to NADH The rest of the path consists of an electron transport chain –This chain involves a series of redox reactions –These lead ultimately to the production of large amounts of ATP

4 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Cellular respiration is an example of a metabolic pathway –A series of chemical reactions in cells All of the reactions involved in cellular respiration can be grouped into three main stages –Glycolysis –The Krebs cycle –Electron transport The Metabolic Pathway of Cellular Respiration

5 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings A Road Map for Cellular Respiration Cytosol Mitochondrion High-energy electrons carried by NADH High-energy electrons carried mainly by NADH Glycolysis Glucose 2 Pyruvic acid Krebs Cycle Electron Transport Figure 6.7

6 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Stage 1: Glycolysis A molecule of glucose is split into two molecules of pyruvic acid

7 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Glycolysis breaks a six-carbon glucose into two three-carbon molecules –These molecules then donate high energy electrons to NAD+, forming NADH

8 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.8 Glucose 2 Pyruvic acid

9 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Glycolysis makes some ATP directly when enzymes transfer phosphate groups from fuel molecules to ADP Figure 6.9 Enzyme

10 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Stage 2: The Krebs Cycle The Krebs cycle completes the breakdown of sugar

11 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings In the Krebs cycle, pyruvic acid from glycolysis is first prepped into a usable form, Acetyl-CoA Figure 6.10 CoA Pyruvic acid Acetic acid Coenzyme A Acetyl-CoA (acetyl-coenzyme A) CO 2

12 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The Krebs cycle extracts the energy of sugar by breaking the acetic acid molecules all the way down to CO 2 –The cycle uses some of this energy to make ATP –The cycle also forms NADH and FADH 2

13 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.11 Input Acetic acid ADP 3 NAD FAD Krebs Cycle Output 2 CO

14 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Stage 3: Electron Transport Electron transport releases the energy your cells need to make the most of their ATP

15 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The molecules of electron transport chains are built into the inner membranes of mitochondria –The chain functions as a chemical machine that uses energy released by the fall of electrons to pump hydrogen ions across the inner mitochondrial membrane –These ions store potential energy

16 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings When the hydrogen ions flow back through the membrane, they release energy –The ions flow through ATP synthase –ATP synthase takes the energy from this flow and synthesizes ATP

17 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.12 Protein complex Electron carrier Inner mitochondrial membrane Electron flow Electron transport chain ATP synthase

18 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The Versatility of Cellular Respiration Cellular respiration can burn other kinds of molecules besides glucose –Diverse types of carbohydrates –Fats –Proteins

19 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.13 Food Polysaccharides FatsProteins SugarsGlycerolFatty acidsAmino acids Amino groups Glycolysis Acetyl- CoA Krebs Cycle Electron Transport

20 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Adding Up the ATP from Cellular Respiration Figure 6.14 Cytosol Mitochondrion Glycolysis Glucose 2 Pyruvic acid 2 Acetyl- CoA Krebs Cycle Electron Transport by direct synthesis by direct synthesis by ATP synthase Maximum per glucose:

21 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings FERMENTATION: ANAEROBIC HARVEST OF FOOD ENERGY Some of your cells can actually work for short periods without oxygen –For example, muscle cells can produce ATP under anaerobic conditions Fermentation –The anaerobic harvest of food energy

22 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Human muscle cells can make ATP with and without oxygen –They have enough ATP to support activities such as quick sprinting for about 5 seconds –A secondary supply of energy (creatine phosphate) can keep muscle cells going for another 10 seconds –To keep running, your muscles must generate ATP by the anaerobic process of fermentation Fermentation in Human Muscle Cells

23 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Glycolysis is the metabolic pathway that provides ATP during fermentation –Pyruvic acid is reduced by NADH, producing NAD+, which keeps glycolysis going –In human muscle cells, lactic acid is a by-product

24 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.15a 2 ADP+ 2 Glycolysis Glucose 2 NAD 2 Pyruvic acid + 2 H 2 NAD 2 Lactic acid (a) Lactic acid fermentation

25 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Various types of microorganisms perform fermentation –Yeast cells carry out a slightly different type of fermentation pathway –This pathway produces CO 2 and ethyl alcohol Fermentation in Microorganisms

26 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.15b 2 ADP+ 2 2 ATP Glycolysis Glucose 2 NAD 2 Pyruvic acid 2 CO 2 released + 2 H 2 NAD 2 Ethyl alcohol (b) Alcoholic fermentation

27 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The food industry uses yeast to produce various food products Figure 6.16

28 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Ancient bacteria probably used glycolysis to make ATP long before oxygen was present in Earths atmosphere EVOLUTION CONNECTION: LIFE ON AN ANAEROBIC EARTH –Glycolysis is a metabolic heirloom from the earliest cells that continues to function today in the harvest of food energy

29 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings SUMMARY OF KEY CONCEPTS Chemical Cycling Between Photosynthesis and Cellular Respiration Visual Summary 6.1 Sunlight Heat Photosynthesis Cellular respiration

30 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The Overall Equation for Cellular Respiration Visual Summary 6.2 Oxidation: Glucose loses electrons (and hydrogens) GlucoseCarbon dioxide Electrons (and hydrogens) Energy Oxygen Reduction: Oxygen gains electrons (and hydrogens)

31 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The Metabolic Pathway of Cellular Respiration Visual Summary 6.3 GlucoseOxygenWater Energy


Download ppt "Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential."

Similar presentations


Ads by Google