Scott K. Powers • Edward T. Howley
Theory and Application to Fitness and Performance
SEVENTH EDITION
Chapter
Bioenergetics
Presentation prepared by:
Brian B. Parr, Ph.D.
University of South Carolina Aiken
Copyright ©2009 The McGraw-Hill Companies, Inc. Permission required for reproduction or display outside of classroom use.
Chapter 3
Objectives
1. Discuss the functions of the cell membrane,
nucleus, and mitochondria.
2. Define the following terms: (1) endergonic
reactions, (2) exergonic reactions, (3) coupled
reactions, and (4) bioenergetics.
3. Describe the role of enzymes as catalysts in
cellular chemical reactions.
4. List and discuss the nutrients that are used as
fuels during exercise.
5. Identify the high-energy phosphates.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Objectives
6. Discuss the biochemical pathways involved in
anaerobic ATP production.
7. Discuss the aerobic production of ATP.
8. Describe the general scheme used to regulate
metabolic pathways involved in bioenergetics.
9. Discuss the interaction between aerobic and
anaerobic ATP production during exercise.
10. Identify the enzymes that are considered rate
limiting in glycolysis and the Krebs cycle.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Outline
 Cell Structure
 Biological Energy
Transformation
Cellular Chemical
Reactions
Oxidation-Reduction
Reactions
Enzymes
 Fuels for Exercise
Carbohydrates
Fats
Proteins
 High-Energy
Phosphates
 Bioenergetics
Anaerobic ATP Production
Aerobic ATP production
 Control of
Bioenergetics
Control of ATP-PC
System
Control of Glycolysis
Control of Krebs Cycle
and Electron Transport
Chain
 Aerobic ATP Tally
 Efficiency of Oxidative
Phosphorylation
 Interaction Between
Aerobic/Anaerobic
ATP Production
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Introduction
• Metabolism
– Sum of all chemical reactions that occur in the body
– Anabolic reactions
 Synthesis of molecules
– Catabolic reactions
 Breakdown of molecules
• Bioenergetics
– Converting foodstuffs (fats, proteins, carbohydrates)
into energy
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Cell Structure
Chapter 3
Cell Structure
• Cell membrane
– Semipermeable membrane that separates the cell
from the extracellular environment
• Nucleus
– Contains genes that regulate protein synthesis
 Molecular biology
• Cytoplasm
– Fluid portion of cell
– Contains organelles
 Mitochondria
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Cell Structure
Chapter 3
A Typical Cell and Its Major Organelles
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.1
Cell Structure
Chapter 3
In Summary
 Metabolism is defined as the total of all cellular reactions
that occur in the body; this includes both the synthesis of
molecules and the breakdown of molecules.
 Cell structure includes the following three major parts:
(1) cell membrane, (2) nucleus, and (3) cytoplasm
(called sarcoplasm in muscle).
 The cell membrane provides a protective barrier
between the interior of the cell and the extracellular fluid.
 Genes (located within the nucleus) regulate protein
synthesis within the cell.
 The cytoplasm is the fluid portion of the cell and contains
numerous organelles
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Cell Structure
Chapter 3
A Closer Look 3.1
Molecular Biology and Exercise Science
• Study of molecular structures and events
underlying biological processes
– Relationship between genes and cellular
characteristics they control
• Genes code for specific cellular proteins
– Process of protein synthesis
• Exercise training results in modifications in protein
synthesis
– Strength training results in increased synthesis of
muscle contractile protein
• Molecular biology provides “tools” for
understanding the cellular response to exercise
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Biological Energy Transformation
Steps Leading to Protein Synthesis
1. DNA contains
information to
produce proteins.
2. Transcription
produces mRNA.
3. mRNA leaves
nucleus and binds to
ribosome.
4. Amino acids are
carried to the
ribosome by tRNA.
5. In translation, mRNA
is used to determine
the arrangement of
amino acids in the
polypeptide chain.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.2
Chapter 3
Biological Energy Transformation
Cellular Chemical Reactions
• Endergonic reactions
– Require energy to be added
– Endothermic
• Exergonic reactions
– Release energy
– Exothermic
• Coupled reactions
– Liberation of energy in an exergonic reaction drives
an endergonic reaction
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Biological Energy Transformation
The Breakdown of Glucose:
An Exergonic Reaction
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.3
Biological Energy Transformation
Chapter 3
Coupled Reactions
The energy given off by the exergonic reaction
powers the endergonic reaction
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.4
Chapter 3
Biological Energy Transformation
Oxidation-Reduction Reactions
• Oxidation
– Removing an electron
• Reduction
– Addition of an electron
• Oxidation and reduction are always coupled
reactions
• Often involves the transfer of hydrogen atoms
rather than free electrons
– Hydrogen atom contains one electron
– A molecule that loses a hydrogen also loses an
electron and therefore is oxidized
• Importance of NAD and FAD
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Biological Energy Transformation
Oxidation-Reduction Reaction Involving
NAD and NADH
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.5
Chapter 3
Biological Energy Transformation
Enzymes
• Catalysts that regulate the speed of reactions
– Lower the energy of activation
• Factors that regulate enzyme activity
– Temperature
– pH
• Interact with specific substrates
– Lock and key model
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Biological Energy Transformation
Enzymes Catalyze Reactions
Enzymes lower the energy of activation
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.6
Biological Energy Transformation
Chapter 3
The Lock-and-Key Model of Enzyme
Action
a)
b)
c)
Substrate (sucrose)
approaches the
active site on the
enzyme.
Substrate fits into
the active site,
forming enzymesubstrate complex.
The enzyme
releases the
products (glucose
and fructose).
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.7
Biological Energy Transformation
Chapter 3
Clinical Applications 3.1
Diagnostic Value of Measuring Enzyme
Activity in the Blood
• Damaged cells release enzymes into the blood
– Enzyme levels in blood indicate disease or tissue
damage
• Diagnostic application
– Elevated lactate dehydogenase or creatine kinase in
the blood may indicate a myocardial infarction
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Biological Energy Transformation
Examples of the Diagnostic Value of
Enzymes in Blood
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Biological Energy Transformation
Classification of Enzymes
• Oxidoreductases
– Catalyze oxidation-reduction reactions
• Transferases
– Transfer elements of one molecule to another
• Hydrolases
– Cleave bonds by adding water
• Lyases
– Groups of elements are removed to form a double bond or
added to a double bond
• Isomerases
– Rearrangement of the structure of molecules
• Ligases
– Catalyze bond formation between substrate molecules
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Biological Energy Transformation
Example of the Major Classes of
Enzymes
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Biological Energy Transformation
Factors That Alter Enzyme Activity
• Temperature
– Small rise in body temperature increases enzyme
activity
– Exercise results in increased body temperature
• pH
– Changes in pH reduces enzyme activity
– Lactic acid produced during exercise
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Biological Energy Transformation
The Effect of Body Temperature on
Enzyme Activity
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.8
Chapter 3
Biological Energy Transformation
The Effect of pH on Enzyme Activity
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.9
Fuels for Exercise
Chapter 3
Carbohydrates
• Glucose
– Blood sugar
• Glycogen
– Storage form of glucose in liver and muscle
 Synthesized by enzyme glycogen synthase
– Glycogenolysis
 Breakdown of glycogen to glucose
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Fuels for Exercise
Chapter 3
Fats
• Fatty acids
– Primary type of fat used by the muscle
– Triglycerides
 Storage form of fat in muscle and adipose tissue
 Breaks down into glycerol and fatty acids
• Phospholipids
– Not used as an energy source
• Steroids
– Derived from cholesterol
– Needed to synthesize sex hormones
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Fuels for Exercise
Chapter 3
Protein
• Composed of amino acids
• Some can be converted to glucose in the liver
– Gluconeogenesis
• Others can be converted to metabolic intermediates
– Contribute as a fuel in muscle
• Overall, protein is not a primary energy source
during exercise
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Fuels for Exercise
Chapter 3
In Summary
 The body uses carbohydrate, fat, and protein nutrients
consumed daily to provide the necessary energy to
maintain cellular activities both at rest and during
exercise. During exercise, the primary nutrients used for
energy are fats and carbohydrates, with protein
contributing a relatively small amount of the total energy
used.
 Glucose is stored in animal cells as a polysaccharide
called glycogen.
 Fatty acids are the primary form of fat used as an energy
source in cells. Fatty acids are stored as triglycerides in
muscle and fat cells.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
High-Energy Phosphates
Chapter 3
High-Energy Phosphates
• Adenosine triphosphate (ATP)
– Consists of adenine, ribose, and three linked
phosphates
• Synthesis
ADP + Pi  ATP
• Breakdown
ATP
ATPase
ADP + Pi + Energy
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
High-Energy Phosphates
Chapter 3
Structure of ATP
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.10
Chapter 3
High-Energy Phosphates
Model of ATP as the Universal Energy
Donor
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.11
Bioenergetics
Chapter 3
Bioenergetics
• Formation of ATP
– Phosphocreatine (PC) breakdown
– Degradation of glucose and glycogen
 Glycolysis
– Oxidative formation of ATP
• Anaerobic pathways
– Do not involve O2
– PC breakdown and glycolysis
• Aerobic pathways
– Require O2
– Oxidative phosphorylation
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
Anaerobic ATP Production
• ATP-PC system
– Immediate source of ATP
PC + ADP
Creatine kinase
ATP + C
• Glycolysis
– Glucose  2 pyruvic acid or 2 lactic acid
– Energy investment phase
 Requires 2 ATP
– Energy generation phase
 Produces 4 ATP, 2 NADH, and 2 pyruvate or 2 lactate
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
The Winning Edge 3.1
Does Creatine Supplementation
Improve Exercise Performance?
• Depletion of PC may limit short-term, high-intensity
exercise
• Creatine monohydrate supplementation
– Increased muscle PC stores
– Some studies show improved performance in shortterm, high-intensity exercise
 Inconsistent results may be due to water retention and
weight gain
– Increased strength and fat-free mass with resistance
training
• Creatine supplementation does not appear to pose
health risks
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
A Closer Look 3.2
Lactic Acid or Lactate?
• Terms lactic acid and lactate used interchangeably
– Lactate is the conjugate base of lactic acid
• Lactic acid is produced in glycolysis
– Rapidly disassociates to lactate and H+
The ionization of lactic acid forms the
conjugate base called lactate
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.12
Bioenergetics
Chapter 3
The Two Phases of Glycolysis
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.13
Bioenergetics
Chapter 3
Interaction Between Blood Glucose and
Muscle Glycogen in Glycolysis
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.14
Bioenergetics
Chapter 3
Glycolysis: Energy Investment Phase
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.15
Bioenergetics
Chapter 3
Glycolysis: Energy Generation Phase
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.15
Bioenergetics
Chapter 3
Hydrogen and Electron Carrier
Molecules
• Transport hydrogens and associated electrons
– To mitochondria for ATP generation (aerobic)
– To convert pyruvic acid to lactic acid (anaerobic)
• Nicotinamide adenine dinucleotide (NAD)
NAD + 2H+  NADH + H+
• Flavin adenine dinucleotide (FAD)
FAD + 2H+  FADH2
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
A Closer Look 3.3
NADH is “Shuttled” into Mitochondria
• NADH produced in glycolysis must be converted
back to NAD
– By converting pyruvic acid to lactic acid
– By “shuttling” H+ into the mitochondria
• A specific transport system shuttles H+ across the
mitochondrial membrane
– Located in the mitochondrial membrane
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
Conversion of Pyruvic Acid to Lactic Acid
The addition of two H+ to pyruvic acid forms NAD and lactic acid
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.16
Bioenergetics
Chapter 3
In Summary
 The immediate source of energy for muscular contraction
is the high-energy phosphate ATP. ATP is degraded via
the enzyme ATPase as follows:
ATP
ATPase
ADP + Pi + Energy
 Formation of ATP without the use of O2 is termed
anaerobic metabolism. In contrast, the production of ATP
using O2 as the final electron acceptor is referred to as
aerobic metabolism.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
In Summary
 Exercising skeletal muscles produce lactic acid.
However, once produced in the body, lactic acid is
rapidly converted to its conjugate base, lactate.
 Muscle cells can produce ATP by any one or a
combination of three metabolic pathways: (1) ATP-PC
system, (2) glycolysis, (3) oxidative ATP production.
 The ATP-PC system and glycolysis are two anaerobic
metabolic pathways that are capable of producing ATP
without O2.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
Aerobic ATP Production
• Krebs cycle (citric acid cycle)
– Pyruvic acid (3 C) is converted to acetyl-CoA (2 C)
 CO2 is given off
– Acetyl-CoA combines with oxaloacetate (4 C) to
form citrate (6 C)
– Citrate is metabolized to oxaloacetate
 Two CO2 molecules given off
– Produces three molecules of NADH and one FADH
– Also forms one molecule of GTP
 Produces one ATP
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
The Three
Stages
of Oxidative
Phosphorylation
Figure 3.17
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
The Krebs Cycle
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.18
Bioenergetics
Chapter 3
Fats and Proteins in Aerobic Metabolism
• Fats
– Triglycerides  glycerol and fatty acids
– Fatty acids  acetyl-CoA
 Beta-oxidation
– Glycerol is not an important muscle fuel during
exercise
• Protein
– Broken down into amino acids
– Converted to glucose, pyruvic acid, acetyl-CoA, and
Krebs cycle intermediates
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
Relationship Between the Metabolism of
Proteins, Carbohydrates, and Fats
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.19
Bioenergetics
Chapter 3
Aerobic ATP Production
• Electron transport chain
– Oxidative phosphorylation occurs in the
mitochondria
– Electrons removed from NADH and FADH are
passed along a series of carriers (cytochromes) to
produce ATP
 Each NADH produces 2.5 ATP
 Each FADH produces 1.5 ATP
– Called the chemiosmotic hypothesis
– H+ from NADH and FADH are accepted by O2 to
form water
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
The Chemiosmotic Hypothesis of ATP
Formation
• Electron transport chain results in pumping of H+
ions across inner mitochondrial membrane
– Results in H+ gradient across membrane
• Energy released to form ATP as H+ ions diffuse
back across the membrane
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
The Electron Transport Chain
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.20
Bioenergetics
Chapter 3
A Closer Look 3.4
Beta Oxidation is the Process of
Converting Fatty Acids to Acetyl-CoA
• Breakdown of triglycerides releases fatty acids
• Fatty acids must be converted to acetyl-CoA to be
used as a fuel
– Activated fatty acid (fatty acyl-CoA) into
mitochondrion
– Fatty acid “chopped” into 2 carbon fragments
forming acetyl-CoA
• Acetyl-CoA enters Krebs cycle and is used for
energy
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Bioenergetics
Chapter 3
Beta Oxidation
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.21
Bioenergetics
Chapter 3
In Summary
 Oxidative phosphorylation or aerobic ATP production
occurs in the mitochondria as a result of a complex
interaction between the Krebs cycle and the electron
transport chain. The primary role of the Krebs cycle is to
complete the oxidation of substrates and form NADH and
FADH to enter the electron transport chain. The end
result of the electron transport chain is the formation of
ATP and water. Water is formed by oxygen-accepting
electrons; hence, the reason we breathe oxygen is to
use it as the final acceptor of electrons in aerobic
metabolism.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Aerobic ATP Tally
Chapter 3
A Closer Look 3.5
A New Look at the ATP Balance Sheet
• Historically, 1 glucose produced 38 ATP
• Recent research indicates that 1 glucose produces
32 ATP
– Energy provided by NADH and FADH also used to
transport ATP out of mitochondria.
– 3 H+ must pass through H+ channels to produce 1
ATP
– Another H+ needed to move the ATP across the
mitochondrial membrane
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Aerobic ATP Tally
Chapter 3
Aerobic ATP Tally Per Glucose Molecule
Metabolic Process
High-Energy
Products
ATP from Oxidative ATP Subtotal
Phosphorylation
Glycolysis
2 ATP
2 NADH
—
5
2 (if anaerobic)
7 (if aerobic)
5
12
—
15
3
14
29
32
Pyruvic acid to acetyl-CoA 2 NADH
Krebs cycle
Grand Total
2 GTP
6 NADH
2 FADH
32
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Efficiency of Oxidative Phosphorylation
Efficiency of Oxidative Phosphorylation
• One mole of ATP has energy yield of 7.3 kcal
• 32 moles of ATP are formed from one mole of
glucose
• Potential energy released from one mole of glucose
is 686 kcal/mole
32 moles ATP/mole glucose x 7.3 kcal/mole ATP
x 100 = 34%
686 kcal/mole glucose
• Overall efficiency of aerobic respiration is 34%
– 66% of energy released as heat
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Efficiency of Oxidative Phosphorylation
In Summary
 The aerobic metabolism of one molecule of glucose
results in the production of 32 ATP molecules, whereas
the aerobic yield for glycogen breakdown is 33 ATP.
 The overall efficiency of aerobic of aerobic respiration is
approximately 34%, with the remaining 66% of energy
being released as heat.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Control of Bioenergetics
Chapter 3
Control of Bioenergetics
• Rate-limiting enzymes
– An enzyme that regulates the rate of a metabolic
pathway
• Modulators of rate-limiting enzymes
– Levels of ATP and ADP+Pi
 High levels of ATP inhibit ATP production
 Low levels of ATP and high levels of ADP+Pi stimulate ATP
production
– Calcium may stimulate aerobic ATP production
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Control of Bioenergetics
Example of a Rate-Limiting Enzyme
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.22
Control of Bioenergetics
Chapter 3
Factors Known to Affect Rate-Limiting
Enzymes
Pathway
Rate-Limiting
Enzyme
Stimulators
Inhibitors
ATP-PC system
Creatine kinase
ADP
ATP
Glycolysis
Phosphofructokinase AMP, ADP, Pi, - pH ATP, CP, citrate, ¯pH
Krebs cycle
Isocitrate
dehydrogenase
++
ADP, Ca , NAD
Electron transport Cytochrome Oxidase ADP, Pi
chain
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
ATP, NADH
ATP
Chapter 3
Control of Bioenergetics
In Summary
 Metabolism is regulated by enzymatic activity. An
enzyme that regulates a metabolic pathway is termed a
“rate-limiting” enzyme.
 The rate-limiting enzyme for glycolysis is
phosphofructokinase, while the rate-limiting enzymes for
the Krebs cycle and electron transport chain are
isocitrate dehydrogenase and cytochrome oxidase,
respectively.
 In general, cellular levels of ATP and ADP+Pi regulate
the rate of metabolic pathways involved in the production
of ATP. High levels of ATP inhibit further ATP
production, while low levels of ATP and high levels of
ADP+Pi stimulate ATP production. Evidence also exists
that calcium may stimulate aerobic energy metabolism.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Interaction Between Aerobic/Anaerobic ATP Production
Interaction Between Aerobic/Anaerobic
ATP Production
• Energy to perform exercise comes from an
interaction between aerobic and anaerobic
pathways
• Effect of duration and intensity
– Short-term, high-intensity activities
 Greater contribution of anaerobic energy systems
– Long-term, low to moderate-intensity exercise
 Majority of ATP produced from aerobic sources
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Interaction Between Aerobic/Anaerobic ATP Production
The Winning Edge 3.2
Contribution of Aerobic/Anaerobic ATP
Production During Sporting Events
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Figure 3.23
Chapter 3
Interaction Between Aerobic/Anaerobic ATP Production
In Summary
 Energy to perform exercise comes from an interaction of
anaerobic and aerobic pathways.
 In general, the shorter the activity (high intensity), the
greater the contribution of anaerobic energy production.
In contrast, long-term activities (low to moderate
intensity) utilize ATP produced from aerobic sources.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Study Questions
1. List and briefly discuss the functions of the three
major components of cell structure.
2. Briefly explain the concept of coupled reactions.
3. Define the following terms: (1) bioenergetics, (2)
endergonic reactions, and (3) exergonic reactions.
4. Discuss the role of enzymes as catalysts. What is
meant by the expression “energy of activation”?
5. Where do glycolysis, the Krebs cycle, and
oxidative phosphorylation take place in the cell?
6. Define the terms glycogen, glycogenolysis, and
glycolysis.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Study Questions
7. What are the high-energy phosphates? Explain
the statement that “ATP is the universal energy
donor.”
8. Define the terms aerobic and anaerobic.
9. Briefly discuss the function of glycolysis in
bioenergetics. What role does NAD play in
glycolysis?
10. Discuss the operation of the Krebs cycle and the
electron transport chain in the aerobic production
of ATP. What is the function of NAD and FAD in
these pathways?
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Study Questions
11. What is the efficiency of the aerobic degradation
of glucose?
12. What is the role of oxygen in aerobic metabolism?
13. What are the rate-limiting enzymes for the
following metabolic pathways: ATP-PC system,
glycolysis, Krebs cycle, and electron transport
chain?
14. Briefly discuss the interaction of anaerobic versus
aerobic ATP production during exercise.
15. Discuss the chemiosmotic theory of ATP
production.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.
Chapter 3
Study Questions
16. List and define the six classes of enzymes
identified by the International Union of
Biochemistry.
17. Briefly discuss the impact of changes in both
temperature and pH on enzyme function.
18. Discuss the relationship between lactic acid and
lactate.
Copyright ©2009 The McGraw-Hill Companies, Inc. All Rights Reserved.