Download Chapter 3 → Bioenergetics Introduction Cell Structure

Chapter 3  Bioenergetics
Introduction
Cell Structure
Cell Structure
1
Cell Structure
A Typical Cell & Its Major Organelles
Figure 3.1
Cell Structure
A Closer Look 3.1
Molecular Biology & Exercise Science
Biological Energy Transformation
Steps Leading to Protein Synthesis
1. DNA contains
information to
produce proteins.
2. Transcription
produces mRNA.
3. mRNA leaves
nucleus & binds to
ribosome.
4. AA are carried to the
ribosome by tRNA.
5. In translation, mRNA
is used to determine
the arrangement of
AA in the polypeptide
chain.
Figure 3.2
2
Biological Energy Transformation
Cellular Chemical Reactions
• Endergonic reactions
• Exergonic reactions
• Coupled reactions
Biological Energy Transformation
The Breakdown of glu:
An Exergonic Reaction
Figure 3.3
Biological Energy Transformation
Coupled Reactions
The energy given off by the exergonic reaction
powers the endergonic reaction
Figure 3.4
3
Biological Energy Transformation
Oxidation-Reduction Reactions
Biological Energy Transformation
Oxidation-Reduction Reaction Involving
NAD & NADH
Figure 3.5
Biological Energy Transformation
Enzymes
4
Biological Energy Transformation
Enzymes Catalyze Reactions
Enzymes lower the energy of activation
Figure 3.6
Biological Energy Transformation
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 (glu &
fructose).
Figure 3.7
Biological Energy Transformation
Examples of the Diagnostic Value of
Enzymes in bld
5
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 b/n substrate molecules
Biological Energy Transformation
Example of the Major Classes of
Enzymes
Biological Energy Transformation
Factors that Alter Enzyme Activity
6
Biological Energy Transformation
The Effect of Body Temperature on
Enzyme Activity
Figure 3.8
Biological Energy Transformation
The Effect of pH on Enzyme Activity
Figure 3.9
Fuels for Exercise
CHO's
7
Fuels for Exercise
Fats
Fuels for Exercise
Protein
High-Energy Phosphates
High-Energy Phosphates
8
High-Energy Phosphates
Structure of ATP
Figure 3.10
High-Energy Phosphates
Model of ATP as the Universal Energy
Donor
Figure 3.11
Bioenergetics
Bioenergetics
• Formation of ATP
9
Bioenergetics
Anaerobic ATP Production
Bioenergetics
The Winning Edge 3.1
Does Creatine Supplementation
Improve Exercise Performance?
• Depletion of PC may limit short-term, high-intensity
exercise
Bioenergetics
A Closer Look 3.2
Lactic Acid or Lactate?
The ionization of lactic acid forms the
conjugate base called lactate
Figure 3.12
10
Bioenergetics
2 Phases of Glycolysis
Figure 3.13
Bioenergetics
Interaction b/n bld glu & Muscle
Glycogen in Glycolysis
Figure 3.14
Bioenergetics
Glycolysis: Energy Investment Phase
Figure 3.15
11
Bioenergetics
Glycolysis: Energy Generation Phase
Figure 3.15
Bioenergetics
H+ & e- Carrier Molecules
Bioenergetics
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 mb
– Located in the mitochondrial mb
12
Bioenergetics
Conversion of Pyruvic Acid to Lactic Acid
The addition of two H+ to pyruvic acid forms NAD & lactic acid
Figure 3.16
Bioenergetics
Aerobic ATP Production
Bioenergetics
3 Stages
of Oxidative
Phosphorylation
Figure 3.17
13
Bioenergetics
The Krebs Cycle
Figure 3.18
Bioenergetics
Fats & Proteins in Aerobic Metabolism
Bioenergetics
Relationship b/n the Metabolism of
Proteins, CHO's, & Fats
Figure 3.19
14
Bioenergetics
Aerobic ATP Production
Bioenergetics
The Chemiosmotic Hypothesis of ATP
Formation
Bioenergetics
The ETC
Figure 3.20
15
Bioenergetics
A Closer Look 3.4
Beta Oxidation is the Process of
Converting Fatty Acids to Acetyl-CoA
Bioenergetics
Beta Oxidation
Figure 3.21
Aerobic ATP Tally
A Closer Look 3.5
A New Look at the ATP Balance Sheet
16
Aerobic ATP Tally
Aerobic ATP Tally Per glu Molecule
Metabolic Process
High-Energy
Products
ATP from Oxidative ATP Subtotal
Phosphorylation
Glycolysis
2 ATP
2 NADH
—
5
2 (if anaerobic)
7 (if aerobic)
Pyruvic acid to acetyl-CoA 2 NADH
5
12
Krebs cycle
—
15
3
14
29
32
2 GTP
6 NADH
2 FADH
Grand Total
32
Efficiency of Oxidative Phosphorylation
Efficiency of Oxidative Phosphorylation
• 1 mole of ATP has energy yield of 7.3 kcal
• 32 moles of ATP are formed from 1 mole of glu
• Potential energy released from 1 mole of glu is 686
kcal/mole
32 moles ATP/mole glu x 7.3 kcal/mole ATP
x 100 = 34%
686 kcal/mole glu
Control of Bioenergetics
Control of Bioenergetics
• Rate-limiting enzymes
• Modulators of rate-limiting enzymes
17
Control of Bioenergetics
Example of a Rate-Limiting Enzyme
Figure 3.22
Control of Bioenergetics
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
ATP, NADH
ATP
Interaction b/n Aerobic/Anaerobic ATP Production
Interaction b/n Aerobic/Anaerobic ATP
Production
18
Interaction b/n Aerobic/Anaerobic ATP Production
The Winning Edge 3.2
Contribution of Aerobic/Anaerobic ATP
Production During Sporting Events
Figure 3.23
19