•Metabolism and Energy•Catabolism vs Anabolism; Exergonic vs Endergonic rxns•Using ATP to make endergonic rxns run
•Enzymes as Biological Catalysts•Lowering of Activation Energy•Specificity, recyclability•Factors which affect Enzymatic Rate (pH, temp, inhib.)
•Metabolic Control•Cellular Respiration: Oxidative Catabolism
•Oxidation-Reduction Reactions(NAD+, FAD+ trucks)•C6H12O6 + 6O2 -->6CO2 + 6H2O + Energy (ATP)•Glycolysis (6C glucose--> 2 pyruvate + 2NADH +2ATP•Krebs Cycle (2 pyruvate-->6CO2 + 8NADH +2FADH2 + 2ATP•Electron Transport Chain (Cashing in on e-)•FADH2 + NADH + O2 --> lots of ATP + H2O + NAD+ + FAD+
•Terminal aerobic electron acceptor O2--->H2O•Anaerobic bacteria use nitrate, sulfate, carbon dioxide
•Fermentation is not anaerobic respiration•Performed by facultative anaerobes•Restart glycolysis by recycling NADH->NAD+ in side rxns•Acid and/or Gas common (pH drop)
•Alcohol Fermentation (yeast, some bacteria)•Ethanol and carbon dioxide produced•Lactic Acid Fermentation (bacteria, muscles)•Heterolactic Fermentation (several bacteria)•Acetoin: a neutral product in VP test
•Use of Other Food Molecules for Energy•Lipid Catabolism to Acetyl CoA•Protein Catabolism to Kreb’s Cycle Molecules
•Deamination, Ammonium, and pH rise
Microbial Metabolism
Food molecules (high energy)
Waste molecules (low energy)
Energy from chemical bonds Usable cellular energy (ATP)
Simple molecules (low energy)
Complex biomolecules (high energy)
Breakdown(Catabolism)
Construction/ Synthesis (Anabolism
)
Metabolism: Breakdown of Food Fuels Construction of Biomolecules
Cellular Reactions Either Use or Liberate Energy
• Catabolic/Breakdown Reactions release energy
o Molecules become more disorganized or less structured
• Anabolic/Buildup Reactions absorb energy
o Molecules become more ordered and complex
o ATP needed to power endothermic reactions
ZX Y + +
CA B + + ATP
Both Breakdown and Buildup Reactions Have Activation Energies
Breakdown Reactions Release Energy: Exergonic/exothermic
Buildup Reactions Absorb or Require Energy: Endergonic/endothermic
Z
X Y + +
CA B + + ATP
En
erg
y L
evel
En
erg
y L
evel
Time
Time
Z
X + Y
A+ B
C
Activation
Energy
Activation
Energy
Metabolism and EnergyCatabolism vs Anabolism; Exergonic vs Endergonic rxnsUsing ATP to make endergonic rxns run
Enzymes as Biological CatalystsLowering of Activation EnergySpecificity, recyclabilityFactors which affect Enzymatic Rate (pH, temp, inhib.)
Metabolic ControlCellular Respiration: Oxidative Catabolism
Oxidation-Reduction Reactions(NAD+, FAD+ trucks)C6H12O6 + 6O2 -->6CO2 + 6H2O + Energy (ATP)Glycolysis (6C glucose--> 2 pyruvate + 2NADH +2ATPKrebs Cycle (2 pyruvate-->6CO2 + 8NADH +2FADH2 + 2ATPElectron Transport Chain (Cashing in on e-)FADH2 + NADH + O2 --> lots of ATP + H2O + NAD+ + FAD+
Terminal aerobic electron acceptor O2--->H2OAnaerobic bacteria use nitrate, sulfate, carbon dioxide
Fermentation is not anaerobic respirationPerformed by facultative anaerobesRestart glycolysis by recycling NADH->NAD+ in side rxnsAcid and/or Gas common (pH drop)
Alcohol Fermentation (yeast, some bacteria)Ethanol and carbon dioxide producedLactic Acid Fermentation (bacteria, muscles)Heterolactic Fermentation (several bacteria)Acetoin: a neutral product in VP test
Use of Other Food Molecules for EnergyLipid Catabolism to Acetyl CoAProtein Catabolism to Kreb’s Cycle Molecules
Deamination, Ammonium, and pH rise
Microbial Metabolism
Activation Energy
• Activation energy
• Energy needed to allow the reactants to form products
• Necessary for a chemical reaction to proceed
• Activation energy is needed even for breakdown reaction to get them going
En
erg
y L
evel
Time
Z
X + Y
Activation
Energy
• In the laboratory, we heat the reactants in order to provide
activation energy for a chemical reaction
• Inside the cell, a different mechanism is required as heating up
the reactants is not possible Lower the energy required for the reaction
Figure 5.8
Enzymes Lower Activation Energy and Speed Up Reactions
Enzymes Are Biological Catalysts
Figure 5.2
Enzymes
Figure 5.3
Metabolism and EnergyCatabolism vs Anabolism; Exergonic vs Endergonic rxnsUsing ATP to make endergonic rxns run
Enzymes as Biological CatalystsLowering of Activation EnergySpecificity, recyclabilityFactors which affect Enzymatic Rate (pH, temp, inhib.)Metabolic ControlCellular Respiration: Oxidative Catabolism
Oxidation-Reduction Reactions(NAD+, FAD+ trucks)C6H12O6 + 6O2 -->6CO2 + 6H2O + Energy (ATP)Glycolysis (6C glucose--> 2 pyruvate + 2NADH +2ATPKrebs Cycle (2 pyruvate-->6CO2 + 8NADH +2FADH2 + 2ATPElectron Transport Chain (Cashing in on e-)FADH2 + NADH + O2 --> lots of ATP + H2O + NAD+ + FAD+
Terminal aerobic electron acceptor O2--->H2OAnaerobic bacteria use nitrate, sulfate, carbon dioxide
Fermentation is not anaerobic respirationPerformed by facultative anaerobesRestart glycolysis by recycling NADH->NAD+ in side rxnsAcid and/or Gas common (pH drop)
Alcohol Fermentation (yeast, some bacteria)Ethanol and carbon dioxide producedLactic Acid Fermentation (bacteria, muscles)Heterolactic Fermentation (several bacteria)Acetoin: a neutral product in VP test
Use of Other Food Molecules for EnergyLipid Catabolism to Acetyl CoAProtein Catabolism to Kreb’s Cycle Molecules
Deamination, Ammonium, and pH rise
Microbial Metabolism
• Enzymes can be denatured by temperature and pH
Factors Influencing Enzyme Activity
Figure 5.6
Enzymes Become Non-Functional at pH Extremes and High Temperatures
0 2 4 6 8 10 12
En
zym
atic
rat
e
(pro
du
cts
fo
rme
d p
er
se
co
nd
)
pH (in pH units)10 20 30 40 50 60 70
En
zym
atic
rat
e
(pro
du
cts
fo
rme
d p
er
se
co
nd
)
Temperature (oC)
Stomach enzyme
OH-
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
OH-
OH-
OH-
OH-
OH-
OH-
OH-
OH-
OH-
H+
H+
Enzyme within a body cell
= folded, functional enzyme= denatured, non-functional enzyme
Reaction rate is slow at cold temperatures because molecules encounter enzyme
less often
Enzyme from hot springs bacterium
Enzyme within a body cell
• Competitive inhibition
Factors Influencing Enzyme Activity
Figure 5.7a, b
• Noncompetitive inhibition
Factors Influencing Enzyme Activity
Figure 5.7a, c
ATP, pyruvate, end amino acid
• Feedback inhibition
Factors Influencing Enzyme Activity
Figure 5.8
Metabolism and EnergyCatabolism vs Anabolism; Exergonic vs Endergonic rxnsUsing ATP to make endergonic rxns run
Enzymes as Biological CatalystsLowering of Activation EnergySpecificity, recyclabilityFactors which affect Enzymatic Rate (pH, temp, inhib.)
Metabolic ControlCellular Respiration: Oxidative Catabolism
Oxidation-Reduction Reactions(NAD+, FAD+ trucks)C6H12O6 + 6O2 -->6CO2 + 6H2O + Energy (ATP)Glycolysis (6C glucose--> 2 pyruvate + 2NADH +2ATPKrebs Cycle (2 pyruvate-->6CO2 + 8NADH +2FADH2 + 2ATPElectron Transport Chain (Cashing in on e-)FADH2 + NADH + O2 --> lots of ATP + H2O + NAD+ + FAD+
Terminal aerobic electron acceptor O2--->H2OAnaerobic bacteria use nitrate, sulfate, carbon dioxide
Fermentation is not anaerobic respirationPerformed by facultative anaerobesRestart glycolysis by recycling NADH->NAD+ in side rxnsAcid and/or Gas common (pH drop)
Alcohol Fermentation (yeast, some bacteria)Ethanol and carbon dioxide producedLactic Acid Fermentation (bacteria, muscles)Heterolactic Fermentation (several bacteria)Acetoin: a neutral product in VP test
Use of Other Food Molecules for EnergyLipid Catabolism to Acetyl CoAProtein Catabolism to Kreb’s Cycle Molecules
Deamination, Ammonium, and pH rise
Microbial Metabolism
• Oxidation is the removal of electrons.
• Reduction is the gain of electrons.
• Redox reaction is an oxidation reaction paired with a reduction reaction.
Oxidation-Reduction
Figure 5.9OIL RIG: Oxidation is loss of e-, reduction is gain of e-
• In biological systems, the electrons are often associated with hydrogen atoms. Biological oxidations are often dehydrogenations.
Oxidation-Reduction
Figure 5.10
Sugars, amino acids, fatty acids
Or FAD+ FADH2
The Energy Stored in ATP Can Be Used to Perform Work in the Cell
• The energy released by ATP breaking down into ADP and P can power a variety of needs in the cell
ADP P
PADP
Energized ATP:
Discharged ATP:
X Y+Z
Powering the synthesis of molecule Z:
Metabolism and EnergyCatabolism vs Anabolism; Exergonic vs Endergonic rxnsUsing ATP to make endergonic rxns run
Enzymes as Biological CatalystsLowering of Activation EnergySpecificity, recyclabilityFactors which affect Enzymatic Rate (pH, temp, inhib.)
Metabolic ControlCellular Respiration: Oxidative Catabolism
Oxidation-Reduction Reactions(NAD+, FAD+ trucks)C6H12O6 + 6O2 -->6CO2 + 6H2O + Energy (ATP)Glycolysis (6C glucose--> 2 pyruvate + 2NADH + 2ATPKrebs Cycle (2 pyruvate-->6CO2 + 8NADH +2FADH2 + 2ATPElectron Transport Chain and ATP Generation FADH2 + NADH + O2 --> lots of ATP + H2O + NAD+ + FAD+
Terminal aerobic electron acceptor O2--->H2OAnaerobic bacteria use nitrate, sulfate, carbon dioxide
Fermentation is not anaerobic respirationPerformed by facultative anaerobesRestart glycolysis by recycling NADH->NAD+ in side rxnsAcid and/or Gas common (pH drop)
Alcohol Fermentation (yeast, some bacteria)Ethanol and carbon dioxide producedLactic Acid Fermentation (bacteria, muscles)Heterolactic Fermentation (several bacteria)Acetoin: a neutral product in VP test
Use of Other Food Molecules for EnergyLipid Catabolism to Acetyl CoAProtein Catabolism to Kreb’s Cycle Molecules
Deamination, Ammonium, and pH rise
Microbial Metabolism
Aerobic Cellular Respiration: Converting Sugar to ATPglucose
NAD+
NADH
2 ATP
2 pyruvatesCell membrane
CO2
CO2
CO2
O2
~ 30 ATP
ATP Synthase
Glycolysis
Krebs Cycle
ElectronTransportChain and ATP Synthase (Ox. Phos.)
H 2O
ATP fuels construction/s
ynthesis reactions inside the
cell
C6H12O6 + O2 CO2 + H2O + 36ATP sugar oxygen carbon dioxide oxygen usable energy
NADH, FADH2
NAD, FAD+
H+
H+
H+
H+
H+
H+
H+H+
H+
H+ H+
H+
Metabolism and EnergyCatabolism vs Anabolism; Exergonic vs Endergonic rxnsUsing ATP to make endergonic rxns run
Enzymes as Biological CatalystsLowering of Activation EnergySpecificity, recyclabilityFactors which affect Enzymatic Rate (pH, temp, inhib.)
Metabolic ControlCellular Respiration: Oxidative Catabolism
Oxidation-Reduction Reactions(NAD+, FAD+ trucks)C6H12O6 + 6O2 -->6CO2 + 6H2O + Energy (ATP)1. Glycolysis (6C glucose--> 2 pyruvate + 2NADH +2ATP2. Krebs Cycle (2 pyruvate-->6CO2 + 8NADH +2FADH2 + 2ATP3. Electron Transport Chain (Cashing in on e-)
FADH2 + NADH + O2 --> lots of ATP + H2O + NAD+ + FAD+Terminal aerobic electron acceptor O2--->H2OAnaerobic bacteria use nitrate, sulfate, carbon dioxide
Fermentation is not anaerobic respirationPerformed by facultative anaerobesRestart glycolysis by recycling NADH->NAD+ in side rxnsAcid and/or Gas common (pH drop)
Alcohol Fermentation (yeast, some bacteria)Ethanol and carbon dioxide produced
Lactic Acid Fermentation (bacteria, muscles)Heterolactic Fermentation (several bacteria)Acetoin: a neutral product in VP test
Use of Other Food Molecules for EnergyLipid Catabolism to Acetyl CoAProtein Catabolism to Kreb’s Cycle Molecules
Deamination, Ammonium, and pH rise
Microbial Metabolism
• Aerobic respiration: The final electron acceptor in the electron transport chain is molecular oxygen (O2) in aerobes.
• Anaerobic respiration: The final electron acceptor in the electron transport chain is not O2. Yields less energy than aerobic respiration because only part of the Krebs cycles operations under anaerobic conditions. Obligate anaerobes perform anaerobic respiration.
• Fermentation: Glycolysis is restarted as NADH is recycled into NAD+. Pyruvate is reduced when electrons are added to it; acids, ethanol and CO2 are common products. Facultative anaerobes perform fermentation in addition to aerobic respiration.
Respiration
Anaerobic respiration by Obligate Anaerobes
O2
~ 30 ATP
ATP Synthase
ElectronTransportChain and ATP Synthase (Ox. Phos.)
H 2O
NADH, FADH2
NAD, FAD+
H+
H+
H+
H+
H+
H+
H+H+
H+
H+ H+
H+
Terminal electron acceptor Products
NO3– (nitrate) NO2
–, NH3, N2 (nitrite, ammonia, and nitrogen gas)
SO4– (sulfate) H2S (hydrogen sulfide)
CO32 – (carbonate) CH4 (methane)
Peee-ewe! (stinky)
Two Net ATP are Made in Glycolysis by Substrate Level Phosphorylation
1 glucose
2 pyruvate
2 (net) ATP made by substrate-level
phosphorylation rather than by
oxidative phosphorylation
Fermentation by Facultative Anaerobes
Figure 5.19
1 glucose
• NADH is recycled to NAD+ in order to keep glycolysis running
• Alcohol fermentation Produces ethyl alcohol + CO2
• Lactic acid fermentation produces lactic acid.
• Homolactic fermentation produces lactic acid only.
• Heterolactic fermentation produces lactic acid and other compounds.
Fermentation Products Are Mostly Acids with Some Gases
Figure 5.18b
Fermentation (Change to Yellow Means Acid is Present; Durham Tubes Collect Gas)
Figure 5.23
Metabolism and EnergyCatabolism vs Anabolism; Exergonic vs Endergonic rxnsUsing ATP to make endergonic rxns run
Enzymes as Biological CatalystsLowering of Activation EnergySpecificity, recyclabilityFactors which affect Enzymatic Rate (pH, temp, inhib.)
Metabolic ControlCellular Respiration: Oxidative Catabolism
Oxidation-Reduction Reactions(NAD+, FAD+ trucks)C6H12O6 + 6O2 -->6CO2 + 6H2O + Energy (ATP)Glycolysis (6C glucose--> 2 pyruvate + 2NADH +2ATPKrebs Cycle (2 pyruvate-->6CO2 + 8NADH +2FADH2 + 2ATPElectron Transport Chain (Cashing in on e-)FADH2 + NADH + O2 --> lots of ATP + H2O + NAD+ + FAD+
Terminal aerobic electron acceptor O2--->H2OAnaerobic bacteria use nitrate, sulfate, carbon dioxide
Fermentation is not anaerobic respirationPerformed by facultative anaerobesRestart glycolysis by recycling NADH->NAD+ in side rxnsAcid and/or Gas common (pH drop)
Alcohol Fermentation (yeast, some bacteria)Ethanol and carbon dioxide producedLactic Acid Fermentation (bacteria, muscles)Heterolactic Fermentation (several bacteria)
Acetoin: a neutral product in VP testUse of Other Food Molecules for Energy
Lipid Catabolism to Acetyl CoAProtein Catabolism to Kreb’s Cycle Molecules
Deamination, Ammonium, and pH rise
Microbial Metabolism
Lipid Catabolism
Figure 5.20
glucose
2 ATP
2 pyruvates
CO2
CO2
CO2
O2
~ 30 ATP
ATP Synthase
Krebs Cycle
H 2O
NADH, FADH2
NAD, FAD+
H+
H+
H+
H+
H+
H+
H+H+
H+
H+ H+
H+
Protein Catabolism Produces Alkaline Ammonium
Protein Amino acids (Peptone)Extracellular proteases
Krebs cycleDeamination, decarboxylation, dehydrogenation
Organic acid
NH4+ CO2 H2
Biochemical tests and Dichotomous Keys Are Used to ID Prokaryotes
Figure 10.8
Metabolism and EnergyCatabolism vs Anabolism; Exergonic vs Endergonic rxnsUsing ATP to make endergonic rxns run
Enzymes as Biological CatalystsLowering of Activation EnergySpecificity, recyclabilityFactors which affect Enzymatic Rate (pH, temp, inhib.)
Metabolic ControlCellular Respiration: Oxidative Catabolism
Oxidation-Reduction Reactions(NAD+, FAD+ trucks)C6H12O6 + 6O2 -->6CO2 + 6H2O + Energy (ATP)Glycolysis (6C glucose--> 2 pyruvate + 2NADH +2ATPKrebs Cycle (2 pyruvate-->6CO2 + 8NADH +2FADH2 + 2ATPElectron Transport Chain (Cashing in on e-)FADH2 + NADH + O2 --> lots of ATP + H2O + NAD+ + FAD+
Terminal aerobic electron acceptor O2--->H2OAnaerobic bacteria use nitrate, sulfate, carbon dioxide
Fermentation is not anaerobic respirationPerformed by facultative anaerobesRestart glycolysis by recycling NADH->NAD+ in side rxnsAcid and/or Gas common (pH drop)
Alcohol Fermentation (yeast, some bacteria)Ethanol and carbon dioxide produced
Homolacticactic Acid Fermentation (bacteria, muscles)Heterolactic Fermentation (several bacteria)
Acetoin: a neutral product in VP testUse of Other Food Molecules for Energy
Lipid Catabolism to Acetyl CoAProtein Catabolism to Kreb’s Cycle Molecules
Deamination, Ammonium, and pH rise
Microbial Metabolism