metabolism and energy catabolism vs anabolism; exergonic vs endergonic rxns using atp to make...

•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


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


Enzymes as Biological CatalystsLowering of Activation EnergySpecificity, recyclabilityFactors which affect Enzymatic Rate (pH, temp, inhib.)Metabolic ControlCellular Respiration: Oxidative Catabolism








• 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


Figure 5.7a, b

• Noncompetitive inhibition


Figure 5.7a, c

ATP, pyruvate, end amino acid

• Feedback inhibition


Figure 5.8

• 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:




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+







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+




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


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




• 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







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



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







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



metabolism and energy catabolism vs anabolism; exergonic vs endergonic rxns using atp to make...

Documents