Transcript Chapter 5: Microbial Metabolism

CHAPTER 5: MICROBIAL METABOLISM
_____________:
sum of all the ________________ in an organism
that are necessary to maintain life !!
Harvesting _______
Converting ______ to ATP
Synthesing new compounds
ORGANIC COMPOUNDS
DEGRADATION BY
CHEMOHETEROTROPHS
Metabolic Diversity Among Organisms
NUTRITIONAL
TYPE
ENERGY
SOURCE
CARBON
SOURCE
EXAMPLE
_______________TROPH
Light
________
Oxygenic:
Cyanobacteria, plants,
algae.
Anoxygenic: Green,
purple bacteria.
CHEMOAUTOTROPH
Chemical
CO2
Hydrogen, Sulfur,
Nitrogen, Iron-oxidizing
bacteria.
PHOTOHETEROTROPH
Light
Organic
compounds
Green, purple nonsulfur
bacteria.
CHEMOHETEROTROPH
Chemical
____________
compounds
Fermentative bacteria.
Animals, protozoa, fungi,
bacteria.
Metabolic Reactions
Two Main Categories of Chemical Reactions:
_________ – larger molecules are
broken down; energy releasing
process-exergonic
_________ – larger molecules are
made from smaller ones; energy
requiring process-endergonic
Catabolic reactions provide the
_______ for anabolic reactions.
The Generation of _________
PHOSPHORYLATION of ADP.
1. ___________ PHOSPHORYLATION- the transfer of a high-energy
PO4- to ADP.
2. _________ - energy released from the transfer(loss) of electrons
(oxidation) from one compound to another (reduction) is used to
generate a proton gradient which is then used to make ATP
3. PHOTOPHOSPHORYLATION – sunlight causes chlorophyll to
give up electrons. Energy released from the transfer of electrons
(oxidation) of chlorophyll through a system of carrier molecules is
used to generate ATP
_____________ Phosphorylation
THE ROLE OF ___________ ANABOLIC AND CATABOLIC
REACTIONS
Key Factors Involved in Energy Production
1._________ REACTIONS
• Transfer electrons from one substrate to
another
• When electrons are removed protons follow
• Oxidation – removal, ___ of electrons
• Reduction – _______ of electrons
Coupled
2. ELECTRON CARRIERS
• Carry electrons
• Reduced electron carriers have reducing power
• Their bonds contain usable __________
3. ENZYMES - catalysts
Oxidation-Reduction Reactions
in chemical reactions
• OXIDATION - removal of electrons; energy _______
• REDUCTION - gain of electrons; energy ________
• REDOX REACTION - an oxidation reaction paired
with a reduction reaction.
Figure 5.9
Oxidation-Reduction Reactions
in ____________ systems
The electrons are often associated with hydrogen
atoms. Biological oxidations are often
dehydrogenations.
Figure 5.10
Electron _________*
note error on slide
Catabolic Mechanisms of Generating Energy from ______
1. CELLULAR RESPIRATION
Chemical reactions that
generate energy from the
breakdown of complex
organic compounds
compounds;
2
2
2 NADH
can occur aerobically or
anaerobically
2
the final electron acceptor is
an __________ compound.
2. _________________
Anaerobic reactions that
generate energy from the
break down of complex
organic compounds
the final electron acceptor is an
__________ compound.
6
4 FADH2
6
2
4
Cellular Respiration:
the chemical process by which compounds are broken down to
release energy and that energy is used to make ATP
ANAEROBIC RESPIRATION
___________ RESPIRATION
• O2 _____ required
• O2 __________
• Relatively ______ amount of
energy is released
• Relatively large amount
of energy is released
• Final electron acceptors
• ____is final electron
acceptor
• ________ compounds (other
than oxygen)
• Nitrate ions (NO3
-)
• Sulfate ions (SO42-)
• Carbonate ions (CO32-)
Ex. C6H12O6
6CO2 + 6H2O
+ Energy
Aerobic Respiration
Carbohydrate ___________
the breakdown of carbohydrates to release energy
PROPERTIES
• ATP generating process
• Redox reactions
• O2 final electron acceptor
4 MAJOR STEPS
1. _______ of Glucose
-___________
-Pentose Phosphate Pathway
-Entner-Doudoroff Pathway
2. Preparatory/Transition Step
3. Krebs cycle
4. Electron transport chain
____________
• __________ of glucose to 2 pyruvic acid,
• produces 4 ATP (2 ATP net), 2 NADH + 2H+
Oxidation
• occurs in cytoplasm
Glucose + 2 ATP + 4 ADP + 4 PO4– + 2 NAD+ 2 pyruvic
acid (pyruvate) + 4 ATP (2ATP net) + 2 NADH + 2H+
Preparatory stage:
__________
Glucose is split to form two
molecules of glyceraldehyde 3phosphate
Energy conserving stage:
The two glyceraldehyde 3phosphate molecules are _____ to 2
pyruvic acid molecules
________are produced
2 NADH are produced
Glyceraldehyde3-Phosphate (x2)
Transition/Intermediate Step
• ________ acid (from
glycolysis) is:
1. _____________
2. decarboyxlated
Produces Acetyl CoA +
NADH +H+ + CO2
Figure 5.13.1
Krebs Cycle/TCA Cycle/Citric Acid
Cycle
Figure 5.13.2
Krebs Cycle (_____ per _______ molecule)
Acetyl CoA(2C) + oxaloacetic acid(4C)
Citric acid (6C)
_________ of citric acid(citrate) produces 3NADH and 1FADH2
• Large energy yield
• Generates high energy ___________
• High energy electrons from citrate are transferred to energy carriers
NAD+ and FAD, which become reduced to NADH and FADH2
(2x)Citric acid(6C)
→
Oxaloacetic acid(4C) +
6 NADH
2 FADH2
4 CO2
Contain most of
energy in ______
molecule
H+ (protons)
2 ATP (substrate level
phosphorylation)
Eukaryotes – mitochondrial matrix; Prokaryotes - ___________
_______________
____ synthesis using an Electron Transport Chain
The other H+ and electrons (plus the energy in the electrons) are transferred to O2
4H+ + 4e- + O2 → 2H20
Final electron acceptor
Figure 5.16.2
The Electron Transport Chain:
a series of carrier molecules that are, in turn,
_________ and ________ as electrons are passed
down the chain.
• Carrier Molecules: flavoproteins, cytochromes,
ubiquinones.
• As electrons are transferred, energy is released:
• Some energy used to pump some of the protons
across mitochondrial membrane (plasma
membrane) in prokaryotes.
_____ concentration builds up on one side of
membrane – creates electrochemical gradient.
• Energy released can be used to produce ____ by
chemiosmosis.
___________ Force
• Protons diffuse across membrane through special
___________
• Channels contain ATP synthase
• Proton motive force drives synthesis of ATP from
ADP using ATP synthase
ATP Synthase
ADP + Pi
→ ATP
H+
CHEMIOSMOSIS-_______
_________ generates ATP
Summary of __________ Respiration in _____karyotes
Energy Tally
• Energy produced from complete oxidation of 1
glucose using aerobic respiration
PATHWAY
GLYCOLYSIS
INTERMEDIATE
STEP
KREBS
CYCLE
TOTAL
ATP
PRODUCED
NADH
_______
PRODUCED PRODUCED
2
2
0
0
2
0
2
___
2
4
10
2
ATP Tally in Prokaryotes
Energy produced from the complete oxidation of 1 glucose in aerobic
respiration
*only 36 ATP are produced in eukaryotes
PATHWAY
SUBSTRATE-LEVEL
PHOSPHORYLATION
GLYCOLYSIS
INTERMEDIATE
STEP
KREBS CYCLE
2
TOTAL
________________________
PHOSPHORYLATION
From NADH From FADH2
6
0
0
6
0
2
____
4
4
30
4
Fermentation Pathways
Fermentation and End Product Diversity
The enzymatic breakdown of carbohydrates where final
electron acceptor is an __________ molecule
Oxidation of glucose releases small
amounts of ATP
Glucose __________ to pyruvate + 2 ATP
produced
Pyruvate _________ to fermentation end
products
O2 not required, therefore an anaerobic process
______________ not required
Final electron acceptor-organic molecule
Comparison of ________ and Alcoholic Fermentation
Bacterial Fermentation
Figure 5.23
Comparison of Cellular ___________ and
Fermentation
_________ Pathways,
Pathways of Synthesis
1) Simple mono- and
disaccharides →
polysaccharides
Ex.: Glycogen-energy storage
Peptidoglycan
Cell wall
2) Glycerol and fatty acids →
lipids
3) Amino acids from glucose
metabolism → __________
4) Glucose → ribose sugars of
nucleotides
Pentose-phosphate pathway
Entner-Doudoroff pathway
_______ of Organic
Food Molecules
_____________ Pathways
metabolic pathways that have both catabolic
and anabolic functions
Figure 5.32.1
Biochemical Assays
• Used to identify
bacteria.
___________ Key
Figure 10.8
Enzymes
• BIOLOGICAL CATALYSTS – speed rate of reaction
• __________ for a chemical reaction; not used up in that
reaction
• STRUCTURE
1. _____enzyme: protein component of enzyme
2. Cofactor: Non_________ component
• _______enzyme: Apoenzyme + cofactor
__________ Activity
Factors Influencing ______ Activity
TEMPERATURE
pH
Substrate
concentration
Figure 5.5a
Factors Influencing Enzyme Activity
Enzymes can be denatured by __________
and _____
Figure 5.6