Module 5 Microbial Metabolism (PPT) Flashcards
bacterial products examples (commercially or medically important)
i.e. Lactococcus and Lactobacillus, Streptococcus mutans
microorganisms that are important in laboratory (identification of microorganisms) (3)
(i.e. E. coli, Klebsiella, and Enterobacter)
- oxidative ; exergonic (releases energy); breaking down
- reductive ; endergonic; building up
- Catabolism
- Anabolism
Energy Source: Sunlight
Carbon Source: Carbon dioxide
Photoautotroph
Energy Source: Sunlight
Carbon Source: Organic compounds
Photoheterotroph
Energy Source: Inorganic chemicals
Carbon Source: Carbon dioxide
Nitrogen Source: Inorganic
Chemolithoautotroph
Energy Source: Organic compounds
Carbon Source: Organic compounds
Nitrogen Source: Organic or Inorganic
Chemoorganoheterotroph
Energy Source: Sunlight
Carbon Source: Carbon dioxide
Nitrogen Source: Inorganic
Hydrogen Source: H2S or H2
Bacteria
Energy Source: Sunlight
Carbon Source: Carbon dioxide
Nitrogen Source: Inorganic
Hydrogen Source: Photolysis of H20
Cyanobacteria
Energy Source: Sunlight
Carbon Source: Carbon dioxide
Nitrogen Source: Inorganic
Hydrogen Source: Organic compounds
Photoorganotrophic Bacteria
- “sugar splitting”
- occurs in cytosol of bacteria
- converts glucose (6-C) to pyruvate (3-C)
- can occur in the absence of oxygen
- enzyme-mediated
Glycolysis
Glycolysis order (11)
- Glucose
- Glucose 6-phosphate
- Fructose 6-phosphate
- Fructose 1,6-bisphosphate
- (optional) Dihydroxyacetone phosphate
- Glyceraldehyde 3-phosphate
- 1,3-Bisphosphate glycerate
- 3-Phosphoglycerate
- 2-Phosphoglycerate
- Phosphoenolpyruvate
- pyruvate
10 enzymes in glycosis
- Hexokinase
- Phosphoglucoisomerase
- Phosphofructokinase
- Aldolase
- Triose Phosphate isomerase
- Glyceraldehyde phosphate dehydrogenase
- Phosphoglycerokinase
- Phosphoglyceromutase
- Enolase
- Pyruvate kinase
Glycolysis gross energy yield and net energy yield
- gross energy yield = 4 ATP + 2 NADH
- net energy yield = 2 ATP + 2 NADH
- phosphogluconate pathway or hexose monophosphate shunt
- other metabolic pathway used by cells to break down glucose
Pentose Phosphate Pathway
- generates NADPH, ribose 5-phosphate, and erythrose 4-phosphate
(intermediates)
Pentose Phosphate Pathway
Pentose Phosphate Pathway (6)
- Glucose
- Glucose 6-P
- 6-Phosphogluconate
- Ribulose 5-P
- Ribose 5-P -> nucleotide synthesis (opt)
- Erythrose 4-P / Xylulose 5-P / Sedoheptulose 7-P
- Fructose 6-P / Glyceraldehyde 3-P
aerobic (O2-requiring) breakdown of nutrients with accompanying synthesis
of ATP
Aerobic Respiration
Aerobic Respiration comprises three stages in the metabolic breakdown of glucose
❑ transition step/conversion of pyruvate to acetyl CoA
❑ Krebs cycle / citric acid cycle
❑ oxidative phosphorylation: electron transport chain and chemiosmosis
Aerobic Respiration takes place in the
cytoplasm
- pyruvate converted to acetyl coenzyme A
Transition Step
Transition Step
- removal of carboxyl group from pyruvate and given off as ________
- 2-C compound is oxidized, ______ is reduced to _______
- _________ joins the 2-C compound forming acetyl-coenzyme A (acetyl CoA)
- CO2
- NAD+ -> NADH
*coenzyme A
Transition Step energy yield (per glucose):
2 NADH
- named after Hans Krebs
- also known as citric acid cycle or tricarboxylic acid cycle
- yields more energy than glycolysis
Krebs Cycle
Krebs Cycle (8)
- Acetyl-CoA (release CoA) + Oxaloacetae
- Citrate
- Isocitrate: (NADH, H+, CO2)
- α-ketoglurate: (ATP, NADH, H+ , CO2)
- succinyl CoA
- succinate: (FADH2)
- fumarate
- Malate: (NADH, H+)
Krebs Cycle energy yield (per glucose)
2 ATP + 6 NADH + 2 FADH2
- final stage of cellular respiration
- “big energy payoff” stage
- uses electron transport chain and chemiosmosis
- located in the cell membrane
Oxidative Phosphorylation
membrane-embedded electron carriers that pass electrons sequentially from one to another
electron transport chain
movement of ions (H+) down their electrochemical gradient that generates ATP
chemiosmosis
Electron carriers (4)
- I – flavoprotein (flavin monunucleotide)
- II – Fe-S protein
- Quinone (Q)- non-protein mobile carrier ; aka CoQ
- Cytochrome (C) – mobile carrier; Q to oxygen
– enzyme that makes ATP from ADP and inorganic phosphate
- uses energy of ion gradient top power ATP synthesis
ATP synthase
Prokaryotes have varied types and arrangement of electron transport chain components which could provide a mechanism to distinguish certain types of
bacteria for example
cytochrome production of Pseudomonas and Campylobacter
Detects the presence of an enzyme “oxidase” produced by certain bacteria which will reduce the dye – tetramethyl-p-phenylene diamine dihydrochloride.
is used to identify bacteria that produce cytochrome c oxidase, an enzyme of the bacterial electron transport chain
Positive test is indicated by the development of a purple colour.
OXIDASE TEST
Oxidase positive (3) PURPLE COLOR
Pseudomonas, Vibrio, Neisseria
Oxidase negative (2)
– Salmonella, Shigella
Energy Conversion
* 1 NADH
* 1 FADH2
- 1 NADH = 3 ATP
- 1 FADH2 = 2 ATP
- oxygen is not the final electron acceptor in the electron transport chain
- anaerobic or facultative bacteria
- less amount of energy is released in the reduction of inorganic chemicals
other than molecular oxygen
Anaerobic Respiration
t or f
aerobic respiration less efficient form of energy transformation than anaerobic Respiration
F
Anaerobic Respiration is less efficient form of energy transformation than aerobic respiration
Anaerobic Respiration examples
- Nitrate reduction E.coli (FAD, FeS, Q, cyt b, Mo) ETC
- sulfate reduction
- carbon dioxide reduction
Nitrate reduction ex
E.coli (FAD, FeS, Q, cyt b, Mo) ETC
sulfate reduction ex
(i.e. Desulfovibro)
carbon dioxide reduction ex
(i.e. Methanobacterium and Methanococcus)
- makes a few ATP molecules
- Krebs cycle and oxidative phosphorylation are shut down
- organic molecule accepts the electrons (not O2)
Fermentation
Fermentation example
E. coli (use any of the three ATP generating options), LAB (obligate fermenters), obligate anaerobes
Fermentation
- Lactic acid
- Ethanol
- Lactic acid : animals
- Ethanol: Yeast
Terminal Electron Acceptor of:
-lactic acid
-ethanol
-2,3-butanediol
- pyruvate
- acetaldehyde
- acetoin
lactic acid fermentation products
Cheese, yogurt, pickles, cured sausages
Causes tooth decay, spoilage of some food
Ethanol and CO2 fermentation products
wine, beer, spirits, bread
(Saccharomyces cerevisiae and Zymomonas)
Example of Products/Importance
- Butyric acid fermentation
- Propionic acid fermentation
Clostridium
Swiss cheese (Propionibacterium)
Lactic acid, succinic acid, ethanol, acetic acid, carbon dioxide, gases fermentation
Differentiate members of Enterobacteriaceae
Mixed Acids fermentation
IMViC test / MR/VP test
- used to identify bacterial species, especially coliforms
methyl red test:
- (+) red: E.coli
- (-) yellow/orange: Klebsiella
Voges-Proskauer test
- (+) pink: Klebsiella
- (-) no pink: E.coli
streptococcus, lactobacillus, bacillus end products of fermentation
lactic acid
Saccharomyces fermentation product
ethanol and co2
propionibacterium fermentation product
propionic acid, acetic acid, CO2, and H2
Clostridium fermentation product
Butyric acid, butanol, acetone, isopropyl alcohol, and CO2
Escherichia and Salmonella fermentation product
Ethanol, lactic acid, succinic acid, acetic acid, CO2 and H2
Enterobacter fermentation product
Ethanol, lactic acid, formic acid, butanediol, acetoin, CO2, and H2
process by which light energy is converted to chemical energy
photosynthesis
photosynthesis takes place in
cell membrane
- contains chlorophyll or chlorophyll-like pigments
- thylakoid membranes (cyanobacteria)
- chlorosomes (green bacteria)
- extensive cell membrane invaginations (purple bacteria)
FOR PHOTOSYNTHESIS
cell membrane
intermediary product and major end product of photosynthesis
ATP (intermediary product) and glucose (major end-product)
prokaryotes that undergoes photosynthesis
green sulfur bacteria, purple sulfur bacteria, cyanobacteria
prokaryotes that undergoes photosynthesis
diatoms, dinoflagellates, algae
T OR F
photosynthesis occurs in the same manner as eukaryotic microorganisms and green plants
T
Mg-containing green pigment that absorbs light energy
chlorophyll a
light-receiving systems
photosystems I and II
chlorophylls of purple and green photosynthetic bacteria
bacteriochlorophylls
accessory pigments of photosynthetic prokaryotes and eukaryotes
carotenoids
accessory pigments of cyanobacteria
and red algae
phycobilins
can be found on photosystems (3)
- chlorophylls and accessory pigments
- reaction center pigments
- antennae pigments –
electron donors in photosynthetic process
reaction center pigments
– “funnel”, make up antenna complex
antennae pigments
- photophosphorylation – light is involved in ATP formation
- energy-fixing reactions
- oxygenic – produces oxygen in photosynthesis
light-dependent reaction
reaction center of the two photosystems
II - P680
I - P700
The three products of the light reaction of photosynthesis are
ATP, NADPH, and O2
Phases of Light independent reaction (Calvin Cycle) (3)
- Carbon Fixation
- Reduction
- Regeneration of the CO2 acceptor
catalyzes a reaction between CO2 and RuBP, which forms a six-carbon compound that is immediately converted into two three-carbon compounds.
RuBisCo
CO2 acceptor in calvin cycle
RuBP (Ribulose bisphosphate)
a sugar output in calvin cycle
G3P (Glyceraldehyde-2-phosphate)
- bacteriochlorophylls – chlorophyll-like pigments
- do not use water as source of hydrogen ions
- fatty acids and other organic or inorganic substances are used as source of H+ ions
- no oxygen is liberated
- anoxygenic
WHAT PROKARYOTE?
green sulfur bacteria and purple sulfur bacteria
bacteriorhodopsin pigment
archaea (extreme halophiles)
Oxygenic photosynthesis and
pigments (chlorophyll a) as in algae
and plants produces
formaldehyde (CH2O)
T OR F
All other photosynthetic bacteria (e.g. green sulfurbacteria) have bacterial chlorophyll and anoxic photosynthesis
T
primary light harvesting pigment (oxygenic and anoxygenic)
chlorophyll a - oxygenic
bacteriochlorophylls - anoxygenic
phycobilins can be found on
cyanobacteria