Ch 15.1-15.3 Flashcards
biosynthesis is aka
anabolism
3 things biosyn requires
essential nutrients transported into the cell (C, N, P, S, O, H) or metals
energy (couple ATP hydrolysis)
reducing power (NADH, NADPH)
prototrophic
microorganism has the same nutritional requirements as it did when isolated in nature
ex. E. coli can make everything it needs
auxotrophic
a mutant that only grows when provided a specific nutrient
fastidious
a microbe that requires many more nutrients than normal
maybe due to enzyme mutation
is biosynthetic capability related to the complexity of the microbe?
yes
unity of biochemistry
biosyn pathways discovered in bacteria are often found in all other organisms including plants/animals
are biosyn pathways and their enzymes physically associated in the cell?
yes, makes the pathways faster
ordered enzymes and pathways
operons
group of genes encoding biosynthetic pathways that are all expressed at once
biosynthetic pathways are linked to ______ _______ pathways
central metabolism
and the formation of precursor molecules which make families of molecules
aa families
aromatics
aspartate
serine
glutamate
pyruvate
other families
nucleotides
phospholipids
cell wall components
biosynthetic pathways can be 3 things
single
parallel
branched or convergent
anaplerotic rxns
make intermediate metabolites
ex. PEP + CO2 –> oxaloacetate
regulation of biosyn pathways occurs in 2 ways
enzyme level (feedback inhibition from buildup of intermediates or end product via allosteric sites)
gene regulation (transcription/translation)
medical uses of biosyn
exploit pathways by targeting enzymes or intermediates to kill pathogens
ex. mimics of essential molecules used for biosyn of peptidoglycan in mycobacterium TB drugs
other bioproduct polydroxyalkanoates
a form of strong polyester made by soil bacteria and synthesized in large amounts by engineered E. coli
make biodegradable sutures
gluconeogenesis
reverse glycolosis to make glucose or fructose
used when microbes are grown on 2-4C sugars
7 shared enzymes, 4 are used only for gluconeogenesis
CO2 fixation by what cycle
Calvin cycle
Calvin cycle used by what 4 groups
plants/algae
oxygenic phototrophs (cyanobacteria)
facultative anaerobic
lithoautotrophs
3 steps of Calvin cycle
carboxylation by rubisco
reduction
regeneration of ribulose 1,5 bisP
rubisco
ribulose bisphosphate carboxylase
catalyzes condensation of CO2 to ribulose 1,5 bisP and splitting of unstable 6C intermediate into two 3C PGA molecules
inefficient and slow, very abundant 3CO2/sec
regulation of calvin cycle
rubisco contained in structures called carboxysomes
carboxysomes
take up bicarbonate which is converted to CO2 by carbonic anhydrase
then CO2 is fixed by rubisco
stoichiometry of calvin cycle
(3) 5C ribulose 1,5 bisP + 3 CO2 –> (6) 3PG
(5) 3PG are recycled to ribulose 1,5 bisP
(1) 3PG is used to make sugars
carbon concentrating mechanism (CCM) in cyanobacteria
different ways CO2/HCO3- brought into cell depending on envir conditions
constitutive low affinity CO2 transporters
inducible high affinity CO2/HCO3- transporters when nutrients low
reductive (reverse) TCA cycle
uses 4-5 ATP to fix (4) CO2 and make (1) oxaloacetate
reduction by NADPH or NADH or FADH2
green sulfur bacteria - chlorobium (PSII)
reductive acetyl CoA pathway used by what 3 groups
acetogenic bacteria
sulfate reducers
methanogens
reductive acetyl CoA pathway
(2) CO2 condensed by converging pathways to make acetyl group of acetyl CoA
carbon monoxide intermediate
reducing agent is H2
3-hydroxypropionate cycle
green phototrophs that are not chlorobium
acetyl CoA + HCO3 and 2 NADPH –> 3-hydroxypropinoate
(3) CO2 fixed into 1 pyruvate used for biosynthesis
secondary metabolites
made through biosynthetic pathways but arent essential for survival
can make survival easier
ex. high affinity transporters, antibiotics
