test 4 lec 23 Flashcards
what bacteria uses more than one type of metabolism
rhodopseudomonas palustris
delta pH is what
the H+ concentration difference
what is photoheterotrophs
absorb light to make ATP, while incorporating pre-formed carbon compounds for biosynthesis
where is the ETS located
in a membrane that separates two aqueous compartments
what are great electron acceptors
H2O and O2
what is a proton motive force
stores energy to make ATP
drives protons across the membrane
what are the three major classes of prokaryotic energy acquiring processes using an ETS
organotrophy
lithotrophy
phototrophy
how else is electrical potential and pH difference affected
includes charges on other ions
metabolic generation of acids or pH changes outside the cell
how do microbes transfer energy
by moving electrons
what is photoautotrophs
couple photolysis to CO2 fixation for biomass production
what are obligate autotrophs
fix CO2 for biosynthesis
besides ATP synthesis what drive many cell processes
delta p
what are facultative lithotrophs
chemooganotrophs that catabolize many substrates
oxidizing sulfur compounds
where is energy stored when protons are pumped across the membrane
electrical potential and the pH difference
what is the proton motive force
the sequential transfer of electrons from one ETS protein to the next yields energy to pump ions across the membrane
ETS proteins and cofactors act as…
electron donors and acceptors, coupled with proton transporting across membrane
function of proton potential
stores energy to drive H+ back across the membrane through devices such as ATP synthase
what is phototrophy
involves light capture by chlorophyll, usually coupled by splitting of H2S or H2O or organic molecules
function of ETS
transfers electrons onto membrane embedded carriers in a series of increasing reduction potential , ending at a terminal electron acceptor
a more positive E’ means that
that reducing the electron acceptor yields more energy
what is the chemiomotic theory
energy from electron transfer between membrane proteins is used to pump protons across the membrane, accumulating a higher H+ concentration in the compartment outside
what does a negative E equal
energy is yielded by the reverse reaction
what is the reduction potential
a measure of the tendency of a molecule to accept electrons
how do electrons move
from reduced electron donors to oxidized electron acceptors
what is lithotrophy
involves inorganic electron donor donors and inorganic or organic terminal acceptors
what are chemolithoautotrophs
obligate autotrophs, fixing CO2 for biosynthesis
a gain of electrons yields what
energy
what is the proton potential
the H+ concentration difference plus the charge differen
a more negative E’ means that
oxidizing the electron donor yields more energy
how does ETS convert its energy
ion potential or electrochemical potential between two compartments separated by the membrane
the ETS must accept electrons from
an initial electron donor consisting of an organic molecule or a reduced mineral
the standard reduction potential represents what
the standard reduction potential per electron
what is organotrophy
involves organic electron donors and inorganic or organic terminal electron acceptor
oxidoreductases consist of
multiple protein complexes that include cytochromes and non cytochromes proteins
what happens if the membrane is disrupted so that protons leak
small leak can dissipate all the energy store as delta pH
uncouple electron transport from ATP synthesis through the membrane ATP synthase
what is a redox couple
the oxidized and reduced states of a compound
what are oxidoreductases
electron transport proteins
oxidize one substrate and reduce another
what are standard reduction potentials
standard values of E
positive E is equal to what Delta G
neg
characterisitcs of rhodopseudomonas palustris
gram neg
purple nonsulfur photosynthetic bacterium
photolithoheterotroph
found in soil and water
in O2, use photosynthesis or lithotrophy
no O2, eats everything to obtain reduced electron carriers
a complete redox reaction combines
two redox couples
one accepting electrons
and one donating electrons
