Lecture 24 Flashcards
Microbe that is an excellent example of a microbe that can perform many types of metabolisms
E. coli
Electron transport and oxidative phosphorylation are basically the same in anaerobes as in aerobes with minor variations in what?
The final electron acceptor, and different electron carrier proteins found in the ETC
In anaerobic respiration, the final hydrogen/electron acceptor is some other inorganic molecule, such as? How many ATP produced?
nitrate (NO3-), sulfate (SO4^2-), nitrite (NO2-), carbonate (CO3^2-)
-more than 2, but less than 38 ATP produced
Energy generation for anaerobic respiration is still by…
oxidative phosphorylation and SLP
When an ORGANIC molecule is the final e- acceptor the process is called what? This can occur under ______ and ______ events. How many ATP are produced?
fermentation, this can occur under aerobic and anaerobic conditions
-2 ATP are made during this process
E. coli chart of different energy generating processes. These adaptations allow E. coli to inhabit its natural intestinal (anaerobic conditions) and its extra-intestinal/or outside the intestine (aerobic or anaerobic) habitats.
?? E. coli can produce energy regardless of the growth conditions. E. coli will grow slower during fermentation (anything that produces less ATP will result in slower growth).
______ is one of the most common anaerobic e- acceptors and can be reduced to:
Nitrate
nitrite NO2-, nitric oxide NO, nitrous oxide N2O, or dinitrogen/nitrogen gas N2
Some organisms can also use sulfate SO4^2- as the final e- acceptor to form
H2S (hydrogen sulfide)
bacteria using nitrate and sulfate as final electron acceptors is essential for what?
nitrogen and sulfur cycles that occur in nature
Archaea can use ______ as the e- acceptor and reduct it to ______ gas. This is a special type of metabolism called what?
can use CO2, and reduce it to methane gas CH4
called Methanogenesis
Some microbes that are able to use various _______ as electron acceptors, such as what?
various metals, such as ferric ion Fe 3+, selenite?, maganic
Nitrate respiration. The final e- acceptor is? What are the complexes here
e- from NADH is transferred to Cytochrom b/c1 complex, and then to quinone pool (Q, QH2), then to nitrate reductase (membrane oxidase complex) resulting in the transport of protons across the membrane – generation of PMF to produce ATP
Equation for nitrate (reduction) respiration
NO3- + 2e- + 2H+ –> NO2- + H2O
The produce of nitrate respiration is either ________ or could be further reduced to what?
excreted or further reduced to ammonia
Bacteria that is able to completely reduce Nitrate to dinitrogen gas (N2). Types of this bacteria
denitrifying bacteria. Eg. Pseudomonas stutzeri and Paracoccus species
Denitrification:
first NADH is oxidized, and electron goes through what?
DH (dehydrogenase complex) - proton pumped out here
from DH what happens to e-
electron is transferred to the quinone pool Q
from quinone pool Q, what happens to the electron? here what happens to nitrate?
it is passed to the cytochrome oxidase (quinol oxidase) nitrate reductase
nitrate is reduced to nitrite and water
in denitrification some e- may be shuttled instead to a _________ complex. Here something else happens?
cytochrome b/c complex. More protons are pumped into the periplasmic space
- from cytochrome b/c complex during denitrification, some of the electrons are shuttled to _________, and _______ ends up being reduced to ______ and water.
nitrite reductases, and end up reducing nitrite NO2- to nitrous oxide N2O and water.
- from cytochrome b/c complex during denitrification, some of the electrons are shuttled to _________, and _______ ends up being reduced to ______ and water.
nitrous oxide reductases that will be used to reduce nitrous oxide N20 to dinitrogen N2 gas
The synthesis of these reductases (nitrate, nitrite, etc) are ________ and their activities ______ by oxygen.
repressed, and activities inhibited by oxygen
Alternative electron acceptors like nitrate, sulfate, etc. do not have as ______ a reduction potential as ______ .
positive, oxygen
Most of these metabolic capabilities are not associated with any one phylogenetic group (with the exception of?), but are found scattered among the various groups of ________ .
exception of methanogenesis (archaea)
bacteria
MR-1 and a special type of bacteria
MR-1 stands for metal reducing, and a bacteria that is being studied currently for it’s bioremediation possibilities is Shewanella oneidensis
