Lecture 24 - Anaerobic Cellular Respiration

MB 251, Exam 2 | Lee, Spring 2025

anaerobic respiration allows for

organisms to occupy a unique ecophysiological niche

end e⁻ acceptor is some ___ molecule

inorganic

inorganic molecule e⁻

nitrate (most common)

nitrite

sulfate

carbonate

nitrate one of the most common e⁻ acceptors - can reduce to

NO₂⁻

NO

N₂O

N₂

sulfate used to

form H₂S

bacteria using nitrate and sulfate as final e⁻ acceptors are

essential for N and S cycles that occur in nature

methanogenesis

metabolism that uses CO₂ as the e⁻ acceptor and reduce it to methane gas (CH₄)

has only been found in archaea

nitrate respiration

NO₃⁻ + 2e⁻ + 2 H⁺ → NO₂⁻ + H₂O

denitrification

happens via denitrifying bacteria

e.g. Pseudomonas stutzeri, Paracoccus

serial denitrifiers dictated by

genes - have a gene that codes for the enzymes that perform denitrification

denitrification advantage

ETC serves as a place to oxidize NADH back into NAD+ and free it for accepting e⁻ again

denitrification important for

facultative bacteria that switch from anaerobic to anerobic respiration when oxygen becomes available

anaerobic characteristics shared w/ cellular respiration

membrane system

anaerobic characteristics shared w/ cellular respiration

generation of ion gradient

anaerobic characteristics shared w/ cellular respiration

formation of ATP via ATP synthase