Bacterial Energy Metabolism

Vocabulary flashcards covering the basic background of bacterial metabolism, organelle structures, and metabolic classifications based on energy and carbon sources.

Prokaryotes

Organisms, such as Bacteria, that do not have a cell nucleus.

The Human Niche Number of Cells

In an average human male, there are approximately $3.0 \times 10^{13}$ human cells and $3.8 \times 10^{13}$ bacterial cells.

Endosymbiosis

The theory that organelles like mitochondria and chloroplasts originated from ancestors such as $\alpha$-proteobacterium and ancestral cyanobacterium.

Chlorosomes

Organelle-like intracytoplasmic membrane systems in green sulphur bacteria that serve as the site of photosynthesis.

Thylakoids

Intracytoplasmic membrane systems in Cyanobacteria which are the site of photosynthesis.

Carboxysomes

Proteinaceous shells that enclose RuBisCO and carbonic anhydrase to enhance $CO_2$ fixation.

Anammoxisomes

Protein-based compartments found in Planctomycetes that are the site of anaerobic ammonium oxidation.

Bacterial Dark Matter

Environmental microbial diversity that lacks cultured representatives due to unknown or highly specific physiological requirements or complex interdependencies.

Chemoorganotrophy

A metabolic classification where energy is obtained from chemicals that are organic compounds, such as fumarate or humic acids.

Chemolithotrophy

A metabolic classification where energy is derived from inorganic chemical compounds, literally meaning 'stone' eating in Greek.

Autotrophy

A carbon source classification where carbon is obtained from $CO_2$, often using the Calvin cycle.

Heterotrophy

A carbon source classification where carbon is obtained from organic sources.

Mixotrophy

A broad and flexible metabolic strategy where an organism obtains energy and carbon from a combination of autotrophic and heterotrophic processes.

Exergonic reaction

A reaction where free energy leaves the system, resulting in a negative $\Delta G$.

Endergonic reaction

A reaction where free energy is gained by the system, resulting in a positive $\Delta G$.

Aerobic

Conditions where $O_2$ is present; in aerobic respiration, $O_2$ is the terminal electron acceptor.

Anaerobic

Conditions characterized by the absence of $O_2$ (anoxic), using other molecules like nitrate ($NO_3^-$) or sulphate ($SO_4^{2-}$) as terminal electron acceptors.

Reverse Electron Transport

A process in chemolithotrophs where electrons are passed to $NAD(P)^+$ to make $NAD(P)H$ using the proton motive force; it requires $5\times$ the forward pathway energy to power $1\times$ the reverse pathway.

Acidiothiobacillus ferrooxidans

A bacterium that utilizes pyrite ($FeS_2$) and operates efficiently because its external pH is acidic.

Campylobacter jejuni

A microaerophilic chemoorganotroph and common cause of gastroenteritis that lacks phosphofructokinase and can use $H_2$ and sulphite ($SO_3^{2-}$) as electron donors.