Lecture 8: The Origin and Evolution of Anaerobic Respiration

Flashcards covering key vocabulary related to anaerobic respiration, chemolithotrophic metabolisms, fermentation processes, isotope fractionation, and microbial evolution.

Anaerobic Respiration

A biological process in which organisms convert energy for growth and maintenance through the breakdown of organic compounds without the need for oxygen.

Chemolithotrophic Metabolism

Metabolism that derives energy from inorganic compounds through the process of oxidation.

Electron Acceptors

Molecules that accept electrons during the redox reactions of respiration, such as Fe3+, S0, or other inorganic substances.

Facilitated Fermentation

A type of fermentation in which the organism aids the process by utilizing certain elements, allowing for electron transfer from microorganisms to solid-phase acceptors.

Tetrapyrrole

A class of organic compounds, of which heme is a member, characterized by a structure with four pyrrole rings.

Isotope Fractionation

The process by which different isotopes of an element are distributed unevenly due to various physical or chemical processes.

Mass-Dependent Isotope Fractionation (MDF)

A predictable change in isotopic abundance based on the mass of the isotopes involved in a reaction.

Mass-Independent Isotope Fractionation (MIF)

A deviation in isotopic abundance that does not follow the predictable patterns based on mass, providing insights into geological and biological processes.

Sulfate-Reducing Microorganisms (SRM)

Microorganisms that use sulfate as a terminal electron acceptor in anaerobic respiration, reducing it to hydrogen sulfide (H2S).

Reverse Citric Acid Cycle (rTCA)

A metabolic pathway used by some anaerobic organisms to fix carbon dioxide, requiring input of ATP for the conversion processes.