Early Life and the Diversification of Prokaryotes

Vocabulary terms related to the origins of life and the diversity of prokaryotes.

Prokaryotes

Unicellular organisms that lack a nucleus and membrane-bound organelles.

Abiotic synthesis

The formation of organic molecules from non-living chemical systems.

Protocells

Simple vesicle-like structures that may have acted as precursors to living cells.

Ribozymes

RNA molecules that can act as enzymes, catalyzing specific biochemical reactions.

Photosynthesis

The process by which certain organisms convert light energy into chemical energy.

Cyanobacteria

Photosynthetic prokaryotes that released oxygen, altering the Earth's atmosphere.

Endospores

Thick-coated, resistant cells produced by some bacteria under harsh conditions.

Biofilms

Surface-coating colonies of one or more species of prokaryotes that engage in metabolic cooperation.

Horizontal gene transfer

The transfer of genes between organisms in a manner other than traditional reproduction.

Metabolic cooperation

A phenomenon where different prokaryotic cells work together to use environmental resources.

Gram-positive bacteria

Bacteria with thick peptidoglycan cell walls that retain the crystal violet stain used in Gram staining.

Gram-negative bacteria

Bacteria with thinner peptidoglycan cell walls and an outer membrane that do not retain the crystal violet stain.

Sex pili

Appendages that allow bacteria to connect and transfer genetic material during conjugation.

F plasmid

A plasmid that contains genes necessary for the formation of sex pili and DNA transfer.

Methanogens

Archaea that produce methane as a metabolic byproduct, typically in anaerobic environments.

Chemoheterotrophs

Organisms that obtain both carbon and energy from organic compounds.

Plasmids

Small, circular, self-replicating pieces of DNA found in bacteria, often carrying accessory genes.

Obligate aerobes

Bacteria that require oxygen for cellular respiration.

Obligate anaerobes

Bacteria that are poisoned by oxygen and can only grow in its absence.

Facultative anaerobes

Bacteria that can use oxygen if present, but can also grow without it.

Exaptation

The process in which existing structures take on new functions through evolution.