Bacteria and Archaea (Exam 2) Terminology

Horizontal gene transfer (HGT)

The process by which genetic material is transferred between organisms through means other than reproduction, allowing for genetic diversity and adaptability.

Web of life

A complex network illustrating the interdependencies and relationships among all living organisms and their ecosystems, emphasizing biodiversity and ecological balance.

Archaea

A distinct domain of single-celled microorganisms that possess unique genetic and biochemical properties, setting them apart from bacteria and eukaryotes, often thriving in extreme habitats.

Antibiotic

A chemical substance produced by microorganisms or synthesized, that inhibits the growth of or kills bacteria, commonly used in medicine to treat bacterial infections.

Bacteria

A significant domain of prokaryotic microorganisms that are unicellular, exhibiting diverse metabolic pathways, and can be either beneficial (e.g., in digestion) or pathogenic (causing diseases).

Crenarchaeota

A phylum of archaea characterized by their adaptation to extreme conditions, particularly high temperatures, commonly found in geothermal features like hot springs.

Biofilm

A structured community of microbial cells attached to a surface, often encased in a self-produced matrix of extracellular polymeric substances (EPS), providing protection and enhanced survival.

Bioremediation

A biotechnological process utilizing microbial metabolism to detoxify or remove environmental pollutants or contaminants, improving ecosystem health.

Capsule

A thick, gelatinous outer layer that surrounds some bacteria, providing a protective barrier against phagocytosis by host immune cells and helping in adherence to surfaces.

Cell wall

A rigid protective layer that encloses the cell membrane in bacteria, providing structural support, shape, and defense against environmental pressures.

Coevolution

An evolutionary phenomenon where two or more interacting species evolve in response to each other's adaptations, influencing each other's survival and reproduction.

Conjugation

A direct transfer of genetic material between two bacteria through physical contact, usually mediated by a pilus, allowing for genetic diversity among bacterial populations.

Cyanobacteria

A group of photosynthetic bacteria known for oxygen production through photosynthesis, often found in aquatic environments and significant to primary productivity.

Euryarchaeota

A diverse phylum of archaea encompassing a variety of organisms including methanogens, halophiles, and hyperthermophiles, found in diverse environments.

Extremophile

A category of organisms that flourish in extreme environmental conditions, such as high salinity, acidity, or temperatures, demonstrating remarkable adaptations.

Gram negative

A classification of bacteria characterized by a relatively thin peptidoglycan layer and an outer membrane, which stain pink during the Gram staining procedure due to the presence of lipopolysaccharides.

Gram positive

Bacteria that retain the crystal violet stain used in the Gram staining process due to their thick peptidoglycan cell wall, appearing purple under a microscope.

Halophile

An organism that thrives in high-salt environments, exhibiting specialized adaptations that enable survival and reproduction under osmotic stress.

Hyperthermophile

An organism that grows optimally at extremely high temperatures, often above 80°C (176°F), commonly found in geothermally heated regions.

Microbial mat

A complex, layered community of microorganisms, primarily found in aquatic environments, which can exhibit diverse metabolic activities and provide ecosystem services.

Peptidoglycan

A polymeric compound forming a significant part of the bacterial cell wall, providing rigidity and support, composed of sugars and amino acids.

Pilus

A hair-like appendage on bacterial cells that enables attachment to surfaces, facilitates conjugation, and can play a role in motility.

Plasmid

A small, circular segment of DNA found in bacteria that exists independently of chromosomal DNA, often carrying genes that confer advantageous traits.

Proteobacteria

A major phylum of diverse bacteria that include various shapes, sizes, and metabolic types, encompassing many important pathogens and environmental bacteria.

Pseudopeptidoglycan

A structural component similar to peptidoglycan found in certain archaea, which provides cell wall stability but differs in composition, lacking the common amino acids found in bacterial peptidoglycan.

Stromatolite

Layered sedimentary formations created by the activity of microbial communities, particularly cyanobacteria, that trap and bind sediments over geological time.

Thaumarchaeota

A phylum of archaea recognized for their crucial role in nitrogen cycling, particularly in marine environments, known for their ability to oxidize ammonia.

Transduction

The process of horizontal gene transfer in which bacterial DNA is transferred from one bacterium to another through the action of a virus (bacteriophage).

Transformation

A form of genetic exchange in bacteria wherein free DNA from the surrounding environment is taken up by a bacterial cell and incorporated into its own genome.