Prokaryotes

Prokaryote

A type of cell that lacks a nucleus and membrane-bound organelles.

Eubacteria

One of the two domains of prokaryotes, commonly referred to as bacteria.

Archaeabacteria

The second domain of prokaryotes, often called archaea, believed to be more ancient than eubacteria.

Pathogenic

Refers to organisms that can cause disease; archaea have not been found to be pathogenic.

Gut microbiome

A community of microorganisms, including archaea and bacteria, that reside in the human gut and aid in digestion and vitamin synthesis.

Binary fission

The process by which prokaryotic cells divide, leading directly to cytokinesis without chromosome formation.

Gram staining

A microbiological technique used to classify bacteria based on their cell wall structure.

Gram-positive bacteria

Bacteria that retain the crystal violet stain and have thicker peptidoglycan walls.

Gram-negative bacteria

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

Exotoxins

Toxins produced and secreted by Gram-positive bacteria.

Antibiotic resistance

The ability of bacteria to survive and grow despite the presence of antibiotics, often due to genetic changes.

Morphology

The study of the shapes and structures of bacteria, including cocci, bacilli, and spirilla.

Motility

The ability of bacteria to move, often facilitated by structures like flagella.

Flagella

Whip-like structures that enable bacterial motility, made of the protein flagellin.

Conjugation

A method of horizontal gene transfer where DNA is transferred between bacteria via a pilus.

Transduction

A method of horizontal gene transfer involving bacteriophages that transfer DNA between bacteria.

Transformation

A method of horizontal gene transfer where bacteria take up DNA from their environment after cell lysis.

Extremophiles

Organisms, including many archaea, that thrive in extreme environmental conditions.

Methanogens

A group of archaea that produce methane and play a role in the human gut microbiome.

Eukaryotic signature proteins

Proteins found in archaea that are involved in processes unique to eukaryotes, suggesting a common ancestry.