Introduction to Prokaryotes and Eukaryotes

These flashcards cover key vocabulary related to prokaryotic and eukaryotic biology, including concepts of classification, genetics, and ecological roles.

Prokaryotes

Single-celled organisms that lack a membrane-bound nucleus, including Bacteria and Archaea.

Three-domain system

A classification system that divides life into Bacteria, Archaea, and Eukarya.

Horizontal gene transfer

The movement of genes between organisms in different species, significant in the evolution of prokaryotes.

Gram-positive bacteria

Bacteria with simple cell walls that contain large amounts of peptidoglycan.

Peptidoglycan

A polymer that makes up the cell walls of bacteria, providing structural integrity.

Endospore

A specialized dormant cell formed by some prokaryotes to survive extreme conditions.

Nitrogen fixation

The process by which certain bacteria convert atmospheric nitrogen (N2) into ammonia (NH3) usable by plants.

Chemotaxis

The movement of organisms toward or away from a chemical stimulus.

Facultative anaerobes

Prokaryotes that can survive with or without oxygen.

Exotoxins

Toxins secreted by bacteria that can cause disease even if the bacteria are not present.

Endotoxins

Toxins that are released only when bacteria die and their cell walls break down.

Rhizobacteria

Bacteria that live in the rhizosphere, playing crucial roles in plant growth and nutrient availability.

Gram-negative bacteria

Bacteria with complex cell walls, including an outer membrane and less peptidoglycan than Gram-positive bacteria.

Binary fission

A form of asexual reproduction in prokaryotes where one cell divides into two identical daughter cells.

Plasmid

Small, circular DNA molecules separate from the bacterial chromosome that can carry genes for antibiotic resistance or other traits.

Transformation

A process of horizontal gene transfer where prokaryotic cells take up and incorporate foreign DNA from the surrounding environment.

Bioremediation

The use of organisms, such as prokaryotes, to detoxify and restore polluted environments.

Extremophiles

Organisms that thrive in physically or geochemically extreme conditions that are detrimental to most life on Earth, often referring to Archaea.

Flagella

Long, whip-like appendages used by some prokaryotes for motility.

Capsule

A dense, well-defined layer of polysaccharide or protein that surrounds the cell wall of many prokaryotes, aiding in adhesion and protection.

Pili

Short, hair-like appendages on the surface of some prokaryotes, primarily used for attachment to surfaces and for conjugation.

Conjugation

A process of horizontal gene transfer where genetic material is transferred directly between two prokaryotic cells via a pilus.

Photoautotrophs

Organisms that use light as an energy source and CO2 as their main carbon source to synthesize organic compounds.

Obligate aerobes

Prokaryotes that require oxygen for cellular respiration and cannot grow without it.

Obligate anaerobes

Prokaryotes that are poisoned by oxygen and must live in an oxygen-free environment.

Nucleoid

The region in a prokaryotic cell where the main chromosome is located, not enclosed by a membrane.

Chemoautotrophs

Organisms that obtain energy by oxidizing inorganic substances and use CO2 as their main carbon source.

Cyanobacteria

Photosynthetic prokaryotes that generate oxygen as a byproduct, playing a vital role in Earth's atmospheric oxygenation.

Biofilms

A complex community of prokaryotes encased in an extracellular polymeric substance, typically attached to a surface.

Fimbriae

Short, hair-like protein appendages on the surface of some prokaryotes that help them attach to surfaces or to other cells.

Methanogens

A group of Archaea that produce methane as a byproduct of their metabolism in anaerobic conditions.

Halophiles

Extremophile organisms, typically Archaea, that thrive in environments with very high salt concentrations.