Kingdoms Archaebacteria & Eubacteria – Lecture Review

Vocabulary flashcards covering the essential terms and concepts related to Archaebacteria, Eubacteria, and prokaryotic biology.

Prokaryote

A single-celled organism that lacks a true nucleus and membrane-bound organelles.

Archaebacteria

Prokaryotes with cell walls that lack peptidoglycan and possess unique membrane lipids; many live in extreme environments.

Eubacteria

The true bacteria; prokaryotes whose cell walls contain peptidoglycan and are found in virtually every habitat on Earth.

Peptidoglycan

A polysaccharide-protein compound that strengthens the cell walls of eubacteria.

Domain Archaea

One of the two prokaryotic domains, containing the archaebacteria.

Domain Bacteria

The prokaryotic domain that includes all eubacteria.

Extremophile

An organism, often an archaean, that thrives in physically or geochemically extreme conditions.

Methanogen

Anaerobic archaea that produce methane gas and live in swamps, sewage, and animal intestines.

Halophile

Salt-loving archaea that inhabit environments such as the Great Salt Lake or the Dead Sea.

Thermoacidophile

Archaea that live in very hot, acidic environments like sulfur springs above 110 °C and pH below 2.

Binary Fission

Asexual reproduction in which a prokaryotic cell divides into two genetically identical daughter cells.

Conjugation (Bacterial)

Genetic recombination process where DNA passes through a pilus bridge between two bacterial cells.

Endospore

A dormant, tough, non-reproductive structure formed by some eubacteria to survive extreme conditions.

Cocci

Spherical-shaped bacteria (singular: coccus).

Bacilli

Rod-shaped bacteria (singular: bacillus).

Spirilla

Spiral-shaped bacteria (singular: spirillum).

Flagellum

Whip-like structure that propels motile bacteria in a propeller-like motion.

Pili

Short, hair-like projections used for attachment to surfaces and for DNA transfer during conjugation.

Capsule (Bacterial)

An outer sticky layer that protects some bacteria and helps them adhere to surfaces.

Nucleoid

The region in a prokaryotic cell where the single circular DNA chromosome is located.

Saprophyte

A heterotrophic bacterium that obtains nutrients from decaying organic matter; a decomposer.

Parasite (Bacterial)

A bacterium that lives on or in a host organism, causing disease (pathogen).

Photoautotroph

Bacterium that uses sunlight, CO₂, and water to make glucose via photosynthesis (e.g., cyanobacteria).

Chemoautotroph

Bacterium that obtains energy by oxidizing inorganic molecules such as sulfur or nitrates.

Nitrogen Fixation

Process by which certain bacteria convert atmospheric N₂ into ammonia usable by plants.

Decomposer

Organism that breaks down dead material, recycling nutrients back into ecosystems; many bacteria perform this role.

Mutualism

Symbiotic relationship in which both organisms benefit, such as gut bacteria aiding human digestion.

Antibiotic

A chemical substance that kills or inhibits the growth of bacteria; ineffective against viruses.

Vaccine

Preparation of weakened or killed pathogens used to stimulate immunity and prevent bacterial diseases.

Antibiotic Resistance

The ability of bacteria to survive and reproduce despite the presence of antibiotics that once killed them.

Metabolic Diversity

The wide range of biochemical strategies bacteria use to obtain energy, contributing to their ecological success.

Rapid Cell Division

Characteristic of many bacteria allowing population doubling in about 20 minutes under ideal conditions.

Archaeal Membrane Lipids

Ether-linked lipids unique to archaea that improve stability in extreme conditions.

Monera

Obsolete kingdom that once grouped all prokaryotes before separation into domains Bacteria and Archaea.

Eubacterial Growth Requirements

Optimal growth conditions: 26–38 °C, moisture, darkness, food source, and space.

Pathogen

Microorganism capable of causing disease; includes some species of bacteria.

Food Fermentation

Use of bacteria to produce foods like yogurt, cheese, sour cream, pickles, and buttermilk.