Lesson 3: Prokaryotes (Eubacteria and Archaea)

Prokaryote

A single-celled organism without a nucleus or membrane-bound organelles.

Eukaryote

An organism whose cells contain a nucleus and organelles enclosed within membranes.

Binary Fission

A form of asexual reproduction where a single organism divides into two identical offspring.

Plasmid

A small, circular piece of DNA found in bacteria, separate from the main chromosome.

Flagella

Long, tail-like structures that help bacteria move.

Gram-Positive Bacteria

Bacteria that retain the purple color of a gram stain due to a thick cell wall.

Gram-Negative Bacteria

Bacteria that do not retain the purple dye and appear pink, often more resistant to antibiotics.

Obligate Aerobe

An organism that requires oxygen to survive.

Obligate Anaerobe

An organism that cannot survive in the presence of oxygen.

Facultative Anaerobe

An organism that can live with or without oxygen.

Conjugation

A process where two bacteria connect and transfer genetic material (plasmid), increasing genetic diversity.

Autotroph

An organism that produces its own food, usually through photosynthesis or chemical processes.

Heterotroph

An organism that obtains food by consuming other living things.

Methanogen

A type of archaebacteria that produces methane gas in oxygen-free environments.

Halophile

An organism that thrives in extremely salty environments.

Thermophile

An organism that thrives in very hot, acidic environments.