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Prokaryotes

Organisms that lack a membrane-bound nucleus and include bacteria and archaea.

Binary Fission

A method of asexual reproduction where a prokaryotic cell divides into two identical cells.

Peptidoglycan

A polymer that makes up the cell wall of most bacteria, consisting of sugars and amino acids.

Gram-positive bacteria

Bacteria that have a thick peptidoglycan layer in their cell wall and stain purple.

Gram-negative bacteria

Bacteria that have a thin peptidoglycan layer and an outer membrane containing lipopolysaccharides, staining pink.

Endospore

A metabolically inactive structure that can remain viable under harsh conditions for long periods.

Pili

Hair-like appendages that allow bacteria to attach to surfaces and exchange DNA.

Flagella

Long, whip-like structures used by prokaryotes for movement.

Transformation

The process by which a prokaryotic cell takes up and incorporates foreign DNA from its environment.

Horizontal Gene Transfer

The transfer of genetic material between organisms that are not parent and offspring.

R plasmids

Plasmids that carry antibiotic resistance genes.

Nitrogen Fixation

The process by which certain prokaryotes convert atmospheric nitrogen (N2) into ammonia (NH3).

Photoautotrophs

Organisms that obtain energy from light and use CO2 as a carbon source.

Obligate Anaerobes

Organisms that cannot survive in the presence of oxygen.

Biofilms

Complex communities of prokaryotes that adhere to surfaces and exchange resources.

Symbiosis

An ecological relationship in which two species live in close contact.

Exotoxins

Toxins secreted by bacteria that can cause disease even in the absence of the bacteria.

Endotoxins

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

Antibiotics

Substances that can kill or inhibit the growth of bacteria.

Cyanobacteria

Photosynthetic bacteria that generate oxygen and contribute to the nitrogen cycle.

Extremophiles

Organisms that thrive in extreme environments, such as high salinity or temperature.

Mutualism

A type of symbiotic relationship where both partners benefit.

Pathogens

Microorganisms that cause disease.

Metabolic Cooperation

Interaction between different prokaryotic species that allows them to utilize resources more efficiently.

Conjugation

The process where genetic material is transferred between prokaryotic cells through direct contact.

Taxis

Movement of an organism in response to a stimulus, such as moving towards nutrients.

Fimbriae

Short hair-like structures that allow prokaryotes to adhere to surfaces.

Halophiles

Microorganisms that thrive in high salt concentrations.

Thermophiles

Organisms that thrive at very high temperatures, often found in hot springs.

Methanogens

Archaea that produce methane gas, often found in anaerobic environments.

Spirochetes

A group of bacteria characterized by their spiral shape and unique mode of locomotion.

Heterocysts

Specialized nitrogen-fixing cells found in some cyanobacteria.

Rhizobium

A genus of bacteria that forms symbiotic relationships with legumes and fixes atmospheric nitrogen.

Nitrosomonas

Bacteria that convert ammonia into nitrite during the process of nitrification.