Chapter 4 Study Guide: Prokaryotes & Bacteria

These flashcards cover key vocabulary terms and concepts from Chapter 4 on Prokaryotes and Bacteria, providing definitions and important distinctions.

Prokaryotes

Organisms with DNA free in the cytoplasm, no membrane-bound organelles, and are generally smaller and simpler than eukaryotes.

Eukaryotes

Organisms with DNA inside a nucleus, membrane-bound organelles, and are generally larger and more complex than prokaryotes.

Coccus

A bacterial shape that is circular or round.

Bacillus

A bacterial shape that is long and rod-shaped.

Spirillum

A bacterial shape that is curved or spiral.

Pleomorphic

A term describing bacteria that can change shape.

Biofilms

Mixed communities of microorganisms that are found living on surfaces and are encased in extracellular polysaccharides.

Quorum Sensing

The ability of bacteria to sense the density of other bacteria and change behavior as a group.

Flagella

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

Monotrichous

A bacterial arrangement with a single flagellum.

Lophotrichous

A bacterial arrangement with a tuft of flagella at one end.

Fimbriae

Structures that help bacteria attach to surfaces.

Pili

Hair-like structures that attach cells together and are used in conjugation.

Glycocalyx

An outer protective layer of bacteria that can be organized into a slime layer or a capsule.

Gram-Positive

Bacteria with a thick peptidoglycan cell wall that appears dark purple after Gram staining.

Gram-Negative

Bacteria with a thin peptidoglycan layer and an outer membrane with LPS that appears lighter after Gram staining.

Chromosome

A single, circular DNA molecule found in prokaryotic cells.

Plasmids

Small circular DNA molecules outside the nucleoid that can carry traits such as antibiotic resistance.

Ribosomes

Cell structures that make proteins and are found in the cytoplasm.

Endospores

Survival structures formed by bacteria under unfavorable conditions.

Germination

The process by which an endospore becomes an active cell again.

Extremophiles

Organisms, such as certain archaea, that thrive in extreme environmental conditions.

Bergey’s Manual

A reference work used for the identification and classification of bacteria based on their characteristics.