Module 3 Study Guide: Microbial Structures

Vocabulary terms covering prokaryotic and eukaryotic structures, cell wall compositions, motility mechanisms, and endospore processes based on the Module 3 Study Guide.

Prokaryotic cell structure

Characterized by a single circular chromosome, specific cell wall chemicals, and reproduction via binary fission.

Eukaryotic cell structure

Characterized by multiple linear chromosomes, membrane-bound organelles, a nucleus, histones, and reproduction via mitosis.

Cell membrane

A fluid mosaic structure composed of a lipid bilayer and proteins that is semipermeable and involved in transport.

Peptidoglycan

The chemical component that makes up bacterial cell walls and is the basis for the Gram stain.

Gram negative

A cell wall type containing an outer membrane, LPS, periplasm, and porins.

Lipopolysaccharide (LPS)

A component of Gram-negative outer membranes consisting of O-polysaccharide and Lipid A.

Lipid A

The specific part of the Gram-negative outer membrane that acts as an endotoxin.

Gram positive

A cell wall type characterized by a thick layer of peptidoglycan and teichoic acid.

Acid-fast wall

A specialized cell wall containing mycolic acid.

Atypical walls

Cell wall types found in archaea and mycoplasma.

Flagella components

Includes the filament, hook, and basal body; composed of the protein flagellin.

Chemotaxis

The movement of an organism toward attractants or away from repellents using runs and tumbles.

Runs and Tumbles

Motility patterns where runs are associated with counter-clockwise ($CCW$) rotation and tumbles with clockwise ($CW$) rotation.

Axial filaments

Also known as endoflagella, these are used for motility in spirochetes.

Pili and fimbriae

Hair-like appendages used for attachment, virulence, and DNA transfer via a sex pilus.

Nucleoid

The region in a prokaryotic cell that contains the DNA.

$70S$ Ribosomes

The size of ribosomes found in prokaryotes and mitochondria.

$80S$ Ribosomes

The size of ribosomes typical of eukaryotic cells.

Endospores

Highly resistant survival structures found in genera such as Bacillus and Clostridium.

Sporulation

The process that forms a spore from a vegetative cell.

Germination

The process that forms a vegetative cell from a spore.