Bacteria & Archaea - Microbiolgy Ch. 3

Cocci/coccus

Circular/sphereical shaped bacterium

Bacilli/bacillus

Rods/cylindrical, filamentous, club-shaped bacterium

Vibrio

Curved bacterium

Spirillum

Cork-screw/spiral shaped bacterium

Chemotaxis

Movement in response to chemical signals

Positive chemotaxis

Movement of a cell in the direction of a favorable chemical stimulus

Negative chemotaxis

Movement of a cell away from a repellant or potentially harmful compound

Phototaxis

Movement towards light

Polar

Flagella attached to one or both ends of the cell

Monotrichous

Single flagella

Lophotrichous

A bunch or tuft of flagella

Peritrichous

Flagella are dispersed randomly over the surface of the cell

Run

Counterclockwise movement of the flagella

Cell swims in a smooth, linear direction

Tumble

Flagellum reverses direction, causing the cell to stop and change course

Fimbriae

Small, bristle-like fibers sprouting off the surface of certain species of bacteria

Allow bacteria to stick to each other and to surfaces to form biofilms

Pili

Long, rigid, tubular structure made of pilin protein

Allow bacteria to attach to one another and transfer DNA from one cell to the other

Nanotubes

Very long, thin, tubular extensions of the cytoplasmic membrane

Used as channels to transfer amino acids or other molecules between cells

S layer

1000s of copies of a protein, linked together

Produced only in hostile environments for protection

Glycocalyx

Repeating polysaccharides, 2 varieties

Slime layer

Forms loosely around the cell

Protects the cell from loss of water and nutrients

Capsule

Dense, thick layer around a cell

Protect bacteria against phagocytic white blood cells

Biofilms

Microbial habitats in which microbes cooperate for resources

Cell envelope

Composed of a cell wall, cytoplasmic membrane, and, in some bacteria, an outer membrane

Gram positive or Gram negative

Cell wall

Provides strong but flexible structural support to keep cells from bursting or collapsing from osmotic pressure

Made of peptidoglycan

Lipopolysaccharide

Specialized polysaccharide whose chains serve as cell markers and receptors

Endotoxin

Chemical that stimulates fever and shock

Porin proteins

Completely spans the outer membrane

Only allows relatively small molecules to penetrate

Cytoplasmic membrane

Lipid bilayer embedded with proteins

Supports energy reactions, nutrient processing, and transport

Outer membrane

Only on Gram negative bacteria

Provides extra barrier to inhibit Gram-positive bacteria

Mycoplasmas

Bacterium that is neither Gram-positive or Gram-negative

Mycolic acid in the cell envelope makes them resistant to certain dyes and chemicals

Cytoplasm

Gelatinous solution contained by the cytoplasmic membrane

Prominent site for the cell’s biochemical and synthetic activities

Cytoskeleton

Long polymers of proteins arranged under the cytoplasmic membrane

Contribute to cell shape

Bacterial genome

Single, circular chromosome of DNA contained in the nucleoid

Plasmids

Small circles of “extra” DNA

Confer protective traits

Ribosome

Made of RNA and protein

Translates mRNA into protein throughout the cytoplasm

Granules/inclusion bodies

Storage sites for nutrients during period of abundance

Bacterial endospores

Formed to withstand hostile conditions and facilitate survival

Extremophiles

Organisms living in extreme conditions

Bergey’s Manual of Systematic Bacteriology

Comprehensive view of bacterial and archaeal relatedness based on mRNA sequencing

Bergey’s Manual of Determinative Bacteriology

Categorizes organisms based on their phenotypic characteristics

Grancilicutes

Division of bacteria and archaea that are Gram-negative with thin cell walls

Firmicutes

Division of bacteria and archaea that are Gram-positive with thick, strong cell walls

Tenericutes

Division of bacteria and archaea that lack a cell wall and are soft

Mendosicutes

Division of archaea that are primitive with unusual cell walls and nutritional habits

Serotype

Representative of a species that stimulate a distinct pattern of antibody responses because of unique surface molecules