Microbial World & Anatomy of Prokaryotic Cells

Prokaryotic Cells

Small, unicellular organisms the majority being bacteria

Cocci

Round, oval, elongated or flattened on one side

Diplococci

Remain in pairs after dividing

Streptococci

Chainlike patterns after dividing

Tetrads

Divide in two planes and remain in a group of four

Staphylococci

Divide in multiple planes and form grapelike clusters or broad sheets

Bacilli

Divide only across their short axis and appear as single rods

Diplobacilli

Pairs after division

Streptobacilli

Chains

Coccobacilli

Oval like cocci

Spiral

Have one or two twists

Vibrios

Curved rods

Spirilla (spirillum)

Helical shape with rigid bodies

Spirochetes

Helical shape with flexible shapes

Monomorphic

Maintaining a single shape

Pleomorphic

Having many shapes

Glycocalyx

Viscous, gelatinous polymer external to the CW that helps everything stay inside

Capsules

Organized and firmly attached to the CW

Contributes to bacterial virulence

Slime Layer

Unorganized and only loosely attached to the cell wall

Extracellular Polymeric Substance

Glycocalyx used to attaching to target environment and to other bacteria

Flagella

Long filamentous appendages (hair) that propel bacteria

Atrichous (without projections)

Bacteria that lack flagella

Peritrichous

Flagella distributed over the entire cell

Monotrichous (P)

Single flagellum at one pole

Lophotrichous (P)

Tuft of flagella coming from one pole

Amphitrichous (P)

Flagella at both poles of the cell

Filament

Longer outer region; constant diameter and contains flagellin in chains that intertwine and form a helix around a hollow core

Hook

Attachment between filament and basal body

Basal Body

Anchors the flagellum to the CW and plasma membrane