microbio- classification of microbes: bacterial cell

bacterial size

0.2 to 2.0 µm diameter and 2 to 8 µm long

bacterial shapes: coccus

low surface to volume (S/V) ratio, resists drying, can last on surfaces longer

bacterial shape: bacillus

inbetween coccis and spiral

bacterial shape: spiral

high S/V ratio sensitive to drying

bacterial arrangement

cell division planes bacterial cell arrangements

diplococci

two cocci next to eachother

streptococci

a STRAND of cocci

Staphylococci

a CLUSTER of cocci

monomorphic

bacteria will always look the same (there are exceptions)

what are bacterial cells shape and arrangement decided by

heredity

pleomorphic

exception for monomorphic cells

• rod-shaped and cubed- shape

Glycocalyx

coat/layer surrounding the bacterial cell

what is glycocalyx made up of

Polysaccharide or polypeptide or both

• it depends on bacteria

Glycocalyx type: Capsule

firmly attached to cell wall/exterior on surface of cell

glycocalyx type: slime layer

loosely attached to cell wall/ exterior on surface of cell

virulence

degree to which a pathogen causes disease

virulence factor

component of an organism that determines its capacity to cause disease

is glycocalyx capsule a type a virulence factor

yes

what is the glycocalyx capsule function

1.) Protects bacteria cell from phagocytosis (being engulfed)

2.) Attachment to host cell tissue

3.) Food source ( because they can eat itself if it is starved for energy)

glycocalyx slime layer functions

1.) Trap nutrients in environment

2.) Prevent dessication (drying)

flagella

long appendages for motility

does all bacterial produce flagella

no

flagella motility

50 µm/sec= 0.0001 mph = 37 cell lengths/sec

how does flagella move

it Rotates like a propellor, clockwise or counter clockwise and Propels bacteria through a series of “runs” and then “tumbles” to change direction

flagella structure: filament

flagellin protein and hollow core

flagella structure: hook

attachment of the filament to the motor

flagella structure: Basal body

anchor and motor

taxonomy

group bacteria

flagella position: Monotrichous

single flagellum

flagella position: Amphitrichous

tuft of flagella at each pole

flagella position: Lophotrichous

tuft of flagella from one pole

flagella position: Peritrichous

flagellum over the whole surface

is flagella angelic

yes highly

is flagellin protein an antigen

yes

Different serovars of bacteria have…

distinct antigens

taxis

movement of bacteria in response to stimuli (attractant or repellent)

Chemotaxis

chemical stimuli

phototaxis

light stimuli

on cell surface bacteria has …

receptors/ protein

where are the receptors on bacteria cells

on the bacterial surface

what can the receptors on the bacterial surface sense

chemicals and/or light leading to flagellar motility.

axial filament

internal flagella only found inbedded in spiral- shaped bacteria

what do axial filaments allow

spirochaetes (spiral-shaped bacteria) to movie through host tissues like a drill.

Fimbriae and Pili

short hair-like appendages used for attachment or conjugation

what type of bacteria is fimbriae and pili

gram negative bacteria only

what is Fimbriae and Pili composed of

the protein pilin

where is fimbriae found

polar position or over whole surface

polar position

found on only one end

how many fimbriae per cell

few to 100

can Gonorrhea colonize your genital tract without fimbria (adherence)

no it cannot

is pili longer then fimbriae

yes

how many pili per cell

1 or 2

what is fimbriae function

adherence

what is the function of pili

transfer of DNA from one bacteria to another during conjugation

sex pili

A bacterium that has a sex pilus can transfer DNA to another bacterial cell

conjugation

mechanism that bacteria use to acquire antibiotic resistance genes.