Bacteria Classification
and Characteristics
By: Sarah Haudrich, Kiley Plenderleith and Jimmy Livingston
Overview
kingdoms of bacteria
classification of bacteria
gram staining
shapes of bacteria
how bacteria moves
Kingdoms
Prokaryotes- unicellular organisms that lack a
nucleus
Prokaryote kingdom- Monera
Kingdoms within the prokaryote kingdomEubacteria and Archaebacteria
prokaryote
Eubacteria
Larger kingdom
cell walls have peptidoglycan (a carb)
can live almost anywhere
fresh water
salt water
humans
eubacteria
Archaebacteria
DNA sequence of genes are more like
eukaryotes than eubacteria
Eukaryotes may be a far ancestor
can live in harsh environments
mud
animal digestive tracts
extremely salty areas
DNA
Similarities between Eubacteria and
Archaebacteria
Small in size
Lacks a nucleus
Has cell walls
Classification
classified by...
a) their shapes
b) their chemical nature of the cell walls
c) the way they move
d) how they obtain energy
gram staining (eubacteria)
technique to differentiate two large groups of bacteria based on cell wall
based on the ability of bacteria cell wall to retaining the crystal violet dye
during solvent treatment
Gram staining helps distinguish between gram positive and gram negative by
coloring red or violet
Gram positive
Stains violet
peptidoglycan in cell walls
The following are characteristics of gram positive bacteria
Thick peptidoglycan layer- polymer consisting of sugar and amino acids
Peptidoglycan chains are cross-linked to form rigid cell walls however, the
decolorized Gram negative cells are stained red.
Gram negative
Stains red
Thinner wall
Does not retain violet during decoloring process
gram staining process
cells are stained with a crystal dye
Decolorization- ethyl alcohol or acetone is added to the sample
Gram positive stains violet
Gram negative stains red
counterstaining
A counterstain is added, staining the sample red
The counterstain will not disrupt the violet stain in Gram positive
However, the decolorized Gram negative cells are stained red
What are 3 Different Shapes of
Eubacteria?
Rod shaped (Bacilli)
Spherically shaped (Cocci)
Spiral shaped (Spirochetes)
How does bacteria move in three
different modes?
Propelled by flagella
Glide slowly (slime)
Whip themselves
Moving bacteria
0
