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