2. Eubacteria
“true” bacteria
 microscopic
 ex cyanobacteria (blue-green algae) on
earth for over 3 billion years
 able to carry out photosynthesis
(produces oxygen)
 oxygen conc of atmosphere increased
allowing oxygen breathers (animals) to
survive

Uses of Eubacteria
digestion
in intestines
yoghurt/cheese production
fermentation (wine, beer, pickling…)
wastewater/oil spill/toxic spill treatment
BiologySource
decomposers
Dangerous Eubacteria
cause health
problems:
 strep throat
 food poisoning (E.
coli and
salmonella)

Structure & Function of Bacteria



1.
2.
3.
microscopic
smallest living cells
classified according
to:
cell shape
cell wall structure
motility (way of
moving)
1. Cell Shape
3 basic cell shapes
 spherical – “cocci”
 rod-shaped – “ bacilli”
 spiral – “spirochetes”

prefixes are added to show living
arrangement of bacteria
 strepto – chain
 stphlyo - cluster

CAN YOU NAME IT???
staphylococcus
diplococcus
streptococcus
2. Cell Wall Structure
2 kinds of cell walls, appear different when
stained with Gram stain
 peptidoglycan – thick coat of sugars,
makes wall strong & rigid (Gram postive)
 less peptidoglycan (Gram negative)

Movement
various methods:
 most mobile bacteria use flagella (whiplike tail)
 others secrete mucous can glide on

Typical Bacteria
How Bacteria Reproduce
1.





Asexual - Binary Fission
1 original cell splits into 2
can occur in 20 minutes for
many bacteria species.
In 12 hours, 1 bacterium can
divide to form a colony of 68
billion cells.
overcrowding, waste, and food
availability do not allow
populations to grow this large.
produces colonies of bacteria
that are genetically identical.
2. Types of Sexual Reproduction
1.
2.
Transformation: bacteria pick up stray
DNA from their surroundings.
Conjugation: two bacterial cells join (=
conjugate) to exchange genetic material
(plasmids, separate from main DNA)
3. Transduction: viruses that infect bacteria
transmit genetic material from another
source
 Endospores form when environmental
conditions make normal functions too
difficult.