18.4 Bacteria and Archaea Kingdom Eubacteria Domain Bacteria

35 Pages·2013·1.49 MB·English

18.4 Bacteria and Archaea
Kingdom Eubacteria Domain Bacteria
18.4 Bacteria and Archaea
Description
Bacteria are single-celled prokaryotes.
18.4 Bacteria and Archaea
Where do they live?
Prokaryotes are widespread on Earth.

( Est. over 1 billion types of bacteria, and over 1030 individual prokaryote
cells on earth.)
Found in all land and ocean environments, even inside other organisms!
18.4 Bacteria and Archaea
Common Examples
• E. Coli
• Tetanus bacteria
• Salmonella bacteria
• Tuberculosis bacteria
• Staphylococcus
• Streptococcus
18.4 Bacteria and Archaea
Modes Of Nutrition
• Bacteria may be heterotrophs or autotrophs
18.4 Bacteria and Archaea
Bacteria Reproduce How?
• by binary fission.
• exchange genes
during conjugation= conjugation bridge
increases diversity.
• May survive by
forming
endospores =
specialized cell
with thick
protective cell wall.
TEM; magnification 6000x

• Can survive for
.
centuries until environment improves Have been found in mummies!
18.4 Bacteria and Archaea
• Bacteria Diagram
– plasmid = small piece of genetic material, can replicate
independently of the chromosome
– flagellum = different than in eukaryotes, but for movement
– pili = used to stick the bacteria to each other or surfaces
pili
plasma
membrance flagellum
chromosome
cell wall
plasmid
This diagram shows the typical structure
of a prokaryote. Archaea and bacteria
look very similar, although they have
important molecular differences.
18.4 Bacteria and Archaea
• Classified by: their need for oxygen, how they gram
stain, and their shapes
18.4 Bacteria and Archaea
Main Groups by Shapes
– rod-shaped, called bacilli
– spiral, called spirilla or spirochetes
– spherical, called cocci
Spirochaeta: spiral
Lactobacilli: rod-shaped
Enterococci: spherical
18.4 Bacteria and Archaea
• Main Groups by their need for oxygen.
• obligate anaerobes
are poisoned by
oxygen
- Ex. Clostridium botulinum
- Ex. Clostridium tetani
– obligate aerobes
need oxygen
- Ex. Mycobacterium

tuberculosis
– facultative aerobes
can live with or without
oxygen

- Ex. E. Coli