Prokaryotes: Kingdoms
Archaebacteria and Eubacteria
Chapter 18
Daily Objective
• Investigate Prokaryotes and their two
Domains: Domain Archaea and Domain
Bacteria
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FAST FACTS
Bacteria are the most numerous organisms on Earth
Earliest life forms
Contain no nucleus or membrane bound organelles
Most are unicellular
• Prokaryotes are divided into 2 domains.
• Domain Archaea and Domain Bacteria
• Review
Domain Archaea live in
extreme enviornments .
They have been found to
have similarites with
eukaryotic cells. i.e. the
ribosomal proteins
Domain Bacteria live
in nearly every
environment on
Earth. Their cell walls
contain
peptidoglycan.
Daily Objective
• Review Characteristics of Prokaryotes
Domain Archaebacteria
• “ancient bacteria”
• Cell walls without peptidoglycan
• Subdivided into 3 groups based on their
habitat– methanogens, thermoacidophiles, &
extreme halophiles
Domain Bacteria
• “true bacteria”
• Most bacteria in this kingdom
• Come in 3 basic shapes cocci (spheres), bacilli
(rod-shaped), spirilla (corkscrew shape)
• Most are heterotrophic
• Can be aerobic, or anerobic
Gram Staining
• Developed in 1884 by microbiologist Hans
Gram
• Bacteria are stained purple with dye and
iodine, rinsed with alcohol to decolorize, then
restained with dye.
• Bacterial cell walls either stain purple or
reddish-pink
Gram +/•
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Gram (+) Bacteria
Stain purple
Thick layer of peptidoglycan
(protein sugar complex in
cell walls)
Examples: streptoccous,
staphylocci
Can be treated with
penicillin (antibiotics)
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Gram (-) Bacteria
Stain reddish-pink
Thin layer of peptidoglycan
Antibiotic resistant
Examples; Rhizobacteria,
Rickettsia (Lyme disease)
Prokaryote Structure
Prokaryote Characteristics
• Bacteria can be identified by their shape, cell
wall, and movement.
• Shape
Prokaryote Characteristics- cell walls
All bacterial cells have peptidoglycan (sugar and
protein) in their cell walls
-can identify bacteria by gram staining.
• Bacteria with a large amount of peptidoglycan
appear dark purple (gram +)
• Bacteria with a lipid layer has less
peptidoglycan, and will stain reddish pink
(gram-)
Reproduction of Prokaryotes
• Most bacteria reproduce asexually by binary
fission- chromosome replicates then the cell
divides
• Bacteria can sexually reproduce by
conjugation- two bacteria from a conjugation
bridge or tube between them.
Which method of Reproduction?
Metabolism of Prokaryotes
• Prokaryotes can obtain their energy in
multiple ways
Heterotrophs
PhotoAutrophs
Chemoautotrophs
Do not synthesize
own food. Obtain
energy by
decomposing
organic molecules.
Photosynthetic.
Release oxygen
into the
atmosphere
Do not require light
for energy. They
break down and
release inorganic
compounds.