Chapter 5:
The Microbial World
Part One:
A Comparison of Prokaryotes
The Classification of Organisms
Prokaryotes
Eukaryotes
Kingdom
Animalia
Kingdom
Protista
Domain Bacteria
Domain Archaea
Kingdom
Fungi
Kingdom
Plantae
Domain Eukarya
Notebook Assignment
1.Create a Venn Diagram to compare and
contrast PROKARYOTIC and
EUKARYOTIC cells
2.Create a table to identify the
characteristics of the six kingdoms
Cell Types
Kingdom
Archaebacteria
Eubacteria
Protista
Fungi
Plantae
Animalia
Characteristics and Examples
Characteristics of Prokaryotes
 Small (0.001 to 0.75 mm)
 Enclosed in a protective cell wall
 Cell membrane lies inside cell wall
 Lack a nucleus and membrane-bound
organelles
 Have a single circular molecule of DNA
 Contain small ribosomes for protein
manufacture
 Two kingdoms of prokaryotes –


Archaea
Bcateria
Domain: Bacteria
Distribution, Shape, & Size
 Abundant in all parts of the ocean.
 Many shapes – spheres, rods,
Bacteria chain from
www.vendian.org/.../
bacteria_chain2.jpg
spirals, and rings
 Often found in chain-like colonies
or filaments in the marine
environment.
 Decay bacteria break down waste
products and dead organic matter
and release nutrients
Domain: Bacteria
Structural Characteristics
 Rigid cell wall containing
peptidoglycan
 Some have a slimy
capsule of glycoprotein
and polysaccharides that
protects the cell
w3.dwm.ks.edu.tw/bio/ activelearner/23/ch23c3.html
Domain: Bacteria
Structural Characteristics
 Short pili cover the
surface of the bacteria
and function in attachment
to specific host cell
surfaces.
 A modified sex pilus can
transfer DNA plasmids
from one bacteria to
another.
w3.dwm.ks.edu.tw/bio/ activelearner/23/ch23c3.html
Domain: Bacteria
Motility
 Bacteria possess flagella
for movement. These
occur singly, in bundles, or
covering the surface of the
cell.
 All prokaryotes lack cilia.
w3.dwm.ks.edu.tw/bio/ activelearner/23/ch23c3.html
Importance of Cyanobacteria
 Photosynthetic bacteria – also
known as “blue-green algae.”
 Believed to be the first
photosynthetic organisms on Earth.
 Played an important role in the
accumulation of oxygen (O2) in the
atmosphere.
Cyanobacteria – Diversity
www.anselm.edu/.../ genbios/surveybi04.html
Ecological Role of Cyanobacteria
 Contain three photosynthetic pigments:



Chlorophyll a - green
Phycocyanin – blue
Phycoerythrin – red
 Pigment – molecule that captures absorbs
certain colors of light but reflects others
 Phycoerythrins from planktonic
cyanobacteria are responsible for harmful
algal blooms or red tides.
© Copyright 2005 by NIWA
www.niwa.co.nz/ncabb/ abb/2003-03/blooms
Ecological Role of Cyanobacteria
 Massive calcareous
mounds called
stromatolites were formed
by cyanobacteria and date
back 3 billion years.
 These “living fossils” still
Modern Stromatolites, Shark Bay,
Australia. Photo courtesy Marjory
Martin, Deakin Univ, Australia
www.calm.wa.gov.au/.../ hamelin_pool_mnr.html
occur in warm, hypersaline
waters of the world.
Ecological Role of Cyanobacteria
 Some capable of nitrogen fixation,
 a process by which nitrogen gas (N2) dissolved
in seawater is converted into ammonia (NH3)
 NH3 can be used directly in bacterial
metabolism.
 Eukaryotes cannot fix nitrogen.
 Some terrestrial bacteria can also fix nitrogen.
 Naturally, nitrogen is a limiting nutrient in
marine ecosystems.
http://www.ibmc.up.pt/webpagesgrupos/cam/cyanobacteria.htm
"A simplified marine nitrogen cycle.." Nitrogen Cycling in the Black Sea. 2008. Max Planck Institute for Marine Microbiology. 11 Nov 2008 <http://www.mpibremen.de/en/Nitrogen_Cycling_in_the_Black_Sea.html>.
Ecological Role of Cyanobacteria
 One species, Anabaena, actually generates specialized
cells called heterocysts for nitrogen fixation.
http://www.ibmc.up.pt/webpagesgrupos/cam/cyanobacteria.htm
Domain: Archaea
Size & Shape
 Sometimes called archaebacteria
 Among the most primitive and oldest
forms of life.
 Cells are small and spherical, spiral,
or rod-shaped.
 More closely related to eukaryotes
than to bacteria.
Domain: Archaea
Distribution
 Many species inhabit extreme
Boiling volcanic pools –
© Dr. Malcolm White
environments and are thus
called “extremophiles.”
 Halophiles – live in
extremely salty conditions
 Methanogens – produce
methane and live in
anaerobic environments
such as the human gut
 Thermoacidophiles – grow
in hot, acidic environments
Domain: Archaea
Distribution
 “Extreme” marine
environments where
archaebacteria are found
include:



Deep-sea hydrothermal vents
Coastal salt pans
Deep water
Prokaryote Metabolism
 Autotrophs – “self feeders”

make their own “food” (organic compounds).

Photoautotrophs



use sunlight
contain photosynthetic pigments
Chemoautotrophs

use energy from inorganic chemicals to create organic
matter
 Heterotrophs

obtain energy/organic matter by consuming other organisms
 Light-mediated ATP synthesis

sunlight energy directly converted into ATP
Overview: Photosynthesis
Sunlight
Metabolized to
create ATP in
cellular
respiration.
Pigments
Glucose + O2
CO2 + H2O
(organic matter)
Cyanobacteria
Kunkel, Dennis. "Education Website." Dennis Kunkel Microscopy Inc. 2007. 11 Nov 2008 <http://www.denniskunkel.com/>.
Overview: Chemosynthesis
Sunlight
CO2 + H2S
Metabolized to
create ATP in
cellular
respiration.
Pigments
Glucose + S (or SO42-)
(organic matter)
Purple-sulfur bacteria
Sloth, N.. "Purple sulfur bacteria." Biopix. 2003. 11 Nov 2008 <http://www.biopix.com/Photo.asp?PhotoId=28071&Photo=Purple-sulfurbacteria>.
Light-mediated ATP synthesis
Photoautotrophy without chlorophyll
 Sunlight energy captured and
stored in ATP directly.
 Domain Bacteria

contain pigment proteorhodopsin
 Domain Archaea



common in halophilic bacteria
live in salterns, saline pools
Contain reddish-purple pigment
bacteriorhodopsin
San Francisco Bay salt ponds
IMAGE: Piquepaille, Roland. "ZDNet." [Weblog Life in extreme environments] 30 Dec 2007. CBS Interactive, Inc. 11 Nov 2008
<http://blogs.zdnet.com/emergingtech/?p=788>.
Resources
http://curriculum.calstatela.edu/courses/builders/lessons/less/les4/a
rchaea.html
w3.dwm.ks.edu.tw/bio/ activelearner/23/ch23c3.html
Villee, C.A. et. al. (1989) Biology, 2nd Edition, Saunders Publishing
Company, Philadelphia, PA.
Castro, P. & M. E. Huber (2005) Marine Biology, 5th Edition,
McGraw-Hill Higher Education, Boston, MA.