PROKARYOTES © 2012 Pearson Education, Inc. Chapter 16 Microbial Life: Prokaryotes and Protists.
Chapter 5: The Microbial World Part One: A Comparison of Prokaryotes.
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Transcript of Chapter 5: The Microbial World Part One: A Comparison of Prokaryotes.
Chapter 5:The Microbial World
Part One:
A Comparison of Prokaryotes
The Classification of Organisms
Domain Bacteria Domain Archaea Domain Eukarya
Kingdom Protista
Kingdom Animalia
Kingdom Plantae
Kingdom Fungi
EukaryotesProkaryotes
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 Characteristics and Examples
Archaebacteria
Eubacteria
Protista
Fungi
Plantae
Animalia
Characteristics of Prokaryotes
Small (0.001 to 0.75 mm) Structurally simple 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 Bacteria
Domain: BacteriaDistribution, Shape, & Size
Abundant in all parts of the ocean. Many shapes – spheres, rods,
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
Bacteria chain from www.vendian.org/.../ bacteria_chain2.jpg
Bacteria
Recently discovered bacteria, SAR11, may be most abundant life form on earth
Role in the ecosystem still unknown
http://www.bios.edu/research/sar11.html
Domain: BacteriaStructural 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: BacteriaStructural 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: BacteriaMotility
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 occur in warm, hypersaline waters of the world.
Modern Stromatolites, Shark Bay, Australia. Photo courtesy Marjory Martin, Deakin Univ, Australia
www.calm.wa.gov.au/.../ hamelin_pool_mnr.html
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 and converted to nitrates.
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
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: ArchaeaSize & 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: ArchaeaDistribution
Many species inhabit extreme 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
Boiling volcanic pools – © Dr. Malcolm White
Domain: ArchaeaDistribution
“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
Kunkel, Dennis. "Education Website." Dennis Kunkel Microscopy Inc. 2007. 11 Nov 2008 <http://www.denniskunkel.com/>.
CO2 + H2OGlucose + O2
(organic matter)
Sunlight Pigments Metabolized to create ATP in cellular respiration.
Cyanobacteria
Overview: Chemosynthesis
Sloth, N.. "Purple sulfur bacteria." Biopix. 2003. 11 Nov 2008 <http://www.biopix.com/Photo.asp?PhotoId=28071&Photo=Purple-sulfur-bacteria>.
CO2 + H2SGlucose + S (or SO4
2-)
(organic matter)
Sunlight Pigments
Metabolized to create ATP in cellular respiration.
Purple-sulfur bacteria
Light-mediated ATP synthesisPhotoautotrophy 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
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>.
San Francisco Bay salt ponds
Resources
http://curriculum.calstatela.edu/courses/builders/lessons/less/les4/archaea.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.