1. Chapter 5: The Microbial World Part One: A Comparison of Prokaryotes

2. 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

3. The Classification of Organisms Domain BacteriaDomain ArchaeaDomain Eukarya Kingdom Protista Kingdom Animalia Kingdom Plantae Kingdom Fungi EukaryotesProkaryotes

4. Domain: Bacteria Distribution, 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. Bacteria chain from www.vendian.org/.../ bacteria_chain2.jpg

5. 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

6. 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

7. 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

8. 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.

9. Domain: Archaea Distribution  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

10. Domain: Archaea Distribution  “Extreme” marine environments where archaebacteria are found include: Deep-sea hydrothermal vents Coastal salt pans Deep water

11. Prokaryote Metabolism  Autotrophs  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

12. Overview: Photosynthesis Kunkel, Dennis. "Education Website." Dennis Kunkel Microscopy Inc. 2007. 11 Nov 2008. CO 2 + H 2 O Glucose + O 2 (organic matter) Sunlight Pigments Metabolized to create ATP in cellular respiration. Cyanobacteria

13. Overview: Photosynthesis Sloth, N.. "Purple sulfur bacteria." Biopix. 2003. 11 Nov 2008. CO 2 + H 2 S Glucose + S ( or SO 4 2- ) (organic matter) Sunlight Pigments Metabolized to create ATP in cellular respiration. Purple-sulfur bacteria

14. 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 (O 2 ) in the atmosphere.

15. Cyanobacteria – Diversity www.anselm.edu/.../ genbios/surveybi04.html

16. Ecological Role of Cyanobacteria  Contain three photosynthetic pigments: Chlorophyll a - green Phycocyanin – blue Phycoerythrin – red  Pigment  Pigment – molecule that captures absorbs certain colors of light but reflects others  Phycoerythrins harmful algal blooms  Phycoerythrins from planktonic cyanobacteria are one species of organism responsible for harmful algal blooms or red tides. © Copyright 2005 by NIWA www.niwa.co.nz/ncabb/ abb/2003-03/blooms

17. 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

18. Ecological Role of Cyanobacteria  Some capable of nitrogen fixation, a process by which nitrogen gas (N 2 ) dissolved in seawater is converted into ammonia (NH 3 ) 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

19. "A simplified marine nitrogen cycle.." Nitrogen Cycling in the Black Sea. 2008. Max Planck Institute for Marine Microbiology. 11 Nov 2008.

20. 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

21. Light-mediated ATP synthesis Light-mediated ATP synthesis Photoautotrophy without chlorophyll  Sunlight energy captured and stored in ATP directly.  Domain Bacteria proteorhodopsin contain pigment proteorhodopsin  Domain Archaea common in halophilic bacteria live in salterns, saline pools bacteriorhodopsin Contain reddish-purple pigment bacteriorhodopsin IMAGE: Piquepaille, Roland. "ZDNet." [Weblog Life in extreme environments] 30 Dec 2007. CBS Interactive, Inc. 11 Nov 2008. San Francisco Bay salt ponds

22. 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, 2 nd Edition, Saunders Publishing Company, Philadelphia, PA. Castro, P. & M. E. Huber (2005) Marine Biology, 5 th Edition, McGraw-Hill Higher Education, Boston, MA.