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Chapter 21 Viruses and Prokaryotes. Viruses. Where do viruses come from ?. Bacteriophage Replication. HIV Replication - Retrovirus. What Do These Pictures Have in Common?. gov.mb.ca. k8science.org. nuclearfamilywarhead.com. gsbs.utmb.edu. Brain Tissue. learn.genetics.utah.edu.
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What Do These Pictures Have in Common? gov.mb.ca k8science.org nuclearfamilywarhead.com gsbs.utmb.edu
Brain Tissue learn.genetics.utah.edu
Protein Structure new-science-press.com
Prions Dr. Stanley Prusiner. cmu.edu stanford.edu
Viroids • Consist of short, fragments of single-stranded RNA. • Only found in plants (so far). • Can interfere with plant’s metabolism, resulting in the plant being stunted or killed. • Ex. Potato spindle tuber Left: normal potatoes; Right – infected potatoes www.unece.org
Prokaryotic Cells Yersinia pestis – Bubonic Plague. science.nationalgeographic.com Clostridium botulism.www.nih.gov
Prokaryotic Cell Size and Shape • Prokaryotic cells are much smaller than eukaryotic cells (about the size of mitochondria) • Prokaryotes have three typical shapes: http://www.bio.miami.edu/~cmallery/150/proceuc/c8.27x3.bact.shapes.jpg, http://sharon-taxonomy2009-p2.wikispaces.com/Archaea
Prokaryotic Fission Esherichia coli undergoing prokaryotic fission
Bacterial Cell Wall Gram-positive Bacteria • Gram-positive Bacteria • Thick layer of peptidoglycan (60-100%) • Gram-negative Bacteria • Thin layer of peptidoglycan (10-20%) • Has outer membrane composed of mostly lipids (80-90%) Gram-negative Bacteria pathmicro.med.sc.edu
Gram Stain Results Gram-positive bacteria stains violet to blue. Gram-negative bacteria stains pink to red. homepage.ntlworld.com
Cyanobacteria Anabaena. http://www.biologie.uni-hamburg.de/b-online/fo42/anabaena.jpg Oscillatoria. http://t2.gstatic.com/images?q=tbn:LsEmj27QxYGiHM:http://botit.botany.wisc.edu
MethanogenicArchaeans 0.5 µm