Chapter 27

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Author:
kamrunsreno
ID:
171999
Filename:
Chapter 27
Updated:
2012-09-19 19:17:47
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Biology
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Exam 1
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  1. Prokaryote size
    • Smaller than eukaryotic cells 
    • –0.5-5 microns vs. 10-100 microns
  2. Prokaryote Morphology
    Cocci (spheres), bacilli (rods), spirilla (spiral)
  3. Prokaryote Cell Surface Structures
    • Cell wall gives shape, provides protection 
    • –Made of peptidoglycan (vs. chitin, cellulose) 
    • –Tested by Gram stain (27.3) 
    • • Gram positive – greater peptidoglycan  
    • • Gram negative – less peptidoglycan   
    • • Capsule for adhesion to others or surface 
    • –Sticky layer of carbohydrate or protein 
    • • Fimbriae for adhesion
  4. Prokaryote Internal Organization
    • Simpler than eukaryotes 
    • –Lack internal membrane bounded spaces 
    • • Do have infoldings of plasma membrane 
    • –Respiratory and photosynthetic membranes 
    • • Nucleoid region has single chromosome 
    • –Chromosome is circular, not linear 
    • • Cells also have plasmids 
    • –Smaller rings of DNA 
  5. Prokaryote Reproduction
    • • Reproduce quickly in good conditions 
    • –As quickly as 20 min, typically several hours 
    • • Binary fission: one cell splits into two 
    • –Simpler process that mitosis 
    • • Can evolve in short periods of time 
    • –Short generation time 
    • –High levels of genetic diversity 
  6. Prokaryote Nutritional Modes
    • Photo- use light energy 
    • Chemo- use chemical energy 
    • Autotrophs use CO2 as carbon source 
    • Heterotrophs use organic compounds as carbon source 
  7. Role of Oxygen in Metabolism in Prokaryotes
    • Obligate aerobes 
    • –Need O2 for aerobic respiration 
    • • Obligate anaerobes 
    • –Are poisoned by O2 
    • –Use fermentation or other forms of anaerobic respiration  
    • • Facultative anaerobes 
    • –Can use O2 if available, otherwise anaerobic 
  8. Domain Archaea
    • Some are extremophiles 
    • –Extreme halophiles: high salinity 
    • –Extreme thermophiles: high temperatures 
    • • Some are methanogens 
    • –Moderate environments (obligate anaerobes) 
    • –Release methane as waste product 
    • • Ex. Wetland “swamp” gas 
    • • Ex. Animal digestive tracts 
  9. Domain Bacteria
    • Proteobacteria – Large, diverse clade 
    • Chlamydias - Can only survive within animal host cells 
    • Spirochetes – Helical morphology  
    • Cyanobacteria – Plant-like photosynthesis 
    • Gram-positive bacteria – Another large, diverse clade 
  10. Prokaryotic Ecological Roles
    • Decomposers - chemoheterotrophs 
    • –Break down corpses, dead vegetation, waste 
    • Producers – photo & chemoautotrophic 
    • –Fix C from CO2 into larger organic molecules 
    • Symbiotic relationships 
    • –Ex. Mutualism – both partners benefit 
    • –Ex. Parasitism – one partner benefits (prokaryote), other is adversely affected 
  11. Pathogenic Bacteria
    • Parasites that cause disease in host 
    • Cause about half of human disease 
    • –Tuberculosis, cholera, typhoid fever etc. etc… 
    • Some bacterial disease requires vector 
    • –Ex. Lyme disease from ticks (27.20) 
    • Often cause illness by producing toxins 
    • –Exotoxins: secreted by living bacteria 
    • –Endotoxins: released when bacterium dies

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