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19 Bacteria And Viruses
- 1. Bacteria and Viruses Chapter 19
- 2. 19.1 Bacteria Come inmany shapes and sizes Most common microorganisms are prokaryotes Average size of 1-5 micrometers Compared to eukaryotic cells that are 10- 100 micrometers in diameter
- 3. Classifying Prokaryotes Eubacteria Largestprokaryote Domain Cell wall of a carbohydrate- Peptidoglycan Cell membrane around cytoplasm Some have an extra cell wall on the outside to resist damage
- 4. Classifying Prokaryotes Archaebacteria Lacknuclei Have cell walls without peptidoglycan Are chemically different from Eubacteria Many live in extremely harsh environments
- 5. Identifying Prokaryotes Shapes Bacilli-Rod shaped Cocci- Spherical shaped Sprilla- spiral and cork-screw shaped Colorized SEM 9,000 Colorized SEM 12,000
- 6. Identifying Prokaryotes Cell walls Gram staining used to tell them apart Gram+ bacteria look purple Gram- bacteria look pink
- 7. Identifying Prokaryotes Movement Flagella Lash, snake or spiral forward They do not move at all
- 8. Metabolic Diversity Heterotrophs Chemoheterotrophs:must take in organic molecules for energy and carbon Photoheterotrophs: Use sunlight for energy but need organic compounds for a carbon source
- 9. Metabolic Diversity Autotrophs Chemoautotrophs:perform chemosynthesis to make carbon from carbon dioxide. Does not require sunlight Photoautotrophs: use light to convert carbon dioxide and water into carbon compounds and oxygen gas.
- 10. Getting Energy Bacterianeed a constant supply of energy Obligate aerobes- require constant supply of oxygen Obligate anaerobes- need no oxygen, for some oxygen will kill it Facultative anaerobes- survive with or with out oxygen
- 11. Growth and Reproduction Binaryfission Conjugation Spore formation
- 12. Importance of Bacteria Decomposers Break down dead matter Nitrogen Fixers Converts nitrogen into a form plants can use Humans use Bacteria
- 13. 19.2 Viruses What isa virus? Particles of nucleic acid and proteins Core made up of DNA or RNA surrounded by a capsid Head DNA Need to infect a Tail Tail fiber living host to reproduce
- 14. Video on Lyticand Lysogenic Cycle http://www.youtube.com/watch?v=gU8X eqI7yts&feature=related
- 15. Viral Infection Lytic Cycle Virus attaches to host cell Injects its DNA Host makes RNA from viral DNA Cell begins to make copies of virus New viruses form Host cell bursts
- 16. Viral Infection Lysogenic Cycle Virus attaches to host cell Injects DNA Viral DNA incorporates itself into the host DNA Viral DNA can be dormant Once it becomes active, it follows the 4 processes in the lytic cycle
- 17. Phage Phage reproductive cycles Attaches 1 to cell Phage DNA Bacterial chromosome Cell lyses, releasing phages Phage injects DNA 7 2 Many cell 4 divisions Lytic cycle Lysogenic cycle Phages assemble Phage DNA Lysogenic bacterium reproduces Prophage circularizes normally, replicating the prophage at each cell division 3 5 6 OR New phage DNA and Phage DNA inserts into the bacterial proteins are synthesized chromosome by recombination Figure 10.17
- 18. Viral Infections Retrovirus: Geneticinformation is RNA Produces DNA copy and creates a prophage Envelope Glycoprotein Protein coat Example: RNA (two HIV/AIDS identical strands) Reverse transcriptase
- 19. 19.3 Diseases Causedby Bacteria and Viruses Pathogens- disease causing agents Bacterial Disease Viral Diseases
- 20. Diseases Caused byBacteria How does bacteria produce disease? Damage the cells and tissues by breaking down the cells for food Releasing toxins (poisons into the body)
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- 23. Diseases Caused byViruses Viruses disrupt the body’s normal equilibrium Cannot be treated with antibiotics Viruses can infect humans and plants
- 24. Viruslike Particles Viroids- singlestranded RNA molecule with no capsid They cause diseases in plants Infect cell and produce more viroids by disrupting the plant metabolism
- 25. Viruslike Particles Prions- containonly protein; no DNA or RNA They cause diseases in animals and humans Prions clump and cause normal protein to clump with it- creating new prions