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Bacteria and Viruses: Characteristics, Replication, and Impact

This chapter explores the characteristics of bacteria and viruses, including their structures, modes of replication, and the impact they have on human health and the environment.

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Bacteria and Viruses: Characteristics, Replication, and Impact

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  1. Chapter 20 Bacteria and Viruses! Open a textbook to p. 574 https://www.youtube.com/watch?v=NeZgwR4DcWM

  2. Virus Latin for “poison” A virus is a particle that can only be seen with an electron microscope.

  3. Viruses are not cells and are not made-up of cells. They don’t… • Contain a nucleus or cytoplasm • Eat • Grow • Carry on respiration • Or reproduce on their own

  4. Sketch the bacteriophage virus in your notebook

  5. A virus is surrounded by a capsid (protein coat) which determines the shape of the virus. The capsid contains nucleic acids (either DNA or RNA). Tail fibers for attachment to host cell.

  6. Viruses are classified by: • type of host cell • presence of DNA or RNA (retroviruses) • shape: Binal Polyhedral Filo

  7. Examples: VIRAL DISEASES

  8. Viral Habitat = EVERYWERENo energy use required. • Some lay dormant for years • Some hide in a vector • Reservoir host animals like rats, bats, mosquitos can pass viruses to humans • Because they are non-living, they don’t require energy or air • How do viruses infect your body? https://www.youtube.com/watch?v=Rpj0emEGShQ

  9. VIRAL REPLICATION Viruses replicate in one of two ways: • Lytic—makes you sick right after infection • Lysogenic—may lay dormant for YEARS! Then enters lytic cycle

  10. Human Concerns: Most viruses have NO cure (Influenza, & HIV), but some viruses like Smallpox have vaccines. Vaccines contain a weakened or killed virus that provides immunity to the disease. How Vaccines Work: https://www.youtube.com/watch?v=3aNhzLUL2ys&t=127s

  11. BACTERIAChapter 20p.580

  12. Draw and label a bacterial cell in your notes!

  13. Size: Small few micrometers (um) long Cell Type: Prokaryotic Body Type: Unicellular Found: Everywhere!! Are they bad? Many Cause Disease Many are Useful Characteristics of Bacteria

  14. Two DOMAINS: Archaebacteria and Eubacteria • Eubacteria • Considered “true bacteria” • Have peptidoglycan. • Live almost everywhere. Archaebacteria • Are ancient! • Lack peptidoglycan. • Live in harsh environments • Salty lakes • Thick mud • Deep ocean vents • Guts of animals

  15. Characteristics Continued • Body Structure:May have flagella (whips) or cilia (hairs) • for movement • Have a cell wall • May contain peptidoglycan(a sugar & protein polymer)

  16. Characteristics Continued • 3 Possible Shapes: • Coccus (Cocci)- round • Bacillus (Bacilli)- • rod shaped • Spirillum (Spirilla)- spiral

  17. Prefixes Used to Describe & Identify Bacteria: • Diplo = 2 • Neisseria meningitidis • (aka diplococcusmeningitidis) • Strepto =chain • Streptococcus pneumonia • Staphylo =clumps • Staphylococcusaureus

  18. Identification Continued • Gram Staining - used to identify bacteria with extra membranes • Extra membrane helps them to better resist damage. • Gram+stain purple(have peptidoglycan) • Gram– stain red(extra membrane)

  19. Food Deep Ocean Vent Eubacteria Compost Archaebacteria Hot Spring Pool @ Yellowstone Cavities

  20. Sources of Energy • Can be autotrophs or heterotrophs • Autotrophs: Photoautotrophs - use light to make food ex: Cyanobacteria (blue-green algae) • Chemoautotrophs -use chemical to make food • ex: Anabaena (nitrifying bacteria) • Heterotrophs: • * Chemoheterotrophs - require nutrition; no photosynthesis (includes many parasites) • * Photoheterotrophs - photosynthetic

  21. Growth & Reproduction • They can reproduce in 3 ways: Binary Fission: splitting in half

  22. 2. Conjugation: swapping genes over a bridge between two bacteria

  23. 3. Spore Formation- endospores form so that bacteria can remain dormant in harsh conditions and then germinate when conditions become favorable

  24. Bacterial Diseases and Treatments Diseases Treatments Antibiotic Apocalypse: https://www.youtube.com/watch?v=xZbcwi7SfZE Rise of the Superbugs: https://www.youtube.com/watch?v=fyRyZ1zKtyA&t=6s

  25. Symbiotic relationships (Mutualism): - E.coli in the intestines aid in digestion and produce vitamins in exchange for food and a warm home.

  26. Biowarfare: Anthrax • Bacillus anthracis • Commonly known as anthrax • Lives in the soil and forms spores • Can be fatal

  27. Helpful Bacteria • Decomposers • Nitrogen Fixation • Photosynthesis (oxygen) • Oil spill clean up • Digestion aid & vitamin production • Foods such as cheese and yogurt • Medicines • Biowarfare

  28. Careers with Bacteria • Microbiologist - studies and cultures bacteria • Epidemiologist -Study infectious diseases and how they spread. • Food Safety Inspector- check slaughtered animal carcasses for disease or bacteria

  29. Bacteria Collection! • With a partner, get a petri dish • Choose 3 locations nearby to test for bacteria • Swab the area, then GENTLY swab the agar area on the plate. • Label with your names, per. • Seal with Parafilm • Place in incubator to grow • We will check these in a few days!

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