Ch. 19 Bacteria and Viruses 19.1 Bacteria Review: Prokaryote and Eukaryote 2 Groups of Prokaryotes Prokaryote has no nucleus, bacteria Eukaryote has nucleus, plants, animals, fungi Archaebacteria Cell wall DOES NOT have pepkdoglycan Different membrane lipids DNA more closely resemble eukaryotes May live in extreme environments Eubacteria Cell wall has pepkdoglycan Very diverse ArKcle on PepKdoglycan hqp://blogs.scienkficamerican.com/disease- prone/2011/09/14/pepkdoglycan- the- bacterial- wonder- wall/ IdenKfy prokaryotes by: 1. Shape 2. Cell wall composikon 3. The way they move (mobility) 4. The way they obtain energy 1
1/30/14 1. Shapes Bacilli rod shaped Bacilli (bacillus)- rod shaped Cocci (coccus)- spherical shaped Spirilla (spirillum)- spiral shaped Cocci spherical Spirilla corkscrew- shaped 2. Cell wall composikon- Gram Staining 3. Mobility Gram- posikve contain pepkdoglycan, stains purple Has only one cell wall Gram- negakve no pepkdoglycan, stains red or pink Flagella Lash, snake or spiral forward gliding Has an outer layer of lipid and carbohydrates = more difficult to kill 2
1/30/14 Flagella Gliding 4. Obtaining Energy 4.b Releasing Energy Heterotrophs Take in organic molecules for energy and carbon Chemoheterotrophs photoheterotrophs Autotrophs Convert inorganic molecules to make food Photoautotrophs Chemoautotrophs ReproducKon Energy released by cellular respirakon and/or fermentakon 1. obligate aerobes must have oxygen 2. Obligate anaerobes must NOT have oxygen 3. FacultaKve anaerobes may/may not have oxygen Binary fission: 1. Binary Fission- asexual form 1 cell divides into two 2. ConjugaKon sexual form 2 cells exchange DNA through a hollow tube 3. Spore formakon Allows bacteria to survive during unfavorable condikons 3
ConjugaKon Spores Why is Bacteria important? Capture energy through photosynthesis Decomposers break down organic maqer Nitrogen fixers on roots of plants to help them get usable nitrogen Human uses Food and beverages, waste treatment List of foods and drinks made with Bacteria hqp://en.wikipedia.org/wiki/ List_of_microorganisms_used_in_food_and_b everage_preparakon What is a virus? 19.2 Viruses 1. Non- living organism that infect living cells 2. ParKcles of nucleic acid (DNA or RNA), protein and somekmes lipids 3. Outer covering = capsid a) Has proteins that allow it to get inside cells b) Also has proteins that can trick cell into NOT recognizing it is a virus 4
What is a virus? Different types of viruses 4. Vary in shape, but are smaller than bacteria 5. Species- specific can only infect certain organisms Viral InfecKon p. 481 1. LyKc infeckon short infeckon, lasts a few days to a week Examples: common cold, flu, AIDS, Ebola a) Virus enters the cell b) Makes copies of itself c) Causes the cell to burst, releases many viruses into the body Viral InfecKon Viral InfecKon (copy diagram) 2. Lysogenic InfecKon long- term infeckon Examples: HIV, Herpes a) Virus injects DNA into host cell b) Host cell copies viral DNA along with its own c) Every Kme the host cell divides, it makes a new cell containing the viral DNA d) Something triggers the virus to come out of dormancy, then enters the lykc cycle 5
Structure: Viruses DNA or RNA and Protein Living Cells Cell membranes, nucleus, organelles, cytoplasm Reproduction: Only inside host Asexual or sexual independent Genetic Code: DNA or RNA DNA 19.3 Growth: Obtain & Use Energy: No No Yes - increase in size and cell number Yes Diseases Caused by Bacteria and Viruses Respond to Environment: No Yes Change over Time: Yes Yes Pathogens Disease- causing agents I. Bacterial Disease in Humans Examples: Lyme disease, tetanus, tuberculosis, bacterial meningiks, strep throat A. 2 Ways Bacteria Cause Disease 1. Use cell/kssue for food 2. Release toxins into the body B. PrevenKng Bacterial Disease 1. Bacterial vaccine 2. AnKbioKcs block growth and reproduckon of bacteria ***Do not work on Viruses*** 6
II. Controlling Bacteria 1. SterilizaKon by heat kill all bacteria by exposure to high heat 2. Disinfectants using chemical s to kill bacteria 3. Food preperakon and storage Store in refrigerator Freeze Boiling, frying, steaming Pickling canning III. Viral Diseases in Humans Viruses produce disease by disrupkng homeostasis Examples: common cold, flu, AIDS, chicken pox, hepakks B, West Nile A. PrevenKng Viruses 1. Viral vaccines 2. OTC medicakons to help with symptoms does NOT cure viruses Animal Viruses SomeKmes enkre groups/herds of animals will be killed C. Plant Viruses Tobacco mosaic virus infects agricultural crops Harder to infect plant cells than animal cells Enter through tears in leaves, roots, and stems 7
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