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Domain Bacteria Kingdom Eubacteria General Characteristics Prokaryotes (No membrane-bound organelle) Have Plasmids, circular DNA Unicellular (single-cell) Cell Walls can contain peptidoglycan, not cellulose First life forms, appeared approximately 3.5 BYA Typical Prokaryote Cell Structure Bacteria Escherichia coli E. coli Oxygen Preferences for Bacteria Obligate aerobes are organisms which must have oxygen to live. Obligate anaerobes cannot live in the Nutrition Autotrophs- organisms that can make their own foods. Photosynthetic autotrophs- use light energy H20 & CO2 to make their foods. Chemosynthetic autotrophs – use inorganic compounds like Hydrogen sulfide and ammonia. Heterotrophs- obtain energy by consuming organic compounds, they cannot make their own foods. Beneficial Uses Chemical Used recyclers (Nitrogen Cycle) in the dairy industry to make cheese, yogurts and sour cream. Genetic Engineering of HGH, Insulin, Etc… Oil spill cleanup Synthesis of Vitamins in your intestines Pathogens: disease-causing agents Escherichia coli (E. coli) – found in the intestines of mammals…. Can be deadly if the wrong species is eaten. Clostridium botulinum – causes “botulism” ….. food poisoning. Clostridium tetani – causes tetanus. 3 ways to prevent getting a foodborne bacteria 1. Keep cooked and raw foods separate. 2. Wash fruits and vegetables before eating them. 3. Refrigerate leftovers. Endospores thick-walled structures that are highly resistant to harsh environmental conditions (high temperature, drying, oxygen, etc.); generally formed only by bacilli, and then each cell only forms one. endospore Classification Considerations Gram-staining characteristics Cell shapes and Groups Methods of obtaining energy Chemical Composition of the Cell Walls Gram Staining Gram-negative cells lack the ability to retain the deep violet dye because they have little, if any, peptidoglycan in their cell walls…. They appear pink in color. Gram-positive cells have cell walls with large amounts of peptidoglycan which retain the deep violet dye and gives the cell a purple color. Bacteria Photos E. coli Which of these cells are Gram +, Gram - ? Clostridium tetani Bacteria Photos Staphylococcus aureus Neisseria gonorrhoeae Cell Shapes and Groups Spherical-shaped cells Coccus (sng) , cocci (pl) A Group of Two is referred to as: Diplo…….. This is diplococccus A Cluster of cells is referred to as: Staphylo…. This is Staphylococcus Staph Infection Methicillin-resistant Staphylococcus aureus ….MRSA can mutate quickly to become resistant to the newest “last resort” antibiotics ”Bacteria are smart, antibiotics are dumb” What a slide of Typical coccus looks like in a microscope. A Chain of cells is referred to as: Strepto…. This is Streptococcus Strep Throat Bacillus (sng) , Bacilli (pl) Rod-shaped cells Bacillus Typical Bacillus in a Microscope Spiral-shaped cells Spirillum (sng) , Spirlli (pl) Spirochetes Cyanobacteria are photosynthetic autotrophs that produce carbohydrates and oxygen tend to cling together in filaments or colonies The “heterocysts contain enzymes that allow them to “fix” atmospheric nitrogen Anabaena _ http://www.bio.mtu.edu/~jkoyadom/algae_webpage/ALGAL_IMAGES/cyanobacteria/Anabaena_jason_dbtow17 2016.jpg Some filamentous cyanobacteria have Heterocysts: which are Nitrogen-fixing structures http://www.people.vcu.edu/~elhaij/IntroBioinf/Scenarios/heterocyst2.JPG Oscillatoria http://botit.botany.wisc.edu:16080/images/130/Bacteria/Cyanobacteria/Oscillatoria/Oscillatoria_MC.jpg Nitrogen-fixation Some soil bacteria live in the ground and take in Nitrogen from the surroundings The Nitrogen is combined with oxygen to form nitrites and nitrates…. Plants use the nitrates and nitrites to make proteins…. (Grow !!) Asexual Reproduction Binary Fission – cells grow in size the split in two…. Genetically identical Sexual Reproduction in Bacteria (methods of exchanging DNA) Conjugation Two bacteria join together and transfer portions of DNA Antibiotics How do Antibiotics Work? Antibiotics can prevent bacteria from making new cell walls…. Therefore the bacteria cells will eventually burst and die. • • Can disrupt Protein Synthesis * Disrupt many other cell metabolic reactions