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Kingdom Monera Chapter 17-2
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Bacteria Bacteria or one-celled prokaryotes are cells without a nucleus and they’re found everywhere! Bacteria are very small; as they don’t have membrane bound organelles like eukaryotes. All Prokaryotes are placed in two kingdoms: the Eubacteria or the Archaebacteria.
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Kingdom Eubacteria Larger kingdom Cell wall made of complex carbohydrates (protection) Cell membrane, which surrounds the cytoplasm. Copy Figure 17-8
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Cyanobacteria: known as the blue green bacteria. Photosynthetic Contain pigment phycocyanin (blue) Contain pigment chlorophyll a (green) The membranes that contain these pigments are different from chloroplast in plant cells. Found everywhere, salt water, fresh water, land, hot springs, and arctic Kingdom Eubacteria-Examples
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Prochlorobacteria: Newly discovered group Contain chlorophyll A & B This makes them more similar to plants. Kingdom Eubacteria-Examples
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Kingdom Archaebacteria Lack complex carbohydrate in cell wall Live in extremely harsh environments
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Methanogens: live in oxygen free environments like thick mud and the digestive tracts of animals. Other archaebacteria live in salty environments & hot springs. Kingdom Archaebacteria
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Identification- Cell Shape 1.Rod or bacilli 2. Spherical or cocci ( coccus Greek word for berries ) 3. Spiral shaped or spirilla Bacteria can also arrange themselves in chains, clusters or pairs. For example: streptococcus form long chains.
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Streptococcus Lactobacillus, Pseudomonas Vibrio, Triponema
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Grouping Diplo- Pairs Streptos- Chains Staphylo- Clusters
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Examples of Spherical-shaped cells Coccus (sng), cocci (pl)
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A Group of two is referred to as: Diplo This is diplococccus
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A Cluster of cells is referred to as: Staphylo This is Staphylococcus
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A slide of typical coccus looks like this in a microscope.
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Coccus
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Streptococcus aurelius
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Strep Throat
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Staph Infection
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Rod-shaped cells Bacillus (sng), Bacilli (pl)
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Typical Bacillus
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Bacillus
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Spiral-shaped cells Spirillum (sng), Spirlli (pl)
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Spirochetes
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Cell Wall We use a method called gram staining to determine what kind of cell wall a bacterium has. Gram stains consists of two dyes: crystal violet (purple) and safranine (red). The bacteria will take up either the purple or the red stain.
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Two kinds of cell wall: 1. One thick layer of carbohydrate and protein molecules. Turns purple: called Gram-positive bacteria 2. Has a second layer of lipid and carbohydrate molecules. Turns red: Called Gram-negative bacteria Cell Wall
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Movement Propel with one or more flagella Others lash, snake or spiral forward Others glide in their own slime like material No movement
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How Do Bacteria Obtain Energy? Phototrophic autotrophs trap the energy from the sun like plants. Chemotrophic autotrophs- use energy from inorganic compounds (sulfur, iron, nitrogen) to build organic compounds. -Live in harsh environments
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Chemotrophic heterotrophs- obtain energy by taking in organic molecules and breaking them down. Ex. Most bacteria and animals. Salmonella competes with us for food by growing in raw meat, poultry and eggs. Phototrophic heterotrophs- they can use the sunlight for energy, but also need organic compounds for nutrition. How Do Bacteria Obtain Energy?
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Respiration and Fermentation (with or without oxygen) Obligate aerobes: any organism that requires a constant supply of oxygen to survive. Obligate anaerobes: must live in the absence of oxygen. Ex: Clostridium botulinum Facultative Anaerobes: doesn’t require oxygen, but isn’t poisoned by its presence. How Do Bacteria Obtain Energy?
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Binary Fission: (asexual reproduction) once a bacterium has doubled in size it replicates its DNA and splits into two identical daughter cells. Types of Bacterial Reproduction
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Conjugation: (sexual reproduction) genetic information is exchanged across a protein bridge that connects two separate bacteria cells. Types of Bacterial Reproduction Note: when environmental conditions are poor, bacteria can for a thick wall called an endospore, which protects the bacteria until external conditions improve.
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Beneficial Roles of Bacteria Production of yogurt, cheese, buttermilk. Clean up of oil spills by digesting petroleum Symbiotic relationships with other organisms. Ex. (humans and E. coli ) (bacteria produce enzyme that enables cows to break down cellulose)
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Recycle, decompose or break down dead material. Break down of human sewage. Nitrogen fixing bacteria. Fig 17-18 Beneficial Roles of Bacteria
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Bacterial Diseases- Examples Diphtheria Tuberculosis Typhoid fever Tetanus Anthrax Botulism Lyme Disease Salmonella Tooth decay
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Controlling Bacteria Antibiotics Heat, disinfectants Refrigeration Sterilization by boiling, frying, steaming, canning, Salting and pickling.
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