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Microbiology : Unit 2 : Bacteria

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    1. Microbiology : Unit #2 : Bacteria Bacteria are small living organisms found almost everywhere on the earth. Bacteria are prokaryotes which are typically unicellular. Bacteria are classified into the monera kingdom.

    2. Classification of Bacteria Bacteria are classified into two major groups : archaebacteria and eubacteria. Archaebacteria : live without oxygen, and obtain their energy from inorganic compounds.

    3. Archaebacteria Archaebacteria can survive and thrive in harsh environments. Examples of archaebacteria include : methane-producting bacteria in cows stomachs, salt-loving bacteria, and heat and acid loving bacteria which thrive in hot springs.

    4. Archaebacteria Archaebacteria found in the stomachs of cows allow for the cow to break down and digest the cellulose in plant cells. These bacteria help cows turn cellulose into glucose. The bacteria produce methane gas in this process.

    5. Eubacteria Eubacteria display a wide array of habitats and metabolism. Eubacteria are divided into groups including : Heterotrophs Photosynthesic Autotrophs Chemosynthetic Autotrophs

    6. Eubacteria Eubacteria differ from Archaebacteria in differences of cell walls, plasma membrane, and sequence of DNA bases.

    7. Eubacteria Most common bacteria are classified as eubacteria. Eubacteria include the phostosynthetic bacteria called cyanobacteria. Cyanobacteria include many different colors, based upon the pigments they contain to trap sunlight to make their own food.

    8. Bacteria Structure Bacteria have different shapes and structures, but a structures found in bacteria include : Flagella (some) Capsule (some) Cell wall Plasma membrane DNA Pili (some)

    9. Bacteria Structure/Function Flagella : allows movement Pili: extensions of plasma membrane, help sticking Plasma membrane: lipid layer Capsule: extra barrier (gelatinous), bacteria with capsules are more likely to cause disease. DNA: genetic material for the cell Cell Wall: rigid, protection for cell, different composition with different bacteria.

    10. Bacteria Shapes Most bacteria are found in colonies. Bacteria can be round, spiral, or rod shaped. Round : coccus Spiral : spirillum Rod : bacillus

    11. Bacteria Groups Bacteria are also classified into the shape of groups or colonies they form. Diplo : paired cells Staphylo: grapelike clusters Strepto: long chains

    12. Journal Activity #1 Using the website below answer the following questions: 1) Describe archaea microbes, and the thermophiles, halophiles, methanogens, and psychrophiles. Name two different bacteria found in the Friend or Foe section of the website. Include its function and other information you can gather about it. http://www.microbe.org/index.html

    13. Journal Activity # 1 Describe the work that Ali S. Khan does as an epidemiologist. Include a brief description of the outbreak of a virus in 1993 in the Southwest U.S. ( Careers tab)

    14. Bacteria Metabolism Most bacteria require oxygen to metabolize. These bacteria are called obligate aerobes. Bacteria which dont use oxygen, and are killed by it are termed obligate anaerobes.

    15. Endospores Some bacteria when faced with unfavorable conditions form an endospore. An endospore has a hard outer covering which is resistant to drying out, or temperature, etc. When conditions are favorable the endospore germinates and reproduces.

    16. Botulism One group of bacteria called clostridia, can form endospores. Clostridium botulinum, produces a toxin. If canned food is not properly sterilized these endospores can become active inside a can and the disease botulism can occur.

    17. Bacteria Reproduction Bacteria reproduce by the process of binary fission. Binary fission involves the copying of the DNA and the splitting into two new cells.

    18. Bacteria Reproduction Under optimum conditions bacteria can reproduce every 20 minutes. Bacteria reproduction is controlled by various factors including : temperature and food availability.

    19. Conjugation Some bacteria can reproduce sexually in a process called conjugation. In conjugation one bacteria is able to transfer its DNA into another bacteria by means of a pilus (pili)

    20. Journal Activity #2 Use the website below to describe the following bacteria. Include the shape and other information: Escherichia coli 0157:H7 Staphylococcus aureus Salmonella enteritidis Clostridium tetini http://www.cat.cc.md.us/~gkaiser/goshp.html

    21. Bacteria- Cell Wall Structure Bacteria are divided into two groups based upon the composition of their cell walls. Gram positive : two layers ( lipid, peptidoglycan sugar/amino acids network) Gram negative : three layers, lipid, peptidoglycan, and lipopolysaccharide.

    22. Antibiotics Bacteria have a cell wall which gives protection. The cell walls of bacteria are made of long sugar chains linked with short amino acid chains. Most bacteria live in a hypotonic environment. (This means theres usually more water outside the cell than inside the cell)

    23. Antibiotics Most antibiotics aim to break down part of the cell wall to cause water to move in and rupture the bacteria cell. Penicillin is one bacteria to work this way.

    24. Journal Activity #3 Using the internet or textbooks answer the following : 1) Describe the discovery of the first antibiotic penicillin. 2) Describe one other antibiotic and explain how it works to kill bacteria cells.

    25. Bacteria/Uses Bacteria can be helpful or harmful to humans. Bacteria play many different roles in their environment. A few ways humans use bacteria is in the production of yogurt, swiss cheese and pickles.

    26. Bacteria One major role of bacteria in the envrironment is to fix nitrogen from the atmosphere into a useable form for plants. Several species of bacteria living in the soil have the ability to take diatomic nitrogen (N2) and convert it into ammonia (NH3). Other bacteria convert this ammonia into nitrite (NO2) and nitrate (NO3)

    27. Nitrogen Fixation Some nitrogen fixing bacteria form symbiotic relationships with legumes. ( beans, peas, soybeans, peanuts, etc.) These bacteria live on the roots of the plants and add nitrate and nitrite (useable forms of nitrogen for plants) into the soil. These crops are sometimes grown in off years to enrich the soil with useable nitrogen

    28. Bacteria - Decomposers Bacteria break down organic matter in dead organisms. These heterotrophic bacteria help recycle nutrients from dead plants and animals back into the soil.

    29. Bacteria Bacteria are very metabolically diverse. Different bacteria produce different waste products during fermentation. (Making ATP without oxygen) These waste products are used to make different food products (yogurt/pickles/swiss cheese/ sauerkraut/ vinegar, etc)

    30. Bacteria Bacteria also are used to make antibiotics. Some helpful bacteria will produce chemicals which will kill pathogenic bacteria. Streptomycin and erythromycin are a few examples of antibiotics made from bacteria.

    31. Journal Activity #4 Use the internet and other sources to answer the following: 1) Pick one food which bacteria is used to produce and explain what bacteria does for the process. 2) Wastewater (sewage) plants use bacteria extensively. Research and describe how bacteria is used wastewater plants.

    32. Harmful Bacteria Most bacteria are not harmful, but a few cause disease in animals and plants. Its estimated that about half of all human diseases are caused by bacteria.

    33. Bacteria Caused Diseases Bacteria can cause the following diseases: Tuberculosis Pneumonia Strep throat Staph infections Scarlet fever Syphilis Gonorrhea Chlamydia Boils Tetanus Lyme disease Ear infections

    34. Bacteria and Disease Bubonic Plague/Black Death. In the 1330s the bubonic plague originated in China. This disease caused by bacteria spread quickly to England and other parts of present day Europe. This bacteria was mainly found on rodents but fleas are thought to have carried it to humans.

    35. Bubonic Plague The bubonic plague killed an estimated 1/3rd of all Europeans. The bacteria caused boils which started as red bumbs on the skin, and then turned into black dots. Black Death. The bacteria Yersinia pestis is thought to have caused this disease.

    36. Pneumonia Pneumonia is a disease which can be caused by a virus or bacteria. Pneumonia involves a build-up of the pathogen in the lungs or respiratory system. The most common pneumonia is caused by the bacteria Streptococcus pneumonia. This bacteria grows in the lungs, causing the disease.

    37. Other Bacterial Diseases Many sexually transmitted diseases (STDs) are caused by bacteria. Gonorrhea Syphilus Chlamydia