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notes of bacterai

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  • notes of bacterai

    Bacteria are simple organisms that consist of one cell lacking a nucleus (prokaryotes). They are among the smallest living things on earth and can only be seen through a microscope.

    Bacteria were likely the only form of life on earth for over two billion years, although they were only first observed them in the late 1600’s by a scientist, Anton van Leeuwenhoek, who was using a microscope to look at scrapings from his teeth. Bacteriology as an applied science began to develop in the 19th century.

    Bacteria are amazingly adaptable to varied environmental conditions. They are found in the bodies of all living organisms and on all parts of the earth and ocean depths, soil, air, Artic ice and glaciers, in hot springs, water, and even in volcanoes. Some can live only deep below the earth’s surface or without sunlight in the high temperature and pressure near hydrothermal vents on the ocean floor.

    There are more bacteria, as separate individuals, than any other type of organism. There can be as many as 2.5 billion bacteria in one gram of fertile soil.

    Characteristics

    Bacteria are grouped in a number of different ways. Most bacteria are of one of three typical shapes: rod- shaped (bacillus), round (coccus, e.g., streptococcus), and spiral (spirillum). The cytoplasm and plasma membrane of most bacterial cells are surrounded by a cell wall. Many bacteria, primarily the rod-shaped and spiral forms, are able to move themselves, swimming about by whip like movements of flagella. The flagella move the cell about by spinning in place like a propeller. A bacterial cell can have many flagella, one, or none. However, most bacteria that do not have flagella cannot move on their own, instead depending on air, water currents, clothing, or other things to carry them from place to place.

    All types of bacterial need certain things to survive: source of food and a way of breaking down the food to release energy. Some bacteria make their own food. This can be done in two ways. Some bacteria make food by capturing and using the sun’s energy as plants do. Others use the energy from chemical substances in their environment. An example of these is the bacteria that live on the ocean floor near the deep-sea vents, where sunlight does not reach. The process of breaking down food to release energy is called respiration. Like many other organisms, most bacteria need oxygen for respiration. However, there are a few kinds that do not, and some may even die in the presence of oxygen.

    Helpful Bacteria

    Most of the ways bacteria interact with living organisms are harmless or positive. How many of you have natural gas in your homes as a form of heat or for the stove? This natural gas is the result of bacterial that died millions of years ago.

    How many of you like cheese? Yogurt? Apple cider? Olives? Sauerkraut? Bacteria are involved in the production of all of these common foods. For example, bacterial that grow in a liquid poured around fresh cucumbers turns the cucumbers into pickles. Bacteria that grow in apple cider change the cider to vinegar. Bacteria that grow in milk produce dairy products such as buttermilk, sour cream, yogurt and cheese.

    Certain types of bacteria live in the intestines of humans and animals. These bacteria help in digestion and in destroying harmful organisms. Intestinal bacteria also produce some vitamins needed to help the human body. Some compete for space with disease-causing organisms, preventing harmful bacteria from attaching to your intestines and making you sick.

    Bacteria in soil and water play a vital role in recycling carbon, nitrogen, sulfur, and other chemical elements used by living things. Many bacteria help decompose dead organisms and animal wastes into chemical elements. These elements are then available for other living things to reuse.

    Pathogenic Bacteria

    How many of your have had strep throat? Food poisoning? Bacteria that cause such infectious diseases are called pathogens. Other infectious diseases caused by bacteria include tuberculosis, cholera, syphilis, typhoid fever, and tetanus. Some bacteria attack the tissues directly; others produce poisonous substances called toxins.

    Our own natural antibodies provide a defense against harmful bacteria. Certain bacterial diseases, e.g., tetanus, can be prevented by injection of antitoxin or of serum containing antibodies against specific bacterial antigens; immunity to some can be induced by vaccination; and certain specific bacterial parasites are killed by antibiotics.

    New strains of more virulent bacterial pathogens, which may be resistant to antibiotics, have appeared in recent years. Many believe this is due to the overuse antibiotics to treat minor ailments.

    Antibiotics

    Antibiotics are chemicals that call kill bacteria without harming a person’s own cells. They do this by inhibiting bacteria growth. In the beginning antibiotic referred only to natural compounds. They are produced by bacteria. Penicillin is the most familiar antibiotic and has been used to fight many infectious diseases including syphilis, gonorrhea, tetanus, and scarlet fever. Another antibiotic, streptomycin, has been used to fight tuberculosis.

    Antibiotics are mainly useful for treating infections caused by bacteria. Antibiotics came into general use during the 1940’s. At the time, they were often called "wonder drugs" because they cured as many bacterial diseases that were once fatal. However, they are not effective against colds, influenza, or viral diseases. The effectiveness of antibiotics is limited because both pathogenic microbes (bacteria) can become resistant to them.

    How Antibiotics Work

    Antibiotics fight bacterial cells by interfering with normal cell functions. The interference occurs in one of three ways: prevention of cell wall formation, damage to cell membrane, or disruption of chemical processes.


    Introduction to bacteria
    Bring in different pictures of types of bacterai: different colors, textures, sizes
    First look at pictures, then swing to Purell activity
    Concept of resistance – Purell hand gel
    Draw and X on hands and show that Purell doesn’t take it off, but it is supposed to be a cleansing product. What does it do?
    Are your hands clean? Almost? Is that good enough?
    What can happen? Antibacterial resistance?
    How do we know something is resistant to antibodies? Need something to compare it to.
    Concept of a control
    Point of comparison
    If something happens in an experiment, how do I know that it’s important? Let baking soda sit on a counter, nothing happens. Put vinegar in the baking soda and it “explodes.”
    Flash back to pictures, and give a 5 minute preview of Tuesday. Hook to the potential harm that some bacteria could do to the human race if they were to develop resistance to our drugs. Emphasize that we will be using a type of bacteria that is not harmful to humans, so they will not be exposed to anything bad. Talk about plating bacteria and that they grow on agar.
    مهما طال الليل لابد من صباح :sm200::sm188::sm199::sm187::sm198:

  • #2
    موضوع عام

    شكرً لك
    الله يعطيك العافية

    تعليق


    • #3
      ايمن كلام مضبوط يعطيك العافية اخوي
      ،، اللهم اغفر لحينا وميتنا ،،
      ،، وشاهدنا وغائـبنا ،،
      ،، و صغيرنا و كبيرنا ،،
      ،، و ذكـرنا و أنـثـانـا ،،
      ،، اللهم من أحييته منا فأحيه على الإسلام ،،
      ،، ومن توفيته منا فتوفه على الإيمان ،،

      " اللهم اغفر لي ولوالدي ولأجدادي ولأقربائي ولجميع المسلمين والمسلمات الأحياء منهم والأموات يا حي يا قيوم يا ذا الجلال والإكرام "

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      • #4
        مشكورين .............لايكتمل الموضوع الابمروركم
        مهما طال الليل لابد من صباح :sm200::sm188::sm199::sm187::sm198:

        تعليق


        • #5
          كلام جميل ولكن ايظا عزيزي ايمن ينقصه الترتيب ليس الا
          وشكرا علي مجهودك الدائم

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          • #6
            موضوع جميل ورائع

            تعليق


            • #7
              antivirus........bohadram...........اسعدنى مروركم وتعليقاتكم
              مهما طال الليل لابد من صباح :sm200::sm188::sm199::sm187::sm198:

              تعليق


              • #8
                بارك الله في علمك وجازاك كل خير وإلي الأمام تقدم.

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