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Bacteria

Learn about bacteria, microscopic organisms that are both helpful and harmful. Explore their shapes, reproduction, survival needs, movement, and their impact on human health and the environment.

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Bacteria

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  1. Bacteria • The Good • The Bad • And… The Ugly!

  2. Bacteria • Microscopic and single-celled • Living and contains DNA • Mostly prokaryotic: no nucleus • Live on earth- in soil, air, water, plants, animals and people. • Group together in colonies (clusters or chains) • Some help humans digest food and protect against harmful bacteria.

  3. DID YOU KNOW? • Seconds after you were born, tiny organisms surrounded and invaded your body. • Millions of these organisms coat your skin. • As you sit in your desk listening to this presentation, they swarm inside your nose, throat, and mouth. • There are more of these organisms living in your mouth than there are people who are living on Earth.

  4. The human body has more bacteria than it has cells. An unborn baby is completely free of bacteria, but the instant they are born they acquire billions of bacteria. Bacteria are essential for a healthy body. www.pregnancy-leads-to-new-babies.com/ images/

  5. There are more than 10,000 kinds of bacteria and an unknown number still waiting to be discovered. www.elements-of-design.net/

  6. BACTERIA INFORMATION • Bacteria are classified into three groups according to their shape: round (cocci{kŏk‘sí}), spiral (spirilla{spí-rĭl'ə}), and rod (bacilli {bə-sĭlỉ}) shape. • Some round shape bacteria can cause infections in people. • Some spiral shape bacteria are used to make cheese. • Some rod shaped bacteria have been known to cause food poisoning. aquat1.ifas.ufl.edu/ guide/bacecoli.jpg www.redcolony.com/ pics/content/bacteria.jpg io.uwinnipeg.ca/.../ 27-03c-HelicalProkaryote.jpg

  7. Bacteria are so small that about 1,000 could fit on the head of a pin. www.agen.ufl.edu

  8. Bacteria Multiplication • Sexual reproduction • Two parents • Conjugation (transfer of genetic material through bridge) • Asexual reproduction • Binary Fission- Simply splitting in two • Let’s watch it!

  9. More on Growth • Rapid reproduction, as fast as once every 20 minutes • Continues until they run out of the basics • Food • Air • Space • Thrive in warm, damp places (e.g. human body, uncovered food)

  10. SURVIVAL NEEDS • Food • Water • Air • Waste Disposal • Temperature of Environment • Reproduction

  11. SURVIVAL NEEDS • Obtaining food • Autotrophs-Make their own food • Some make food by capturing and using the sun’s energy as plants do. • Some use energy from chemical substances in their environment to make food. • Heterotrophs-Obtain food by consuming autotrophs or other heterotrophs • Heterotrophic bacteria may consume a variety of foods- from milk and meat to decaying leaves on a forest floor.

  12. SURVIVAL NEEDS CONTINUED • Respiration-bacteria need a constant supply of energy to carry out their functions. This energy comes from food. The process of breaking down food to release its energy is call respiration.

  13. MOVEMENT • The typical bacterial cell has a flagellum (plural is flagella.) They may have many, one, or none. • A flagellum is a long, whip like structure that extends from the cell wall and helps the bacterium move by spinning like a propeller. • Most bacteria that do not have flagella cannot move on their own. Instead they depend on air, water currents, clothing, and other objects to carry them from one place to another.

  14. The Good:HELPFUL BACTERIA • How? • ~95% don’t hurt you!

  15. HELPFUL BACTERIA • Human Body • Helps our digestive system and helps fight off bad bacteria • FOOD • Cheese, yogurt, apple cider, sour cream • Environmental recycling • Bacteria that lives in the soil are decomposers • Organisms that break down large chemicals in dead organisms into small chemicals. • Decomposer- an organism, often a bacterium or fungus, that feeds on and breaks down dead plant or animal matter. (vocabulary section) • Environmental Cleanup • Some bacteria are used to convert the dangerous chemicals in an oil spill into harmless substances.

  16. Strep Throat Tooth Decay E coli Plague Tetanus Anthrax The Bad:Diseases Caused by Bacteria Health and Medicine and prevention Washing your hands, washing and protecting open wounds, and staying healthy by exercising are, ways to prevent bacteria from entering your body. Vaccines are a weakened form of the disease that are injected into a person. The person’s body then makes antibodies to prevent the actual disease.

  17. PREVENTING HARMFUL BACTERIA IN FOODS • Food manufacturers use a variety of methods to prevent harmful microbes from infecting foods. • Heating or cooling will affect the number of bacteria that can grow in it. • Boiling liquids at high temperatures destroys microbes. • Freezing food makes it too cold for microbes to grow quickly. • Six ways to control the growth of bacteria in foods are: • Pasteurization • Drying • Refrigeration • Freezing • Dehydration • Vacuum-pack • Pasteurization is a heating process to kill bacteria in foods.

  18. Canning first destroys bacteria through heating and then the food is placed in a sterilized container and sealed. • Drying removes water from the food that bacteria need to grow and reproduce. • Freezing slows down the spoilage process by changing water into ice; a form that the bacteria cannot use. • Pasteurization destroys most of the existing spoilage organisms by heating the food to a high temperature for a short duration. • Pickling or fermentation (culturing) leaves the food with a higher level of acid, making it an inhospitable environment for spoilage bacteria. • UHT (ultra-high temperature) uses heat higher than pasteurization: then pressure is applied resulting in a sterile product.

  19. Vacuum packaging uses a vacuum sealed, abrasion-resistant moisture-impermeable film that inhibits molds, yeasts, and bacterial growth on the surface of the things such as meat. Since there is no air in the package, vacuum-packaged meat will have a darker, purple color before being opened. Once the meat is exposed to oxygen, it will turn the familiar bright red color, because of the natural reactions within the package. Fresh vacuum-packaged meat will give off a slight odor when opened. The smell will dissipate within a few minutes. This should not be confused with spoilage. • Smoking adds smoke-born chemicals to food that help destroy potential spoilage organisms. • Chemical additives are designed to destroy spoilage organisms or inhibit their growth. Sugar and salt are examples of additives that have been in use for centuries. Both of these work by drawing water out of the spoilage organisms, thus preventing their growth.

  20. Irradiation is a process that pasteurizes food by using energy, just like milk is pasteurized using heat. Irradiation DOES NOT make food radioactive. The food never touches a radioactive substance. Irradiation destroys insects, fungi, and bacteria. Fewer nutrients are lost during irradiation than in cooking and freezing. Food irradiation has been approved in 37 countries for more than 40 products. Astronauts have eaten irradiated foods for years. • Food additives are any substances added to food. Sugar, salt, and corn syrup are the most commonly used food additives. Food additives keep foods fresh, slow microbial growth, give desired texture and appearance, and aid in processing and preparation.

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