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BACTERIA ON YOUR CLOTHES… VIRUS IN YOUR NOSE. Look out, you’re surrounded! Bacteria and viruses are all around us…. Examples: Bacteria Used in Food Making Bacteria used in Digestion ( E. coli ) Some bacteria cause disease (pathogenic) ALL viruses cause disease (all pathogenic).
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Look out, you’re surrounded! Bacteria and viruses are all around us…. Examples: Bacteria Used in Food Making Bacteria used in Digestion (E. coli) Some bacteria cause disease (pathogenic) ALL viruses cause disease (all pathogenic) BACTERIA & VIRUSES
Bacteria Structure
LIVING, microscopic and lacking internal membranes Prokaryotic
Bacteria cells are usually much smaller than plant and animal cells and do not contain as many internal structures.
Bacteria cells contain cytoplasm surrounded by a cell membrane and a cell wall.Its hereditary material is found in the cytoplasm.
Some bacteria have a thick, gel-like capsule around the cell wall to protect it.
Bacteria in moist environments have whiplike tails called flagella that help them move.
Let's review what we know about bacteria.
Archaebacteria and Eubacteria
Archaebacteria Bacteria that live in harsh environments (extremophiles) where few kinds of other organisms can live: * methanogens: * thermophiles: * halophiles
Eubacteria The larger of the two groups of bacteria. These usually live in less harsh environments.
Most bacteria are beneficial.All bacteria that cause known diseases are eubacteria.
Bacteria can be classified according to: • Shape • Cell Walls • Movement • Metabolic diversity • (the way they obtain energy)
There are three major shapes of bacteria.
Sphere-shaped bacteria (cocci) sometimes grow in chains or in clumps like abunch of grapes. Streptococcus(strep throat)Staphylococci (responsible for "staph" infections and gangrene) Cocci
Rod-shaped bacteria (bacilli) can also form in chains. Some types of these bacteria also have whiplike structures called flagella to help them move around. Escherichia coli or E.coli(found in the intestines of mammals)Salmonella typhi(causes typhoid fever and food poisoning) Bacilli
Spiral-shaped bacteria (spirilla) can use their shape to propel themselves by twisting like a corkscrew. Treponema pallidumcholera(syphilis)Borrelia burgdorferi (Lyme disease) Spirilla
Bacteria are often found in groups or colonies.
Bacterial Colony Types
Monococcus - a singlespherical bacterium, living alone Diplococcus - twospherical bacteria, living in a pair Streptococcus: chains of nearly spherical bacteria. Streptobacillus: chains of rod-shaped bacteria. Staphylococcus : spherical bacterium occurring in grape-like clusters. Staphylobacillus - a cluster of rod shaped bacteria
Streptococcus Streptococcus: chains of nearly spherical bacteria.
Streptobacillus Streptobacillus: chains of rod-shaped bacteria.
Staphlococcus Staphylococcus : spherical bacterium occurring in grape-like clusters.
Other ways to classify and identify bacteria...
Gram stain Some cell walls change colors when stained and other cell walls do not. The bacteria that have the stained cell walls are called Gram positive (have much peptidoglycanin cell walls). The bacteria with cell walls that do not stain are called Gram negative (no peptidoglycan). Doctors regularly use gram staining to select the proper antibiotic to treat bacterial infections.
How do bacteria reproduce?
Bacteria reproduce by means of binary fission, in which a copy of the DNA is made and then the outer membrane of the bacterium begins to grow inward and divides into two identical cells. Also, to exchange genetic material one bacterium attaches itself to another bacterium and introduces DNA directly into it by means of a pilus through the process of conjugation.
Some bacteria are able to produce thick walls around themselves when evironmental conditions are unfavorable. They form an endospore and can become dormant for hundreds of years.
Aerobic bacteria require oxygen to survivebacteria can live with or without oxygenbacteria use other organisms for energybacteria produce their own food through photosynthesis Anaerobic Heterotrophic Autotrophic
Bacteria and your Health
Bacteria doesn’t just make you sick, it can also keep you healthy. You cannot survive without some bacteria living in or on your body.(Ex: E. coli in digestive tract)
Some bacteria produce chemicals called antibiotics that limit the growth of other bacteria. Overuse of antibiotics has led to more resistant bacteria.
Pathogen Bacteria that cause disease are called pathogens.A vaccine is made from a deadened or weakenend version of a virus or bacterium. Immunization with certain vaccines can prevent other bacterial diseases.
Many pathogens produce poisons called toxins as they grow in your body or as they grow in food that you might eat. Toxins
Botulism is a type of food poisoning that is the result of a toxin produced by bacteria whose endospores can survive in canned food.
Bacteria and Industry
Cheeses, buttermilk, chocolate, vinegar, sauerkraut Food made with bacteria
Pasteurization is a process that is used to kill most harmful bacteria and lengthen the time foods can be stored without spoiling.
Courtesy of: Quiz time!
At any given time you have about a billion bacteria on every tooth in your mouth.
True. Warm and moist, your mouth is a breeding ground for bacteria. Some of these bacteria feed on bits of food trapped between the teeth. Immediately after brushing you still have up to a hundred thousand bacteria living on each tooth! Photograph by David Scharf/Peter Arnold Inc.
Swamps produce terrible odors because owls shower them with nasty-smelling antibacterial sprays.