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WARM UP: What is a microbe? What are the four types of microbes we will be studying? • Before we get started: check your agar plates. Make observations on your lab sheet. Return your agar plate to the incubator. • DO NOT OPEN THE LID!!!!!!! 1 Introduction to Bacteria 2 TYPES OF BACTERIA: •Bacteria -Get food from an outside source •Blue-green Bacteria -Make their own food 2 BACTERIA Bacteria - small one celled monerans Bacteria like a warm, dark, and moist environment They are found almost everywhere: -water -air -soil -food -skin -inside the body -on most objects 3 3 Shapes of Bacteria Bacteria are classified by shape into 3 groups: Spiral: spirilla rod-shaped: bacilli, bacillus Round: cocci 4 1. The coccus • The cocci are spherical or oval bacteria having one of several distinct arrangements based on their planes of division. • a. Division in one plane produces either a diplococcus or streptococcus arrangement. • b. Division in two planes produces a tetrad arrangement. 5 1. The coccus • d. Division in random planes produces a staphylococcus arrangement. • An average coccus is about 0.5-1.0 micrometer (µm) in diameter. (A micrometer equals 1/1,000,000 of a meter.) 6 2. The rod or bacillus • Bacilli are rod-shaped bacteria. Bacilli all divide in one plane producing a bacillus, streptobacillus, or coccobacillus arrangement. • a. bacillus: single bacilli 7 2. The rod or bacillus • b. streptobacillus: bacilli arranged in chains • c. a coccobacillus: oval and similar to a coccus • An average bacillus is 0.5-1.0 µm wide by 1.0-4.0 µm long 8 3. The spiral • Spirals come in one of three forms, a vibrio, a spirillum, or a spirochete. • a. vibrio: a curved or comma-shaped rod • b. spirillum: a thick, rigid spiral 9 3. The spiral • c. spirochete: a thin, flexible spiral • Spirals range in size from 1 µm to over 100 µm in length. 10 3 Shapes of Bacteria Bacillus anthracis – (bacillus) Neisseria meningitidis (coccus) Leptospira interrogans – (spirilla) 11 7 Major Structures of a Bacteria Cell •Capsule •Cell wall •Ribosomes •Nucleoid •Flagella •Pilli •Cytoplasm 12 7 Major Structures of a Bacteria Cell Capsule keeps the cell from drying out and helps it stick to food or other cells 13 7 Major Structures of a Bacteria Cell Cell wall Thick outer covering that maintains the overall shape of the bacterial cell 14 7 Major Structures of a Bacteria Cell Ribosomes cell part where proteins are made Ribosomes give the cytoplasm of bacteria a granular appearance in electron micrographs 15 7 Major Structures of a Bacteria Cell Nucleoid a ring made up of DNA 16 7 Major Structures of a Bacteria Cell Flagella a whip-like tail that some bacteria have for locomotion 17 7 Major Structures of a Bacteria Cell Amimation of E.coli 18 7 Major Structures of a Bacteria Cell Pilli hollow hair-like structures made of protein allows bacteria to attach to other cells. Pilli-singular Pillus-plural 19 7 Major Structures of a Bacteria Cell Cytoplasm clear jelly-like material that makes up most of the cell 20 Reproduction of Bacteria •Binary Fission- the process of one organism dividing into two organisms •Fission is a type of asexual reproduction •Asexual reproduction- reproduction of a living thing from only one parent How?... The one main (circular) chromosome makes a copy of itself Then it divides into two 21 WARM UP: • What are the three shapes of bacteria? • What are the 7 major structures of the bacteria? • DON’T FORGET TO CHECK YOUR AGAR PLATES! DO NOT OPEN THE LIDS! 22 Reproduction of Bacteria BINARY FISSION Bacteria dividing Completed 23 Reproduction of Bacteria •The time of reproduction depends on how desirable the conditions are •Bacteria can rapidly reproduce themselves in warm, dark, and moist conditions •Some can reproduce every 20 minutes (one bacteria could be an ancestor to one million bacteria in six hours) 24 Bacterial Cell & Nucleiod DNA Ring DNA replication Cell wall synthesis Cell separation 25 Bacteria Survival Endospore•a thick celled structure that forms inside the cell •they are the major cause of food poisoning •allows the bacteria to survive for many years •they can withstand boiling, freezing, and extremely dry conditions •it encloses all the nuclear materials and some cytoplasm 26 Bacteria Survival Bacillus subtilis Endospore-the black section in the middle highly resistant structures can withstand radiation, UV light, and 27 boiling at 120oC for 15 minutes. Bacteria Survival – Food sources parasites – bacteria that feed on living things saprophytes – use dead materials for food (exclusively) decomposers – get food from breaking down dead matter into simple chemicals important- because they send minerals and other materials back into the soil so 28 other organisms can use them Harmful Bacteria • some bacteria cause diseases •Animals can pass diseases to humans Communicable Disease – Disease passed from one organism to another This can happen in several ways: •Air •Touching clothing, food, silverware, or toothbrush •Drinking water that contains bacteria 29 Harmful Bacteria Human tooth with accumulation of bacterial plaque (smooth areas) and calcified tartar 30 (rough areas) Helpful Bacteria •Decomposers help recycle nutrients into the soil for other organisms to grow •Bacteria grow in the stomach of a cow to break down grass and hay •Most are used to make antibiotics •Some bacteria help make insulin •Used to make industrial chemicals 31 Helpful Bacteria E.coli on small intestines 32 Helpful Bacteria •Used to treat sewage Organic waste is consumed by the bacteria, used as nutrients by the bacteria, and is no longer present to produce odors, sludge, pollution, or unsightly mess. •foods like yogurt, cottage & Swiss cheese, sour cream, buttermilk are made from bacteria that grows in milk 33 Controlling Bacteria 3 ways to control bacteria: 1) Canning- the process of sealing food in airtight cans or jars after killing bacteria •endospores are killed during this process 2) Pasteurization- process of heating milk to kill harmful bacteria 3) Dehydration- removing water from food •Bacteria can’t grow when H2O is removed •example: uncooked noodles & cold cereal 34 Controlling Bacteria Antiseptic vs. Disinfectants Antiseptic- chemicals that kill bacteria on living things •means – “against infection” Examples: iodine, hydrogen peroxide, alcohol, soap, mouthwash Disinfectants- stronger chemicals that destroy bacteria on objects or nonliving things 35 BLUE-GREEN BACTERIA Autotrophs – make their own food through photosynthesis larger than most bacterial cells commonly grow on water and surfaces that stay wet…such as rivers, creeks and dams Some live in salt water, snow, and acid water of hot springs food source for animals that live in the 36 water BLUE-GREEN BACTERIA can be toxic to humans and animals Blooms- occur when the bacteria multiplies in great numbers and form scum on the top of the water 37 Bacillus anthracis rod, vegetative stage prokaryote (bacterium) Image Number: 21185A 38 Neisseria meningitidis - coccus prokaryote (bacterium) Image Number: 97214E 39 Leptospira interrogans - spiral shaped prokaryote (spirochete) 40 Ecoli movement animatoin http://www.hybridmedicalanimation.com/pa 41 ges/jjani_qt/ecoli_qt.html