warm up: what is a microbe? what are the four types of microbes we will be studying? before we get...
TRANSCRIPT
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!!!!!!!
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Introduction to Bacteria
2 TYPES OF BACTERIA:
•Bacteria
-Get food from an outside source
•Blue-green Bacteria
-Make their own food
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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
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Spiral:spirilla
rod-shaped: bacilli, bacillus
Round:cocci
3 Shapes of 3 Shapes of BacteriaBacteria
Bacteria are classified by shape into 3 groups:
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.
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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.)
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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
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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
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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
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3. The spiral
• c. spirochete: a thin, flexible spiral
• Spirals range in size from 1 µm to over 100 µm in length.
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3 Shapes of 3 Shapes of BacteriaBacteria
Bacillus anthracis – (bacillus)
Neisseria meningitidis (coccus)
Leptospira interrogans – (spirilla)
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7 Major Structures of a Bacteria Cell
•Capsule
•Cell wall
•Ribosomes
•Nucleoid
•Flagella
•Pilli
•Cytoplasm
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Capsule
7 Major Structures of a Bacteria Cell
keeps the cell from drying out and helps it stick to food or other cells
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Cell wall
7 Major Structures of a Bacteria Cell
Thick outer covering that maintains the overall shape of the bacterial cell
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Ribosomes
7 Major Structures of a Bacteria Cell
cell part where proteins are made
Ribosomes give the cytoplasm of bacteria a granular appearance in electron micrographs
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Flagella
7 Major Structures of a Bacteria Cell
a whip-like tail that some bacteria have for locomotion
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7 Major Structures of a Bacteria Cell
Amimation of E.coli
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Pilli
7 Major Structures of a Bacteria Cell
hollow hair-like structures made of protein
allows bacteria to attach to other cells.
Pilli-singular Pillus-plural
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Cytoplasm
7 Major Structures of a Bacteria Cell
clear jelly-like material that makes up most of the cell
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•Binary Fission- the process of one organism dividing into two organisms
•Fission is a type of asexual reproduction
Reproduction of Reproduction of BacteriaBacteria
How?...The one main (circular) chromosome makes a copy of itselfThen it divides into two
•Asexual reproduction- reproduction of a living thing from only one parent
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!
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BINARY FISSION
Bacteria dividing Completed
Reproduction of Reproduction of BacteriaBacteria
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•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)
Reproduction of Reproduction of BacteriaBacteria
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Bacteria Survival
Endospore- •a thick celled structure that forms inside the cell
•they are the major cause of food poisoning
•they can withstand boiling, freezing, and extremely dry conditions•it encloses all the nuclear materials and some cytoplasm
•allows the bacteria to survive for many years
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Bacillus subtilisEndospore-the black section in the middle
highly resistant structures
can withstand radiation, UV light, and boiling at 120oC for 15 minutes.
Bacteria Survival
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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 other organisms can use them
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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
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Human tooth with accumulation of bacterial plaque (smooth areas) and calcified tartar (rough areas)
Harmful Bacteria
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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
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•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
Helpful Bacteria
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Controlling Bacteria3 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
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Controlling BacteriaAntiseptic 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
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BLUE-GREEN BACTERIAAutotrophs – make their own
food through photosynthesis
commonly grow on water and surfaces that stay wet…such as rivers, creeks and dams
larger than most bacterial cells
Some live in salt water, snow, and acid water of hot springs
food source for animals that live in the water
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BLUE-GREEN BACTERIA
Blooms- occur when the bacteria multiplies in great numbers and form scum on the top of the water
can be toxic to humans and animals