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BACTERIA
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What is Bacteria? BACTERIUM: (singular)
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Bacteria are Prokaryotes Prokaryotes were the initial inhabitants of Earth and today are found almost everywhere Have no _______________________nor membrane enclosed _______________ Inside the cell is one large circular strand of ____ or ____
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PROKARYOTES Prokaryotes exist in 2 kingdoms:
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Bacteria In General: Are the _______ most ____________ living organisms on Earth All share basic structures but are diverse in cell ____ and ________________ patterns Affect humans in various ways: cause _______, spoil foods, can be resistant to ____________ Fix nitrogen for plants, decompose organic matter, manage hazardous waste, aid animal digestion, help create dairy products
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Bacteria!
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General Structure of Bacteria:
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Further Investigation... http://www.cellsalive.com/cells/bactcell.htm
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Archaebacteria: ____________ of all life forms Hypothesized that all life kingdoms descended from ancestors of this group! Organisms in this taxon possess:
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Archaebacteria Found in extremely _____________ environments Over half the ______ in archaebacteria differ from those of eubacteria Different ___________ classify them into different kingdoms Contain specific chemical make-up of cell walls different from Eubacteria
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3 Main Orders of Archaebacteria: METHANOGENS -
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3 Main Orders of Archaebacteria: HALOPHILES -
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3 Main Orders of Archaebacteria: EXTREME THERMOPHILES - -develop at temperatures between 45-80°C, but some need hotter temperatures! -first found living in the hot springs of Yellowstone National Park
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In Fact.... Many other organisms are found in the hot springs of Yellowstone National Park and those microorganisms are responsible for the vibrant colors of the springs. Because thermophiles are ancient, and because they prefer the steamy conditions that were typical of the early times on Earth, many scientists think they could help us understand _____________.
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Eubacteria Most successful of _________________ Categorized according to their mRNA into phylogentic groups: GRAM-POSITIVE, spirochaetes, chlamydias, cyanobacteria proteobacteria
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Eubacteria Organisms belonging to this taxon possess:
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Basic Bacteria Structure: Both archaebacteria and eubacteria are classified according to:
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1. Cell Shape Bacteria cell shapes come in 3 basic forms: 1. Round – 2. Rod – 3. Spiral -
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1. Cell Shape Cocci that live as _________ cells = monococci. Cocci live in ______ = diplococci Cocci live in _______ chains = steptochocci. Cocci live in ____________ clusters = staphlococci
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1. Cell Shape Mono = Di or diplo = Strepto = Staphyto =
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1. Cell Shape Bacilli also exists as single, pairs or chains or random attachments Spiral bacteria exist only as single cells
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2. Gram Stain Gram staining is a differential staining procedure that allows the categorization of bacteria into 2 groups based on their 2 groups: OR
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2. Gram Stain GRAM POSITIVE -Cell walls stain a ________ colour (they retain the stain) -Gram positive bacteria have a different cell wall structure than gram – negative bacteria and the stain shows this - Gram positive bacteria are quite common and usually not as pathogenic (cause disease in a host organism)
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2. Gram Stain GRAM NEGATIVE -Cell walls stain ______ (unable to retain the stain) -usually more ________; bacteria that cause typhoid, gonorrhoea, meningitis and pneumonia
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3. Nutrition All cells need energy and a source of carbon for cellular respiration. major energy source light= Inorganic compounds = Photoautotrophs photoheterotrophs chemoautotrophs chemoheterotrophs
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3. Nutrition Photoautotrophs: -can _____________ their own organic compounds from sunlight -Cyanobacteria (a.k.a. Blue green algae) -forms blooms in polluted water due to nitrate and phosphate run-off into the water -use up oxygen in lakes/ponds/water source
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3. Nutrition Chemoautotrophs: -obtain energy by ____________________ bonds in inorganic compounds such as hydrogen sulphide and ammonia
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3. Nutrition Chemoheterotrophs: -live everywhere -some are _____________ and live off _________ -some are ________ and consume decomposing hosts
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4. Respiration All living things must carry out ______________to receive energy for life’s functions Bacteria differ in whether or not they ___________ Bacterial respiration falls into 2 basic categories: 1. Aerobes -cellular respiration ______________ to produce energy from food that is broken down -_______________________absolutely need oxygen for survival
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4. Respiration 2. Anaerobes -bacteria that carry out cellular respiration in an ______________________________ -if the presence of oxygen kills these organisms, they are called ____________________
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4. Respiration Example: obligate anaerobe = soil bacterium called Clostridium botulinum that produces toxins that can cause an extreme form of food poisoning called botulism 3. __________________ can survive in either environment
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Bacterial Reproduction Depending on environmental conditions, bacteria can reproduce in a variety of manners:
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Under Favourable Conditions: All bacteria use _______________(asexual reproduction) under ideal conditions Produce ___________ copies of themselves: parent cell divides into 2 identical offspring Can divide every ________ minutes In 12 hours there is 10 to 100 million bacteria! Genetic _________________ occur which increase their diversity and ability to survive Due to fast reproduction rate bacteria mutate often – ____________ If the mutation is favourable then it spreads through the population quickly
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Binary Fission
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Under Unfavourable Conditions Will reproduce using _____________ if conditions begin to fail (lack of food, heat, dessication –drying out- or space) 2 bacteria cells connect to each other by long protein bridges called a _______ between them 1 cell transfers a copy of their ___ (smaller ring of DNA with fewer genes than chromosomes) to the other cell The bacteria that received this plasmid now has a different genetic make up and this thereby ____________their chances of survival Example: bacteria become resistant to antibiotics
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Conjugation
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Under Extreme Conditions: Bacteria form structures called spores – one such is called an _____________________ Many gram positive bacteria form these spores Endospore: This enables them to remain _______ for long periods (months) until conditions are once again favourable So, endospores do not metabolize or reproduce but simply ______ until conditions become favourable
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Endospores
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Example of Clostridium bacteria with characteristic drumstick-shaped endospore- producing cells. The dark rod-shaped cells are vegetative cells. The clear ovals are endospores, and the objects consisting of both dark rod and clear oval are vegetative cells producing endospores.
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