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08 prokaryotes

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08   prokaryotes 08 prokaryotes Presentation Transcript

  • What do these products have in common? We need bacteria to make them!
  • 1) The Prokaryotes: Eubacteria and Archaea 2) Protista 3) Fungi 4) Plants 5) Animals 6) ??? The Kingdoms of Life: A 6-part Series
  • Recall: Prokaryotes are cells that have a nucleus and membrane-bound organelles. Which of the following is a prokaryote? Prokaryote Everything just floats around in the cytoplasm Eukaryote Most things are wrapped- up in membranes View slide
  • Eubacteria Bacteria are extremely important to humans. Their uses include: 1) production of antibiotics to combat diseases 2) digestion, and production of vitamins K and B12 3) sewage treatment (1) (2) (3) View slide
  • Eubacteria Bacteria are extremely important to humans. Their uses include: 4) production of food 5) participation in biogeochemical cycles (ex. nitrogen fixing) 6) as a natural defense in and on our bodies (4) (5) (6)
  • Common Bacteria Structure The structure of a typical bacterium: B E A – Flagellum B – Nucleoid C – Ribosome D – Pilus E – Plasmid F – Capsule G – Cell Wall H – Plasma Membrane I – Cytoplasm
  • Common Bacteria Structure B E A – Flagellum (plural: flagella) – Used for motility. B – Nucleoid – Densely packed loop of the bacterium's DNA. C – Ribosome – Performs protein synthesis.
  • Common Bacteria Structure D – Pilus (plural: pili) – Used to attach to surfaces and other cells. E – Plasmid – Loop of DNA containing several genes. F – Capsule – Thick slimy protective outer layer. B E
  • Common Bacteria Structure G – Cell Wall – Rigid peptidoglycan layer provided shape and structure. H – Plasma Membrane – Controls what goes in and out of the cell. I – Cytoplasm – Fluid suspension containing the cell's contents. B E
  • Eubacteria Bacteria are classified in several different ways, such as: - cell shape - reaction to staining - cell arrangement - metabolism
  • Bacteria Cell Shape The 3 most common shapes of bacteria are: Shape Image Advantages Coccus (plural – cocci) round shape Resists drying-out. Compact. Bacillus (plural – bacilli) rod shape Larger surface area increases nutrient absorption. Spirillum (plural – spirilli) spiral shape Can travel through fluids with less resistance.
  • Bacteria Arrangement Bacteria commonly associate in different shapes. Their names are given prefixes based on how they attach together: In pairs Prefix: diplo- In Chains Prefix: strepto- In clumps Prefix: staphylo-
  • Bacteria Arrangement For example, cocci that attach in these ways are given the following names: coccus diplococci steptococci staphylococci
  • Think. Pair. Share. How would you name these bacteria? streptobacilli staphylobacillistaphylococci spirillumdiplobacillidiplospirilli
  • Bacteria Staining The most common stain performed to identify bacteria is the Gram stain – invented by Hans Christian Gram. Gram staining uses crystal violet dye that targets the peptidoglycan in the bacteria's cell wall, turning it purple.
  • Bacteria Staining After the crystal violet dye has been applied, safranin dye is added to the slide to turn the remaining unstained cells pink.
  • Bacteria Staining Gram-positive bacteria: have a thick peptidoglycan cell wall; turn purple. Gram-negative bacteria: have a thin or no peptidoglycan cell wall; turn pink. Gram +ve bacteria Gram -ve bacteria
  • Bacteria Metabolism The metabolism of bacteria is described in a variety of ways: 1) food source Bacteria can produce nutrients and energy from either: i) inorganic chemicals - including carbon dioxide (CO2), hydrogen sulphide (H2S), or methane (CH4)
  • Bacteria Metabolism ii) organic chemicals – from or produced by living organisms
  • Bacteria Metabolism The metabolism of bacteria is described in 2 ways: 2) oxygen requirements i) obligate aerobe – requires oxygen to survive Bacteria grow best at the top of the tube where oxygen is most available.
  • Bacteria Metabolism The metabolism of bacteria is described in 2 ways: 2) oxygen requirements ii) obligate anaerobe – will not survive in the presence of oxygen Bacteria grow best at the bottom of the tube where little oxygen is present.
  • Bacteria Metabolism The metabolism of bacteria is described in 2 ways: 2) oxygen requirements iii) facultative aerobe – can survive with or without oxygen, but prefers to have oxygen present Bacteria prefer to grow at the top of the tube, but will survive anywhere.
  • Reproduction - Asexual Bacteria can reproduce either sexually or asexually. Asexual reproduction is called binary fission. Both daughter cells are identical to the mother cell:
  • Reproduction - Asexual Septum is forming Septum
  • Reproduction - Asexual
  • Reproduction - Sexual Sexual reproduction occurs when a bacterium gains a new usable piece of DNA. Conjugation: Two cells attach to each other and exchange DNA. A conjugative pilus has connected these two cells and a piece of DNA can be passed through it.
  • Reproduction - Sexual After the transfer, the cell that received the DNA performs binary fission.
  • Reproduction - Sexual A cell may also uptake and use DNA from its environment. This is called transformation.
  • Reproduction - Sexual
  • Think. Pair. Share. When conditions are favourable and unchanging, bacteria prefer to perform binary fission rather than sexual reproduction. Why? VS
  • Think. Pair. Share. Method Advantages Disadvantages Asexual Reproduction - Faster - Requires less energy - No mate required - Fast increase in population may create competition for resources. - Daughter cells are identical to parent. Lack of diversity is vulnerable to disease. Sexual Reproduction - Genetic diversity is increased, making a more resilient population. - Slower - Requires more energy - Requires 2 cells
  • Endospores If environmental conditions become unfavourable for growth (such as lack of food), a bacterium may produce an endospore. A tough shell forms around the cell's nucleoid and some of the cytoplasm.
  • Endospores The bacterium becomes dormant and the tough endospore can survive radiation, extreme heat or cold, harsh chemicals, and lack of food or water. Endospore has formed. Remainder of the cell is left to decay.
  • Endospores Endospores can last thousands of years. When conditions improve, they can revert back to active bacteria. Endospores have been found surviving on ancient mummified remains.
  • Sauerkraut explosion prompts quarantine Last Updated: Saturday, September 11, 2010 | 2:58 PM PT The Canadian Press Twenty-four students and four staff members at a central B.C. high school were briefly quarantined after a can of sauerkraut exploded Friday in a food science class. The fire department, a hazardous materials unit and RCMP were called to Kelly Road Secondary School in Prince George at about 2 p.m. PT. RCMP Const. Lesley Smith said school officials were concerned about a possible botulism outbreak after the contents of a years-old can of pickled cabbage splattered on students. Officials later determined there was no cause for alarm. The students briefly returned to their classes, then were dismissed early.
  • Famous Bacteria Bacteria are common pathogens (disease causing agents). For example: Clostridium botulinum It produces a toxin that paralyzes human muscles. Ingestion can be deadly. This disease is called botulism. C. botulinum is a common cause of preserved food spoilage.
  • Famous Bacteria Bacteria are common pathogens (disease causing agents). For example: Clostridium botulinum The cosmetics industry now uses this muscle- paralyzing toxin to make people look younger by removing wrinkles.
  • Famous Bacteria Bacteria are common pathogens (disease causing agents). For example: Escherichia Coli E. coli is best known as one of the human body's natural flora that lives in the intestines. Fecal-oral transmission of E. coli is a common cause of disease.
  • Famous Bacteria Bacteria are common pathogens (disease causing agents). For example: Escherichia Coli E. coli can also produce toxins in improperly preserved food or untreated water, causing diarrhea, cramps, or vomiting. This "cronut burger" made news at the 2013 CNE for making many people sick. The maple bacon jam topping was not stored properly.
  • Famous Bacteria Bacteria are common pathogens (disease causing agents). For example: Chlamydia trachomatis Body cell Chlamydia is a common sexually transmitted infection (STI). Common symptoms are inflammation, burning sensations, pregnancy complications, irregular discharge, and blindness. The bacterium is a parasitic cell that lives inside of host cells.
  • Archaea Three major reasons that Archaea are different from Bacteria are: 1) Most Archaea cell walls do not contain peptidoglycan. 2) Archaea live in extremely unfavourable conditions. 3) Archaea do not perform conjugation. Archaea have been found growing in this highly acidic mining run-off
  • Archaea Because Archaea are able to survive extreme conditions, scientists believe that they were among the first organisms on Earth.
  • Archaea Archaea are classified based on the conditions that they live in: Name Image Condition Psychrophile Cold places (-10oC to -20oC) like the poles and deep ocean water. Methanogen Create methane in low-oxygen environments. Common in swamps bogs, and sewers. Thermophile Hot places (70oC to 90oC) like volcanoes and geothermal vents. Halophile Highly saline (salty) places like salt flats, salt water, and preserved food. Acidophile Acidic places (pH less than 2) such as factory run-off and volcanoes.