Bacteria What are Bacteria Living Microscopic Unicellular Earliest
Bacteria
What are Bacteria? Living Microscopic Unicellular Earliest Prokaryotic Cells – They DO NOT contain a nucleus or membrane bound organelles • The most numerous organism on Earth! • Earliest bacterial fossils date back 2. 5 billion years. • •
What are Bacteria? • Most grow best at p. H of 6. 5 to 7. 0 • Many act as decomposers recycling nutrients • Some are beneficial • Some cause disease
Bacterial Structure • Contain ribosomes • Single, circular chromosome in nucleoid region • Cell Wall for protection • May have a sticky coating called the Capsule • Some may have flagella for locomotion
Bacterial Structure Ribosome Cytoplasm Chromosome Flagellum Pili Cell Wall Cell Membrane
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Bacterial Shapes • Coccus: Coccus Spherical (round) • Bacillus: Bacillus Rod shaped • Spirillum: Spirillum Spiral shape
Grouping of Bacteria • Diplo Groups of two – Diplococcus • Strepto chains – Strephtococcus • Strep throat • Staphylo Grapelike clusters – Staphylococcus
Gram Staining • Developed in 1884 by Hans Gram • Bacteria treated with purple Crystal Violet & red Safranin stains • Cell walls either stain purple or reddish pink
Gram Positive • Have thick layer of peptidoglycan (protein-sugar complex) • Single lipid layer • Stain purple • Can be treated with antibiotics
Gram Negative • Thin layer of peptidoglycan in cell wall • Extra thick layer of lipids – This keeps out more stain • Stain pink or reddish • Hard to treat with antibiotics
Bacterial Reproduction There are 3 ways in which bacteria reproduce 1. Binary Fission 2. Conjugation: Sexual Reproduction 3. Spore Formation
Bacterial Reproduction 1. Binary Fission – Similar to Mitosis: Mitosis Splitting – New cells are identical 2. Conjugation: Conjugation Sexual Reproduction – Passing of genetic material – New cells NOT identical 3. Spore Formation – Form endospore (hard coating) for protection protectio when habitat conditions become harsh (little food) – Able to survive for long periods of time as endosperm – Difficult to destroy (heat resistant)
How Do They Eat? • Saprobes: Decomposers – feed on dead organic matter • Parasites – feed on a host cell • Photoautotroph – use sunlight to make food • Chemoautotroph – oxidize inorganic matter such as iron or sulfur to make food
Methods of Respiration • Obligate Aerobes – require O 2 • Example: tuberculosis • Obligate Anaerobes – die if O 2 is present • Example: tetanus • Facultative Anaerobes – don’t need O 2, but aren’t killed by it • Example:
Kingdoms of Bacteria Archaebacteria: The Extremists • Found in harsh environments Eubacteria: The True Bacteria • Most bacteria are in this group
Archaebacteria Subdivided into 3 groups: • Methanogens • Thermoacidophiles • Extreme Halophiles
Archaebacteria 1. Methanogens • Break down cellulose in a cow’s stomach • Produce marsh (methane) methane gas
Archaebacteria 2. Extreme Halophiles • Live in very salty water • Use salt to generate ATP (energy) • Dead Sea, Great Salt Lake inhabitants
Archaebacteria 3. Thermoacidophiles or Thermophiles • Live in extremely hot/ hot acidic environments • Found in volcanic vents, hot springs, cracks on ocean floor that leak acid
Eubacteria • May be aerobic or anaerobic • Identified by Gram staining • Three types: 1. Heterotophs : include most bacteria 2. Photosynthetic Autotrophs 3. Chemosynthetic Autotrophs
Eubacteria 1. Heterotophs : include most bacteria • Use organic molecules as their food source • Some are parasitic 2. Photosynthetic Autotrophs • Live in areas with sun; they use sun to make their food. • Ex: cyanobacteria ( can be blue-green, red or yellow; commonly live in ponds) 3. Chemosynthetic Autotrophs • Breakdown inorganic compounds containing sulfur and nitrogen • Nitrogen Fixation: Fixation they convert atmospheric nitrogen in to a compound that plants need to survive
How Does Bacteria Harm Us? • Bacteria poison our cells with metabolic waste • Your Immune system usually can not fight bacterial infections alone. • Antibiotics can kill bacteria!
Diseases of Bacteria • Coccus – Streptococcus pharyngitis (Strep Throat) Throat – Necrotizing fasciitis (Flesh-eating Bacteria) • Baccilus – Bacillus anthracis (Anthrax) Anthrax – Yersinia Pestis (Bubonic Plague) • Spirillum – Treponema pallidum (Syphilis) Syphilis – Borellia burgdorferia (Lyme disease)
Penicillin • Discovered by Alexander Flemming – A complete accident – Mold grew in a petri dishes of bacterial cultures left in the – The mold killed the bacteria sink
Beneficial Bacteria • Some bacteria can degrade oil –Used to clean up oil spills
Beneficial Bacteria • Some bacteria act as decomposers –Break down and recycle dead and decaying organic matter.
Beneficial Bacteria • Some bacteria carry out Nitrogen Fixation – transform atmospheric nitrogen into fixed nitrogen, usable by plants.
Viruses vs. Bacteria • Living • Reproduce on their own • Non-Living • Genetic Material • Contain proteins • Can be treated • Cause Disease with antibiotics • Can be beneficial • Many different shapes
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