Presentation on theme: "Prokaryotes are widespread on Earth."— Presentation transcript:
1KEY CONCEPT Kingdoms Eubacteria and Archaeabacteria are composed of single-celled prokaryotes.
2Prokaryotes are widespread on Earth. Prokaryotes can be grouped by their need for oxygen.obligate aerobes are need oxygenfacultative aerobes can live with or without oxygenobligate anaerobes are poisoned by oxygen
3plasmid (circular DNA) flagellum Pili (genetic exchange) Eubacteria and Archaebacteria are structurally similar but have different molecular characteristics.flagellumpiliplasmidcell wallchromosomeplasma membranceThis diagram shows the typical structure of a prokaryote. Archaea and bacteria look very similar, although they have important molecular differences.plasmid (circular DNA)flagellumPili (genetic exchange)
4Domain Archaea, Kingdom Archaebacteria Archaebacteria are typically obligate anaerobes.Live in extremely harsh environments, ex.stomachs of cows, high salt concentrated areas such as the Dead Sea and in sulfur springs or deep sea vents.Divided into 3 groups: methanogens (methane producers, halophiles (salt loving) and thermophiles (heat loving)Come in a variety of shapes, similar to Eubacteria.There is no peptidoglycan in their cell walls, contain entirely different lipids than Eubacteria.***Eubacteria is actually evolutionary older than Archeabacteria
5Domain Bacteria, Kingdom Eubacteria Eubacteria commonly come in three forms.rod-shaped, called bacillispiral, called spirilla or spirochetesspherical, called cocciLactobacilli: rod-shapedSpirochaeta: spiralEnterococci: spherical
7EubacteriaThe amount of peptidoglycan within the cell wall can differ between Eubacteria: Gram negative has extra outer membrane, Gram positive cell wall just peptidoglycanGRAM NEGATIVEGRAM POSITIVE
8Gram staining identifies bacteria. stains polymer peptidoglycan gram-positive stains purple, more peptidoglycangram-negative stains pink, less peptidoglycanGram-negative bacteria have a thin layer of peptidoglycan and stain red.Gram-positive bacteria have a thicker peptidoglycan layer and stain purple.
9Bacteria have various strategies for survival. Form of genetic recombination is conjugation.Prokaryotes exchange genes using piliconjugation bridgeTEM; magnification 6000x
10Other forms of genetic exchange Transduction: exchange of genes using a virusTransformation: endocytosis of DNA
11Bacteria survivalBacteria may survive by forming endospores.Resistant to most cleaning agents and temperature changesCreates double membrane around DNA to survive harsh conditionsSterilize versus disinfect?
12Prokaryotes provide nutrients to humans and other animals. Prokaryotes live in digestive systems of animals.make vitamins and medicinesbreak down foodfill niches (role in ecosystem)
13Bacteria help ferment many foods. yogurt, cheesepickles, sauerkrautsoy sauce, vinegar
14Prokaryotes play important roles in ecosystems. Prokaryotes have many functions in ecosystems.photosynthesizerecycle carbon, nitrogen, hydrogen, sulfurfix nitrogen (make it useable)
15Bioremediation uses prokaryotes to break down pollutants. oil spillsbiodegradable materials
16Some bacteria cause disease. Bacteria cause disease by one of two methods:invading tissuesmaking toxins (poison released by an organism)
17Normally harmless bacteria can become destructive. immune system may be lowered
18Ex. Tuberculoses (Mycobacterium tuberculosis) Bacteria multiply in the lungs, killing WBCsHost releases histamines which cause swelling
19Ex. Staph poisoining (Staphylococcus aureus) Food poisoning caused by mishandling of foodInfection of the skin
20Ex. Botulism (Clostridium botulinum) Improperly canned foods contaminated with endospores
21Ex. Flesh eating bacteria (Streptococci) Colonize tissue through cut or scrape
22Antibiotics are used to fight bacterial disease. Antibiotics may stop bacterial cell wall formation.Their role is to interfere with the ability of the bacteria’s reproduction process.
23Overuse of Antibiotics Bacteria become resistant due to exposureUnderuse of AntibioticsKill the weak bacteria while stronger bacteria become resistantMisuse of AntibioticsViruses cannot be treated with antibiotics, allowing normal bacteria to become resistant or killing them
24Bacteria can evolve resistance to antibiotics. 1. Bacterium carries genes for antibiotic resistance on a plasmid (circular DNA).2. Copy of the plasmid is transferred through conjugation (using pili).3. Resistance is quickly spread through many bacteria.