2Methods of Feeding Saprophytic Nutrition Parasitism Predation feed on dead organic matter, get energy from it, and recycle it back into the environment.decomposers.Parasitismorganism (parasite) feeds off of another (host) at the expense of the host.Predation- organism (predator) hunts, kills, and eats another organism (prey). Scavengingfeed on organisms killed by something else.
4What are Bacteria? Bacteria are PROKARYOTES The smallest known living cellsThey are foundeverywhere!!Bacteria onhead of a pinStarr, 317Did you know? There are over 80species of bacteria in your mouth!Bacteria in dental plaquemicrobeworld.org
5Obtaining Energy Autotrophs (make energy) Photoautotrophs- capture energy from lightEx- cyabobacteriaChemoautotrophs- obtain energy from chemical reactions with inorganic molecules (ammonia, hydrogen sulfide, nitrites, sulfur, Iron)make glucose using energy from chemical compoundsEx. Ocean vent bacteria
7Obtaining Energy cont… Heterotrophs- most bacteria obtain their energy from organic moleculesThese bacteria are often feeding in, on and around us…Some bacteria are photoheterotrophsCapture sunlight and digest organic molecules
8Releasing EnergyBacteria can use both cell respiration and fermentationMany bacteria have different oxygen requirements:Obligate aerobes- must have oxygen for respirationFacultative anaerobes- can function with or without oxygenObligate anaerobes- poisoned by oxygen (use fermentation)
11CoccusSpheresCocci (plural)a variety of arrangements11
12Bacillus Cylindrical or rod-shape Bacilli (plural) Variations in cell arrangementDiplobacillus (paired)12
13Spirillium Spiral or “squiggle” shaped bacteria Vibrio Spirillum Spirochete13
14Simple Colonies Staphylo = clusters Strepto = chains Diplo = double Bacterial colony shapes have specific names that are used asA prefix that combines with the name of their shape.Staphylo = clustersStrepto = chainsStaphylococcuswisc.eduDiplo = doubleDiplococcuscat.cc.md.usStreptobacillus
18Many can MOVE Some have flagella - made of rope-like proteins, not microtubules.Some slide on a slimy secretion.Many can form dormantcells called endosporesto survive harsh conditions.SalmonellaStreptomyces spores
19Bacterial Reproduction Bacterial cells reproduce asexually through fission which is the splitting of a cell into two new cells.
20Bacterial Reproduction cont… Some bacteria utilize conjugation to exchange pieces of genetic information to increase variation*Not considered sexual reproduction- not complete exchange of DNA, no offspring made
22Structure of a Bacterial Cell Cell WallOutside membrane- maintains cell structureMay have cell wall + capsule (second wall)Protects the cellEubacteria-composed of peptidoglycan, a polymer of sugars and amino acidsPlasma MembraneControls what enters and exits, selectively permeablephospholipid bilayer surrounding cellcontains proteins that play a role in transport of ions, nutrients, and wastesFlagella (not found in all bacteria)tail-like structure used for locomotion
23Structure of a Bacterial Cell Nucleoidregion DNA is found in prokaryotessingle double-stranded circular chromosomeContains all genetic informationPlasmid (some bacteria)small circular chromosome carrying special genesmay carry an antibiotic resistance geneCan be exchanged through conjugationRibosomessite of protein synthesis (translation)Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College.
24Bacterial Structure Respiratory Enzymes Cytoplasm Use enzymes in the cytoplasm to undergo respirationCytoplasmFluid filling cell
25Two Kingdoms of Bacteria Kingdom Archaebacteria- “Ancient”, most primitiveearliest known form of life-Fluorescent micrograph of an archaeonmicrobeworld.orgKingdom Eubacteria- includes bacteria andcyanobacteria (blue-green)
28Cell Wallseubacterial cells have two different cell wall structures. A technique called gram staining can distinguish between:Gram-positive: cell wall containing mainly peptidoglycan- stains purpleGram-negative: bacterial cell has a second, outer layer of lipids and carbs- stains pink
29Kingdom Eubacteria Photosynthetic – 2 groups 1) cyanobacteria (aerobes)Have chlorophyll aand phycocyanin (blue)Other colors, tooMost live in fresh waterOthers live in salt water,soil and lichensStarr, 315NostocSchraer, 637
30- colors range from pink to black - photosynthesize without water More photosynthetics2) green-sulfur and purple bacteria- anaerobic- colors range from pink to black- photosynthesize without water- make no oxygen- live in pond and sea mud
31CyanobacteriaThis is a group of bacteria that includes some that are single cells and some that are chains of cells. You may have seen them as "green slime" in your aquarium or in a pond.Cyanobacteria can do "modern photosynthesis", which is the kind that makes oxygen from water. All plants do this kind of photosynthesis and inherited the ability from the cyanobacteria.
32Cyanobacteria were the first organisms on Earth to do modern photosynthesis and they made the first oxygen in the Earth's atmosphere.
33Biologic Importance of Bacteria Essential to nutrient cyclingDecomposers – in soil, inside animalsEnterobacteria – live inside us, break down waste, make vitaminsvitamin K is essential to blood clot formation.Process foods – cheese, yogurt etc..Some MAKE antibiotics (streptomyacin)
34Bacterial uses cont. 6) Help with sewage treatment Break down wastes7) Can be utilized in genetic engineering, molecular research…Insert foreign genes into new organismCan be used to make specialized products like insulin8) Indicate pollution levelsProvide visual clue to presence of pollution
359) Nitrogen FixationStill other Bacteria live on the roots of certain plants, converting atmospheric nitrogen into a usable form.
36Some cause disease We call these “pathogens” Anthrax, as seen by Kochmicrobeworld.orgBut most arebeneficialBacteria ferment cheeseSchraer, 641
37Kingdom Archaebacteria Why a separate kingdom?Archae differ chemically from other bacteria.1) cell wall - different amino acids and sugars.Eubacteria have peptidoglycanArchaebacteria have varied polysaccharidesbut not peptidoglycan.2) unique membrane lipids3) ribosomes4) enzymes >5) gene sequences And MORERNA polymerase
38Archaebacteria Lack important carbohydrate found in cell walls Have different lipids in their cell membraneDifferent types of ribosomesVery different gene sequencesArchaebacteria can live in extremely harsh environmentsThey do not require oxygen and can live in extremely salty environments as well as extremely hot environments.
39Archae are extremophiles Live in habitats like early earthToo harsh for most organisms1) methanogens – decomposers,live in intestines, swamps & bogssewage treatment2) Halophiles – “love salt”Great Salt Lake, Dead Sea3) Thermophiles – hot springs, geysers4) Acidophiles – acidic environmentsStarr,635
40Archaea, the “extremophiles” methanogens, thermophiles, halophiles
41Nitrogen-fixing Chemosynthetic Eubacteria and Archaebacteria make glucose using energyfrom chemical compounds**Mostly archaeTube worms at ocean ventFed by chemoautotrophsStarr, 745Nitrogen-fixingFix nitrogen in specialcells called heterocystsLegume roots – nodules containnitrogen-fixing bacteriaStarr, 314