By Alexis Avila & Nilanka Lord

 Relatively new discovery so we don’t know too much about them  Classification is very difficult  Originally classified under Kingdom Monera with the rest of the bacteria  Studies showed that 50% of their genes did not resemble those of other bacteria

 Can only live in areas without oxygen  Extremophillic (thrive under extreme conditions)  Prokaryotic (very similar to bacteria)  Single-celled  No nucleus  No membrane bound organelles  Navigate using one or more flagella

 Volume is about one-thousandth that of eukaryotes  Can be cocci, bacilli, or spirilla in shape

 Cell wall that lacks peptidoglycan  Phospholipid bilayer  Composed of glycerol-ether lipids, unlike bacteria  One or more flagella

 Reproduce asexually via binary fission (prokaryotic)  Binary fission: when a single DNA molecule replicates and two identical cells are created from original cell

 World's most prolific methane producers  Play a big role in digestion in many organisms  Some are found in the gut of humans and assist in digestion  Forms symbiotic relationships with: ▪ Giant tube worms (Riftia pachyptila) ▪ Termites ▪ Herbivores (like cows and horses)  Suspected to play a role in periodontal disease, but not proven

 Archaebacteria have 4 ways of getting food:  Photoautotrophic- Calvin Cycle (light energy + CO 2 )  Chemoautotrophic- reverse Krebs cycle (inorganic chemicals + CO 2 )  Photoheterotrophic- use light + organic chemicals to make food  Chemoheterotrophic- undergo respiration, either Krebs, TCA, or Citric Acid cycle, and then ETC (organic chemicals + CO 2 )

 Thermotaxis (movement toward extreme temperatures)  Evolution of thermotaxis due to lack of competition for survival

Methanogens (Make METHANE) Thermoacidophiles (Love HEAT & ACID) Halophiles (Love SALT)

 Found in oxygen-free environments  Produce methane gas from HO 2 & CO 2  Can live and produce in conditions other bacteria can’t survive in  Most are coccoid or rod-like in shape (few exhibit a plate-like shape) Cluster of coccoid methanogens

 Found in the guts of rumen (like cows)  Turn H 2 into CH 4 (methane)  Cows release this methane into the atmosphere  Scientists looking for a way to limit their production of methane

 Require salt-rich environments to survive (due to high internal salt concentration)  Like plants, they use sunlight as a source of photosynthetic energy  Get their color and chemical energy from bacteriorhodopsin (a light-sensitive pigment)  Most are rod-shaped (bacilli)

 Prevalent bacteria in the Great Salt Lake  Can survive in salt concentrations 10x saltier than that of the oceans

 Can live and thrive in extremely hot, sulferic, and/or acidic environments  Include:  Thermophiles= thrive in extremely high temperatures  Acidophiles= pH tolerant (function at 1-5 pH)  Sulfolobus= thrive in sulfur-rich environments

 Live in giant, deep-sea tube worms called Riftia pachyptila  Share a symbiotic relationship with the tube worms  Make food and energy for the tube worms via chemosynthesis

 Found in sulfur-rich, acidic environments  Grows optimally at 80⁰C  Capable of living in extremely acidic circumstances (1-5 pH)

a) peptidoglycan b) flagellin c) bacteriorhodopsin d) chitin e) phycobilins

a) archaea b) viruses c) protists d) fungi e) plants

 Archaebacteria  nce&disableHighlighting=false&prodId=SCIC&action=e&windowstate=normal&catId=&documentId=GALE %7CCV &mode=view nce&disableHighlighting=false&prodId=SCIC&action=e&windowstate=normal&catId=&documentId=GALE %7CCV &mode=view    hool&HOMEPAGE=H hool&HOMEPAGE=H   Methanogens      Halophiles    Thermoacidophiles  SORT&inPS=true&prodId=GPS&userGroupName=lcpsh&tabID=T003&searchId=R1&resultListType=RESUL T_LIST&contentSegment=&searchType=BasicSearchForm&currentPosition=2&contentSet=GALE%7CA &&docId=GALE|A &docType=GALE&role=ITOF SORT&inPS=true&prodId=GPS&userGroupName=lcpsh&tabID=T003&searchId=R1&resultListType=RESUL T_LIST&contentSegment=&searchType=BasicSearchForm&currentPosition=2&contentSet=GALE%7CA &&docId=GALE|A &docType=GALE&role=ITOF