3 How Many Kingdoms? Extant 8 5 3 Extinct 2 Long Time with 1 Multicellular AnimalsMyxozoansProtozoansTracheophytesBryophytesTrue FungiSlime MoldsRed algaeBrown AlgaeGreen AlgaeChrysophytesEuglenoidsArchezoansArchaebacteriaBacteria853Extinct21Long Time withProkaryotes onlyOriginal Cell
4 Bacteria - Eubacteria Ancient fossils 3.5 billion years b.p. Archetype for prokaryotic organismsPhototrophsChemoautotrophsHeterotrophsSaprobesParasites (bacteria benefit, host harmed)Commensals (bacteria benefit, host unharmed)Mutualists (bacteria and host both benefit)Unicellular, colonial, filamentousBacillus, coccus, spirillum
13 Cell Structure: Boundary Defenses Capsule or Sheathmucoid polysaccharidescell adhesionchemical resistance - defensedesiccation resistanceEndosporespore coat + DNA + other materialsexterior may be lostfrozen for long periodsboiled for long periodsdesiccated for long periodsthen germinates to new cellBacillus anthracis
15 Cell Structure: Movement hookdirectional rotation?basal rings and rodanchoragerotationstiff helical flagellumflagellin proteinis rotated by “motor apparatus”in the membrane by H+ ATPaseat rates of rps(>12,000 rpm!)Taxis:movement toward stimulusExceptions:myxomycetes, some cyanobacteria use slime, but how?spirochetes have flexible internal microtubules(endosymbiotic source of flagella in eukaryotes?)((gut parasite in termites have spirochete symbiosis))phototaxis:movement toward lightchemotaxis:movement to chemicals
16 Lophotrichous: flagella found at one end of the cell
17 Amphitrichous: flagella at both ends (but not many on sides) Peritrichous: flagella all around cell
18 Prokaryotic Growth Cells are generally very small Cells may double in size but only before binary fissionGrowth mostly in terms of cell number or colony size, etc.Doubling time in cell numbers may be 20 minutes in ideal conditionsCould quickly take over the earth if conditions could remain idealVery competitive in ideal environmentsUltimate survivors billion years!
19 Cell Structure: Nucleoid Nucleoid - genomeone circular DNA moleculeno histone protein associationattached to cell membranetranscription by RNA polymerasereplication by DNA polymeraseseparation of chromosomescytokinesis by furrowing70S RibosomeProcess called binary fissionNOT mitosis!Genome and copy are identicalGenome is haploidThere is no synapsisThere is no recombinationrRNA + protein + ribozymestranslation of mRNA into protein
Your consent to our cookies if you continue to use this website.