Chapter 27 Prokaryotes Organisms that run the world Dominant Life forms on Earth Dominant Life forms on Earth 10x the biomass of all 10x the biomass of all Eukaryotes Eukaryotes 101014 14 prokaryotic cells in your prokaryotic cells in your cells make up your gut 101313 cells make up your gut 10 body body Extreme metabolic diversity Extreme metabolic diversity The basis for eukaryotic The basis for eukaryotic metabolism more on Fri metabolism more on Fri Chapter 27 Prokaryotes Organisms that run the world Prokaryotes vs Eukaryotes Understand Unlike Eukaryotes prokaryotes have Unlike Eukaryotes prokaryotes have No nuclear envelope No nuclear envelope No membrane bound organelles No membrane bound organelles Circular DNA with relatively few genes Circular DNA with relatively few genes Figs 6 5 6 8 Prokaryotes vs Eukaryotes Understand Evolutionary Evolutionary ClockClock Prokaryotes Prokaryotes Began 3 5 bya Began 3 5 bya Bacteria Bacteria Archaea Archaea EvolutionaryEvolutionaryClockClock Prokaryotes Classification Formerly all prokaryotes Formerly all prokaryotes lumped together lumped together Prokaryotes Classification Prokaryotes Two Domains Bacteria Archaea Eukarya Organelles nucleus Linear chromosomes Mitosis and meiosis LUCA C RNA world Abiogenesis DNA Proteins RNA ribosomes Circular Chromosome See www tolweb org for phylogeny Prokaryotes Two Domains Unlike Swapping Genes Horizontal Lateral Gene Transfer Eukaryotes Unlike mostmost Eukaryotes prokaryotes can prokaryotes can laterally transfer laterally transfer genes genes Very important Very important for evolution for evolution See Fig 26 22 Various mechanisms Various mechanisms Know general phenomenon not details Know general phenomenon not details p 553 p 553 Swapping GenesHorizontal Lateral Gene Transfer Energy and Carbon Energy and Carbon Two Basic Requirements Two Basic Requirements ENERGY ENERGY CARBON for synthesis of organic compounds CARBON for synthesis of organic compounds Needn t come from the same source Needn t come from the same source 1 Energy 1 Energy Phototrophs Chemotrophs 2 Carbon 2 Carbon Autotrophs Heterotrophs use light Phototrophs use light use chemical compounds Chemotrophs use chemical compounds Autotrophs use CO use CO22 use organic compounds they consume Heterotrophs use organic compounds they consume Energy and CarbonEnergy and Carbon Energy and Carbon Energy Two ways Energy Two ways Phototrophs Phototrophs Energy from light Energy from light E g plants some E g plants some prokaryotes e g prokaryotes e g cyanobacteria cyanobacteria Chemotrophs Chemotrophs Energy from chemicals Energy from chemicals E g Animals Fungi E g Animals Fungi some prokaryotes some prokaryotes Carbon Two ways Carbon Two ways Autotrophs Autotrophs Carbon from CO Carbon from CO22 E g plants some E g plants some prokaryotes e g prokaryotes e g cyanobacteria cyanobacteria Heterotrophs Heterotrophs Carbon from organic Carbon from organic compounds compounds E g Animals Fungi E g Animals Fungi some prokaryotes some prokaryotes TABLE 27 1 Energy and Carbon Energy and Carbon Combinations Autotrophs Autotrophs Photoautotrophs Photoautotrophs Energy from light carbon Energy from light carbon from CO22 from CO E g plants some prokaryotes E g plants some prokaryotes e g cyanobacteria e g cyanobacteria Chemoautotrophs Chemoautotrophs Energy from inorganics Energy from inorganics carbon from CO22 carbon from CO E g Some prokaryotes E g Some prokaryotes e g archaea NH33 CH CH44 e g archaea NH Energy and Carbon Combinations Energy and Carbon Heterotrophs Heterotrophs Photoheterotrophs Photoheterotrophs Energy from light Carbon Energy from light Carbon from organic sources from organic sources E g Some prokaryotes E g Some prokaryotes Chemoheterotrophs Chemoheterotrophs Energy and Carbon from Energy and Carbon from organic sources organic sources E g some prokaryotes us E g some prokaryotes us Energy and Carbon The very early The very early history of life history of life Fig 25 7 Photosynthesis Energy from the sun Use light as an energy source for making Use light as an energy source for making ATP Light reaction ATP Light reaction OO22 as a by product usually as a by product usually Use ATP to create sugars from CO Use ATP to create sugars from CO22 These are now photoautotrophs These are now photoautotrophs The oxygen revolution The oxygen revolution 2 5 billion years ago 2 5 billion years ago Good news bad news Good news bad news PhotosynthesisEnergy from the sun The oxygen revolution Good news bad news Origin of cyanobacteria Origin of cyanobacteria Increased Oxygen levels eventually Increased Oxygen levels eventually Oxygen is very reactive breaks bonds Oxygen is very reactive breaks bonds Bad news for anaerobic organisms Bad news for anaerobic organisms But allowed the evolution of aerobic But allowed the evolution of aerobic respiration respiration The oxygen revolution Good news bad news Aerobic Respiration Much greater yield of ATP Much greater yield of ATP In some ways the opposite of Photosynthesis In some ways the opposite of Photosynthesis Photosynthesis Photosynthesis ATP from Light rxn CO22 Sugar O ATP from Light rxn CO Sugar O22 Aerobic respiration Aerobic respiration Sugar O22 ATP CO Sugar O ATP CO22 Aerobic Respiration Evolution is a tinkerer 1 Pathways for production of ATP in aerobic 1 Pathways for production of ATP in aerobic respiration apparently borrowed from respiration apparently borrowed from photosynthesis photosynthesis 2 Anaerobic origins of photosynthesis 2 Anaerobic origins of photosynthesis apparent even in modern plants apparent even in modern plants Enzymes used for fixing CO are interfered with Enzymes used for fixing CO22 are interfered with photorespiration by Oby O2 2 photorespiration For help on concept see article posted on ELMS by Jacob For help on concept see article posted on ELMS by Jacob under Lecture 28 under Lecture 28 Evolution is a tinkerer Prokaryotic Metabolism Very diverse Very diverse All combinations discussed and more exist All combinations discussed and more exist Form basis for Eukaryotic metabolism Form basis for Eukaryotic metabolism See Table 27 1 See Table 27 1 Influence on a global scale Influence on a global scale E g The nitrogen cycle E g The nitrogen cycle Symbiosis mutualism Symbiosis mutualism E g biogeochemical cycling E g biogeochemical cycling E g Parasitism disease E g Parasitism disease E g research technology E g research technology Prokaryotic Metabolism