3 17 15 Bio Ch 15 Proterozoic eon from 2 5 BYP and Phanerozoic eon 550 MYP from time line know Cenozoic 65 mbp to present Mesozoic 250 65 mbp Paleozoic 550 250 mbp Bacteria lived on and evolved alone on earth for billion years 15 2 figure know 1 2 and 3 4 1 Simple precursor chemicals are preset in a watery environment soup 2 Precursor chemicals react to form small organic molecules 3 Organic monomers join to form polymers 4 Genetic material encodes proteins lipids form spheres 5 Formations of protocell a self replicating system finish Reactions are possible when molecules are concentrated catalysts are also important to speed up reactions Microbes were the first organisms The miller experiment simulated early earths atmosphere Simple molecules combined into organic compounds such as amino acids Figure 15 3 Clay and iron pyrite might have catalyzed the first synthesis reactions Catalyst helps a reaction to faster and is not used in reaction Once a self replicating molecule like RNA formed and replicated natural selection took over Stable molecules that could self replicate became more common Figure 15 4 Lipid membranes might have enclosed some self replicating systems forming the first protocells Lipids tend to stick together 3 more bullets RNA world hypothesis Idea that RNA was early important self replicating molecule simpler than DNA single stranded Single stranded molecule o mRNA ribosomal RNA transfer RNA Hundreds of microRNAs Central to process of translation translating genetic info into proteins 2 more bullets Eons which term refers to longer time frame Figure 15 6 Example of scientific revolution Carl Woese Basis of domains is the nucleotide sequences in ribosomes What is function of Ribosomes What are they made of Single celled organism that lacks nucleus and membrane bounded Bacteria and Achaea are prokaryotes belonging too distinct What are prokaryotes organelles domains Figure 15 7 Most prokaryotes have similar parts Nucleoid region where DNA resides Plasmids are circles of DNA apart from chromosome Ribosomes where something is synthesized get right definition Pilus like surfaces Cell Wall shape 3 different shapes bacteria come in Spherical Bacillus rod shaped Spirillum Bacteria can survive harsh conditions Clostridium Botulinum the cause of botulism respiratory distress Prokaryotes obtain carbon and energy Table 15 1 Know what photoautotroph and chemoautotroph mean Diversity of Domain Bacteria Read slides Proteobacteria Cyanobacteria Domain Achaea Or extremophiles first discovered in extreme habitats Lack oxygen Hot Salty Acidic Organize Achaea into phyla Land and in water Ecosystems would shut down without prokaryotes Essential in many ways In root nodules Nitrogen fixation Atmospheric pressure N2 Converted to ammonia Harmless bacteria in our bodies help crowd out pathogenic bacteria Live with trillions of bacteria Ecoli in undercooked meat Bacteria occurs in BIOFILMS which is not organism but approaching one Endosymbiosis explains the origin of mitochondria and chloroplasts