Biology Reading for 2/2/15 Pages 127-129Key Concepts for Chapter 66.1 Structural and functional adaptations contribute to prokaryotic success6.2 Rapid reproduction, mutation, and genetic diversity in prokaryotes6.3 Diverse nutritional and metabolic adaptations have evolved in prokaryotes6.4 Prokaryotes have radiated into a diverse set of lineages6.5 Prokaryotes play crucial roles in the biosphere6.6 Prokaryotes have both beneficial and harmful impacts on humansMasters of AdaptationHalobacterium: Species that is among the most salt-tolerant organisms on earthProkaryotic species are very well adapted to what humans would call “more normal” habitats. Prokaryotic species are the most abundant organisms on earth because of their ability to adapt to a broad range of habitats.Concept 6.1: Structural and Functional adaptations contribute to prokaryotic successProkaryotes were the first organisms to inhabit the Earth 3.5 million years ago. They remain subject to natural selection in all environments.Description of Prokaryotes: Unicellular, are typically 0.5-5 μm in diameter, well organized, achieving all of an organism’s life functions within a single cellCell-surface structuresKey feature of almost all prokaryotic cells: The Cell WallThe function of a cell wall in a prokaryotic cell: Maintaining the cell’s shape, protection for the cell, prevents the cell from bursting in a hypotonic environment.Hypertonic environments: Prokaryotes lose water and shrink away from their cell wall which can inhibit cell reproductionCell walls in Eukaryotes: Usually made from cellulose or chitinPeptidoglycan: A polymer composed of modified sugars cross-linked by short polypeptidesMost bacterial cell walls contain Peptidoglycan. IT encloses the entire bacterium and anchors other molecules that extend from their surface.Gram stain: The categorization of many bacterial species according to differences in cell wall composition.The gram stain was developed by a Danish physician named Hans Christian Gram in the 19th Century.Gram-Positive bacteria: Have less peptidoglycan. It is also less toxic.Gram-Negative bacteria: Has less peptidoglycan and are structurally more complex. The outer membrane contains lipopolysaccharides.Lipopolysaccharides: Carbohydrates bonded to lipidsCapsule: a sticky layer of polysaccharide that surrounds the cell wall of many ProkaryotesEndospores: A thick-coated, resistant cell produced by some bacterial cells when they are exposed to harsh conditionsQuizlet Link: