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Lecture 1 - Prokaryotes posted

Lecture 1 - Prokaryotes posted - Prokaryotes are...

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Most prokaryotes are microscopic…but what they lack in size they more than make up for in numbers Bacteria from soil E. coli The number of prokaryotes in a single handful of fertile soil Is greater than the number of people who have ever lived Prokaryotes are Everywhere! (almost)
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Prokaryotes thrive almost everywhere Including places too acidic, too salty, too cold, or too hot for most other organisms They have been found in …… Figure 27.1 Antarctic Mono Lake Sulfur Springs How do they do this??
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Prokaryotes have an astonishing diversity Structural, functional, and genetic adaptations contribute to prokaryotic success & have allowed them to radiate into many environments. Prokaryotes vary in size, shape, cell wall structure, generation time, community structure, __________, reproduction, mobility, life history Bacteria Colony Thiomargarita namibiensis Most prokaryotes are _________. Although some species form colonies SIZE RANGE?
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2 domains of Prokaryotes Bacteria and Archaea More details to come Domain Bacteria Domain Archaea Domain Eukarya Alpha Beta Gamma Epsilon Delta Proteobacteria Chlamydias Spirochetes Cyanobacteria Gram-positive bacteria Korarchaeotes Euryarchaeotes Crenarchaeotes Nanoarchaeotes Eukaryotes Universal ancestor Prokaryote Diversity
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1 μ m 2 μ m 5 μ m (a) Spherical (cocci) (b) Rod-shaped (bacilli) (c) Spiral Prokaryote Shapes Prokaryotic cells have a variety of shapes The 3 most common shapes are: Prokaryote Diversity
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The cell wall is one of the most important features of nearly all prokaryotic cells It serves several purposes: ________________ ______________________________________ Prokaryotic Cell Walls Prokaryote Diversity
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Prokaryotic Cell Walls Prokaryotic cell walls VS. Eukaryotic Cell walls Eukaryotes : cell walls of cellulose or chiton Prokaryotes : Bacterial cell walls contain_______________ Archaen cell walls contain _____________ & ______ , but like peptidoglycan Bacterial Cell Wall Eukaryotic Cell Wall
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A technique developed in the 19 th century that allows scientists to classify many bacterial species into two groups (________________ ____________) based on cell wall composition, (a) Gram-positive. Gram-positive bacteria have a cell wall with a large amount of peptidoglycan that traps the violet dye in the cytoplasm. The alcohol rinse does not remove the violet dye, which masks the added red dye. (b) Gram-negative. Gram-negative bacteria have less peptidoglycan, and it is located in a layer between the plasma membrane and an outer membrane. The violet dye is easily rinsed from the cytoplasm, and the cell appears pink or red after the red dye is added. Figure 27.3a, b Peptidoglycan layer Cell wall Plasma membrane Protein Gram- positive bacteria 20 μ m Outer membrane Peptidoglycan layer Plasma membrane Cell wall Lipopolysaccharide Protein Gram- negative bacteria Prokaryotic Cell Walls Gram Stain Hans Christian Gram
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Gram Positive bacteria (turn violet when stained) have simpler walls with large amount of _____________ Gram Negative bacteria (don’t turn violet when stained) have less ___________ & are structurally more complex, with an outer membrane that contain ______________ (often toxic). Outer membrane protects bacteria against antibodies and makes them more ____________.
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