Viruses - PowerPoint PPT Presentation

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Viruses

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  1. Viruses -Not considered “cells” -They have no metabolic activity and there main purpose is to infect target cells and prolong the virus’ DNA by transplanting their DNA into a healthy cell which then produces more Virus parasites. -Viruses that infect bacteria are known as bacteriophage.

  2. Energy Sources -Chemoorganotrophs Obtain energy by oxidation of organic compounds. -Chemolithotrophs Obtain energy from oxidation of inorganic compounds.(Prokaryotes) -Phototrophs May be oxygenic or anoxygenic and obtain energy from sunlight captured by specific pigments. -Autotrophs Are primary producers, which means the autotroph can live off of carbon solely from fixating CO2. -Heterotrophs Rely on the organic molecules made by the Autotrophsfor energy.

  3. Archaea Classifications -Methanogens The organic matter that they degrade produces methane. -Extreme Halophiles If environment doesn’t have a high enough salt concentration they can not reproduce or survive. -Thermoacidophiles Thrive and grow in high temperatures and at abnormally low pH compared to bacterial environments.

  4. Cell Morphology -CoccusSpherically shaped, generally found in groups. -SpirillaShaped like “crimped” spaghetti. -Rod Small cylindrical bar; also generally found in groups. -Filamentous Long hair like bacteria that can bend in any direction. -Budding/Stalking Have a pod-like shape that grows appendages from the main base. The advantage of being small is that they have a higher surface area to volume ratio which allows them to support a higher metabolic rate, a higher growth rate/faster evolution and have a higher waste/nutrient exchange per unit volume.

  5. Carrier Mediated vs. Simple Diffusion -Even though carrier mediated transport is initially faster there are downfalls to this type of transport opposed to transport via simple diffusion. - There is a point of saturation, where all carrier proteins are being used up and can’t surpass a specific rate of transport and speed is levelled off. - Where as simple diffusion may be slow initially, depending on the concentration of the two mediums simple diffusion could be relatively quick and an advantage to this method is that no energy is being used up like ATP for example.

  6. Gliding Motility - This motility is used in non-aqueous environments • A “slime layer” is secreted by the cell which is mainly composed of polysaccharides • Bacteria that travel with this method have specialized outer membrane proteins that allow for movement through this “slime layer” • Powered by the proton motive force, interlocking internal membrane proteins move the outer surface proteins which results in a “crawling” action.

  7. Binary Fission

  8. Binary Fission • Generation time depends on three major factors; (1)temperature, (2) nutrient conditions, (3) space available for growth • The divisome is a protein complex which defines the plane of division in the cell with Fts proteins forming the FtsZ ring. • New peptidoglycan forms in separated cells to cover the growth zones.