F13 17 Viruses and Prions

Viruses have not independent metabolic activity

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Unformatted text preview: tion). VIRUSES HAVE NOT INDEPENDENT METABOLIC ACTIVITY, CANNOT GENERATE OWN ATP, USE HOST MACHINERY TO GENERATE ATP. THEY ARE DIFFERENT THAN CELLED ORGANISMS, HAVE SAME GENETIC CODE, BUT CAN HAVE EITHER DNA OR RNA, SINGLE OR DOUBLE STRANDED. VIRUSES ARE VERY SPECIFIC TO STRUCTURE ON HOST CELL, DEPENDS ON STRUCTURE THAT VIRUS INTERACTS WITH. IF STRUCTURE IS FOUND IN DIFFERENT CELLS, THE VIRUS CAN ALSO INFECT DIFFERENT TYPE OF CELLS. 30:02 VIRUS HAS ADHESIN, HOST HAS A RECEPTOR THIS INTERACTION IS VERY SPECIFIC. General structure of viruses: • Protein coat (capsid) composed of subunits called capsomers. virion infectious particle • The genome within the protein coat is called a nucleocapsid. • Some viruses are enveloped in which the nucelocapsid is contained VIROID: JUST LIKE A VIRUS EXCEPT IT HAS NO CAPSID OR within a membrane (naked/enveloped). ENVELOPE, IT’S JUST DNA. • Variations in Morphology: – Helical symmetry/Polyhedral symmetry/Complex – Viroids or envelope no capsid PROTEIN COAT IS CALLED A CAPSID AND CONTAINS SUBUNITS CALLED CAPSOMERS. IF YOU HAVE A VIRUS IN A CAPSID, IT IS CALLED A NUCLEOCAPSID. IF YOU HAVE AN INFECTION VIRUS PARTICLE, THAT IS CALLED A VIRION. SOME VIRUSES ARE ENVELOPED, MEANING THEY HAVE A MEMBRANE ON THE OUSIDE OF THE PROTEIN. SOME VIRUSES ARE NAKED (NO ENVELOPE, JUST PROTEIN COAT) THREE BASIC MORPHOLOGIES: HELICAL: CAPSOMERS ARE IDENTICAL, AND PROTECTS RNA CORE. INFORMATION FOR ASSEMBLY OF VIRUS IS CONTAINED WITHIN CAPSOMERS POLYHEDRAL: GEODESIC DOME SHAPE. DIFFERENT VIRUSES HAVE DIFFERENT NUMBERS OF DOME FACES AND SPIKES. NOT A COMPLEX STRUCTURE LIKE A CELL WALL COMPLEX VIRUS: COMBO TMV: Helical morphology CAPSOMERS SELF ASSEMBLE, MAKE UP VIRUS Variations in complex virus morphology ALL ARE DNA VIRUSES...
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