MicroLecturePresentCh.13(2).pptx - Chapter 13 Viruses Viroids and Prions Lanier Technical College Biology Department Presenter Prof Thompson Lecture

MicroLecturePresentCh.13(2).pptx - Chapter 13 Viruses...

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Chapter 13Viruses, Viroids, and PrionsLanier Technical CollegeBiology DepartmentPresenter: Prof. Thompson
Lecture Study-Guide QuestionsKnow how viruses differ from bacterialKnow Characteristics and how Viruses are ClassifiedKnow how viruses are cultured (ex lab animals, embryo eggs etc)Know what is meant by “Lysogeny”Know the steps involved in the “envelop”Know the following: Transduction, budding, abduction, lysogeny, penetrationKnow how bacteriophage replication differs from animal virus replicationKnow what happens when an infection caused by a DNA containing viruswhat does the host cell suppliesKnow Mechanism “enveloped Virus leaves a host cellKnow all the host “Bateriophages derive from (ex. rRNA, ATP, Nucleotides etc.)
Lecture Study-Guide QuestionsKnow the correct order for DNA-virus replicationKnow what families of viruses that utilize “Reverse Transcriptase”Know: Latent viruses, Lytic viruses, and slow virusesKnow the step that occur during multiplication of retrovirusesKnow what is necessary for Replication of a PrionKnow what is a “Viroid”Know the first step in “Biosynthesis" of a Virus w/strand of RNAKnow what enzymes are mostly carried by the RNA virusesKnow the steps involved in Multiplication of retroviruses
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General Characteristics of VirusesObligatory intracellular parasitesRequire living host cells to multiplyContain DNA or RNAContain a protein coatNo ribosomesNo ATP-generating mechanism
Table 13.1 Viruses and Bacteria Compared
Host RangeThe spectrum of host cells a virus can infectMost viruses infect only specifictypes of cells in one hostDeterminedby specific host attachment sites and cellular factorsBacteriophagesviruses that infect bacteriaRange from 20 nm to 1000 nm in length
Viral StructureVirion—complete, fully developed viral particleNucleic acidDNA or RNA can be single- or double-stranded; linear or circularCapsid—protein coat made of capsomeres(subunits)Envelope—lipid, protein, and carbohydrate coating on some virusesSpikes—projections from outer
Figure 13.2 Morphology of a nonenveloped polyhedral virus.Nucleic acidCapsomereCapsid
Figure 13.3 Morphology of an enveloped helical virus.Nucleic acidCapsomereSpikesEnvelope
General MorphologyHelical viruses—hollow, cylindrical capsidPolyhedral viruses—many-sidedEnveloped viruses Complex viruses—complicated structures
Figure 13.4 Morphology of a helical virus.Nucleic acidCapsomereCapsid
Figure 13.5 Morphology of complex viruses.65 nmCapsid (head)DNASheathTail fiberPinBaseplateA T-even bacteriophageOrthopoxvirus
Taxonomy of VirusesViral species:a group of viruses sharing the same genetic information and ecological niche (host) Descriptive common names are used for speciesSubspecies are designated by a numberGenus names end in -virusFamily names end in -viridaeOrder names end in -ales
Growing Bacteriophages in the LaboratoryThis Describe how bacteriophages are cultured

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