Exam (elaborations)
BIO 390 Exam 2
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Exam of 38 pages for the course BIO 390 Exm 2 at BIO 390 Exm 2 (BIO 390 Exam 2)
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BIO 390 Exam 2 Virus - CORRECT ANSWER-Latin for poison (Pasteur) Not living Not cellular Obligate intracellular parasite - CORRECT ANSWER-Perform no metabolism Can not freely reproduce No protein synthesis Carry no or few enzymes Naked virus (non-enveloped virus) anatomy: - CORRECT ANSWER-Genetic material (DNA or RNA) Capsid-protein coating (composed of capsomere proteins) Enveloped virus anatomy: - CORRECT ANSWER-Genetic material (DNA or RNA) Capsid Envelope - phospholipid bilayer Spikes (often) - virally-encoded membrane proteins Complex viruses: - CORRECT ANSWER-Example: poxviruses - DNA surrounded by layers of lipoproteins Example: T4 Bacteriophage - DNA or RNA surrounded by capsid, helical protein tail, tail fibers Classifications: International Committee on the Taxonomy of Viruses (ICTV) - CORRECT ANSWER-1.) Nucleic acid type (single-stranded or double-stranded DNA; single-stranded or double-stranded RNA) 2.) Replication process 3.) Morphology (envelope, capsid type, etc.) 4.) Effects Commonly used: Family, Genus, species (common name): Picornaviridae, Enterovirus, Polio virus Viral multiplication - CORRECT ANSWER-Absorption (attachment) Penetration/uncoating Replication (biosynthesis) Assembly/maturation Release (budding or lysis) Viral host range - CORRECT ANSWER-Types of cells within a host species which can be infected by the virus Determined by attachment (susceptible) and cellular components necessary for viral replication processes (permissive). Bacteriophage multiplication: - CORRECT ANSWER-1.) Attachment - phage attaches to host cell. 2.) Penetration - phage penetrates host cell and injects its DNA. 3.) Biosynthesis - phage DNA directs synthesis of viral components by the host cell. 4.) Maturation - viral components are assembled into virions 5.) Release - host cell lyses and new virions are released. Animal viruses - CORRECT ANSWER-Variations on the same 5 basic viral multiplication steps based on: Genetic material Surface structures Enzymes of virus and/or host cell DNA animal virus - CORRECT ANSWER-1.) Virion attaches to host cell. 2.) Virion enters cell, and its DNA is uncoated 3.) A portion of viral DNA is transcribed, producing mRNA that encodes "early" viral proteins. 4.) Viral DNA is replicated, and some viral proteins are made. 5.) Late translation; capsid proteins are synthesized. 6.) Virions mature. 7.) Virions released. RNA viral multiplication (ssRNA; + or sense strand; Picornaviridae) - CORRECT ANSWER-1.) Attachment 2.) Entry and uncoating. Uncoating releases viral RNA and proteins. 3.) RNA replication by viral RNA-dependent RNA polymerase. - strand is transcribed from + viral genome. mRNA is transcribed from the - strand. 4.) Translation and synthesis of viral proteins. 5.) Maturation and release. RNA viral multiplication (ssRNA; - or antisense strand; Rhabdoviridae - CORRECT ANSWER-1.) Attachment. 2.) Entry and uncoating. Uncoating releases viral RNA and proteins. 3.) RNA replication by viral RNA-dependent RNA polymerase. The + strand (mRNA) must first be transcribed from the - viral genome before proteins can be synthesized. Additional - strands are transcribed from mRNA. 4.) Translation and synthesis of viral proteins. - strands are incorporated into capsid. 5.) Maturation and release RNA viral multiplication (dsRNA; + or sense strand with - or antisense strand, Reoviridae - CORRECT ANSWER-1.) Attachment 2.) Entry and uncoating. Uncoating releases viral RNA and proteins. 3.) RNA replication by viral RNA-dependent RNA polymerase. mRNA is produced inside the capsid and released into the cytoplasm of the host. 4.) Translation and synthesis of viral proteins. RNA polymerase initiates production of - strands. The mRNA and - strands form the dsRNA that is incorporated as new viral genome. 5.) Maturation and release. Retroviral multiplication: enveloped RNA - CORRECT ANSWER-Two identical + strands of RNA 1.) Retrovirus enters by fusion between attachment spikes and the host cell receptors. 2.) Uncoating releases the two viral RNA genomes and the viral enzymes reverse transcriptase, integrase, and protease. 3.) Reverse transcriptase copies viral RNA to produce double-stranded DNA. 4.) The new viral DNA is transported into the host cell's nucleus, where it is integrated into a host cell chromosome as a provirus by viral integrase. The provirus may be replicated when the host cell replicates. 5.) Transcription of the provirus may also occur, producing RNA for new retrovirus genomes and RNA encodes the retrovirus capsid, enzymes, and envelope proteins. 6.) Viral proteins are processed by viral protease; some of the viral proteins are moved to the host plasma membrane. 7.) Mature retrovirus leaves the host cell, acquiring an envelope and attachment spikes as it buds out. Viruses that induce cancer - CORRECT ANSWER-Human papilloma viruses (HPVs) Adenoviruses Epstein-Barr virus (EBV - commonly known as mono) Pox viruses Hepatitis B virus (HBV) and Hepatitis C virus (HCV) Human herpes virus 8 (HHV-8) Human T-lymphotrophic virus - 1 & 2 (HTLV - 1/2) Acute infection - CORRECT ANSWER-Short, large number of virions when host cell is invaded. Example: influenzaThe benefits of buying summaries with Stuvia:
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