Foundations in Microbiology Chapter 6 Test Questions and Correct Answers Already Passed

Foundations in Microbiology Chapter 6 Test Questions and Correct Answers Already Passed Viruses - Answers -Obligatory intracellular parasites -contain DNA or RNA -contains protein coat -some enclosed by envelope -some have spikes Host range - Answers ____ ____ is determined by specific host attachment sites and cellular factors. most abundant - Answers Viruses are ___ ___ microbes on earth with NO universal agreement on how and when viruses originate Capsid Envelope (not in all) - Answers The covering of viruses contain? Nucleic acid molecule (RNA or DNA) Matrix proteins (not found in all) - Answers Central core of viruses contain? Capsids - Answers All viruses have ____ Capsids - Answers -protein coats that enclose and protect their nucleic acid Nucleic acid - Answers RNA or DNA nucleocapsid - Answers The capsids together with the nucleic acid is called envelope; naked - Answers Some viruses have an external covering called an ____, those lacking an envelope are _____. capsomers - Answers Each capsid is made of identical protein subunits called Viral envelope - Answers -mostly animal viruses -acquired when the virus leave the host cell Spikes - Answers The viral envelope exposes proteins on the outside of the envelope called ____- essential for attachment of the virus to host cell. Capsid/envelope - Answers _______ protects the nucleic acid when the virus is outside of the host cell- also helps virus bind to cell surface, penetration of DNA or RNA in host cell Two structure capsid types - Answers -Helical -Icosahedral Helical - Answers -continuous helix of capsomers forming a cylindrical nucleocapsid Icosahedral - Answers -20-sided with 12 corners Complex viruses - Answers -Atypical viruses bacteriophages - Answers Some ____ have a polyhedral (isosahedral) nucleocapsid along with a helical tail and attachment fibers Types of Viruses - Answers a. Complex viruses b. Enveloped viruses -Helical -icosahedral c. NonEnveloped viruses -Helical -icosahedral Complex viruses - Answers -poxvirus, large DNA virus -flexible-tailed bacteriophage Enveloped viruses (w/ helical nucleocapsid) - Answers -mumps virus -rhabdovirus Enveloped viruses (w/ icosahedral nucleocapsid) - Answers -herpes virus -HIV (aids) Naked (w/ helical capsid) - Answers -plum poxvirus Naked (w/ icosahedral capsid) - Answers -poliovirus -papillomavirus Viral genome - Answers -either DNA or RNA but not both DNA viruses - Answers -usually double stranded (ds) but may be single stranded (ss) -Parvoviridae -circular or linear RNA viruses - Answers -usually single stranded (ss) but may be double stranded (ds) -Reoviridae -may be segmented into seperate RNA pieces DNA; Nucleus - Answers ___ viruses generally are replicated and assembled in the ___. RNA: Cytoplasm - Answers ___ viruses generally are replicated and assemble in the ___. A enzyme present in DNA or RNA - Answers -Polymerases A enzyme (copy of RNA) - Answers -Replicases Reverse transcriptase - Answers A enzyme responsible for synthesis of DNA from RNA (Aids virus) How viruses are classified - Answers -main criteria presently used are structure, chemical composition, and genetic makeup.