MICR 221 - Final Exam Questions
Complete With Verified Answers
\Q\.what is an HERV and what does it represent - ANSWERS✔-human endogenous retroviruses;
represent footprints of ancient germline retroviral infections
\Q\.viruses do not encode information for - ANSWERS✔-energy production, ribosomes, tRNAs
(some exceptions), lipid membrane synthesis
\Q\.each plaque represents - ANSWERS✔-one single "successful" viral infection
\Q\.virion - ANSWERS✔-mature infectious virus particle
\Q\.capsid - ANSWERS✔-protein shell that encloses and protects the viral nucleic acid
\Q\.capsomere - ANSWERS✔-subunit of a viral capsid
\Q\.core - ANSWERS✔-internal part of the virus particle consisting of nucleic acid and closely
associated proteins
\Q\.nucleocapsid - ANSWERS✔-structure formed by capsid containing the nucleic acid or core
\Q\.envelope - ANSWERS✔-viral membrane consisting of a lipid bilayer containing spike proteins
,\Q\.spike proteins - ANSWERS✔-viral glycoproteins projecting from the envelope
\Q\.two general mechanisms for viruses to package their genomes (capsids) - ANSWERS✔-
helical capsids and capsids with icosahedral symetry
\Q\.what type of naked helical viruses have never been found - ANSWERS✔-animal viruses
\Q\.what type of nucleic acid is found in enveloped animal viruses with helical capsids -
ANSWERS✔-RNA only, never DNA
\Q\.why are helical capsids "open structures" - ANSWERS✔-the ends aren't sealed
\Q\.icosahedrons have how many vertices and what shape are their subunits - ANSWERS✔-20
vertices, triangle subunits
\Q\.how does genetic economy apply to icosahedral capsids - ANSWERS✔-the same proteins
are used to create the triangle subunits
\Q\.how do non-enveloped viruses typically exit the cell - ANSWERS✔-lysis
\Q\.how do enveloped viruses typically acquire their envelope - ANSWERS✔-budding through a
membrane in the host cell into some extra-cytoplasmic compartment
\Q\.3 roles of glycoproteins - ANSWERS✔-1. entry and host range determination 2. assembly
and egress 3. evasion from vertebrate immune system
, \Q\.what two things does Gag polyprotein bind to? why? - ANSWERS✔-binds the retrovirus RNA
genome and the tail of the glycoprotein in the membrane of the cell; does this to drag RNA to
the surface of the cell and a budding reaction occurs to form an enveloped virus
\Q\.mRNA is what type of strand? why? - ANSWERS✔-(+) strand; it contains immediately
translatable information
\Q\.circularity/linearity of RNA and DNA viruses? - ANSWERS✔-RNA can be only be linear. DNA
can be linear or circular
\Q\.most DNA viruses replicate in the - ANSWERS✔-cell nucleus
\Q\.most RNA viruses replicate in the - ANSWERS✔-cell cytoplasm
\Q\.which type of nucleic acid can be ambisense - ANSWERS✔-RNA
\Q\.how does a dsDNA virus create mRNA - ANSWERS✔-the (-) strand DNA serves as a template
for the creation of mRNA
\Q\.how does a (+) ssDNA create mRNA - ANSWERS✔-(+) ssDNA used to create dsDNA, and the
(-) strand DNA can be used as a template for the creation of mRNA
\Q\.how does dsRNA create mRNA - ANSWERS✔-the (-) strand RNA is used as a template to
create the (+) strand mRNA
\Q\.how does (+) ssRNA create mRNA - ANSWERS✔-most (+) strand RNA genomes can be used
directly as mRNA. to create template strands, the (+) strand RNA is used as a template to create
(-) strand RNA, which can then serve as a template to create mRNA
Complete With Verified Answers
\Q\.what is an HERV and what does it represent - ANSWERS✔-human endogenous retroviruses;
represent footprints of ancient germline retroviral infections
\Q\.viruses do not encode information for - ANSWERS✔-energy production, ribosomes, tRNAs
(some exceptions), lipid membrane synthesis
\Q\.each plaque represents - ANSWERS✔-one single "successful" viral infection
\Q\.virion - ANSWERS✔-mature infectious virus particle
\Q\.capsid - ANSWERS✔-protein shell that encloses and protects the viral nucleic acid
\Q\.capsomere - ANSWERS✔-subunit of a viral capsid
\Q\.core - ANSWERS✔-internal part of the virus particle consisting of nucleic acid and closely
associated proteins
\Q\.nucleocapsid - ANSWERS✔-structure formed by capsid containing the nucleic acid or core
\Q\.envelope - ANSWERS✔-viral membrane consisting of a lipid bilayer containing spike proteins
,\Q\.spike proteins - ANSWERS✔-viral glycoproteins projecting from the envelope
\Q\.two general mechanisms for viruses to package their genomes (capsids) - ANSWERS✔-
helical capsids and capsids with icosahedral symetry
\Q\.what type of naked helical viruses have never been found - ANSWERS✔-animal viruses
\Q\.what type of nucleic acid is found in enveloped animal viruses with helical capsids -
ANSWERS✔-RNA only, never DNA
\Q\.why are helical capsids "open structures" - ANSWERS✔-the ends aren't sealed
\Q\.icosahedrons have how many vertices and what shape are their subunits - ANSWERS✔-20
vertices, triangle subunits
\Q\.how does genetic economy apply to icosahedral capsids - ANSWERS✔-the same proteins
are used to create the triangle subunits
\Q\.how do non-enveloped viruses typically exit the cell - ANSWERS✔-lysis
\Q\.how do enveloped viruses typically acquire their envelope - ANSWERS✔-budding through a
membrane in the host cell into some extra-cytoplasmic compartment
\Q\.3 roles of glycoproteins - ANSWERS✔-1. entry and host range determination 2. assembly
and egress 3. evasion from vertebrate immune system
, \Q\.what two things does Gag polyprotein bind to? why? - ANSWERS✔-binds the retrovirus RNA
genome and the tail of the glycoprotein in the membrane of the cell; does this to drag RNA to
the surface of the cell and a budding reaction occurs to form an enveloped virus
\Q\.mRNA is what type of strand? why? - ANSWERS✔-(+) strand; it contains immediately
translatable information
\Q\.circularity/linearity of RNA and DNA viruses? - ANSWERS✔-RNA can be only be linear. DNA
can be linear or circular
\Q\.most DNA viruses replicate in the - ANSWERS✔-cell nucleus
\Q\.most RNA viruses replicate in the - ANSWERS✔-cell cytoplasm
\Q\.which type of nucleic acid can be ambisense - ANSWERS✔-RNA
\Q\.how does a dsDNA virus create mRNA - ANSWERS✔-the (-) strand DNA serves as a template
for the creation of mRNA
\Q\.how does a (+) ssDNA create mRNA - ANSWERS✔-(+) ssDNA used to create dsDNA, and the
(-) strand DNA can be used as a template for the creation of mRNA
\Q\.how does dsRNA create mRNA - ANSWERS✔-the (-) strand RNA is used as a template to
create the (+) strand mRNA
\Q\.how does (+) ssRNA create mRNA - ANSWERS✔-most (+) strand RNA genomes can be used
directly as mRNA. to create template strands, the (+) strand RNA is used as a template to create
(-) strand RNA, which can then serve as a template to create mRNA
