Portage Microbiology Exam #6 Questions With Complete Solutions
True or False: Because the genome is contained within an enclosed space, (much like the nucleus of a
cell) viruses are classified as eukaryotic - (ANSWER)False. Viruses are neither eukaryotic nor prokaryotic
Describe the two basic components of a virus (short answer) - (ANSWER)A virus has 1. genomic material
comprised of either DNA or RNA and 2. a capsid, a membrane-like protective structure that contains the
genetic material, similar to the nucleus of a eukaryotic cell
The _____ surrounds the capsid of some viruses - (ANSWER)Envelope
The envelope surrounds the _____ of some viruses - (ANSWER)Capsid
True or False: You would expect to see a viral envelope on a virus infecting a plant cell - (ANSWER)False.
The overwhelming majority of animal viruses are enveloped whereas the majority of plant or bacteria-
infecting viruses are not
True or False: You would expect to see a viral envelope on a virus infecting a bacterial cell -
(ANSWER)False: Not all the viruses have envelopes
Rank the following viruses based on their size from largest to smallest: orthomyxovirus, poliovirus,
variolavirus - (ANSWER)Variolavirus>Orthomyxovirus>Poliovirus
Rank the following viruses based on their size from largest to smallest:Paramyxovirus, Poliovirus,
Smallpox virus - (ANSWER)Smallpox>Paramyxovirus>Poliovirus
True or False: Viral replication occurs after it attaches and enters the host cell - (ANSWER)True. The viral
genome is never replicated before attachment and entry
True or False: Highly infectious viruses undergo genome replication prior to viral attachment and entry. -
(ANSWER)False. The viral genome is never replicated before attachment and entry regardless of its level
of infectivity.
, Portage Microbiology Exam #6 Questions With Complete Solutions
Place the following viral life cycle steps in order beginning with viral attachment and provide a
description of each step (short answer) - (ANSWER)Uncoating: the viral capsid disassembles
Release: New virus particles are produced and leave the cell
Replication: the viral genome is the 'blueprint' to make copies of itself
Attachment: viral receptors bind to host proteins on the surface of the cell
Entry: the virus fuses with the host membrane and enters the cell
New Infection: newly produced viruses that left the host cell now go on to infect new cells
A virus that infects bacteria is called a _____ and contains a _____ -side polygon capsid (fill in the blank)
- (ANSWER)Bacteriophage; 20-sided
True or False: Structurally bacteriophages are similar to viruses that infect animals - (ANSWER)False.
Bacteriophages have a distinct composition and structure
True or False. Structurally, bacteriophages are distinct from viruses that infect plant or animal cells. -
(ANSWER)True. Bacteriophages are structurally distinct from viruses that infect plant and animals cells.
Identify the following components of a bacteriophage (picture) - (ANSWER)1. Capsid
2. Collar
3. Tail
4. Base
5. Tail fibers
Describe the main differences between lytic and temperate phages (short answer) - (ANSWER)Lytic
bacteriophages replicate within the host bacteria until it ruptures, whereas temperate phages primarily
exist in a non-replicative state that does not kill the host cell
Lytic phages replicate all viral proteins needed for the assembly of new virus particles whereas lysogenic
phage genomes are integrated into the host genome but production of viral proteins is suppressed
True or False: Because the genome is contained within an enclosed space, (much like the nucleus of a
cell) viruses are classified as eukaryotic - (ANSWER)False. Viruses are neither eukaryotic nor prokaryotic
Describe the two basic components of a virus (short answer) - (ANSWER)A virus has 1. genomic material
comprised of either DNA or RNA and 2. a capsid, a membrane-like protective structure that contains the
genetic material, similar to the nucleus of a eukaryotic cell
The _____ surrounds the capsid of some viruses - (ANSWER)Envelope
The envelope surrounds the _____ of some viruses - (ANSWER)Capsid
True or False: You would expect to see a viral envelope on a virus infecting a plant cell - (ANSWER)False.
The overwhelming majority of animal viruses are enveloped whereas the majority of plant or bacteria-
infecting viruses are not
True or False: You would expect to see a viral envelope on a virus infecting a bacterial cell -
(ANSWER)False: Not all the viruses have envelopes
Rank the following viruses based on their size from largest to smallest: orthomyxovirus, poliovirus,
variolavirus - (ANSWER)Variolavirus>Orthomyxovirus>Poliovirus
Rank the following viruses based on their size from largest to smallest:Paramyxovirus, Poliovirus,
Smallpox virus - (ANSWER)Smallpox>Paramyxovirus>Poliovirus
True or False: Viral replication occurs after it attaches and enters the host cell - (ANSWER)True. The viral
genome is never replicated before attachment and entry
True or False: Highly infectious viruses undergo genome replication prior to viral attachment and entry. -
(ANSWER)False. The viral genome is never replicated before attachment and entry regardless of its level
of infectivity.
, Portage Microbiology Exam #6 Questions With Complete Solutions
Place the following viral life cycle steps in order beginning with viral attachment and provide a
description of each step (short answer) - (ANSWER)Uncoating: the viral capsid disassembles
Release: New virus particles are produced and leave the cell
Replication: the viral genome is the 'blueprint' to make copies of itself
Attachment: viral receptors bind to host proteins on the surface of the cell
Entry: the virus fuses with the host membrane and enters the cell
New Infection: newly produced viruses that left the host cell now go on to infect new cells
A virus that infects bacteria is called a _____ and contains a _____ -side polygon capsid (fill in the blank)
- (ANSWER)Bacteriophage; 20-sided
True or False: Structurally bacteriophages are similar to viruses that infect animals - (ANSWER)False.
Bacteriophages have a distinct composition and structure
True or False. Structurally, bacteriophages are distinct from viruses that infect plant or animal cells. -
(ANSWER)True. Bacteriophages are structurally distinct from viruses that infect plant and animals cells.
Identify the following components of a bacteriophage (picture) - (ANSWER)1. Capsid
2. Collar
3. Tail
4. Base
5. Tail fibers
Describe the main differences between lytic and temperate phages (short answer) - (ANSWER)Lytic
bacteriophages replicate within the host bacteria until it ruptures, whereas temperate phages primarily
exist in a non-replicative state that does not kill the host cell
Lytic phages replicate all viral proteins needed for the assembly of new virus particles whereas lysogenic
phage genomes are integrated into the host genome but production of viral proteins is suppressed
