BIOL 271 Module 6 | Microbiology w/Lab Exam Q&A |
Portage Learning
1. Which of the following statements is true regarding viruses?
A) They are living, eukaryotic organisms
B) They contain both DNA and RNA
C) They are acellular and cannot reproduce independently
D) They are classified as prokaryotes
Correct Answer: They are acellular and cannot reproduce independently
Rationale: Viruses are not living organisms; they lack cellular structure and cannot
reproduce independently. They require a host cell's machinery to replicate. Viruses
contain either DNA or RNA, never both, and are neither prokaryotic nor eukaryotic.
2. What are the two essential components of every virus?
A) A cell wall and a nucleus
B) Genomic material and a capsid
C) A capsid and an envelope
D) DNA and RNA
Correct Answer: Genomic material and a capsid
Rationale: All viruses possess nucleic acid (either DNA or RNA) as their genomic
material and a protein capsid that surrounds and protects the genome. Not all
viruses have an envelope; some are considered "naked" viruses and lack this outer
lipid layer.
3. The protein coat that surrounds the viral genome is called the:
A) Envelope
B) Capsid
,C) Capsomere
D) Nucleocapsid
Correct Answer: Capsid
Rationale: The capsid is the protein shell that encloses and protects the viral nucleic
acid. It is composed of protein subunits called capsomeres. The capsid and the
nucleic acid together form the nucleocapsid.
4. Which of the following structures surrounds the capsid of some viruses and is
derived from the host cell membrane?
A) Cell wall
B) Envelope
C) Capsomere
D) Matrix protein
Correct Answer: Envelope
Rationale: Some viruses acquire an envelope, a lipid bilayer membrane, by budding
through the host cell membrane. This envelope surrounds the viral capsid and
serves as an additional barrier to the external environment. It is not found on all
viruses.
5. True or False: Because the genome is contained within an enclosed space (much
like the nucleus of a cell), viruses are classified as eukaryotic.
A) True
B) False
Correct Answer: False
,Rationale: Viruses are neither eukaryotic nor prokaryotic. They are acellular entities
that lack cellular structure and are not classified within any domain of life. The
presence of a capsid containing genetic material does not make them eukaryotic.
6. The viral envelope both aids in cell entry and helps the virus evade immune
detection by:
A) Containing proteins that bind to host receptors and camouflaging the virus with
host membrane lipids
B) Preventing the virus from being recognized by antibodies
C) Allowing the virus to replicate inside the host cell
D) Destroying host immune cells
Correct Answer: Containing proteins that bind to host receptors and camouflaging
the virus with host membrane lipids
Rationale: The viral envelope contains proteins required for interaction with host
cells to facilitate entry. Additionally, because the envelope is derived from the host
cell membrane, it camouflages the virus and lowers the likelihood of immune
detection.
7. Which of the following correctly describes the difference between enveloped and
non-enveloped (naked) viruses?
A) Enveloped viruses are more resistant to disinfectants
B) Naked viruses are always more pathogenic
C) Enveloped viruses have a lipid membrane derived from the host cell
D) Naked viruses contain both DNA and RNA
Correct Answer: Enveloped viruses have a lipid membrane derived from the host
cell
Rationale: Enveloped viruses possess a lipid bilayer membrane acquired from the
host cell, while naked viruses lack this envelope. The envelope is derived from the
host cell membrane during viral budding.
, 8. What type of microscope would be used to study the detailed shape of a viral
capsid?
A) Compound light microscope
B) Fluorescence microscope
C) Electron microscope
D) Phase-contrast microscope
Correct Answer: Electron microscope
Rationale: Viruses are too small to be visualized with a light microscope. An electron
microscope, which uses a beam of electrons, provides the high resolution necessary
to study the detailed structure and shape of viral capsids.
9. Which of the following lists the stages of the viral life cycle in the correct order?
A) Entry, Attachment, Replication, Uncoating, Release
B) Attachment, Entry, Uncoating, Replication, Release
C) Attachment, Replication, Entry, Uncoating, Release
D) Entry, Uncoating, Replication, Attachment, Release
Correct Answer: Attachment, Entry, Uncoating, Replication, Release
Rationale: The correct sequence of the viral life cycle is: Attachment (viral receptors
bind to host proteins), Entry (the virus fuses with the host membrane), Uncoating
(the viral capsid disassembles), Replication (the viral genome is copied), and
Release (new virus particles are produced and leave the cell).
10. A virus that infects bacteria is called a:
A) Viroid
B) Prion
C) Bacteriophage
Portage Learning
1. Which of the following statements is true regarding viruses?
A) They are living, eukaryotic organisms
B) They contain both DNA and RNA
C) They are acellular and cannot reproduce independently
D) They are classified as prokaryotes
Correct Answer: They are acellular and cannot reproduce independently
Rationale: Viruses are not living organisms; they lack cellular structure and cannot
reproduce independently. They require a host cell's machinery to replicate. Viruses
contain either DNA or RNA, never both, and are neither prokaryotic nor eukaryotic.
2. What are the two essential components of every virus?
A) A cell wall and a nucleus
B) Genomic material and a capsid
C) A capsid and an envelope
D) DNA and RNA
Correct Answer: Genomic material and a capsid
Rationale: All viruses possess nucleic acid (either DNA or RNA) as their genomic
material and a protein capsid that surrounds and protects the genome. Not all
viruses have an envelope; some are considered "naked" viruses and lack this outer
lipid layer.
3. The protein coat that surrounds the viral genome is called the:
A) Envelope
B) Capsid
,C) Capsomere
D) Nucleocapsid
Correct Answer: Capsid
Rationale: The capsid is the protein shell that encloses and protects the viral nucleic
acid. It is composed of protein subunits called capsomeres. The capsid and the
nucleic acid together form the nucleocapsid.
4. Which of the following structures surrounds the capsid of some viruses and is
derived from the host cell membrane?
A) Cell wall
B) Envelope
C) Capsomere
D) Matrix protein
Correct Answer: Envelope
Rationale: Some viruses acquire an envelope, a lipid bilayer membrane, by budding
through the host cell membrane. This envelope surrounds the viral capsid and
serves as an additional barrier to the external environment. It is not found on all
viruses.
5. True or False: Because the genome is contained within an enclosed space (much
like the nucleus of a cell), viruses are classified as eukaryotic.
A) True
B) False
Correct Answer: False
,Rationale: Viruses are neither eukaryotic nor prokaryotic. They are acellular entities
that lack cellular structure and are not classified within any domain of life. The
presence of a capsid containing genetic material does not make them eukaryotic.
6. The viral envelope both aids in cell entry and helps the virus evade immune
detection by:
A) Containing proteins that bind to host receptors and camouflaging the virus with
host membrane lipids
B) Preventing the virus from being recognized by antibodies
C) Allowing the virus to replicate inside the host cell
D) Destroying host immune cells
Correct Answer: Containing proteins that bind to host receptors and camouflaging
the virus with host membrane lipids
Rationale: The viral envelope contains proteins required for interaction with host
cells to facilitate entry. Additionally, because the envelope is derived from the host
cell membrane, it camouflages the virus and lowers the likelihood of immune
detection.
7. Which of the following correctly describes the difference between enveloped and
non-enveloped (naked) viruses?
A) Enveloped viruses are more resistant to disinfectants
B) Naked viruses are always more pathogenic
C) Enveloped viruses have a lipid membrane derived from the host cell
D) Naked viruses contain both DNA and RNA
Correct Answer: Enveloped viruses have a lipid membrane derived from the host
cell
Rationale: Enveloped viruses possess a lipid bilayer membrane acquired from the
host cell, while naked viruses lack this envelope. The envelope is derived from the
host cell membrane during viral budding.
, 8. What type of microscope would be used to study the detailed shape of a viral
capsid?
A) Compound light microscope
B) Fluorescence microscope
C) Electron microscope
D) Phase-contrast microscope
Correct Answer: Electron microscope
Rationale: Viruses are too small to be visualized with a light microscope. An electron
microscope, which uses a beam of electrons, provides the high resolution necessary
to study the detailed structure and shape of viral capsids.
9. Which of the following lists the stages of the viral life cycle in the correct order?
A) Entry, Attachment, Replication, Uncoating, Release
B) Attachment, Entry, Uncoating, Replication, Release
C) Attachment, Replication, Entry, Uncoating, Release
D) Entry, Uncoating, Replication, Attachment, Release
Correct Answer: Attachment, Entry, Uncoating, Replication, Release
Rationale: The correct sequence of the viral life cycle is: Attachment (viral receptors
bind to host proteins), Entry (the virus fuses with the host membrane), Uncoating
(the viral capsid disassembles), Replication (the viral genome is copied), and
Release (new virus particles are produced and leave the cell).
10. A virus that infects bacteria is called a:
A) Viroid
B) Prion
C) Bacteriophage
