GCSU BACHOON Microbiology Final Exam Questions with Correct Answers Latest Update
2025/2026
definition of a virus - Answers a submicroscopic, parasitic, filterable agent consisting of a
nucleic acid surrounded by a protein coat
which is smaller, viruses or bacteria? - Answers bacteria
what can a virus infect? - Answers -invertebrates
-vertebrates
-plants
-protists
-fungi
-bacteria
when are viruses considered to be alive? - Answers ONLY when they are inside the host they
infect
where do they multiply? - Answers inside living cells
are viruses sensitive to antibiotics? - Answers NO
what are viruses sensitive to? - Answers interferon
host range - Answers - the spectrum of host cells a virus can infect
- most can only infect one specific host because it requires a specific site to attach to its host
- those that infect bacteria are called "bacteriophage" or "phage"
what 3 things makes up a virus? - Answers 1) nucleic acid
2) capsid
3) envelope (on some viruses)
1) nucleic acid - Answers - have DNA (or) RNA; not both
- double stranded or single stranded
- linear or circular
genome size? - Answers ranges from a few thousand nucleotides to as many as 250,000
2) capsid - Answers - protein coat surrounding and protecting the nucleic acid
, what is the capsid composed of? - Answers protein subunits called "capsomeres"
3) envelope - Answers - on some viruses, it covers the capsid.
- some envelopes may have "spikes" which are carbohydrate protein complexes that project
from the surface
what is the envelope made up of? - Answers - lipids
- proteins
- carbohydrates
what does the host immune system produce to the virus surface protein? - Answers antibodies
what causes multiple infections by the same virus? - Answers in response to the immune
system producing antibodies to the virus surface protein, the virus can mutate these proteins at
a high rate causing multiple infections by the same virus
- ex: influenza virus
what are the different morphologies of a virus - Answers - helical
- polyhedral
- enveloped
- complex
helical viruses - Answers - long rods; may be rigid or flexible
- ex: causes rabies and ebola
polyhedral viruses - Answers - icosahedron shape (20 triangular faces and 12 corners)
- ex: poliovirus
enveloped viruses - Answers - capsid covered with an envelope
- roughly spherical
- ex: influenza virus, herpes virus
complex viruses - Answers - complex shape
- these are bacteriophages when infecting bacteria
2025/2026
definition of a virus - Answers a submicroscopic, parasitic, filterable agent consisting of a
nucleic acid surrounded by a protein coat
which is smaller, viruses or bacteria? - Answers bacteria
what can a virus infect? - Answers -invertebrates
-vertebrates
-plants
-protists
-fungi
-bacteria
when are viruses considered to be alive? - Answers ONLY when they are inside the host they
infect
where do they multiply? - Answers inside living cells
are viruses sensitive to antibiotics? - Answers NO
what are viruses sensitive to? - Answers interferon
host range - Answers - the spectrum of host cells a virus can infect
- most can only infect one specific host because it requires a specific site to attach to its host
- those that infect bacteria are called "bacteriophage" or "phage"
what 3 things makes up a virus? - Answers 1) nucleic acid
2) capsid
3) envelope (on some viruses)
1) nucleic acid - Answers - have DNA (or) RNA; not both
- double stranded or single stranded
- linear or circular
genome size? - Answers ranges from a few thousand nucleotides to as many as 250,000
2) capsid - Answers - protein coat surrounding and protecting the nucleic acid
, what is the capsid composed of? - Answers protein subunits called "capsomeres"
3) envelope - Answers - on some viruses, it covers the capsid.
- some envelopes may have "spikes" which are carbohydrate protein complexes that project
from the surface
what is the envelope made up of? - Answers - lipids
- proteins
- carbohydrates
what does the host immune system produce to the virus surface protein? - Answers antibodies
what causes multiple infections by the same virus? - Answers in response to the immune
system producing antibodies to the virus surface protein, the virus can mutate these proteins at
a high rate causing multiple infections by the same virus
- ex: influenza virus
what are the different morphologies of a virus - Answers - helical
- polyhedral
- enveloped
- complex
helical viruses - Answers - long rods; may be rigid or flexible
- ex: causes rabies and ebola
polyhedral viruses - Answers - icosahedron shape (20 triangular faces and 12 corners)
- ex: poliovirus
enveloped viruses - Answers - capsid covered with an envelope
- roughly spherical
- ex: influenza virus, herpes virus
complex viruses - Answers - complex shape
- these are bacteriophages when infecting bacteria
