Exam 6 Flashcards
True or False: Structurally bacteriophages are similar to viruses that infect animals
False. Bacteriophages have a distinct composition and structure
A patient diagnosed with German measles may additionally experience what disease? Select all that apply
A. Impetigo
B. Conjuctivitis
C. Rheumatic fever
D. Influenza-like symptoms
B and D
The _____ surrounds the capsid of some viruses
Envelope
Which of the following cannot be spread via airborne particles
A. Measles
B. Mumps
C. Rubella
D. A and B
E. None of the above
E. Measles, mumps and rubella can all be spread via airborne particles formed while coughing, sneezing, etc.
True or False: Someone who had chicken pox as a child is likely to develop shingles while in college, where the median age of college students is 18-22 years old
False. The most common age for shingles reactivation and shingle diagnosis tends to occur in people greater than 60 years of age
Which of the following diseases does a linear, double-stranded DNA virus cause?
A. Measles
B. Mumps
C. Rubella
D. B and C
E. None of the above
E. Measles, mumps, and rubella are linear, single-stranded RNA virus
While traveling abroad, should you be worried about coming into contact with either the Variola major or Variola minor viruses?
You do not need to worry about coming into contact with either virus. They are both variants of smallpox, which was eradicated in 1977.
True or False. Structurally, bacteriophages are distinct from viruses that infect plant or animal cells.
True. Bacteriophages are structurally distinct from viruses that infect plant and animals cells.
True or False: You would expect to see a viral envelope on a virus infecting a bacterial cell
False. Not all the viruses have envelopes
Described the main underlining differences between the Salk and Sabin polio vaccine
The Salk vaccine was injected and contained an inactivate form of the virus. The Sabin vaccine contained a live weakened form of the virus and was administered orally
True or False: Similar to chickenpox, the blisters that appear with Shingles can cover the entire body
False. Unlike chickenpox blisters, which can form anywhere, the blisters associated with shingles are localized and limited to small areas
Describe the two basic components of a virus (short answer)
- Genomic material made up of either DNA or RNA
- A capsid that contains the DNA or RNA
True or False: The viral capsid of HIV is dumbbell shaped and contains ~2,000 copies of the viral protein p24
False. The HIV capsid is conical (cone shaped)
Which subtype of Influenza is the most virulent?
Influenza A
You go to visit a friend who has chickenpox. While visiting what are two things you will be sure to avoid so you don’t also become infected?
- You would want to be sure to keep a distance especially if your friend is coughing or sneezing as chickenpox can be transmitted through air-borne droplets (sneezing/coughs).
- You would also have to be absolutely certain to avoid direct contact with the blisters of an infected individual
What small (~30nm) single-stranded, non-enveloped RNA virus causes temporary or permanent paralysis by infiltrating (infecting) motor neurons within the spinal cord, brain stem or motor cortex?
Polio, also known as poliomyelitis
The envelope surrounds the _____ of some viruses
Capsid
True or False: A patient infected with Rubella is considered infectious one week before and after the appearance of the trademark rash
True
By whom and where was the first Polio vaccine developed?
Jonas Salk along with his research team, at the University of Pittsburgh, developed the first polio vaccine in 1955
What linear, double-stranded, enveloped DNA virus is the first virus (as of Oct. 26, 1977) to be officially declared eradicated? (short answer)
Smallpox
Explain why the flu shot given each year may not be 100% effective at preventing the flu?
You may be exposed to a viral strain that is not included in the making of the vaccine of the flu shot you took. The flu vaccine is made to prevent the previous year’s strain.
Rank the following viruses based on their size from largest to smallest: orthomyxovirus, poliovirus, variolavirus
Variolavirus > Orthomyxovirus > Poliovirus
Place the following viral life cycle steps in order beginning with viral attachment and provide a description of each step (short answer)
- Attachment: receptors bind to host proteins on the surface of the cell
- Entry: virus fuses with the host membrane, enters cell
- Uncoating: viral capsid disassembles
- Replication: viral genome makes copies of itself from the “blueprint”
- Exit: new viruses are made and leave cell
- New infection: new viruses go on to infect new cells, process restarts.
True or False. A patient infected with Rubella is only considered infectious when the trademark rash is visible.
False. A patient infected with Rubella is infectious one week before and one week after the appearance of the rash.
Describe the main differences between lytic and temperate phages (short answer)
Lytic bacteriophages will replicate within the host bacteria causing it to rupture. This destroys the host bacterial cell. Temperate phages can survive in a non-replicative state, they do not kill the host cell. They host the phage DNA without risk of cell death.
A drug company is trying to develop a new drug that will inhibit the release of newly produced viral particles. Would the drug company target hemagglutin proteins or neuraminidase proteins? Why?
Neuraminidase proteins because they involve the production and release of viral particles from the host cell
The HIV surface glycoprotein gp120 binds what host cellular receptor? (multiple choice)
CD4
As individual infected with HIV is placed on anti-retroviral medication. Describe how the medication will affect the virus.
Anti-retrovirals interfere with the process of reverse-transcription. Reverse-transcription is how the virus multiples, it makes copies of itself. Once the virus enters the cell and uncoating is complete, the viral enzyme reverse transcriptase acts on the two RNA copies, creating a supporting DNA strand. This is the step the medication will try to stop. By stopping the virus from multiplying, anti-retroviral medications make the immune system strong enough to fight HIV.
True or False: You would expect to see a viral envelope on a virus infecting a plant cell
False. The overwhelming majority of animal viruses are enveloped whereas the majority of plant or bacteria-infecting viruses are not
Based on the following image, would you expect the viral titer to be high or low? Why? (cloudy)
Low. As turbidity is a function of the number of intact bacterial cells present in the media, the amount of virus contained within the above tube must be low. As the lytic continues more and more bacterial cells will be destroyed, effectively clearing the media.
True or False: Viral replication occurs after it attaches and enters the host cell
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.
False. The viral genome is never replicated before attachment and entry regardless of its level of infectivity.
True or False: The viral capsid of HIV is cone shaped and contains ~2,000 copies of the viral protein p24
True
What disease is best characterized by painful swelling of the parotid? (short answer)
Mumps. A patient infected with mumps (aka epidemic parotitis) has swelling in the parotid (salivary glands) located in the neck
A virus that infects bacteria is called a _____ and contains a _____ -side polygon capsid (fill in the blank)
Bacteriophage
20-sided
A person who has neither previously had chickenpox nor been administered the VZV vaccine is exposed to someone with an active VZV (shingles) outbreak and becomes infected. Explain why (or why not) the person will only develop shingles
The now infected individual will develop chicken pox. Shingles is the reactivation of the dormant varicella-zoster virus, therefore someone who is unvaccinated and has never been exposed would develop chickenpox first.
The HIV surface glycoprotein gp41 binds what host cellular receptor? (multiple choice)
CXCR4
What diseases displays as a secondary characteristic swelling of the testes/ovaries and pancreas? (short answer)
Mumps. They will have primary swelling in the parotid in the neck but will also have swelling in the testes/ovaries and pancreas
True or False: Because the genome is contained within an enclosed space, (much like the nucleus of a cell) viruses are classified as eukaryotic
False. Viruses are neither eukaryotic nor prokaryotic
Rank the following viruses based on their size from largest to smallest:Paramyxovirus, Poliovirus, Smallpox virus
Smallpox > Paramyxovirus > Poliovirus
