Viruses: Structure, Replication, and Diseases, Exams of Microbiology

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• BIOD 171 Essential Microbiology Portage Learning Module

Question 1

2 / 2 pts

True or False. Because the genome is contained within an enclosed space (much like the nucleus of a cell), viruses are classified as eukaryotic. True Correct! False False. Viruses are neither eukaryotic nor prokaryotic. Your Answer:

• genomic material that can be either DNA or RNA
• Capsid that is a membrane like structure which protects the genetic matrials 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. Your Answer: capsid capsid

Question 2

5 / 5 pts

Describe the two basic components of a virus.

Question 3

3 / 3 pts

The envelope surrounds the _________ of some viruses.

True Correct! False False. The viral genome is never replicated before attachment and entry regardless of its level of infectivity.

Question 7

2.5 / 5 pts

Place the following viral life cycle steps in order beginning with viral attachment and provide a description of each step. Uncoating: Release: Replication: Attachment: Entry: New infection: Your Answer: Attachment Entry Uncoating Replication New infection Released 3- Uncoating: the viral capsid disassembles

5-Release: New virus particles are produced and leave the cell 4-Replication: the viral genome is the ‘blueprint’ to make copies of itself 1-Attachment: viral receptors bind to host proteins on the surface of the cell 2-Entry: the virus fuses with the host membrane and enters the cell 6-New infection: newly produced viruses that left the host cell now go on to infect new cells. provide a description of each step 1)Bacteriophage

2. icosahedral 20 sided

**1. Bacteriophage

2. 20** True True. Bacteriophages are structurally distinct from viruses that infect plant and animals cells. False

Question 8

3 / 3 pts

A virus that infects bacteria is called a [answer1] and contains a [answer2] -sided polygon capsid. Your Answer:

Question 9

pts

True or False. Structurally, bacteriophages are distinct from viruses that infect plant or animal cells. Correct!

3- Tail 4- Base plate 5- Tail fibers Your Answer: lytic bacteriophage replicate within host bacteria till they lyses, but temperate or lysogenic bacteriophage can survive in non replicative state and its viral genome integrated in to host genome Lytic bacteriophages replicate within the host bacteria until it ruptures, whereas temporate (or lysogenic) 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.

UnansweredQuestion 12

0 / 5 pts

Based on the following image, would you expect the viral titer to be high or low? Why?

Question 11

5 / 5 pts

Describe the main differences between lytic and temperate phages.

Your Answer: 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 cycle continues more and more bacterial cells will be destroyed, effectively clearing the media. Measles Mumps Rubella A and B Correct!

Question 13

2 / 2 pts

Which of the following can be spread via airborne particles:

Influenza-like symptoms A patient may experience a combination of symptoms such as fever, flu-like symptoms (influenza), cough, conjuctivitis, and a red blotchy skin rash. Measles Mumps Rubella B and C Correct! All of the above Measles, mumps and rubella are all linear, single-stranded RNA viruses. Mumps

Question 16

2 / 2 pts

Which of the following diseases does a linear, single-stranded RNA virus cause?

Question 17

pts

What disease displays as a secondary characteristic swelling of the testes/ovaries and pancreas? Your Answer:

Mumps. A patient infected with mumps (aka epidemic paratitis) has primary swelling in the paratoid (salivary glands) located in the neck but also may have secondary swelling in the testes/ovaries and pancreas.

Question 18

Your Answer:

• air borne droplet
• direct contact with blisters of infected people Chickenpox is highly contagious and can be transmitted (1) through both airborne droplets (sneezing/coughs) or via (2) direct contact with the blisters of an infected individual. True True. The most common age for VZV reactivation and shingle diagnosis tends to occur in people around 60 years of age. False True Correct!

5 / 5 pts

Describe two ways chickenpox can be spread.

Question 19

2 / 2 pts

True or False. The development of shingles is most often seen in an older adult population (> 60 years old). Correct!

Question 20

pts

True or False. Similar to chickenpox, the blisters that appear with shingles can cover the entire body.

Your Answer: Poliovirus Polio, also known as poliomyelitis.

Question 24

3 / 3 pts

By whom and where was the first polio vaccine developed? Your Answer: Jonas Salk in pitsburg university Jonas Salk and his research team developed the polio vaccine at the University of Pittsburgh in 1955. Your Answer: subtype A Influenza A

Question 26

5 / 5 pts

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 hemagglutinin proteins or neuraminidase proteins? Why? Your Answer: Neuraminidase protein because this protein is responsible for release of new viral particles from host cells but the Hemaglutinin protein involves in the entry of the viral particle to the host cell Neuraminidase (N) proteins are directly involved in the budding and release of new viral particles and would thus be the correct target. Hemagglutinin (HA) proteins would not be advisable targets as they are directly involved in viral attachment and entry into the host cell.

Question 25

3 / 3 pts

Which subtype of Influenza is the most virulent?

Your Answer: till now 16 subtype of hemaglutinin and 9 subtype of neuraminidase have been discovered and can be shown on different combination of viral envelope, so all HA and N cannot present on each virion. So due to large number of possibility of variants flu vaccine cannot be protective against all subtype and a person who received a flu shot has the probability to gain flue disease It is possible to receive a flu vaccine and yet (unfortunately) still get the flu in the same season if you are exposed to a viral strain that was not included in the vaccine. There are a large number of variants and the flu vaccine is unable to vaccinate against all subtypes. Medical researchers predict and then distribute flu vaccines based current trends and the available data relative to the most common circulating strains. Unfortunately, this model is not always 100% accurate. True Correct! False False. The HIV capsid is conical (cone) shaped. CD

Question 27

pts

Explain why the flu shot given each year may not be 100% effective at preventing the flu?

Question 28

pts

True or False. The viral capsid of HIV is dumbbell shaped and contains ~2,000 copies of the viral protein p24.

Question 29

2 / 2 pts

The HIV surface glycoprotein gp41 binds what host cellular receptor?