Exam 13: Viruses, Viroids, and Prions

You are a volunteer for Nurses Without Borders and are being sent to a country in Africa. You are excited, because you will have opportunities to go on safari, but you are also somewhat concerned because you have learned from the CDC website that there is currently cholera in the country to which you are going. Patients with cholera experience vomiting and severe diarrhea, producing several liters of liquid stool in a day. This results in signs of dehydration, including sunken eyes, muscle cramps, and in a few cases, convulsions and death. Cholera is caused by the bacterium Vibrio cholerae. You make a list of questions about V. cholerae that you answer with the help of your nursing school study group. -The signs and symptoms of cholera are caused by cholera toxin that is synthesized and secreted by the bacteria. The toxin causes chloride and other electrolytes to leave the intestinal cells. Water follows the electrolytes, resulting in an outpouring of water into the intestinal lumen. The gene for cholera toxin is a bacteriophage gene. This situation is an example of ________.

Bacteriophages, unlike animal viruses, often have special viral-specific enzymes carried in the capsid, which enter the host cell at the same time as the nucleic acid.

Assembly of the T4 phage

Using phages to treat a bacterial infection is an interesting idea because

Cells infected with animal viruses lyse because

A key feature of all viral infections is the

A virion is composed of

Most enveloped viruses, like hepatitis B, are released by budding, a process whereby the virus acquires its envelope. Before budding occurs, virally encoded protein spikes insert into specific regions of the host cell's membrane. Given this information, which of the following would you tell your friend best describes the structure of the viral envelope?

What are two ways that phage can replicate without directly lysing their host cell?

The correct order for the stages of a phage infection is

The replicative form of nucleic acid in filamentous phages is

Plant viruses may be transmitted by

Why are viroids resistant to nucleases?

Which is a filamentous phage?

Which statement regarding phage replication is True?

You are a volunteer for Nurses Without Borders and are being sent to a country in Africa. You are excited, because you will have opportunities to go on safari, but you are also somewhat concerned because you have learned from the CDC website that there is currently cholera in the country to which you are going. Patients with cholera experience vomiting and severe diarrhea, producing several liters of liquid stool in a day. This results in signs of dehydration, including sunken eyes, muscle cramps, and in a few cases, convulsions and death. Cholera is caused by the bacterium Vibrio cholerae. You make a list of questions about V. cholerae that you answer with the help of your nursing school study group. -The phage from which the cholera toxin gene originates is a ________ phage.

You are graduating from nursing school in three months and have already lined up a new job. However, your employer informs you that before you start your job, it is mandatory for you to be vaccinated against hepatitis B, a double-stranded DNA virus that can cause the disease hepatitis. Your boyfriend, a biology major, wonders why you need to get the vaccine. You aced your microbiology class and you know a lot about both viruses and vaccines, so you understand why getting this vaccination is essential. You give your boyfriend a mini lesson on this by answering a few of his questions. -Your boyfriend wonders whether hepatitis B is really a problematic disease. He says that the job of your immune system is to get rid of viruses and virus-infected cells. You tell him that hepatitis B causes an infection in which the causative agent remains in the body for years or even a lifetime, often without causing symptoms of disease. This type of infection is characterized by the continuous low-level production of viral particles and is called a(n) ________ infection.

Transduction often involves defective virus.

Explain why HIV becomes resistant so quickly when a single drug is used therapeutically.

Retroviruses are unique in that they