Mastering Microbio 4

One group of medications used to treat HIV infections is the reverse transcriptase inhibitors. There are two types of these medications, nucleoside reverse transcriptase inhibitors (like AZT) and non-nucleoside reverse transcriptase inhibitors. AZT resembles thymine and is inserted into DNA during replication, leading to the termination of replication. Non-nucleoside reverse transcriptase inhibitors bind to reverse transcriptase and inhibit it in that manner. Non-nucleoside reverse transcriptase inhibitors tend to have fewer side effects. Which of the following best describes why this is the case? Nucleoside reverse transcriptase inhibitors may interfere with DNA replication by the host, not just by the virus. HIV can rapidly develop resistance to nucleoside reverse transcriptase inhibitors. Non-nucleoside reverse transcriptase inhibitors are less specific and therefore more effective. Non-nucleoside reverse transcriptase inhibitors are less likely to stimulate cell growth.

Nucleoside reverse transcriptase inhibitors may interfere with DNA replication by the host, not just by the virus.

A positive tuberculin test means a patient has active disease. has been previously exposed to Mycobacterium tuberculosis. has a current inappropriate infection. has active disease, has been previously exposed to Mycobacterium tuberculosis, or has a current inappropriate infection.

has active disease, has been previously exposed to Mycobacterium tuberculosis, or has a current inappropriate infection.

Human immunodeficiency virus (HIV) __________. infects and replicates only in T-helper cells infects and replicates in macrophages only infects and replicates in macrophages and T-helper cells infects and replicates in all immune system cells

infects and replicates in macrophages and T-helper cells

Toxic shock syndrome __________. is always associated with tampon usage is life-threatening because of the superantigen toxin produced is life-threatening because of the endotoxin produced is associated only with Staphylococcus species

is life-threatening because of the superantigen toxin produced

Borrelia burgdorferi is an interesting spirochete that is unusual when compared to other bacteria. Which of the following is the reason that it is so unusual? it has a linear chromosome it has flagella it has a cell wall it has ribosomes

it has a linear chromosome

The sexually transmitted infection that can lead to infection of the central nervous system if not treated early is __________. syphilis chlamydia herpes simplex 1 gonorrhea

syphilis

The Plasmodium life cycle is very complex, involving two hosts. Which of the choices shows the correct sequence of events in this cycle? 1. Red blood cells are infected. 2. Mosquito bite occurs. 3. Plasmodium enters the liver. 4. Red blood cells are destroyed. 5. Plasmodium grows and develops sporozoites. 2, 5, 3, 1, 4, 2 2, 3, 1, 5, 4, 2 1, 5, 4, 3, 2, 1 3, 5, 1, 4, 2

2, 5, 3, 1, 4, 2

During malarial infection, splenomegaly can occur. What causes this? The spleen always enlarges in response to infection. The spleen becomes enlarged in response to fever. The malarial sporozoites colonize the spleen and cause inflammation. The spleen filters the blood and destroys old erythrocytes.

The spleen filters the blood and destroys old erythrocytes.

Once a person has been infected with Neisseria gonorrhoeae, the individual requires immunization by a vaccine. acquires no immunity, and thus could be reinfected immediately. requires immunization by an antiserum. acquires transient immunity, which prevents subsequent infection for about a year.

acquires no immunity, and thus could be reinfected immediately.

A major cause of helminthic infectious blindness is __________. onchocerciasis Bancroft's filariasis trichinosis schistosomiasis

onchocerciasis

If a human is bitten by an animal that has rabies, then it is recommended that the human receive immune globin (human rabies antibodies) and a rabies vaccination (with inactive virus) as well. Which of the following is the best (and most specific) explanation for why both are recommended in this case? The rabies vaccination is relatively new and ineffective, so it is important to give the immune globin as well to make certain that the viruses cannot cause disease. Using both is needed because an individual who has received this type of bite is more likely than someone else to receive another bite. While the immune globin is sufficient to prevent rabies infection, the vaccination helps to prevent the individual from the risk of a future bite. The rabies antibodies provide a rapid response but short-lived response while the vaccination provides slower but longer-lasting protection. Because rabies is such a serious illness, using antibodies and a vaccine provides the strongest possible immediate protection. Both antibodies and the vaccine provide a rapid immediate response to prevent illness from developing.

The rabies antibodies provide a rapid response but short-lived response while the vaccination provides slower but longer-lasting protection.

Of the arthropod-borne diseases, there is a vaccine to prevent __________. yellow fever Lyme disease dengue fever West Nile fever

yellow fever