Question 1

Which of the following requires a host cell because they aren't able to make proteins on their own?

Accepted Answer

Viruses require a host cell to replicate and make proteins. Unlike bacteria, protozoans or blue-green algae, they lack the cellular machinery to carry out their own protein synthesis.

Question 2

The Epstein-Barr virus causes

Accepted Answer

The Epstein-Barr virus (EBV) is known for causing infectious mononucleosis, which is commonly referred to as "mono" or the "kissing disease." Symptoms of mono include fatigue, fever, sore throat, swollen lymph nodes, and enlarged spleen. While it is not the only cause of mono, EBV is one of the most common culprits.

Question 3

Which of the following is a common feature of a virus?

Accepted Answer

A capsid, or protein coat, is a common feature of viruses. It surrounds the genetic material (either DNA or RNA) of the virus. Cell walls, nuclei, and plasmids are not present in all viruses.

Question 4

AZT is an effective drug for treating HIV-infected individuals because it prevents the replication of new viral particles. The HIV virus has a genome made of RNA. Of the following, which represents the most likely target for the action of AZT?

Accepted Answer

AZT is a nucleoside reverse transcriptase inhibitor (NRTI), which means it inhibits the action of reverse transcriptase enzyme that the virus uses to convert its RNA genome into DNA for integration into the host cell. By inhibiting this process, AZT prevents the virus from replicating and producing new viral particles. It does not target the DNA of the host cell, the cell wall of the virus, or DNA ligase in the host cell.

Question 5

One of the reasons that viruses are such effective infectious organisms is their ability to gain entry into host cells. Which component of a virus is primarily responsible for this feat?

Accepted Answer

The viral envelope is a membrane surrounding some viruses that allows them to enter host cells by fusing with the host cell membrane. This is a key factor in the ability of viruses to infect and replicate in host cells.

Question 6

The relationship between the protist, Plasmodium, that causes malaria and its host is beneficial to both of them.

Accepted Answer

The relationship between Plasmodium and its host is parasitic in nature. Plasmodium benefits by deriving nutrients from the host's blood, while the host is harmed by the infection, leading to symptoms of malaria.

Question 7

Why is it important to keep your leftover chicken salad in the refrigerator?

Accepted Answer

Infectious bacteria like Salmonella reproduce more quickly at room temperature, so it is important to keep leftover chicken salad in the refrigerator to slow down any potential bacterial growth.

Question 8

What would be an action that public health officials could take to reduce the risk of West Nile virus infection?

Accepted Answer

West Nile virus is spread by mosquitoes, so public health officials can work with natural resource managers to spray areas where mosquitoes breed to reduce the number of mosquitoes and therefore reduce the risk of infection. Vaccines for the virus are currently not available for humans, so option A is not a viable action. Handwashing and cough etiquette are important for preventing the spread of respiratory illnesses but are not directly related to West Nile virus, so option B is not a relevant action. Requiring pet owners to vaccinate their pets would be helpful in preventing pets from getting infected, but it does not directly address the risk of human infection, so option C is not the best action.

Question 9

Disease-causing organisms are called

Accepted Answer

Pathogens are specifically disease-causing organisms, while the other choices may have broader or slightly different meanings. Microbes can refer to any type of small living organism, including those that are harmless or even beneficial. Parasites specifically live on or within another organism and may or may not cause disease. Contagious simply means that a disease can be spread from person to person, but it does not necessarily indicate the cause of the disease.

Question 10

Which of the following is a disease caused by bacteria that can paralyze respiratory muscles?

Accepted Answer

Botulism is a disease caused by the Clostridium botulinum bacteria which produces a toxin that can paralyze respiratory muscles. E. coli infection is caused by a different type of bacteria and typically affects the gastrointestinal system. Staph infection is caused by Staphylococcus bacteria and can manifest in various ways, such as skin infections, pneumonia, or sepsis. Tuberculosis is caused by Mycobacterium tuberculosis and primarily affects the lungs, causing coughing and difficulty breathing, but it does not directly paralyze respiratory muscles.

Question 11

A young woman with rhinovirus goes to the doctor to see if she can get a prescription for antibiotics. How would the antibiotics affect the rhinovirus?

Accepted Answer

Antibiotics are only effective against bacterial infections, not viral infections like rhinovirus. Therefore, the rhinovirus would not be affected by the antibiotics.

Question 12

Where would you be most likely to encounter E. coli bacteria?

Accepted Answer

E. coli is a type of bacteria that is commonly found in the intestines of animals and humans. It can be shed in their feces and can contaminate food or water. Unpasteurized milk is a common source of E. coli and can cause illness if consumed.

Question 13

A research scientist is trying to design a new antibiotic that would break down the gelatinous capsule that surrounds each bacterial cell. This antibiotic would be effective in preventing human illness by preventing the bacteria from doing which of the following actions?

Accepted Answer

The gelatinous capsule is a protective outer layer that helps bacteria attach to body cells in order to cause infection. Therefore, breaking down the capsule would prevent bacteria from attaching to body cells and causing illness.

Question 14

A disease-causing organism that can spread from one organism to another is said to be

Accepted Answer

A disease-causing organism that can spread from one organism to another is said to be contagious. Contagious refers to a disease that can be transmitted from one person to another through direct or indirect contact.

Question 15

Why are latent viruses more likely to be transmitted to unsuspecting hosts than other types of viruses?

Accepted Answer

Latent viruses can remain dormant in a host for long periods of time without causing symptoms or being detected by the immune system. This enables infected individuals to unknowingly transmit the virus to others, making it more likely for the virus to be spread to unsuspecting hosts.

Question 16

Many bacteria carry plasmids containing bacterial genes that are easily and rapidly spread through an entire bacterial colony. Why are plasmids of particular concern to humans?

Accepted Answer

Plasmids carrying antibiotic resistance genes can spread quickly through bacterial populations, making it difficult to treat infections caused by antibiotic-resistant bacteria.

Question 17

Viruses aren't classified as living organisms because

Accepted Answer

Viruses require a host cell to replicate and complete their life cycle. They cannot replicate on their own, which is a key characteristic of living organisms.

Question 18

Infectious diseases differ from genetic diseases in that infectious diseases are usually contagious.

Accepted Answer

The answer of Infectious diseases differ from genetic diseases in...

Question 19

Some RNA viruses, such as HIV, require the enzyme ________ (two words)to convert the viral RNA genome into a DNA version.

Accepted Answer

The answer of Some RNA viruses, such as HIV, require...

Question 20

You have developed an antibiotic that inhibits a bacterial enzyme critical for the formation of the cell wall. However, after only a short time, the bacteria become resistant to the antibiotic, and it's no longer effective. Which of the following may be a mechanism by which the bacteria are no longer sensitive to your antibiotic?

Accepted Answer

The development of antibiotic resistance through the selection of bacteria containing a gene that codes for an enzyme capable of metabolizing the antibiotic is a common mechanism. This is known as enzymatic degradation or modification, where bacteria produce enzymes that modify or degrade the antibiotic, making it ineffective against the bacteria.

Quiz 19: Vaccinations: Protection and Prevention or Peril? Immune System