Biology Chapter 8

24. List and explain the events that occur during the reproductive cycle of an HIV virus.

1. Attachment: HIV binds to receptors on the plasma membrane of the target cell. 2. Fusion: HIV fuses with the plasma membrane, and the virus enters the host cell. 3. Entry: The capsid and protein coats are removed, releasing RNA and viral proteins into the host cell's cytoplasm. 4. Reverse transcription: HIV's single-stranded RNA is converted into a double-stranded viral DNA code. 5. Integration: The viral DNA, along with the viral enzyme integrase, migrates into the nucleus of the host cell. The viral DNA is spliced into the host cell's DNA, making it part of the host genome. 6. Biosynthesis and cleavage: The host cell's machinery directs the production of more viral RNA. Some of the viral RNA becomes material for new viruses, while the rest is used to code for viral proteins. 7. Assembly: Capsid proteins, viral enzymes, and RNA are assembled into new viruses. 8. Budding: The new virus leaves the cell, acquiring an envelope from the host cell's plasma membrane.

30. List and describe the opportunistic diseases that individuals in category C of AIDS usually die from.

1. Pneumocystis jiroveci pneumonia: a fungal infection of the lungs 2. Mycobacterium tuberculosis: a bacterial infection of the lymph nodes or lungs 3. Toxoplasmic encephalitis: a protozoan parasitic infection, often seen in the brains of AIDS patients 4. Kaposi sarcoma: a cancer of the blood vessels that gives rise to reddish-purple spots or lesions on the skin 5. Invasive cervical cancer: a cancer of the cervix that can spread to other tissues

6. Describe the structure of a typical virus.

A virus consists of two basic parts: an outer capsid composed of protein subunits surrounding an inner core of nucleic acids.

51. When were the first cases of SARS reported? A. 2002 B. 1992 C. 1820 D. 1920 E. 2012

A. 2002

47. Why is bird flu (H5N1) considered an emerging disease whereas HIV is not? A. Bird flu (H5N1) has only been recognized in the past 20 years. B. Bird flu (H5N1) is more deadly than HIV. C. Bird flu (H5N1) is bacterial whereas HIV is viral. D. Bird flu (H5N1) has infected more people than HIV. E. Bird flu (H5N1) has not infected as many people as HIV.

A. Bird flu (H5N1) has only been recognized in the past 20 years.

60. There is no point to taking antibiotics for a cold. True/False

TRUE Antibiotics are useful against bacterial infections, not viral infections. The common cold is caused by a virus.

43. The drugs that treat malaria can be used prophylactically, or before infection. True/False

TRUE Antimalarial drugs can be used prophylactically. They do not prevent the initial infection, but they prevent the development of the parasites in the blood.

52. SARS is thought to have arisen in China due to the consumption of civets. True/False

TRUE Civets, a type of exotic cat-like creature, are considered a delicacy in China. It is thought that some civets were possibly infected by exposure to horseshoe bats.

58. The use of antibiotics does not cause antibiotic resistance. True/False

TRUE Development of antibiotic resistance is a form of natural selection. Antibiotic use does not cause the resistance. Instead, pathogens become resistant, and there are some organisms in a population that are naturally resistant to the drug. The drug regimen kills the susceptible ones while leaving naturally resistant ones to multiply and repopulate the patient's body. The new population is then resistant to the drug.

48. Streptococcus is now considered to be a reemerging pathogen. True/False

TRUE Due to increased resistance to antibiotics, Streptococcus is now considered to be a reemerging pathogen.

65. MRSA can be fatal. True/False

TRUE Infections with methicillin-resistant Staphylococcus aureus can be fatal, especially if there are no antibiotics available to treat the infection.

31. The envelope of the HIV virus is actually part of the host cell plasma membrane. True/False

TRUE The HIV envelope is acquired during budding of the virus through the host cell plasma membrane.

42. Unlike AIDS, both tuberculosis and malaria can be cured. True/False

TRUE There currently is no guaranteed effective cure for AIDS. There are effective cures for both tuberculosis and malaria.

22. There currently is no effective cure for AIDS True/False

TRUE There is no guaranteed cure for AIDS, but patients are living longer than they used to on antiviral drugs.

36. Describe the causative agents and transmission of tuberculosis.

Tuberculosis is caused by the bacterium Mycobacterium tuberculosis. Its cells have a thick, waxy coating that allows the bacterium to exist in a dehydrated state for weeks at a time. The organisms are spread by airborne droplets, introduced into the air when a person coughs or sneezes. The bacteria can actually float in the air for hours after being released and still be infectious.

21. In the "kitchen-sink model" for CD4 T-cell loss, what does the sink's drain represent? A. the destruction of CD4 T cells by the virus B. the production of new CD4 T cells C. the amplification of the virus in the blood D. the destruction of the virus by the immune system E. the wide variety of possible opportunistic infections

A. the destruction of CD4 T cells by the virus

55. Once SARS appeared in China, how long did it take for it to reach nine other countries/provinces via air travel? A. three months B. six months C. one year D. two years E. five years

A. three months

29. Of the following modes of HIV transmission, which is the least common mode and rare in many countries? A. transfusions of infected blood B. vaginal/rectal intercourse with an infected person C. needle sharing among IV drug users D. babies born to HIV-infected women E. oral-genital contact with an infected person

A. transfusions of infected blood

3. What are fimbriae, and what is their function? A. They are long, thin appendages that allow bacteria to be motile (move). B. They are stiff fibers that allow bacteria to adhere to surfaces. C. They are elongated, hollow appendages that allow for the transfer of DNA. D. They are small, circular pieces of DNA that frequently contain genes for antibiotic resistance. E. They are a thick, gelatinous substance surrounding some bacterial cells that allow them to stick to surfaces and protect them from phagocytic white blood cells.

B. They are stiff fibers that allow bacteria to adhere to surfaces.

50. Why is Helicobacter pylori considered an emerging disease? A. It is highly resistant to antibiotics. B. Ulcers were not known to have an infectious cause until recently. C. It is now present on all of the continents. D. It can jump from humans to pigs and back again. E. It had declined in the 1960s but appears to be back again.

B. Ulcers were not known to have an infectious cause until recently.

35. Tuberculosis is caused by a A. virus. B. bacterium. C. fungus. D. protist. E. worm.

B. bacterium.

16. Why might an HIV test be negative within the first two to three weeks of an HIV infection? A. because there is no HIV in the blood B. because there are no detectable levels of HIV antibodies in the blood C. because there are no symptoms D. because the CD4 T-cell count is above 500 cells/mm3 E. because there are no opportunistic infections yet

B. because there are no detectable levels of HIV antibodies in the blood

28. Which of the following is important for the attachment stage of the HIV life cycle? A. acquisition of an envelope from the host B. gp120 spike proteins C. cleavage of the proteins by protease D. integration of the viral DNA into the host genome E. uncoating

B. gp120 spike proteins

45. Most people with malaria exhibit chills and fevers every 48 to 72 hours. This is due to A. reinfection with new Plasmodium. B. the bursting of red blood cells in the body. C. the formation of Plasmodium gametes within the body. D. the fusion of the male and female Plasmodium gametes to form new organisms. E. waves of activity from the body's B and T cells.

B. the bursting of red blood cells in the body.

63. How many different "lines" of antibiotics against TB are there? A. one B. two C. three D. four E. five or more

B. two

56. When penicillin was introduced, how long did it take for penicillin-resistant strains of bacteria to emerge? A. 6 months B. 1 year C. 4 years D. 10 years E. 25 years

C. 4 years

17. Patient X has 150 CD4 T cells/mm3. What phase of an HIV infection is this patient in? A. acute phase (A) B. chronic phase (B) C. AIDS (C) D. transmission phase (D) E. terminal phase (E)

C. AIDS (C)

64. What do MDR TB and MRSA have in common? A. Both are transmitted by mosquitoes. B. Both cause tuberculosis. C. Both are multidrug-resistant bacteria. D. Both have seen their numbers of infections decline dramatically in recent years. E. Both are viruses.

C. Both are multidrug-resistant bacteria.

32. HIV strains may differ by 10% within one person and by 35% in people around the globe. This is due to A. both cellular and antibody-mediated responses. B. the fact that HIV inserts its genome into the host genome. C. HIV's high rate of mutation. D. the fact that HIV targets T cells. E. the fact that most people do not die from HIV infection.

C. HIV's high rate of mutation.

27. Which of the following is not important for classifying HIV as a retrovirus? A. reverse transcriptase B. RNA genome C. an envelope obtained from the host D. the production of viral DNA E. integration into the host genome

C. an envelope obtained from the host

5. If an epidemic is confined to a local area, it is usually called A. an opportunistic infection. B. a pandemic. C. an outbreak. D. a slow infection. E. a chronic infection.

C. an outbreak.

37. What are the symptoms of a TB infection? A. skin rash, fever B. opportunistic infections, chronic diarrhea C. bad cough, chest pain, coughing up blood or sputum D. runny nose, sore throat, postnasal drip E. lethargy, general malaise

C. bad cough, chest pain, coughing up blood or sputum

44. Where does the life cycle of the Plasmodium protist take place? A. in mosquitoes B. in humans C. in both mosquitoes and humans D. in snails E. in pigs

C. in both mosquitoes and humans

8. HIV/AIDS and tuberculosis are both examples of current A. outbreaks. B. epidemics. C. pandemics. D. opportunistic infections. E. acute infections.

C. pandemics.

40. The organism that causes malaria is a A. virus. B. bacterium. C. protist. D. fungus. E. worm.

C. protist.

14. When was the first documented case of HIV in the United States? A. 1884 B. 1924 C. 1959 D. 1969 E. 1982

D. 1969

13. How does HIV know which cells to infect? A. It can infect any cell it comes in contact with. B. It can only infect cells on surfaces of the body where the temperature is lower. C. It can only infect cells that are actively growing and dividing. D. It can infect cells with particular surface receptors. E. It only infects cells that line the reproductive tract.

D. It can infect cells with particular surface receptors.

19. Which of the following diseases is not categorized as an opportunistic infection found in AIDS patients? A. prolonged diarrhea B. yeast infections of the mouth or vagina C. shingles D. Kaposi sarcoma

D. Kaposi sarcoma

54. Legionnaires disease emerged in 1976 due to A. exposure to wild monkeys. B. the consumption of horseshoe bats. C. a mutation of the influenza virus. D. contamination of an air-conditioning system. E. the abuse of antibiotics.

D. contamination of an air-conditioning system.

2. Which of the following molecules is not found in eukaryotic cells? A. phospholipids B. DNA C. RNA D. peptidoglycan E. All of these are found in eukaryotic cells.

D. peptidoglycan

25. Which of the following is not a layer of the protein coat that surrounds the HIV genetic material? A. matrix B. capsid C. nucleocapsid D. protease E. gp120

D. protease

23. The HIV virus contains a genome composed of A. double-stranded DNA. B. single-stranded DNA. C. double-stranded RNA. D. single-stranded RNA. E. one strand of DNA and one strand of RNA.

D. single-stranded RNA.

Arrange the steps of the HIV life cycle in the correct order: 1. Assembly 2. Integration 3. Entry 4. Fusion 5. Attachment 6. Budding 7. Biosynthesis and cleavage 8. Reverse transcription A. 1, 3, 2, 4, 5, 7, 6, 8 B. 1, 2, 3, 4, 5, 6, 7, 8 C. 8, 1, 7, 2, 6, 3, 5, 4 D. 4, 6, 3, 7, 2, 8, 1, 5 E. 5, 4, 3, 8, 2, 7, 1, 6

E. 5, 4, 3, 8, 2, 7, 1, 6

4. Which of the following is not a characteristic found in Gram-negative bacteria? A. Plasmids and antibiotic resistance. B. A peptidoglycan cell wall. C. An outer membrane composed of lipopolysaccharide. D. They Gram stain pink. E. A thick peptidoglycan cell wall that stains purple.

E. A thick peptidoglycan cell wall that stains purple.

49. Which of the following diseases is considered an emerging disease? A. SARS B. H1N1 C. H5N1 D. strep throat E. All of these are considered emerging diseases.

E. All of these are considered emerging diseases.

59. Which of the following has/have developed antibiotic resistance? A. tuberculosis B. malaria C. gonorrhea D. enterococci E. All of these diseases and organisms have developed drug resistance.

E. All of these diseases and organisms have developed drug resistance

53. Which of the following factors is/are helping increase the incidence of emerging diseases? A. global warming B. expansion of range by insect vectors C. abuse of antibiotics D. poor implementation of vaccination programs E. All of these factors are helping increase the incidence of emerging diseases.

E. All of these factors are helping increase the incidence of emerging diseases.

61. Which type(s) of antibiotic(s) is MRSA resistant to? A. methicillin B. penicillin C. amoxicillin D. none of these E. all of these

E. all of these

41. How is malaria spread? A. airborne droplets B. blood transfusions C. sexual intercourse D. breast-feeding E. mosquitoes

E. mosquitoes

38. How long does treatment for TB take? A. one to two days B. one to two weeks C. one month D. two months E. six months or more

E. six months or more

46. An emerging disease is one that A. is newly recognized in the last two decades. B. has suddenly caused an epidemic. C. is now present on multiple continents. D. can infect both humans and animals. E. can be transmitted in multiple ways.

A. is newly recognized in the last two decades.

11. What types of cells does HIV infect? A. helper T cells and macrophages B. B cells and red marrow cells C. liver cells and cardiac muscle cells D. epithelial cells and eosinophils E. basophils and killer T cells

A. helper T cells and macrophages

15. In which phase of an HIV infection is a person typically asymptomatic? A. acute phase (A) B. chronic phase (B) C. AIDS (C) D. AIDS (D) E. terminal phase (E)

A. acute phase (A)

39. How is Mycobacterium tuberculosis spread? A. airborne droplets B. contaminated food or water C. sexual intercourse D. IV drug abuse E. blood transfusions

A. airborne droplets

7. Why aren't viruses considered living organisms? A. because they do not replicate B. because they do not possess genetic material C. because they are not composed of cells D. because they lack the metabolic machinery to acquire and use nutrients E. None of these are correct.

A. because they do not replicate

62. Which of the following is an unwise use of antibiotics? A. discontinuing antibiotics when you feel better B. not taking antibiotics for a viral infection C. not saving unused antibiotics D. not skipping doses of antibiotics E. taking antibiotics only to treat the infection for which they were prescribed

A. discontinuing antibiotics when you feel better

12. Which category of disease classification is described as having more cases than expected in a given period of time? A. epidemic B. outbreak C. pandemic D. opportunistic infection E. none of these

A. epidemic

9. A disease is called an epidemic if people all over the world have the same disease.

FALSE A disease is called an epidemic if there are more cases of the disease than expected in a certain area for a certain period.

1. Prokaryotic cells do not possess DNA. True/False

FALSE All living things possess DNA as the molecule of inheritance. In eukaryotic cells, the DNA is in a separate membrane-bound compartment called the nucleus. Prokaryotes do not possess a nucleus.

18. The vast majority of new HIV infections are in people under the age of 15. True/False

FALSE Approximately 11% of the 2.0 million new HIV infections are in people under the age of 15.

57. People can become resistant to antibiotics. True/False

FALSE Bacteria can become resistant to antibiotics and people can harbor those bacteria, but people do not become resistant to antibiotics.

20. Infection with HIV is listed as the cause of death for an AIDS patient.

FALSE Persons with AIDS die from one or more AIDS-related (opportunistic) illnesses rather than from the HIV infection directly.

34. AIDS is the new name for what used to be called consumption. True/False

FALSE Tuberculosis (TB), not AIDS, used to be called consumption.

33. An HIV vaccine would be the cure for AIDS that science has been looking for. True/False

FALSE Vaccines do not cure diseases; rather, they prevent people from being infected in the first place.

10. There are normally one or two cases of measles per month in a particular city. However, in the month of September, there were 15 cases. Is this an epidemic? Yes/No

YES Yes. An epidemic is defined as more cases of the disease than expected in a certain area for a certain period.