Microbiology Virology Flashcards

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0
Q

2) Viruses are parasitic for what chemical in the host cell?

A

Obligated Intracellular Molecular Parasites (OIMP)

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1
Q

1) Why are virus referred to as filterable agents?

A

Because they are able to separate from bacteria with a 0.2 micrometer millipore filtration.

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2
Q

3) What genetic material are viruses made from?

A

Either DNA or RNA, but never both of DNA and RNA.

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3
Q

4) What chemical in the human body are viruses most sensitive to?

A

Viruses are sensitive to alpha-interferon.

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4
Q

5) What is the smallest Virus? What is the largest Virus?

A

The smallest Virus is Poliovirus that is 30 nm. The largest virus is Ebola that is 970 nm.

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5
Q

6) What virus is a genetically engineered cross between cowpox and smallpox viruses and used to eradicate smallpox?

A

Vaccinia Virus

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6
Q

7) What are the 5 types of viral morphology?

A

1) Non-enveloped polyhedral: Adenovirus
2) Non-enveloped helical: TMV
3) Enveloped Polyhedral: Herpes
4) Enveloped Helical: Influenza
5) Complex Virus: Vaccinia, Rabies, Bacteriophage

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7
Q

8) How do enveloped viruses exit from the host cell?

A

To depart, the enveloped virus buds off from the host cell. (Budding)

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8
Q

9) What are 4 media for cultivating viruses in vitro?

A

1) Embryonated hen eggs (influenza) [EE]
2) Primary Cell Culture (Monkey Kidney Cells) [Polio, Measles, Mumps, Rubella, EFC]
3) Diploid Fibroblast Cell Culture (Rabies Vaccine)
4) Continuous Cell Cultures (HeLa)

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9
Q

10) What viruses are commonly cultivated in embryonated hen eggs?

A

Influenza

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10
Q

11) What viruses are commonly cultivated in monkey kidney cells?

A

Polio, Measles, Mumps, and Rubella.

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11
Q

12) What is programmed cell inhibition?

A

Primary Cell Culture (monolayer growth) was programmed as cell inhibition.

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12
Q

13) What virus is cultivated in DFCC for mating a vaccine?

A

It was used to prepare the rabies vaccine.

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13
Q

14) What does it mean that continuous cell cultures are immortal?

A

CCC does not age or die.

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14
Q

15) What are the 3 ways viruses affect host cells in vitro? Give examples of viruses in each of these categories.

A

Lytic: Kills Host Cells (Ex: cold viruses)
Cytopathic: Changes Appearances (Ex: herpesviruses)
Transformation: Oncogenic Viruses (Ex: EBV, HPV, HBV)

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15
Q

16) What are viruses called that transform primary cell cultures into continuous cell cultures?

A

Oncogenic Viruses

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16
Q

17) What genes are found in all human cells that regulate embryo genesis, but also triggers unregulated, undifferentiated, rapid growth, and loss of cell inhibition?

A

Protooncongenic

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17
Q

18) What are the 5 viruses affect host cells in vivo?

A

1) Cold Viruses
2) Persistent Chronic Viral Infections
3) Persistent “Slow Wasting” Viral Infections
4) Herpesviruses
5) Oncogenic Viruses

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18
Q

19) What are the category in the relationship between viruses and host cells in vivo involves acute infections that kill host cells and are of short duration?

A

Lytic Viral Infections

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19
Q

20) How are cold viruses transmitted?

A

Cold viruses can be transmitted by Nasal Secretion, 1 meter aerosol droplet (Indirect: viable on in-animated objects for up to one hour)

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20
Q

21) What are the four families of cold viruses? What is the most common infectious cold virus family?

A

1) Picornavirus
2) Coronavirus
3) Adenovirus
4) Paramyxovirus

The most common infectious cold virus family would be Coronavirus.

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21
Q

22) What categorical relatioship between virus and host cells in vivo consists of viruses that multiply at low levels and normally do not kill host cells?

A

Persistent Chronic Viral Infections

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22
Q

23) What two virus are examples of persistent chronic infections?

A

Hepatitis B Virus and Liver Cancer

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23
Q

24) What categorical relationship between viruses and host cells in vivo requires that viruses kill host cells very slowly?

A

Persistent “slow wasting” viral infections

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24
Q

25) What unique enzyme does family retrovirus possess ?

A

Reverse Transcriptase

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25
Q

26) An example of a virus in the persistent slow wasting virus category?

A

HIV (Human Immunodeficiency Virus)

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26
Q

27) What category of infections involves dormant viruses living in the host cells without adverse effects until triggered by environmental stress?

A

Latent Viral Infections

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27
Q

What family of viruses are classically latent?

A

Herpesviruses

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28
Q

29) Name 5 Herpesviruses, and in what specific tissues are these 5 viruses latent?

A

1) HSV-I (Herpes Simplex Virus Type I): Dormant or Latent in Trigeminal Nerve
2) HSV-II (Herpes Simplex Virus Type II): Dormant in Sacral Ganglia
3) VZV (Varicella Zoster Virus): Dormant in thoracic ganglia
4) CMV (Cytomegalovirus): Dormant in parotid gland
5) EBV (Epstein Barr Virus): Dormant in parotid gland

29
Q

30) Name the diseases caused by these 5 Herpesviruses.

A

HSV-I: Oral Herpes
HSV-II: Genital Herpes
VZV: Chicken Pox in children and shingles on thoracic skin region
CMV: Birth defects during pregnancies –> Mononucleosis
EBV: Classic Mononucleosis, Nasopharyngeal carcinoma, Hodgkin’s lymphona, and Burkitt’s lymphona.

30
Q

31) List the acronyms for 3 oncogenic viruses in humans?

A

EBV, HPV, HBV

31
Q

32) What type of cancer is caused by EBV in the tropical belt of Africa? (Has two names)

A

B Lymphocytes or Burkitt’s lymphoma

32
Q

33) What 3 conditions determine what type of disease EBV will cause?

A

Geographical Location, Age, and Environmental Cofactor

33
Q

34) What is the environmental cofactor for Burkitt’s lymphoma? At what age does Burkitt’s lymphoma occur?

A

Exposed to malaria at the age of 5, then get Burkitt’s lymphoma at the age of 7-8 years old.

34
Q

35) What is an antibody titer?

A

Antibody titer is a test that detects the presence and measures that amount of antibodies within a person’s blood.

35
Q

36) What is the environmental cofactor for nasopharyngeal carcinoma? In what region of the world does this type of cancer occur? What age are people with this form of cancer?

A

The environmental cofactor of nasopharyngeal carcinoma is being exposure to high quantities of nitrates while curing fishes. The region of the world that has nasopharyngeal carcinoma would be located in Southeast coast of N. Africa and Asia. Most people who gets that form of cancer are usually men at the age of 60+.

36
Q

37) What disease does EBV cause in the Western Hemisphere? At what age does it typically occur? What are the clinical symptoms of infectious mononucleosis?

A

About 15% of the people in the Western Hemisphere gets mononucleosis at the age of 15 to 25 years old (teenagers). The symptoms are flu-like (headaches and lymphadenopathy) within 3-5 days. Clinically, there is also B-Cell leukopenia.

37
Q

38) What virus causes genital warts and cervical cancer?

A

HPV

38
Q

39) What cofactor predisposes women to cervical cancer?

A

HSV-II

39
Q

40) What oncogenic viruses also cause persistent chronic infections?

A

HBV

40
Q

41) What is the incubation period for HBV? What percentage of people are infected by HBV becomes active chronic carriers? How many deaths per year in the U.S.? What are the M.O.T.’s for HBV?

A

The incubation period for HBV is 4 to 26 weeks. About 5 to 10 percent are active chronic carriers. About 4,000 death per year in the U.S. The M.O.T. for HBV is STD, IDVU, Perinatal Birth, Semen, and Blood Transfusion (Rare).

41
Q

42) What is the incubation period for HCV? What percentage of people are infected to become active chronic carriers? How many deaths per year in the U.S.?

A

The incubation period takes about 20 years for HCV. About 50% are active chronic carriers. About 15,000 deaths per year in the U.S.

42
Q

43) Which virus has a vaccine, HBV or HCV?

A

HBV

43
Q

44) What segmented helical RNA virus causes partial loss of immune recognition in humans due to antigenic drift of the H or N spikes?

A

Orthomyxovirus

44
Q

45) Compare antigenic shift with antigenic drift?

A

Antigenic shift: Annual mutation in the H or N spike genes. Antigenic shift causes n partial loss of immune recognition.
Antigenic drift: Major changes in spike and envelope genes. Due to recombination of viral segments with swine or bird influenza virues, it caused severe failure of her immunity. (Killed about 22 million people in the 20th century in 1918)

45
Q

46) What is the M.O.T. for influenza virus?

A

MOT can be direct and indirect contact. It is transmissible a day before, and can be transmissible 5 days after the symptoms.

46
Q

47) What is the pathogenesis of influenza virus?

A

It invades the oropharyngeal cells, disrupts mucociliary escalator, and depresses the immune system.

47
Q

48) Name two bacteria tat cause sever secondary bacterial infections in humans after a primary viral infection with the influenza virus?

A

Hib Type B and Streptococcus pneumoniae.

48
Q

What does the acronym Hib stands for?

A

Haemophilus Influenza

49
Q

50) Why does Haemophilus influenzae type B in name imply that it causes the flue when it is notorious for bacterial meningitis in infants?

A

Everyone assumes it is the flu because of the word “influenza”. Hib has nothing to do with the flu but meningitis in infants.

50
Q

What was the first virus discovered by Beijerinck, Iwanowski, and Mayer in 1898?

A

Tobacco Mosaic Virus

51
Q

What are the characteristic of a virus?

A

Create genetic diversity, replicate (does not reproduce), and it is made of DNA or RNA (never both).

52
Q

What is the most common viral infection in humans? How is it transmitted?

A

It would be Dengue Fever Virus. It is transmitted by Aedes agypti (mosquitos found in Mexico, S. America, C. America, Africa, and India)

53
Q

Is virus sensitive to antibiotics/bacterial anti-microbic?

A

No.

54
Q

What is virus sensitive to?

A

Virus is sensitive to alpha-interferon.

55
Q

What does an alpha-interferon does?

A

When a human cell are infected by a virus, they signal neighboring cells with alpha-IFN to build anti-viral proteins for protectsion.

56
Q

What microscope can view a virus?

A

An electron microscope.

57
Q

What is viroids?

A

It is molecule of RNA confined to the nuclei of diseased plant cells. (non-contagious)

58
Q

What is prions?

A

It is an infectious protein spread by contact with central nerve tissues of an animal.

59
Q

Examples of prions.

A

Mad Cow Disease, Kuru, Creitzfield Jacob disease.

60
Q

What is a non-contagious prion?

A

Alzheimer.

61
Q

What types of viral morphology usually lyse (burst) from the host cell?

A

Usually it is the nonenveloped viruses.

62
Q

What types of viral morphology has a phospholipid bilayer with spikes and depart the cell by budding?

A

Usually it is the enveloped virueses.

63
Q

Embryonated Hen Eggs

A

1) Provides a cheap sterile enviroment. (Chiron Corp. Serratia O4 Contamination)
2) Used to prepare vaccines against influenza (not with egg allergry) and yellow fever.

64
Q

Primary Cell Culture

A

1) Homogenous collections of adult eukaryotic cells (Monkey Kidney Cells)
2) Fetal Calf Serum (Provides nutrient broth)
3) Primary Cell Culture (Monolayer growth) and programmed cell inhibition.
4) Primary cell cultures can survive only about 4 or 5 generations of culture passage. (Programmed to age or die)
5) Used to prepare vaccines like polio, measles, mumps, and rubella.
6) High risk for contamination with monkey and cow viruses.
7) Mostly for P.h.D. research, and it is used for retroviral research in the 1960s and early polio, also HBV experimental vaccines in Africa during the 1950s.

65
Q

Diploid Fibroblast Cell Cultures

A

1) Human Fetal Tissues (IVF) [Ex: fetal tonsil diploid fibroblasts]
2) Grow as a monolayer
3) last approximately 100 generations
4) Most expensive cell cultures
5) most pure rarely contaminated
6) used to prepare the rabies vaccine.

66
Q

Continuous Cell Cultures

A

1) Derived from human cancer cell lines (Example: HeLa)
HeLa is named after Henrietta Lacks who died of cervical cancer in 1951.
2) Used for rapid growth of viruses.
3)Inexpensive but often contaminated.
4) Can be frozen, stored, and shipped.
5) Grow as a multilayer due to the absence of cell inhibition.
6) Cancer cells are immortal in vitro.
7) Used for master students in research projects.

67
Q

Viruses In Vitro

A

Productive Response
Lytic Cycle: Kills cells during burst and releases many naked virus particles or from budding enveloped viruses released in large numbers.
Cytopathic Effect
Lysogenic cycle: Virus integrates into chromosome. Host cells are not killed but their appearances changes.
Transformation
Few viruses transform primary cell cultures into continuous cell lines. (Cancer causing or oncogenic viruses)
Oncogenic: Mass generating
10% cancer believed to be caused by oncogenic viruses
Oncogenic viruses carries oncogenes causing infected host cells to start dividing rapidly and lose cell inhibition (viral transformation).
The same genes found in oncogenic viruses are found in normal human cells. Oncogenes in human cells are called protooncogenes. (Potential cancer causing genes)
Protooncogenes regulate embryo-genes and are normally turned off at the end of the first trimester.
Human cancer cells are fast-growing embryonic-like tissure. (result: de-regulated by inherited mutations, environmental mutagens, or oncogenic viruses).

68
Q

Influenza A Pandemics During the Past 100 Years

A

1918-19: H1N1 caused up to 50 million deaths world wide. Virus has avian flu-like genes.
1957-58: H2N2 caused about 70K deaths in the U.S. First identified in China in late Feb. 1957. Viruses contained a combination of genes from a human influenza virus and an avian influenza virus.
1968-69: H3N2 caused about 34K deaths in the U.S. Virus contained genes from human influenza virus and an avian influenza virus.
2009-10: H1N1 caused at least 14K deaths worldwide. Vaccine was available in developed and developing countries 3 months after the first case.

69
Q

Persistent Chronic Viral Infections

A

Multiply at low levels and normally do not kill host cells. (usually budding)
Ex: HBV (Hepatitis B Virus) - serum hep produces only 10 virus particles per cell. Result: many carriers for HBV setting up a chronic persistent infection of the liver.

70
Q

Persistent Slow Wasting Viral Infections

A

Kills cells slowly.
Ex: Family Retroviruses - Lysogenic and reverse transcriptase.
Ex: HIV (Human Immunodeficiency Virus) - infects and slowly kills a specialized lymphocytes called T-Helper cell.

71
Q

Latent Viral Infections

A

Herpesvirus are dormant in host cells w/o adverse effects. If the host experience environmental stress (fever, hypothermia, sunburn, lack of sleep, menses, or psychological) the virus is triggered to excise from chromosome and starts replicating.