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BMS 622 Exam 3 > Lecture 18: Retrovirus, Hepatitis virus, Prions - Chap 54, 55, 56 > Flashcards

Lecture 18: Retrovirus, Hepatitis virus, Prions - Chap 54, 55, 56 Flashcards

1
Q

What is the significance of the 1911 discovery of Rous Sarcoma Virus?

A

It was the first virus shown to cause cancer.

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2
Q

Which retrovirus was linked to cancer in humans in 1981?

A

HTLV-1 (discovered by Robert Gallo)

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3
Q

How do retroviruses like HIV convert RNA to DNA?

A

Using reverse transcriptase.

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4
Q

What genetic material structure do retroviruses carry?

A

Two copies of positive-strand RNA.

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5
Q

Which genes are basic to all retroviruses?

A

gag, pol, and env.

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6
Q

Name two accessory genes found in HIV.

A

tat and nef.

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7
Q

Where does the HIV virus assemble inside the host?

A

Plasma membrane.

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8
Q

What enzyme in HIV cleaves proteins for virus assembly?

A

Protease.

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9
Q

What role does GP120 play in HIV infection?

A

It binds to CD4 on immune cells.

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10
Q

Which protein helps HIV fuse with cell membranes?

A

GP41.

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11
Q

What happens in the synthesis stage of HIV’s life cycle?

A

RNA is reverse transcribed to DNA.

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12
Q

How does HIV’s high mutation rate benefit the virus?

A

It helps evade immune detection.

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13
Q

What is the main impact of HIV on the immune system?

A

Destroys CD4+ T cells, weakening immunity.

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14
Q

What are nucleoside reverse transcriptase inhibitors (NRTIs) used for?

A

Blocking HIV’s reverse transcription.

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15
Q

How do protease inhibitors work against HIV?

A

They prevent the virus from maturing.

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16
Q

What is HBsAg and what does its presence indicate?

A

Hepatitis B surface antigen; indicates infection.

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17
Q

How does Hepatitis B virus (HBV) evade the immune system?

A

Produces non-infectious HBsAg particles.

18
Q

What is the structure of HBV’s genome?

A

Partially double-stranded circular DNA.

19
Q

Name the primary route of transmission for Hepatitis B.

A

Blood-to-blood contact.

20
Q

What is the ‘Dane particle’ in HBV?

A

The fully infectious HBV particle.

21
Q

Which hepatitis virus is the most environmentally stable?

A

Hepatitis A.

22
Q

How does Hepatitis A typically spread?

A

Fecal-oral route, often via contaminated food or water.

23
Q

What is a common long-term risk of chronic Hepatitis B and C?

A

Liver cancer.

24
Q

How does Hepatitis C virus (HCV) enter liver cells?

A

By binding to receptors like CD81 and Claudin-1.

25
Q

What diagnostic test detects PrP^Sc in prion diseases?

A

Proteinase K-resistant form detection in Western blot.

26
Q

What is the main impact of prion proteins (PrP^Sc) in the brain?

A

They cause neurodegeneration and spongiform changes.

27
Q

How is Creutzfeldt-Jakob Disease (CJD) most commonly transmitted?

A

Through ingestion of or exposure to infected tissue.

28
Q

What makes prion diseases different from typical viral infections?

A

No immune response or inflammation.

29
Q

Why are IV drug users at high risk for Hepatitis C?

A

Due to sharing needles, exposing them to blood.

30
Q

What are protease inhibitors’ role in HIV treatment?

A

They block viral protein cleavage, stopping maturation.

31
Q

What are signs of AIDS progression?

A

Low CD4 count and presence of opportunistic infections.

32
Q

How does Hepatitis C virus (HCV) cause chronic infection?

A

By evading immune detection and establishing in the liver.

33
Q

How is HIV primarily diagnosed?

A

Through antibody tests like ELISA and confirmatory Western blot.

34
Q

What is the HIV ‘provirus’?

A

Integrated viral DNA within the host genome.

35
Q

What are the high-risk factors for HIV?

A

Unprotected sex, IV drug use, and transfusions (in unscreened cases).

36
Q

Which component of the HIV virus mutates frequently to avoid immunity?

A

GP120 protein.

37
Q

What is the purpose of ART (antiretroviral therapy) in HIV?

A

To slow HIV progression and reduce viral load.

38
Q

Which prion disease is associated with ritual cannibalism?

A

Kuru.

39
Q

What disease can arise from consuming BSE-infected meat?

A

Variant Creutzfeldt-Jakob Disease (vCJD).

40
Q

Why does Hepatitis C infection have a long ‘window period’?

A

Antibodies may take weeks to months to develop, delaying detection.

BMS 622 Exam 3 (12 decks)

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