Biology ยท General Awareness

Viral Diseases and Immunity

807 Questions

Viral diseases and immunity cover the structure, transmission, and diagnosis of viruses like HIV. Questions focus on disease pathways, immune responses, and prevention. Strong knowledge here provides an edge in biology scoring.

HIV and AIDS structureVirus transmission methodsImmune system deficiencyPathogen risk groupsMedical diagnosis methods

Viral Diseases and Immunity Questions

Multiple choice

Which of the following viruses is being talked about in the above passage?

Directions: Read the following information and answer the question that follows.

Since December 2013, an ongoing outbreak in West Africa has infected at least 567 people in Guinea, Sierra Leone and Liberia, including 350 who died, according to the World Health Organisation. The outbreak appears to be the largest in history, surpassing the 425 cases that occurred in an earlier outbreak in Uganda in 2000.

  1. HIV virus

  2. H1N1 virus

  3. Ebola virus

  4. Small pox virus
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Since December 2013, an ongoing outbreak of Ebola in West Africa has infected at least 567 people in Guinea, Sierra Leone and Liberia, including 350 who died, according to the World Health Organisation. The outbreak appears to be the largest in history, surpassing the 425 cases that occurred in an Ebola outbreak in Uganda in 2000.

Multiple choice

The genus to which HIV belongs is

  1. Epsilonretrovirus

  2. Deltaretrovirus

  3. Lentivirus

  4. Alpharetrovirus
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

HIV belongs to the genus Lentivirus. They are characterised by a long incubation period. Lentiviruses can deliver a significant amount of viral RNA into the DNA of the host cell and have the unique ability among retroviruses of being able to infect non-dividing cells.

Multiple choice

Which of the following groups of cells are destroyed by HIV?

(a) Helper T-cells and killer T-cells (b) Helper T-cells and B-cells (c) Helper T-cells, memory T-cells, killer T-cells, cytotoxic T-cells (d) Helper T-cells, memory T-cells, killer T-cells, cytotoxic T-cells and B-cells

  1. Option (a)

  2. Option (b)

  3. Option (c)

  4. Option (d)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

HIV infects all T-cells and B-cells, thereby eradicating the complete immune system.

Multiple choice

In which form are lentiviruses transmitted?

  1. Single stranded DNA virus

  2. Single stranded negative sense RNA virus

  3. Single stranded positive sense RNA viruses

  4. Double stranded RNA virus
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lentiviruses are transmitted as single-stranded, positive-sense, enveloped RNA viruses.

Multiple choice

Name the confirmatory test for HIV diagnosis.

  1. ELISA

  2. Western blot

  3. Fluorescent microscopy

  4. RIA
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Western blot is the confirmatory test for HIV. Only specimens that are repeatedly reactive by ELISA and reactive by Western blot are considered HIV-positive and indicative of HIV infection. Specimens that are repeatedly ELISA-reactive occasionally provide an indeterminate Western blot result, which may be either an incomplete antibody response to HIV in an infected person or nonspecific reactions in an uninfected person.

Multiple choice

Which was the first HIV protease inhibitor?

  1. Ritonavir

  2. Saquinavir

  3. Indinavir

  4. Nelfinavir
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The first HIV protease inhibitor, saquinavir, is a peptidomimetic hydroxyethylamine and was marketed in 1995.

Multiple choice

Which of the following is an HIV-related myth?

  1. HIV cannot be transmitted through mosquito bites.

  2. One can get HIV even after using birth control methods like diaphragms, cervical caps, sponges, spermicides, DepoProvera, Norplant, or the Pill.

  3. HIV can spread through body fluids like sweat and tears.

  4. There is a risk for HIV even in oral sex.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

It is a myth. Contact with sweat or tears has never been shown to result in transmission of HIV.

Multiple choice

Which is at present the major target for HIV vaccine efforts?

  1. Viral genome

  2. Envelope protein

  3. Reverse transcriptase enzyme

  4. Lipid membrane
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The envelope protein allows the virus to attach to the host surface, causing fusion of viral and host membrane and releasing the viral contents into the cell and initiating the infectious cycle. As proteins are highly antigenic and this is the sole viral surface protein, it is at present the major target for HIV vaccine efforts.

Multiple choice

How many genes does HIV viral genome code for?

  1. 19 or 20

  2. 7 or 8

  3. 9 or 10

  4. 3 or 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Positive single-stranded RNA codes for the virus's nine genes. They are gag, pol and env, tat, rev, nef, vif, vpr, vpu, and sometimes a tenth tev, which is a fusion of tat env and rev.

Multiple choice

Reverse transcriptase enzyme is present in

  1. viral genome

  2. virus particle

  3. host cytoplasm

  4. host nucleus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Reverse transcriptase enzyme is present in viral particle. It gets transferred to the host cell along with genome.

Multiple choice

HIV-2 came into humans from

  1. common chimpanzee

  2. sooty mangabeys

  3. rhesus monkey

  4. gorilla
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

HIV-2 came to humans from sooty mangabeys.

Multiple choice

Find out the WRONG statement regarding the human immunodeficiency virus.

  1. The reverse transcriptase enzyme is a prominent feature of retroviruses.

  2. p10 is a protease enzyme that breaks gag precursor.

  3. p32 is an integrase enzyme of retrovirus.

  4. Gag gene encodes for the lipid bilayer of the virus.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The gag gene is encoded as a large gag-pol protein with another gene then cleaved to the precursor protein assembling, which is then cleaved to Gag. It is involved in virion assembly and produces some of the capsid and nucleocapsid proteins. It does not encode for the lipid bilayer of the virus.