Biology · 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

In a person suffering from AIDS, the HIV nef protein affects antigen presentation mainly by

  1. causing MHC class I endocytosis

  2. containing glycine-alanine repeats which inhibit proteasome-mediated processing of the virus

  3. preventing peptide binding to TAP

  4. preventing peptide transport through the TAP pore

  5. competing for peptide binding to the MHC class I heavy chain
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

it thereby prevents effective presentation of antigen peptides to the T-cell receptor

Multiple choice

Which of the following statements is incorrect regarding the virosoids?

  1. Virusoids are circular single-stranded DNAs.

  2. Virusoids are similar to viroids in size.

  3. Virusoids are not considered as viruses.

  4. Virosoids depend on helper viruses.

  5. The term virusoid is also sometimes used more generally to refer to all satellites.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Virusoids are circular single-stranded RNAs dependent on plant viruses for replication and encapsidation.[1] The genome of virusoids consist of several hundred nucleotides and does not code for any proteins

Multiple choice

Cytomegalovirus (CMV) is a common virus that can infect almost anyone. Which of the following statements is false about CMV?

  1. Cytomegalovirus is a member of the retroviral group of viruses.

  2. Herpes viruses are DNA viruses.

  3. CMV can down regulate the host response.

  4. CMV is named for the large inclusion bodies in the nucleus of the infected cell.

  5. Primary CMV infection can be mild and similar to glandular fever (infectious mononucleosis).
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

CMV is an example of a herpes virus; these are all large DNA viruses of which CMV is the largest; is also known as human herpesvirus-5 (HHV-5).

Multiple choice

A viral antigen is a protein encoded by the viral genome. Viral antigen shift involves

  1. single point mutation

  2. random point mutations

  3. interchange of large segments of the viral genome with other viruses

  4. rearrangement of the viral structural architecture

  5. regression to an earlier variant
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The ability to interchange large segments of the genome with a viral reservoir in other animal species is the basis of antigenic shift leading to radical change in antigen, particularly crucial antigens giving protective immunity such as the viral hemagglutinin.

Multiple choice

HIV is found in the body fluids of an infected person (semen and vaginal fluids, blood and breast milk). A coreceptor for HIV inside the body is

  1. RANTES

  2. CD8

  3. CD54

  4. CR5

  5. CXCR4
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

CXCR4 is a chemokine receptor which HIV utilizes as a coreceptor for entry into naive CD4+ T-cells and mature dendritic cells. Another chemokine receptor, CCR5, is used particularly for entry of HIV into immature dendritic cells, macrophages and activated effector or memory CD4+ T-cells.

Multiple choice

Which of the following HIV antigens provides a potential target for neutralising antibody?

  1. U3

  2. gp120

  3. Reverse transcriptase

  4. Protease

  5. Tat
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

gp120 is an envelope protein which binds to CD4 on the T-cell. Antibodies to the V3 loop of gp120 arise during the disease and are particularly effective as neutralising agents in vitro, although less so in vivo. Generally, neutralising antibodies are more effective against HIV-2 than against HIV-1.

Multiple choice

Which of the following statements regarding the replication of Ebolavirus is incorrect?

  1. Replication presumably starts when enough nucleoprotein is present.

  2. Fusion of virus membrane with the vesicle membrane is triggered by either low pH or NPC1 binding.

  3. The virion enters early endosomes by Micropinocytosis.

  4. In some culture cells, GP glycoprotein can be processed by host Cathepsin L and Cathepsin B into 19kDa GP1.

  5. Sequential transcription, and viral mRNAs are capped.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The virion enters early endosomes by Macropinocytosis.Attachment to host receptors through GP glycoprotein mediates is endocytosed into vesicles in the host cell. Host DC-SIGN and DC-SIGNR play a role in virion attachment.

Multiple choice

The whole genome of ___________ virus is translated in a polyprotein.

  1. Human Immunodeficiency Virus (HIV)

  2. T4 bacteriophage

  3. Tobacco mosaic virus(TMV)

  4. Flavivirus

  5. Ebolavirus
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The virion RNA is infectious and serves as both the genome and the viral messenger RNA. The whole genome is translated in a polyprotein, which is processed co- and post-translationally by host and viral proteases.

Multiple choice

AIDS virus has

  1. single stranded DNA

  2. single stranded RNA

  3. double stranded DNA

  4. double stranded RNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice

PCR is used for

  1. making multiple copies of a gene

  2. detection of HIV

  3. diagnosis of heart disease

  4. detection of lung diseases

  5. detection of lactose intolerance
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The polymerase chain reaction (PCR) is a technique used in molecular biology to amplify a single copy or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence.

Multiple choice

HBV stands for

  1. Hormone B Virus

  2. High B Voltage

  3. Human B Virus

  4. Hepatitis B Virus
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

HBV stands for Hepatitis B Virus, which is a virus that infects the liver and can cause both acute and chronic disease. It is a major global health problem and is transmitted through contact with infectious body fluids.