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Biology And Human Welfare

Description: This test is based on biology and human welfare which is highly beneficial for learning aspirants.
Number of Questions: 15
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Tags: AIDS Cancer Western Blotting Reverse transcriptase inhibitors etc. AIDS and Cancer: Causes and Control Human Blood Components of Blood Body Fluids and Circulation
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In humans, the specific binding of HIV to the CD 4 + surface molecules of the host cell membrane is done by

  1. gp120

  2. gp41

  3. gp32

  4. p55


Correct Option: A
Explanation:

The surface protein gp120 conjoins the virus to the host lymphoid tissue by binding to the primary receptor CD4. It signals through several cell surface receptors.

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.


Correct Option: D
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.

Which of the following does not code by pol gene?

  1. Proteases

  2. Reverse transcriptase

  3. Integrase

  4. RNA polymerase


Correct Option: D
Explanation:

This enzyme is involved in the production of RNA from DNA through transcription. It adds ribonucleotides to growing RNA transcripts at the 3' end. The pol gene does not encode for RNA polymerase.

Which among the following genes activates viral gene expression?

  1. tat gene

  2. nif genes

  3. rev gene

  4. gag gene


Correct Option: A
Explanation:

This gene from human immunodeficiency virus type 1 activates viral gene expression and is essential for HIV replication.

Which among the following techniques is used for the detection of viral nucleic acids?

  1. ELISA

  2. Polymerase chain reaction (PCR)

  3. Western blot

  4. Viral isolation


Correct Option: B
Explanation:

In case of HIV infection, this test finds either the RNA of the HIV virus or the HIV DNA in white blood cells infected with the virus. The PCR test is very useful to find a very recent infection.

Which immune marker is observable during the window period of HIV infection?

  1. Antigen p24

  2. Antibodies to gp 120

  3. Antibodies to gp 41

  4. Antigen p17


Correct Option: A
Explanation:

The window period is the period between the onset of HIV infection and the appearance of detectable antibodies to the virus. The purpose of the p24 antigen portion of the test is to detect HIV before body has made antibodies, i.e. in the window period.

CD 4 + cells are dominant cells that are an indispensable part of the human immune system. Which of the following is NOT a CD 4 + cells?

  1. Monocytes

  2. T-helper cells

  3. T-cytotoxic cells

  4. Macrophages


Correct Option: C
Explanation:

These cells are vital parts of the cellular immune response, destroying the cells which bear any foreign antigen on their surface mainly virus-infected cells.

Which of the following techniques does not provide a rapid diagnosis for HIV infection in humans?

  1. Western blotting

  2. Dot blot assays

  3. Particle agglutination test

  4. HIV spot and comb test


Correct Option: A
Explanation:

It is not a rapid test for the diagnosis of HIV infection. Western blots are considered as the benchmark and seropositivity is diagnosed when antibodies against both the env and the gag proteins are detected.

Which among the following treatments is regarded the best for HIV infection?

  1. Reverse transcriptase inhibitors

  2. Protease inhibitors

  3. Integrase inhibitors

  4. Highly active anti-retroviral therapy (HAART)


Correct Option: D
Explanation:

HAART is used to suppress HIV viral replication and the progression of HIV disease. It conjoins three or more different drugs such as two nucleoside reverse transcriptase inhibitors (NRTIs) and a protease inhibitor. These HAART regimens have proven to reduce the amount of active virus in many cases.

The structural component of HIV required for cell -cell fusion is

  1. gp 120

  2. gp 41

  3. p24

  4. P2 protein


Correct Option: B
Explanation:

For the HIV infection to occur, the cell fusion is essential. This is done by the trans-membrane glycoprotein gp 41. HIV-1 utilises two major co-receptors along with CD4 to bind to, fuse with and enter target cells.

The immunoglobulin present in tears and saliva is

  1. IgM

  2. IgA

  3. IgD

  4. IgE


Correct Option: B
Explanation:

This immunoglobulin being an antibody plays a vital role in mucosal immunity. It is dominantly present in mucous secretions, including tears and saliva.

Recently after a severe accident, Raman has undergone blood transfusion. The excessive citrate in transfused blood must have caused

  1. metabolic alkalosis

  2. metabolic acidosis

  3. respiratory alkalosis

  4. respiratory acidosis


Correct Option: A
Explanation:

Metabolic alkalosis is a pH imbalance in which the body has accumulated huge amount of an alkaline substance, such as citrates or bicarbonates, and does not have enough acid to effectively neutralize the effects of the alkali. Thus, Raman must be suffering from metabolic alkalosis.

After a blast in the mine, a mine worker was brought in an unconscious state to the emergency room. His blood carboxyhemoglobin level was high and the doctors diagnosed him with CO poisoning. CO is a known inhibitor of electron transport chain. Which complex of electron transport chain is inhibited by CO?

  1. Complex I

  2. Complex II

  3. Complex III

  4. Complex IV


Correct Option: A
Explanation:

Complex I is the first enzyme of the respiratory chain with a significant role in cellular energy production, coupling electron transfer between NADH and quinone to proton translocation. Mal function of it can cause human neurodegenerative diseases.

Carbonic anhydrase is absent in

  1. gastric parietal cells

  2. red blood cells

  3. renal tubular cells

  4. blood plasma


Correct Option: D
Explanation:

Blood plasma is the fluid part of blood, making about half of the total blood volume. Plasma, itself, is around 90% water, with the 10% remainder including proteins, minerals, waste products, clotting factors, hormones, and immunoglobins. The enzyme carbonic anhydrase is absent in plasma.

In human beings, the dietary fats are transported as

  1. micelles

  2. chylomicrons

  3. emulsion droplets

  4. liposome


Correct Option: B
Explanation:

Chylomicrons are lipoproteins, special particles that are designed for the transport of the dietary fats in the circulation.

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