AIDS Questions in English

(B) $HIV/AIDS$ infected people require help,support,and sympathy from society rather than being ostracized.
Unless society recognizes this as a collective problem that needs to be addressed together,the risk of the disease spreading further increases significantly.
This is a malady that can only be effectively managed when society and the medical fraternity work in collaboration to prevent the spread of the infection.

(A) The $AIDS$ virus,known as $HIV$ ($Human$ $Immunodeficiency$ $Virus$),belongs to the group of retroviruses.
These viruses possess an envelope containing a protein coat (capsid) and their genetic material consists of two identical molecules of single-stranded $RNA$.
Therefore,the correct option is $A$.

(B) $AIDS$ (Acquired Immuno Deficiency Syndrome) was first reported in the year $1981$ in the United States of America. It is caused by the Human Immunodeficiency Virus $(HIV)$.

(C) The process labeled $P$ represents the conversion of viral $RNA$ into viral $DNA$ within the host cell.
This process is known as reverse transcription.
The enzyme responsible for catalyzing the synthesis of $DNA$ from an $RNA$ template is called reverse transcriptase.
Therefore,the correct option is $C$.

(C) $AIDS$ (Acquired Immuno Deficiency Syndrome) is caused by the Human Immunodeficiency Virus $(HIV)$.
$HIV$ specifically targets and infects helper $T$-lymphocytes (also known as $CD4^+$ $T$-cells).
As the virus replicates within these cells,it leads to their destruction.
The progressive reduction in the number of helper $T$-lymphocytes severely weakens the body's immune system,making the individual susceptible to opportunistic infections and cancers.

(D) The diagnosis of $AIDS$ involves several techniques to detect the presence of the $HIV$ virus or antibodies against it.
$1$. $ELISA$ (Enzyme-Linked Immunosorbent Assay) is the primary screening test used to detect antibodies against $HIV$.
$2$. $Western \ Blot$ $(WB)$ is a confirmatory test used to verify positive results from an $ELISA$ test.
$3$. $PCR$ (Polymerase Chain Reaction) is used to detect the viral genetic material $(RNA)$ directly,which is especially useful in early diagnosis or when antibody levels are low.
Therefore,all these methods are used in the diagnosis of $AIDS$.

(A) World $AIDS$ Day is observed globally on $1$ December every year.
This day is dedicated to raising awareness about the $AIDS$ pandemic caused by the spread of $HIV$ infection and mourning those who have died of the disease.
It serves as an opportunity for people worldwide to unite in the fight against $HIV$,show support for people living with $HIV$,and commemorate those who have died.

(C) $HIV$ (Human Immunodeficiency Virus) belongs to the group of viruses known as $Retroviruses$.
These viruses contain $RNA$ as their genetic material and possess an enzyme called $Reverse \text{ } Transcriptase$.
This enzyme allows the virus to transcribe its $RNA$ into $DNA$ inside the host cell, which then integrates into the host genome.

(A) The incubation period of $HIV$ (the virus that causes $AIDS$) is the time between the initial infection and the onset of clinical symptoms.
This period is highly variable and typically ranges from a few months to many years,commonly estimated between $5$ to $10$ years.
During this time,the virus continues to replicate and progressively destroys the host's immune system,specifically the $CD4^+$ $T$-helper cells.

(C) $AIDS$ (Acquired Immuno Deficiency Syndrome) is caused by the $HIV$ virus. It spreads through the following modes:
$I -$ Sexual contact with an infected person (Responsible).
$II -$ Wearing clothes of an infected person (Not responsible).
$III -$ Transmission from infected mother to the foetus through the placenta (Responsible).
$IV -$ Shaking hands with an infected person (Not responsible).
$V -$ Use of contaminated blood and blood products (Responsible).
$VI -$ Use of contaminated needles or syringes by drug addicts (Responsible).
Thus,factors $I, III, V,$ and $VI$ are responsible for the spread of $AIDS$. The total number of such factors is $4$.

(B) Retroviruses are a group of viruses that contain $RNA$ as their genetic material.
Upon entering a host cell,the enzyme reverse transcriptase converts the viral $RNA$ into $DNA$,which then integrates into the host genome.
Therefore,the primary genetic material of a retrovirus is $RNA$.

(C) The $PCR$ ($Polymerase$ $Chain$ $Reaction$) technique is highly sensitive and is commonly used for the early detection of $HIV$ in a potential $AIDS$ patient.
It allows for the amplification of specific viral $DNA$ sequences,making it possible to detect the presence of the virus even when the viral load is very low in the patient's blood.
Therefore,$PCR$ is a standard diagnostic tool for $HIV$ detection.

(B) The correct answer is option $B$ because $HIV$ enters into helper $T$-lymphocytes ($T_H$ cells) after entering the body of the person.
Inside these cells,the viral $RNA$ genome replicates to form viral $DNA$ with the help of the enzyme reverse transcriptase.
This viral $DNA$ gets incorporated into the host cell's $DNA$ and directs the infected cells to produce virus particles.
The $T_H$ cells act as a factory for the production of progeny viruses,which are then released into the blood to attack other helper $T$-lymphocytes.

(B) $AIDS$ (Acquired Immuno Deficiency Syndrome) was first reported in the United States of America in $1981$. It is caused by the Human Immunodeficiency Virus $(HIV)$.

(D) The $HIV$ structure consists of two $ssRNA$ molecules at the center.
These are enclosed within a protein capsid.
The inner protein layer (capsid) is composed of $p24$ protein.
The outer protein layer (matrix) is composed of $p17$ protein.
Therefore,the correct sequence is $I - p17$ and $II - p24$.

(D) After entering the human body,the $HIV$ virus first infects macrophages. These macrophages act as a factory for the virus,producing more viral particles. Subsequently,the virus spreads to helper $T$-lymphocytes ($T_H$ cells) in the blood,where it continues to replicate and cause a progressive decrease in the number of helper $T$-lymphocytes,leading to the weakening of the immune system. Therefore,the correct option is $D$.

(C) After entering the human body,the $HIV$ virus enters into macrophages where the $RNA$ genome of the virus replicates to form viral $DNA$ with the help of the enzyme reverse transcriptase.
This viral $DNA$ gets incorporated into the host cell's $DNA$ and directs the infected cells to produce virus particles.
The macrophages continue to produce virus particles and in this way,they act like an $HIV$ factory.
Simultaneously,$HIV$ enters into $Helper$ $T$-lymphocytes ($T_H$ cells),replicates,and produces progeny viruses.
The progeny viruses released in the blood attack other $Helper$ $T$-lymphocytes.
This leads to a progressive decrease in the number of $Helper$ $T$-lymphocytes in the body of the infected person.

(C) $HIV$ is a retrovirus that contains $RNA$ as its genetic material.
Upon entering the host cell (macrophage),the viral $RNA$ genome is converted into $DNA$ by the enzyme $Reverse \ Transcriptase$.
This $DNA$ then integrates into the host cell genome,allowing the virus to replicate.
Therefore,the correct enzyme is $Reverse \ Transcriptase$.

(A) The correct answer is $(A)$ Reverse transcriptase.
In the replication cycle of a retrovirus,the viral $RNA$ enters the host cell. The enzyme Reverse transcriptase (also known as $RNA$-dependent $DNA$ polymerase) catalyses the synthesis of viral $DNA$ from the viral $RNA$ template. This process is known as reverse transcription,which is represented by the step labelled '$M$' in the diagram.

(B) The correct answer is $B$.
When a retrovirus (such as $HIV$) infects a host cell,it introduces its genetic material,which is viral $RNA$,into the host cell.
Inside the host cell,the virus sheds its protein coat.
$A$ viral enzyme called reverse transcriptase then reads the viral $RNA$ strand and makes a complementary $DNA$ copy.
This viral $DNA$ copy is then integrated into the host cell's genome,allowing the virus to replicate using the host's machinery.