Assertion (A): There is always a time-lag between the infection and appearance of AIDS symptoms.
Reason (R): HIV is a retrovirus.
Assertion (A): There is always a time-lag between the infection and appearance of AIDS symptoms.
Reason (R): HIV is a retrovirus.
AIDS or acquired immunodeficiency syndrome is caused by the Human Immunodeficiency virus (HIV) which attacks and weakens the human immune system. Due to a compromised immune system, the patient becomes vulnerable to opportunistic microbes which can cause fatal diseases.
HIV infection is characterised with very long incubation periods, i.e, the time between the infection or entry of the virus into the body and the appearance of the first symptoms. It can vary from a few months to many years (5-10 years).
The HIV inserts its RNA in the host cell and the viral reverse transcriptase enzyme converts the RNA of HIV into viral DNA which integrates into the host genome. This integrated viral DNA remains hidden from the immune system and directs the host cell to form multiple copies of itself.
Initially the rate of viral replication is slow which extends the incubation period as the viral load in the body is not high enough to manifest symptoms of AIDS. Once a large number of helper T cells in the body are destroyed, the symptoms of AIDS are exhibited during the last stage of HIV infection.
The length of the incubation period depends on age of the patient and ability to fight (immunity).
Since expression of the viral proteins requires the conversion of the genomic RNA of HIV into a DNA, within the host cell, HIV is known as a retrovirus.
Thus, both the assertion and reason are correct but reason is not the correct explanation of assertion.
AIDS or acquired immunodeficiency syndrome is caused by the Human Immunodeficiency virus (HIV) which attacks and weakens the human immune system. Due to a compromised immune system, the patient becomes vulnerable to opportunistic microbes which can cause fatal diseases.
HIV infection is characterised with very long incubation periods, i.e, the time between the infection or entry of the virus into the body and the appearance of the first symptoms. It can vary from a few months to many years (5-10 years).
The HIV inserts its RNA in the host cell and the viral reverse transcriptase enzyme converts the RNA of HIV into viral DNA which integrates into the host genome. This integrated viral DNA remains hidden from the immune system and directs the host cell to form multiple copies of itself.
Initially the rate of viral replication is slow which extends the incubation period as the viral load in the body is not high enough to manifest symptoms of AIDS. Once a large number of helper T cells in the body are destroyed, the symptoms of AIDS are exhibited during the last stage of HIV infection.
The length of the incubation period depends on age of the patient and ability to fight (immunity).
Since expression of the viral proteins requires the conversion of the genomic RNA of HIV into a DNA, within the host cell, HIV is known as a retrovirus.
Thus, both the assertion and reason are correct but reason is not the correct explanation of assertion.
