Human Health & Disease - 2 - Free MCQ Practice Test with solutions, NEET

Common cold and AIDS are viral disease caused by rhinovirus and HIV virus respectively.

• Early detection of cancer is essential as it allows the disease to be treated successfully in many cases.
• Cancer detection is based on biopsy and histopathological studies of the tissue and the blood and bone marrow tests for increased cell counts in the case of leukaemias.

The primary and secondary immune response are carried out with the help of two special types of lymphocytes present in our blood called B-lymphocytes and T-lymphocytes.

Suspension of attenuated pathogen that are not able to cause disease, that stimulates antibody formation is called vaccine. It is prepared by killing the pathogen.

The treatment of snake bite by anit-venom is an example of artificial acquired passive immunity. Anti-venom neutralize the effect of venom in the body.

ELISA stands for enzyme linked immuno sorbent assay. ELISA is diagnostic test for AIDS.

Utilization of clothes used by AIDS patient do not cause HIV infection in healthy person. It is transmitted by utilization of syringe used by AIDS patient, foetus of AIDS infected mother and by breast feeding to children by AIDS patient.

Development of vaccine is difficult for AIDS because HIV gene undergoes mutation at rapid. Virus cannot be killed by antibiotics produced by vaccine.

• Inflammatory response in allergy is due to the release of histamine by mast cells.
• Histamine along with IgE antibodies act as allergy mediator.
• It dilates arteries and causes fluid accumulation which causes the inflammatory response.

The correct answer is:

2. Both assertion and reason are correct.

Explanation:

• Assertion: There is a time lag between the infection and appearance of the first symptoms of AIDS.

  • This is correct. After an individual is infected with HIV, there is a period of latency where the virus is present but may not show symptoms. This time lag can vary greatly.

• Reason: This period may vary from a few months to many years up to 10 years.

  • This is also correct. The asymptomatic period after HIV infection can range from a few months to several years, often up to 10 years or more before symptoms of AIDS manifest.

The reason accurately explains the assertion.

Benign tumors normally remain confined to their original location and do not spread to other parts. The malignant tumors are mass of proliferating cells that grow very rapidly. The mass of proliferating cells called neoplastic or tumors cells.

After entering the body, HIV infects macrophages where its RNA genome replicates to form viral DNA with the help of the enzyme reverse transcriptase. This viral DNA then integrates into the host cell’s DNA and directs the cell to produce new virus particles.