Spot the false claim in each set

Exercise and reference answers

Questions

1. False statement

   HIV spreads by merely touching or sitting beside an infected person.

   Statements

   1. HIV spreads through transfusion of contaminated blood and blood products.
   2. HIV passes from an infected mother to her child through the placenta.
   3. HIV spreads by merely touching or sitting beside an infected person.

2. False statement

   The count of helper T-lymphocytes climbs steadily as HIV keeps replicating.

   Statements

   1. The count of helper T-lymphocytes climbs steadily as HIV keeps replicating.
   2. Inside the body HIV enters macrophages, which then act like a virus factory.
   3. Reverse transcriptase builds viral DNA from the RNA genome of HIV.

3. False statement

   Malignant tumors stay confined to one site and spread no further.

   Statements

   1. Cancer cells appear to have lost the property of contact inhibition.
   2. Malignant tumors stay confined to one site and spread no further.
   3. Cells sloughed from a malignant tumor travel in blood and seed new tumors.

4. False statement

   Proto oncogenes are found only inside cancer causing viruses, never in normal cells.

   Statements

   1. X-rays and gamma rays are ionising radiations that cause DNA damage.
   2. Chemical carcinogens in tobacco smoke are a major cause of lung cancer.
   3. Proto oncogenes are found only inside cancer causing viruses, never in normal cells.

Instructions

Three statements appear together. Tap the one that is false.

Explanation