Immunity & Cancer
Read the following passage carefully and answer the given questions.
If the pathogens succeed in gaining entry to our body, specific antibodies and cells serve to kill these pathogens. The B-lymphocytes produce an army of proteins in response to pathogens into our blood to fight with them. The T-cells themselves do not secrete antibodies but help B cells to produce them. The principle of immunisation or vaccination is based on the property of ‘memory’ of the immune system. In vaccination, a preparation of antigenic proteins of pathogen or inactivated/weakened pathogen (vaccine) are introduced into the body. The antibodies produced in the body against these antigens would neutralise the pathogenic agents during actual infection. The exaggerated response of the immune system to certain antigens present in the environment is called allergy. The human immune system consists of lymphoid organs, tissues, cells and soluble molecules like antibodies. Cancer causing viruses called oncogenic viruses have genes called viral oncogenes. Furthermore, several genes called cellular oncogenes (c-onc) or proto oncogenes have been identified in normal cells which, when activated under certain conditions, could lead to oncogenic transformation of the cells.
Which one of the following radiations does not lead to transformation of normal cells into cancerous cells?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Infrared radiation
Agents that turn normal cells into cancer cells are called carcinogens. Among physical agents, radiations that damage DNA can cause cancer.
(1) X-rays — Causes cancerous transformation. X-rays are ionising radiations and damage DNA.
(2) Infrared radiation — Does not cause cancerous transformation. Infrared carries little energy and is felt only as heat. It does not damage DNA the way the other three do.
(3) Gamma rays — Causes cancerous transformation. Gamma rays are ionising radiations and damage DNA.
(4) UV rays — Causes cancerous transformation. UV (ultraviolet) rays are non-ionising, but they still damage DNA and can lead to cancer.
Note: This passage is taken from NCERT as it is. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Cancer – …
