Health and diseases
Read the following passage carefully and answer the given questions.
Health is not just the absence of disease. It is a state of complete physical, mental, social and psychological well-being. Diseases like typhoid, cholera, pneumonia, fungal infections of skin, malaria and many others are a major cause of distress to human beings. When the functioning of one or more organs or systems of the body is adversely affected, characterised by appearance of various signs and symptoms, we say that we are not healthy, i.e., we have a disease. Our immune system plays the major role in preventing these diseases when we are exposed to disease-causing agents. Immune system has memory. On subsequent exposure to same pathogen, the immune response is rapid and more intense. This forms the basis of protection afforded by vaccination and immunisation. Among other diseases, AIDS and cancer kill a large number of individuals worldwide. Many cancers are curable if detected early and appropriate therapeutic measures are taken.
Which one of the following processes is involved when cells from the malignant tumors reach distant sites through the bloodstream, forming a new tumor?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Metastasis
The cells of a malignant tumor grow very fast and can break away from it. They travel through the blood to distant sites, lodge there and start a new tumor. This property is called metastasis. It is the most feared property of malignant tumors.
(1) Transformation — Incorrect. This is the change of normal cells into cancerous cells, caused by physical, chemical or biological agents.
(2) Metastasis — Correct. This is the spread of tumor cells to distant sites.
(3) Allergy — Incorrect. This is an exaggerated response of the immune system to substances in the environment. It has nothing to do with tumors.
(4) Contact inhibition — Incorrect. This is the property of normal cells that stops them from dividing when they touch other cells. Cancer cells lose it. It does not describe spreading to distant sites.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Cancer – “… Cells sloughed from such tumors reach distant sites through blood, and wherever they get lodged in the body, they start a new tumor there. This property called metastasis is the most feared property of malignant tumors.”
