Final answer:
A mutagen is an agent that causes genetic alterations in living cells, potentially leading to mutations and cancer. Examples include ionizing radiation like X-rays and chemical agents such as polycyclic aromatic hydrocarbons found in smoke.
Step-by-step explanation:
A mutagen is an agent that causes alterations in the genetic material of living cells. These can be physical or chemical agents that change the DNA of organisms and increase the probability of mutations, which can lead to cancer. Radiation, certain chemicals, and even some infectious agents can act as mutagens. For example, ionizing radiation such as X-rays can cause significant damage to DNA, including breaks in the DNA strands and modifications to bases, which may lead to uncontrolled cell growth or cancer. Similarly, chemicals like polycyclic aromatic hydrocarbons (PAH) found in smoke are also known mutagens and potential carcinogens.
It is important to note that not all mutations lead to cancer. Some mutations might actually be harmless or even beneficial. However, the cumulative effect of mutations can lead to the development of tumors. Tumors can be benign or malignant, with malignant ones being cancerous. Research into mutagens is crucial because it helps us understand how cancer develops and how it can be prevented or treated.