AP BIOLOGY

Detailed explanation-1: -Tobacco smoke contains a mixture of nicotine, carcinogens and toxicants. Nicotine is not a direct chemical carcinogen, however, it causes addiction leading to the chronic exposure to tobacco smoke that increases cancer risk for tobacco users.

Detailed explanation-2: -The smoke from these products is a complex mixture of chemicals produced by burning tobacco and its additives. Tobacco smoke is made up of thousands of chemicals, including at least 70 known to cause cancer. These cancer-causing chemicals are referred to as carcinogens.

Detailed explanation-3: -Furthermore, cigarette smoke contains compounds that can induce inflammation resulting in enhanced pneumocyte proliferation, 12 as well as co-carcinogens, tumor promoters, inducers of oxidative damage and gene promoter methylation, all processes which undoubtedly contribute to lung cancer development.

Detailed explanation-4: -Of the more than 7, 000 chemicals in tobacco smoke, at least 250 are known to be harmful, including hydrogen cyanide, carbon monoxide, and ammonia (1, 2, 5). Among the 250 known harmful chemicals in tobacco smoke, at least 69 can cause cancer.

Detailed explanation-5: -Some carcinogens cause cancer by changing a cell’s DNA. Others do not affect DNA directly, but lead to cancer in other ways. For example, they may cause cells to divide at a faster than normal rate, which could increase the chances that DNA changes will occur.