Chemicals & Human Health

Lung Toxicology Problem Set

Problem 8: Oxidants

For help to answer the question:

Oxidants are one toxic component of cigarette smoke. Why are they dangerous?
A. They block surfactant secretion so that alveoli collapse.
B. They block the oxygen carrying capacity of hemoglobin.
C. They cause cilia to quit beating so lungs get clogged with particles.
D. They can damage the DNA of lung cells much like the sun damages skin cells.


An oxidant is a chemical that can oxidize molecules, which means to remove electrons from molecules. Molecules that are missing electrons are highly reactive and are called free radicals. Free radicals are dangerous to cells because they can react chemically with important biological molecules and cause cell damage. For example, free radicals can chemically react with the DNA in cells. This can lead to mutations in the genetic sequence. These mutations could eventually lead to cancer.

The body has some natural defenses again oxidative damage. These defense molecules are called antioxidants. Some that you may be familiar with are vitamin E and vitamin C. These molecules defend the body's cells from oxidative damage by reacting with the dangerous free radicals and converting them to safer chemicals.

Toxicology Problem Set Chemicals & Human Health

The Southwest Environmental Health Sciences Center
The Biology Project
The University of Arizona
Tuesday, October 14, 1997
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