Chemistry for a Healthier World
Chemists want to understand how biology works so they can manipulate it. Inventing environmentally friendly approaches that make chemical reactions more efficient and produce minimal toxic byproducts is an important goal of modern chemistry.
Whether inside the body or in the lab, all chemical reactions do the same thing. They convert starting materials, or reactants, into products. Catalysts make these reactions go faster.
Made for Speed
A catalyst works by providing a route for the reaction pathway to make its product using less energy.
Catalysts are facilitators—they are not used up in the reaction and can be recycled. Researchers are continually looking for catalysts that are more efficient and friendlier to the environment. Such catalysts are an important aspect of "green chemistry."
One recent advance in this area is the development of "click chemistry," which allows chemists to tailor reactions very precisely. Thus, they can generate substances quickly and reliably. Click chemistry also produces fewer byproducts—some of which can be hazardous—and less waste.
Harnessing biology's magic through chemistry underlies the field of biotechnology—the use of biological systems or living organisms to make useful products and processes. Biotechnology has applications in a wide range of areas that benefit the United States and the world.
Taking advantage of microbes' innovative metabolism and defense mechanisms can help us preserve our environment, as well. This is the case for methane, the main component of natural gas that is used in industrial chemical processes and is second only to carbon dioxide as a greenhouse gas that contributes to global warming. In the United States, the most significant sources of methane gas are landfills and agricultural livestock manure.
Methane is chemically inert, meaning it does not break down easily. But for some bacteria that live in extreme environments like hot springs, chewing up methane is a way of life. Understanding how enzymes in these bacteria convert methane into methanol and water could possibly spur more efficient use of the world's supply of natural gas.
Metals: Good, Bad or Ugly?
Some chemists study the role of metal-containing molecules in biological systems. Many processes in our bodies—like respiration and reproduction—depend on metals like iron, zinc and copper.
Iron, for instance, helps the protein hemoglobin transport oxygen to organs throughout the body. Many metals act to stabilize the shapes of enzymes.
But handling metals is a tricky business. Since metals are elements, the building blocks of all chemical compounds, they are already in their simplest form and our bodies cannot break them down.
Thus, our bodies take great care to make sure metals go only where they need to go, and in exactly the proper amount. In many cases that means one or two atoms in an individual cell. That's in contrast to thousands to millions of proteins or other molecules.
Some toxic metals aren't good in any amount. They can poison important enzymes, preventing them from doing their jobs of keeping the body healthy. Lead from the environment, for instance, can mess up the body's synthesis of a vital component of hemoglobin called heme, disabling the blood's oxygen transport system.
Certain forms of mercury can be deadly, causing irreversible damage in the brain. Other dangerous metals, such as arsenic, cause cancer in the skin and lungs. Recently, scientists discovered single-celled algae that thrive in Yellowstone National Park hot springs and chemically change arsenic to make it less hazardous. Such natural cleansers may find use in reclaiming mine waste or creating safer foods and herbicides.
Scientists are working to eliminate these and other harmful substances from the environment and also to detect and reduce human exposure to such substances. The medical researchers who study the harmful effects of chemicals on living organisms are called toxicologists.
Metals in Health and Disease
|METAL (Chemical Symbol )||WHERE IS IT?||WHAT DOES IT DO?||HOW DO I GET IT?|
|Iron (Fe)||Binds to enzymes throughout the body (e.g., hemoglobin, nitric oxide synthase)||Helps body transport oxygen and certain chemical messengers||Meats (highest in beef, pork, liver), baked or lima beans, molasses, spinach|
|Copper (Cu)||Binds to enzymes throughout the body (e.g., superoxide dismutase)||Defends body against damage from free radicals||Shellfish (crab, lobster), dried beans, nuts|
|Zinc (Zn)||Binds to enzymes throughout the body, to DNA, and to some hormones (e.g., insulin)||Plays role in sexual maturation and regulation of hormones, helps some proteins stick tightly to DNA||Shellfish (oysters), chick peas, baked beans, whole grains, nuts|
|Throughout the body (Na outside cells, K inside cells)||Helps communicate electrical signals in nerves, heart||Na: Table salt
and baking soda
K: Bananas, oranges, avocados
|Calcium (Ca)||Bones, muscle||Muscle and nerve function; blood clotting||Dairy products, broccoli, figs, sardines|
|Cobalt (Co)||Forms the core of vitamin B12||Necessary ingredient for making red blood cells||Meats, dairy products, leafy green vegetables|
|Arsenic (As)||Rocks, soil||Can cause cancer, death||Toxic|
|Lead (Pb)||Old paint (before 1973)||Can cause cancer, neurological damage, death||Toxic|
|Mercury (Hg)||Contaminated fish (especially from the Great Lakes region of the United States)||Binds to sulfur-containing molecules in organelles; can cause neurological damage, death||Toxic|
Some scientists in this field focus on forensics, combining toxicology, chemistry, pharmacology and medicine to help criminal investigations of death, poisoning and drug use.
These researchers record symptoms reported by a victim as well as any evidence collected that could narrow the search for a perpetrator.
This evidence could include pill bottles, powders and trace residues of chemicals.
Since it is rare for a chemical to remain in its original form after being ingested, toxicologists rely on a solid understanding of metabolism and of chemical reactions to get the job done right.