1.1. What is Chemistry? http://www.ck12.org
Biotechnology is an emerging field that involves the manipulation of DNA, the chemicals that store the genetic
information that gets passed on from one generation to the next. Genes are the pieces of DNA that contain this
genetic information. Biochemists can transfer genes from one organism to another in order to take advantage of
useful traits. For example, genes from a certain bacteria produce a chemical that confers resistance to certain crop-
eating pests. Inserting these genes into the genetic material of corn plants results in genetically modified corn that is
able to resist the pest without having to be sprayed with a chemical pesticide. Bacteria can also be used as “chemical
factories” to produce useful drugs such as insulin, which is used to treat some forms of diabetes.
Materials
Chemists are also involved in the design and production of new materials. Some of the materials that chemists
have helped discover or develop in recent years include polymers, ceramics, adhesives, coatings, and liquid crystals.
Liquid crystals are used in electronic displays, such as those found in watches and calculators. Silicon-based com-
puter chips have revolutionized modern society, and chemists have played a key role in their design and continued
development. Many chemists are currently working in the field of superconductivity. Superconductors are materials
that can conduct electricity with 100% efficiency. Unlike conventional conducting materials, like copper cables, no
energy is lost during electrical transmission through superconductors. Unfortunately, most known superconductors
only exhibit this property at extremely low temperatures. A current challenge in this field is to design materials that
can act as superconductors at normal temperatures.
The Environment
There is a great deal of concern about the deleterious effects that humankind has had and continues to have on the
natural environment. The burning of fossil fuels pumps millions of tons of carbon dioxide into the atmosphere.
Carbon dioxide is a greenhouse gas, which means that it traps the heat from the sun and prevents it from being
released back out into space in the form of infrared radiation. As a result, the temperature of Earth is slowly
climbing. Chemists, along with environmental scientists, are searching for ways to slow or reverse the effects of
global warming. One way, as mentioned previously, is to develop alternative energy sources such as wind power that
do not emit carbon dioxide.
Many other chemicals that were once commonly used were later found to be harmful to the environment, to human
health, or both. The element lead was once a common additive to gasoline and to paint. Plumbing pipes were once
typically made of lead. Only since the 1970s has the danger of lead become apparent. Too much exposure to lead can
cause brain damage, and small children (who often chewed on objects painted with lead-based paint) are particularly
susceptible to this effect. The use of lead in gasoline, paint, and plumbing pipes is now banned. Mercury is another
toxic element whose use was once far more widespread than it is today, especially in many industrial processes.
Chemists continue to look for threats to our health and the environment and to search for substitutes so that harmful
chemicals can be replaced with equally effective but less harmful alternatives.
Agriculture
The world’s population has increased dramatically over the last century. It is becoming challenging to feed this
population, since the amount of land available to grow food is limited. Even worse, the amount of usable land is
declining as some of it is being converted to living areas. Chemists are involved in efforts to make the land that is
used for agriculture as efficient and productive as possible. Some factors that decrease productivity include poor
soil quality, lack of sufficient water, crop-eating pests, weeds, and diseases. Chemists are involved in the study of
soils, including how to improve existing soils and to develop techniques so that soils do not lose their nutrients.
Fertilizers are used to provide crop plants with vital nutrients, but the excessive use of fertilizers is harmful to the
environment, particularly when the fertilizer runs off the land and into the water supply (Figure1.6). Herbicides
and insecticides have traditionally been applied to crops in order to reduce losses from weeds and insects. However,