11/13/13
“Silent Springs” Test
Content Questions:
1. Carlson classifies modern insecticides into two groups of chemicals. The first group, represented by DDT, is known as the “chlorinated hydrocarbons” and the other group, represented by Malathion and parathion, consists of the organic phosphorus insecticides. Although both are organic, the organic phosphorous insecticides are more poisonous than the chlorinated hydrocarbons and have the ability to destroy enzymes.
2. When insecticides “are built on a basis of carbon atoms,” it is both ingenious and threatening because carbon atoms are the basic building blocks of the living world. They can be modified to become the chemistry of all life, but they can also be modified to become the agents of death.
3. Carbon is a basic element whose atoms have almost an infinite capacity for uniting with each other through chains, rings, and other various configurations. Also, its ability to link with atoms of other substances allows the element to serve as a basis for other naturally occurring molecules and a wide variety of synthetic pesticides.
4. The ingestion and accumulation of DDT and other insecticides even when foods directly treated with these chemicals are avoided is possible because it can be present as tiny residue on foodstuffs that was not necessarily injected. DDT and other insecticides are passed on from one organism to another through all the links of the food chains and can also be passed on from mother to offspring. Storage at low levels then makes these chemicals a threat that is able to persist for a long time.
5. The organic phosphorous insecticides attack the nervous system by destroying enzymes that perform necessary functions in the body such as cholinesterase that destroys the transmitting chemical acetylcholine.
6. Malathion is considered the least toxic of the organic phosphates because the mammalian liver is able to detoxify the substance using one of its enzymes, rendering