Glossary: Examples from biology

1. caoutchouc: natural rubber (cis-polyisoprene). While it is useful in warm climates, but it becomes stiff and brittle in the cold. What's more, it gets runny and sticky when it gets too warm. That all changed in 1839, when Charles Goodyear (1800-1860) accidentally spilled a mixture of rubber latex, sulfur, and white lead on a hot stovetop. See synthetic rubber.

2. cellulose: a polysaccharide polymer, main composant of cell walls of plants ("wood fiber")

3. DNA: a huge double stranded polymer made by joining together a precise sequence of nucleic acids.
   

   In April 1953, the journal Nature reported what was probably the most important scientific discovery of the 20th century - the double helix structure of DNA - the molecule of life. Watson and Crick conjectured a mechanism for DNA replication in which two strands of the double helix separate, each becoming the template for the production of a new strand.

   Before cell division, the DNA in our chromosomes replicates so each daughter cell has an identical set of chromosome. In addition, the DNA is responsible for coding for all proteins. Each amino acid is designated by one or more set of triplet nucleotides. The code is produced from one strand of the DNA by a process called "transcription". This produces mRNA which then is sent out of the nucleus where the message is translated into proteins. The cartoon to the right shows the basic sequence of transcription and translational events.

4. hemoglobin: the oxygen-carrying protein responsible for the color of the blood. Its molecular mass of 66,000 was first measured by Svedberg. This demonstrated that proteins are macromolecules.

5. protein: long, chainlike molecules made by joining together a precise sequence of many small molecules called amino acids. Examples: hemoglobin, ...

6. RNA:

7. silk: material made of a natural protein fiber.

8. starch: Starch is found in many foods. Who can resist the beloved starchy potato?