SCIENCE NOTES

Collagen Collagen is the most abundant protein in the animal kingdom. Approximately one third of the protein in a mammal’s body is collagen. It makes up a major portion of the connective tissue found in skin, joints, ligaments, muscles, ten-dons, and bones. Different types of collagen occur in different species. That is, the collagen found in humans is somewhat different from that found in cows, and both human and cow collagen differ from the collagen found in other animals, such as dogs and ats. Nonetheless, all forms of collagen have a common molecular structure that consists of three rope-like strands intertwined with each other. Each strand (called tropocollagen) is a polymer consisting of amino acids, the most common of which are glycine, proline, and hydroxyproline. Collagens differ from each other in regard to the relative amounts of each amino acid present. HOW IT IS MADE Collagen is synthesized in the bodies of all higher verte-brates in a complex series

Caffeine Caffeine  is an organic base that occurs naturally in a number of plant products, including coffee beans, tea leaves, and kola nuts. It occurs as a fleecy white crystal-line material, often in the form of long, silky needles. It usually exists as the monohydrate, C 8 H 10 N 4 O 2 H 2 O, although it gives up its water of hydration readily when exposed to air. Scientists believe that humans have been drinking beverages that contain caffeine for  thousands of years. The first recorded reference to a caffeine drink can be found in a Chinese reference to the consumption of tea by the emperor Shen Nung in about 2700 BCE . Coffee is apparently a much more recent drink, with the earliest cultivation of the coffee tree dated at about 575 CE in Africa. Caffeine was first studied scientifically by two French chemists, Joseph Bienaime´ Caventou  (1795–1877) and Pierre Joseph Pelletier (1788–1842), who were very interested in the chemical properties of the