Chest pain is always an alarming symptom since it usually raises the fear of heart disease. And because chest pain may indeed be a sign of angina or of some other heart problem, it is always a good idea to have it checked out. But heart disease is only one of the many types of conditions that can produce chest pain.
Concept 27 Mutations are changes in genetic information. Hermann Muller received the 1946 Nobel Prize in Physiology or Medicine for his work on mutations induced by X-rays. Seymour Benzer used genetics to prove that mutations were caused by changes in the DNA sequence.
Theodor Schwann Theodor Schwann (7 December 1810 â 11 January 1882) was a German scientist who isolated and named the enzyme pepsin. He also played a key role in promoting the idea of the cell as the foundation of living organisms. His work on the cell has recently been re-assessed, because the idea had been discussed before him. Cell history