Since 1901, when the Nobel Prize in Chemistry was first awarded, 177 people have captured the honor. On Wednesday, Frances H. Arnold became only the fifth woman to be awarded the prize.

Dr. Arnold, 62, an American professor of chemical engineering, bioengineering and biochemistry at the California Institute of Technology in Pasadena, earned the award for her work with the directed evolution of enzymes.

She shared this year’s chemistry Nobel — worth close to $1 million — with George P. Smith, 77, and Gregory P. Winter, 67. Dr. Arnold received half of the prize, and Dr. Smith and Dr. Winter split the other half… Continue reading.