It is generally accepted that the first living cells on Earth were some form of prokaryote. In biology, a prokaryote is generally a single-celled organism that lacks membrane-bound organelles such as a nucleus, mitochondria, and chloroplasts. Genetic material is instead organized into a ring-like structure called a nucleoid. Most prokaryotes are bacteria, and the two terms are often treated as synonyms. What are the three basic shapes of prokaryotic cells?
Back in the day
When Ruth Handler, wife of Mattel toy company co-founder Elliot Handler, realized that there were no adult-bodied dolls on the toy market, she suggested to her husband that Mattel begin producing one. In 1959, Barbie made her debut. She was based on a German doll called Bild Lilli and was marketed as a "Teen-age Fashion Model." According to estimates, over a billion Barbie dolls have been sold worldwide and many have become collector's items. How much is a mint-condition original Barbie worth?
Born on a day like today
Gagarin was a Russian cosmonaut who, in 1961, became the first human being to successfully travel into space. Gagarin circled the earth once during his 1-hour-and-48-minute flight aboard the Vostok 1. His success is believed to have ushered in the modern era of man in space, and Gagarin toured widely to promote the Soviet achievement. Ironically, he died in a plane crash just a few years later. What factors did Soviet officials consider when choosing Gagarin for the historic space flight?