Ciliate conjugation is a sexual phenomenon that results in genetic recombination and nuclear reorganization within the cell. In most ciliate groups, however, the cells separate after conjugation, and both form new macronuclei from their micronuclei.
Before the bun, hamburgers are said to have been served between two pieces of bread. In fact, a ground beef patty was known as Hamburger steak (first mentioned in an American cookbook in 1891); when this was put between bread or in a bun it was called a Hamburger sandwich.
As with the invention of the hamburger, the exact origins of the cheeseburger are unknown. Several chefs claim to have been the first to add a slice of cheese to a hamburger. Lionel Sternberger of Rite Spot in Pasadena, California takes credit for the cheeseburger, claiming that he invented it between 1924 and 1926.