15 million people were self-employed in 2015, or 10.1 percent of all U.S. workers. Self-employment continues to be an important source of jobs in the United States. In 2015, 15.0 million people, or 10.1 percent of total U.S. employment, were self-employed, including those who had incorporated their businesses and those who had not.
DNA helicase is the enzyme that unwinds the DNA double helix by breaking the hydrogen bonds down the center of the strand. It begins at a site called the origin of replication, and it creates a replication fork by separating the two sides of the parental DNA.
As we go through this, remember, all that is happening is the DNA is being unzipped and each side of the zipper is being copied. The first step in DNA replication is to separate or unzip the two strands of the double helix. The enzyme in charge of this is called a helicase (because it unwinds the helix). The point where the double helix is opened up and the DNA is copied is called a replication fork.