basal membrane, a sheet of tissue that forms the outer layer of the choroid and lies just under the pigmented layer of the retina. It is composed of elastic fibers in an otherwise thin homogenous layer.asal membrane, a sheet of tissue that forms the outer layer of the choroid and lies just under the pigmented layer of the retina. It is composed of elastic fibers in an otherwise thin homogenous layer.
There are several enzymes that 'unzip' DNA. These enzymes are collectively known as DNA helicases. DNA helicases are helix-destabilizing enzymes that bind to DNA at the origin of replication and break hydrogen bonds, thereby separating the two strands.. Solomon, Eldra P., Linda R. Berg, and Diana W. Martin. Biology. 8th ed. Belmont, CA: Thomson Brooks/Cole, 2008.
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. This 'unzipping' of the molecules will expose the nitrogenous bases of the nucleic acid chain so that new nucleotides can be added to create the daughter strand.