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.
Confidence votes 355. DNA helicase unzip, or separate, a strand of DNA at positions called origins. This means that the hydrogen bonds between complementary base pairs are removed (DNA is double stranded!). When they separate double-stranded DNA into single strands, it allows each strand to be copied (replication).