Freebase(0.00 / 0 votes)Rate this definition: Bollard. A bollard is a short vertical post. Originally it meant a post used on a ship or a quay, principally for mooring. The word now also describes a variety of structures to control or direct road traffic, such as posts arranged in a line to obstruct the passage of motor vehicles.
Which of the following events occurs directly after a DNA molecule is unzipped? A. Mismatched nucleotide bases are identified and replaced. B. Free-floating nucleotides pair up with exposed bases.hich of the following events occurs directly after a DNA molecule is unzipped? A. Mismatched nucleotide bases are identified and replaced. B. Free-floating nucleotides pair up with exposed bases.
However, DNA does not unzip entirely. It unzips in a small area called a replication fork, which then moves down the entire length of the molecule. Let's look at the details: 1  An enzyme called DNA gyrase makes a nick in the double helix and each side separates. 2  An enzyme called helicase unwinds the double-stranded DNA. 3  Several small proteins called single strand binding proteins (SSB) temporarily bind to each side and keep them separated.