Question

How does the antiparallel structure of the double helix affect replication?

Answer 1

Double helix is a description of the DNA molecule structure. The DNA double helix comprises two intertwined sugar-phosphate chains, the flat base pairs forming the steps between them. Each strand has a backbone composed of alternate groups of sugar (deoxyribose) and phosphate. The two strands are linked together by bonds between the bases, adenine forming a base pair with thymine, and cytosine forming a base pair with guanine.

Complete answer:
The discovery in 1953 of the double helix, the ladder structure of deoxyribonucleic acid (DNA), by James Watson and Francis Crick, marked a landmark in the history of science and gave rise to modern molecular biology, primarily concerned with understanding how genes regulate chemical processes within cells.
DNA replication is a mechanism by which DNA is basically duplicated. It's an essential process that's taking place within the dividing cell. Replication is an important process since, if a cell divides, the two new daughter cells should possess the same genetic data or DNA as that of the parent cells. The replication process is based on the fact that each strand of DNA will act as a duplication template. The DNA replication is initiated at unique locations, called roots, where the DNA double helix is unwound.

One of the important ways in which the antiparallel structure of DNA influences replication is the manner in which DNA polymerases create new DNA strands. DNA polymerase is the enzyme that binds nucleotides to create the new DNA in the process. DNA polymerases only operate in the direction of 3' to 5' so this is simple on one of the DNA strands as it opens in that direction. But on the other strand (the lagging strand) the enzyme has to function in the reverse direction, which means that it can only create discontinuous fragments as the double helix unwinds.

Note: DNA is present in every human cell, and if we unravel each strand, it's almost two metres long. It's incredible that it fits into 0.09 micrometres of space. If we unravelled the entire DNA of a human being, it would be 10 billion miles away. It will be the same as a return trip to Pluto. The DNA in every human cell is damaged more than 100 times a day. Even then, our bodies have very smart mechanisms in place to serve as a repair mechanism.