Describe the location and structure of DNA, the process of DNA replication and the significance of this process for mitosis - NSC Life Sciences - Question 4 - 2020 - Paper 2

DNA is a double-stranded molecule that forms a helical structure. Each strand is made up of nucleotides, with each nucleotide comprising a deoxyribose sugar molecule, a phosphate group, and a nitrogenous base. The bases involved are adenine (A), thymine (T), cytosine (C), and guanine (G). They pair up with each other complementarily: adenine pairs with thymine, and cytosine pairs with guanine. The bases are held together by hydrogen bonds.

During DNA replication, the original DNA double helix unwinds, and the hydrogen bonds between the bases break, resulting in the separation of the two strands. Both strands serve as templates for synthesizing new complementary strands using free nucleotides obtained from the nucleoplasm. This process produces two identical DNA molecules, with each comprising one original and one new strand.

The replication of DNA is crucial for mitosis as it ensures that the genetic material is doubled. This allows each daughter cell to receive the same amount of DNA, guaranteeing that they are genetically identical to each other, which is essential for proper cellular function and organismal growth.