Final answer:
Nucleotide sequences are written from the 5' to 3' end using one-letter abbreviations for the bases. They specify the genetic information and are key for biological functions such as DNA replication.
Step-by-step explanation:
The primary structure of nucleic acids, such as DNA and RNA, is made up of a sequence of nucleotides. This sequence encodes the genetic information vital to biological functions and heritability. By convention, nucleotide sequences are written from the 5' end to the 3' end, using the one-letter abbreviations for the nitrogenous bases: A (adenine), C (cytosine), G (guanine), and T (thymine) for DNA, with U (uracil) replacing T for RNA sequences. The sequence not only specifies the genetic code that determines amino acid sequences in proteins but also guides the structure and function of RNA molecules.
In DNA, the sequence is often preceded by a lowercase 'd' to denote deoxyribonucleotides. For example, the sequence '5'-dG-dT-dA-dC-3'' could be abbreviated to 'dGTAC' or simply 'GTAC'. Sequencing is essential for understanding the molecular biology of genes and genetic variation and is a cornerstone in the fields of genetics and bioinformatics.
The primary structure of nucleic acids is important in many biological processes, such as DNA replication, where each strand acts as a template for forming a complementary strand with the help of DNA polymerase. Additionally, the sequence of pairs, known as Watson-Crick base pairs, is predictable: A pairs with T (or U in RNA), and C pairs with G.