nukleiinihappujen

Nukleiinihappojen, known in English as nucleic acids, are essential macromolecules for all known forms of life. They are polymers, meaning they are composed of repeating structural units called nucleotides. Each nucleotide consists of three parts: a phosphate group, a five-carbon sugar, and a nitrogenous base. The two most important types of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

DNA carries the genetic instructions used in the growth, development, functioning, and reproduction of all known organisms and many viruses. It is typically a double-stranded helix, with the two strands held together by hydrogen bonds between complementary nitrogenous bases. The four bases in DNA are adenine (A), guanine (G), cytosine (C), and thymine (T). Adenine always pairs with thymine, and guanine always pairs with cytosine.

RNA plays a crucial role in protein synthesis and gene regulation. Unlike DNA, RNA is usually single-stranded and its sugar is ribose instead of deoxyribose. The nitrogenous bases in RNA are adenine (A), guanine (G), cytosine (C), and uracil (U), with uracil replacing thymine. There are several types of RNA, including messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA), each with specific functions in gene expression. The sequence of nucleotides in nucleic acids encodes the genetic information that determines an organism's traits.