polinukleotidszálból

A polinukleotidszálból, which translates to "from a polynucleotide strand," refers to a fundamental component of genetic material. In biological contexts, it typically denotes a single strand of nucleic acid, either DNA (deoxyribonucleic acid) or RNA (ribonucleic acid). These strands are polymers, meaning they are composed of repeating subunits called nucleotides. Each nucleotide consists of three parts: a phosphate group, a five-carbon sugar (deoxyribose in DNA, ribose in RNA), and a nitrogenous base. The nitrogenous bases in DNA are adenine (A), guanine (G), cytosine (C), and thymine (T), while in RNA, uracil (U) replaces thymine.

The nucleotides within a polynucleotide strand are linked together by phosphodiester bonds, forming a sugar-phosphate backbone. This linear arrangement is characteristic of a single strand. In the case of DNA, two such polynucleotide strands typically associate to form a double helix, held together by hydrogen bonds between complementary bases (A with T, and G with C). RNA, on the other hand, is usually single-stranded, although it can fold upon itself to form complex three-dimensional structures that are crucial for its various functions, such as messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). The sequence of bases along a polynucleotide strand carries the genetic information.