Nucleic Acid Chemistry and DNA Structure

A nucleotide is composed of three parts: a nitrogenous base, a five-carbon sugar (pentose), and a phosphate group.

The two chemically distinct types of nucleic acids are ribonucleotides and deoxyribonucleotides. They differ in the sugar molecule they contain: ribose for ribonucleotides and deoxyribose for deoxyribonucleotides.

Phosphates can attach to the 3' or 5' carbon atoms of the sugar in a nucleotide.

Nucleic acids are responsible for storing and expressing genetic information within living organisms.

RNA, or ribonucleic acid, is a polymer of ribonucleotides, meaning it's made up of many ribonucleotide units linked together.

A nucleotide is composed of three key components: a pentose sugar (either ribose or deoxyribose), a nitrogenous base (either purine or pyrimidine), and a phosphate group.

When a pentose sugar is linked to a purine or pyrimidine base through an N-glycosidic bond, it forms a nucleoside. This bond connects the nitrogenous base to the sugar.

The phosphate groups within a nucleotide are negatively charged. This is because of the presence of oxygen atoms with a partial negative charge.

The primary structure of DNA is determined by the sequence of nucleotides and the phosphodiester bonds that link them together. This sequence forms the genetic code.

The double helix structure of DNA is formed by hydrogen bonds between the nitrogenous bases of two complementary nucleotide strands. These bonds form specific pairings: adenine with thymine and guanine with cytosine.

In RNA, uracil (U) pairs with adenine (A). This pairing is similar to the thymine (T)-adenine pairing in DNA.

The two chains in the double helix of DNA are paired in an antiparallel manner, which means they run in opposite directions. One strand runs 5' to 3', while the other runs 3' to 5'.

Unlike DNA, which is a double helix, RNA exists as a single strand of nucleotides. This single strand can fold into complex 3D structures.

A low-energy bond, known as an ester bond, connects the phosphate group to the sugar in a nucleotide.