Amino sugar phosphate ester

Formamide is itself hydrolyzed by water, meaning that it persists only in a relatively dry environment, such as a desert. Desert environments recently proposed as being potential sites for the prebiotic synthesis of ribose18 may hold formamide as well. Since formamide boils at —400 K, a mixture of formamide and water, if placed in the desert, would lose its water over time and end up as a pool of formamide. Within this pool, many syntheses are thermodynamically favorable polypeptides from amino acids, nucleosides from sugars and bases, nucleotides from nucleosides and inorganic phosphate, and RNA from nucleotides. Indeed, phosphate esters are also spontaneously synthesized. This includes ATP (from ADP and inorganic phosphate), nucleosides (from ribose borates and nucleobases), peptides (from amino acids), and others.19-21... 

The backbone of a nucleic acid is a polymer of ribofuranoside rings (five-membered rings of the sugar ribose) linked by phosphate ester groups. Each ribose unit carries a heterocyclic base that provides part of the information needed to specify a particular amino acid in protein synthesis. Figure 23-21 shows the ribose-phosphate backbone of RNA. 

Sugars in which a hydroxyl group has been replaced by an amino group are called amino sugars. The amino groups in these compormds are invariably acetylated. When hydroyxl groups are replaced by phosphate or sulfate groups they are known as phosphate and sulfate esters, respectively. 

Nucleotides bear the same relation to a nucleic acid that amino acids do to a protein they are its monomeric units. The connecting links in proteins are amide groups in nucleic acids they are phosphate ester linkages. Phosphate esters link the 3 -OH of one ribose (or deoxyribose) with the 5 -OH of another. This makes the nucleic acid a long unbranched chain with a backbone of sugar and phosphate units with heterocyclic bases protruding... 

The repair and replication of cells involves metabolism - interconversions of hundreds of low molecular weight metabolites that ultimately yield the precursors for much larger, more complex macromolecules such as phospholipids (based on phosphatidic. acids or long chain fatty acid esters of glycerol phosphate), polynucleotides such as RNA and DNA (polymers of nucleotide monomers), proteins (polypeptides or amino acid monomers linked by peptide bonds) and polysaccharides (polymers of simple sugars or monosaccharides). 

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