<P> In the first step of peptidoglycan synthesis, glutamine, which is an amino acid, donates an amino group to a sugar, fructose 6 - phosphate . This turns fructose 6 - phosphate into glucosamine - 6 - phosphate . In step two, an acetyl group is transferred from acetyl CoA to the amino group on the glucosamine - 6 - phosphate creating N - acetyl - glucosamine - 6 - phosphate . In step three of the synthesis process, the N - acetyl - glucosamine - 6 - phosphate is isomerized, which will change N - acetyl - glucosamine - 6 - phosphate to N - acetyl - glucosamine - 1 - phosphate . </P> <P> In step 4, the N - acetyl - glucosamine - 1 - phosphate, which is now a monophosphate, attacks UTP . Uridine triphosphate, which is a pyrimidine nucleotide, has the ability to act as an energy source . In this particular reaction, after the monophosphate has attacked the UTP, an inorganic pyrophosphate is given off and is replaced by the monophosphate, creating UDP - N - acetylglucosamine (2, 4). (When UDP is used as an energy source, it gives off an inorganic phosphate .) This initial stage, is used to create the precursor for the NAG in peptidoglycan . </P> <P> In step 5, some of the UDP - N - acetylglucosamine (UDP - GlcNAc) is converted to UDP - MurNAc (UDP - N - acetylmuramic acid) by the addition of a lactyl group to the glucosamine . Also in this reaction, the C3 hydroxyl group will remove a phosphate from the alpha carbon of phosphenolpyruvate . This creates what is called an enol derivative that will be reduced to a "lactyl moiety" by NADPH in step six . </P> <P> In step 7, the UDP--MurNAc is converted to UDP - MurNAc pentapeptide by the addition of five amino acids, usually including the dipeptide D - alanyl - D - alanine . Each of these reactions requires the energy source ATP . This is all referred to as Stage one . </P>

Peptidoglycan monomers have which of the following characteristics