‘Peptidoglycan' is a characteristic constituent of the cell wall o A Eubacteria and unicellular eukaryotes B Bacteria and cyanobacteria C Archaebacteria and eukaryotes D All members of 'Monera' and 'Protista'
Hint: Peptidoglycan, also known as murein, is a polymer made up of sugars and amino acids that forms a mesh-like layer outside of most bacteria's plasma membrane, forming the cell wall.
Complete answer: Peptidoglycan consist of two types of sugars. The sugar component is made up of alternating residues of N-acetylglucosamine (NAG) and N-acetylmuramic acid with a -(1,4) bond (NAM). It determines the shape of a bacterial cell and is needed for osmotic stability. Peptidoglycan is a peptide-carrying heteropolymer made up of glycan strands. Peptidoglycan is a part of the bacterial cell wall that can be found on the outside of the cytoplasmic membrane of nearly all bacteria. A four-amino-acid short peptide is found in the side party. Prokaryotic species include bacteria and cyanobacteria. They have a lot in common. Real cell organelles are absent in each of them. They both have a nucleoid rather than a real nucleus. In both bacteria and cyanobacteria, peptidoglycan is a key component of the cell wall. They both live in a saprophytic state of life. In terms of cell division, they're both identical.
Hence the correct answer is 'Bacteria and Cyanobacteria.
Note: Gram-negative bacteria have a thin peptidoglycan cell wall, which is surrounded by a lipopolysaccharide-containing outer membrane. Gram-positive bacteria do not have an outer membrane, but are surrounded by peptidoglycan layers that are several times thicker than those present in Gram-negative bacteria.