Which class of glycoconjugates contain both d and l-amino acids?

The right answer is B. peptidoglycans.

Peptidoglycan (or murine, or mucocomplex, or mucopeptide) is a component of the bacterial wall maintaining the shape of cells and providing mechanical protection against osmotic pressure. It forms a thin layer in Gram-negative bacteria and a thick layer in Gram-positive bacteria.

It consists of a carbohydrate moiety (= polysaccharide) and a peptide moiety. The polysaccharide is a glycosaminopeptide polymer wherein N-acetylglucosamine (NAG) and N-acetyl-muramic acid (NAM) are linked by beta (1-4) osidic bonds. This bond can be cut off by lysozyme. NAM is a specific compound of bacterial walls. Two polysaccharides are linked by peptide bridges at the level of the NAM, formed by different amino acids: D-alanine, L-alanine, glutamic acid, L-lysine, diaminopimelic acid (lysine analog). Amino acids D are specific for the bacterial wall, they are never found elsewhere.

cramming before a final is bad because it makes a student's stress level higher. students who embrace cramming to get through a final exam week find themselves struggling to perform consistently, once the brain adjusts to prolonged sleep deprivation.

multiplying and dividing the two decimals and the eqations by the same number of the overalls