Chapter 5, Problem 2Q

Summary Introduction

To review:

The reason, due to which the immune cells that are responsible for attacking foreign cells cannot destroy certain bacterial species that havepolymers of D-amino acid in their outer layer.

Introduction:

The outer layer of bacteria is known as cell wall, which is made up of peptidoglycan. It is a polysaccharide of N-acetylglucosamine and N-acetylmuramic acid, which are crosslinked by tetrapeptide of L-alanine, D-glutamine, L-lysin, and D-alanine. D- and L- are the forms of molecules, known as optical isomers; they are called so because of their ability to rotate plane polarized light. L-form is more common in biological molecules than D-form.