Select the wrong statement. Pili and fimbriae are mainly involved in motility of bacteria cells. Bacterial cell wall is made up of peptidoglycan. Mycoplasma is a wall-less microorganism. Cyanobacteria lack flagellated cells.

Cyanobacteria are motile or nonmotile non-flagellated organisms. The cell walls of bacteria are composed of a macromolecule, peptidoglycan which is a repeating framework of long glycan chains having alternate N-acetyl glucosamine and N-acetyl muramic acid. Mycoplasma is the smallest prokaryotic organism that lacks the cell wall but has rigid plasma membrane rich in sterols and lipoglycans. Pili are elongated, hollow appendages, made of a special protein, pilin, and are found in gram-negative bacteria only. Pilli serves in the attachment of bacteria with substratum, not in movement. Therefore, the correct answer is option D.