The cell membrane of mycoplasma contains sterols. Sterols function as regulators of membrane fluidity during changes in growth temperature or alterations in the fatty acid composition of membrane lipids.

The inner-surface proteins cooperate with other proteins in energy yielding reactions.

18S rRNA is not present in bacterial ribosomes. It is found in eukaryotic ribosomes.

Volutin granule production is used for the identification of bacterium Corynebacterium diphtheriae. These are either stained by Albert's stain and viewed microscopically or they produce distinct colonies on Loffler's medium.

Microcompartments are the polyhedral membrane bound compartments in the bacterial cell that are made up of a protein shell and enclose various enzymes. These polyhedral organelles localise and compartmentalise bacterial metabolism, a function performed by the membrane-bound organelles in eukaryotes.

Bacillus cereus has centrally placed endospores.

DD-transpeptidase helps in cross linking between amino acids in different linear sugar amino chains. It results in a 3-dimensional structure that is strong and rigid.

Myxococcus uses fimbriae for motility. It facilitates the assembly of multicellular structures.

a, e and f are false. Bacterial flagella operate at low Reynolds number. Campylobacter jejuni has 7 protofilaments. Fasciculi are seen in Selanomonas.

S-layer acts as a partial permeability barrier for large substrates. It keeps extracellular proteins near the cell membrane by preventing their diffusion away from the cell.

Bacillus subtilis is a Gram-positive bacillus and pili are absent in Gram-positive bacteria. They possess pili-like proteins or Type 4 pilins which assemble into pili (long polymeric fibers that function in bacterial adhesion and motility).

In Gram-negative cells, M-ring of flagella is embedded in plasma membrane.

Lipoteichoic acid confers antigenic properties to Gram-positive organisms. It stimulates specific immune responses and is released from the bacterial cells mainly after bacteriolysis is induced by lysozymes, cationic peptides from leucocytes or beta-lactam antibiotics.

Fimbriae are present in most members of Proteobacteria.

D-alanine is present only in Gram-positive cell walls.