$S.\ epidermidis$ and $S.\ aureus$ are prokaryotes. Table 3.1 lists some cell features that may be true for a typical prokaryotic cell, a typical eukaryotic cell, or both. Finish Table 3.1 by writing a tick ($\checkmark$) where the feature applies to the cell type, or a cross ($\times$) where it does not. Enter a tick ($\checkmark$) or a cross ($\times$) in every box.
One way in which $S.\ aureus$ can infect humans is through wounds or breaks in the skin. Populations of $S.\ aureus$ form on human skin as part of a biofilm. The biofilm contains $S.\ aureus$ cells within a mixture of polymers secreted by the cells. $S.\ epidermidis$ makes a protease enzyme that stops $S.\ aureus$ populations from growing on human skin. Proteases catalyse the breakdown of proteins. Fig. 3.1 is a diagram showing populations of $S.\ epidermidis$ and $S.\ aureus$ on human skin cells. Suggest and explain how the protease made by $S.\ epidermidis$ cells stops an $S.\ aureus$ population from growing on human skin.
$S.\ aureus$ can infect many tissues in the human body, including tissues in the gas exchange system. Describe the role of goblet cells in protecting tracheal tissues from infection by $S.\ aureus$.
$S.\ aureus$ cells can infect tissues by moving between the cells that line the lumen of the trachea. State the name of a cell type, other than goblet cells, that lines the lumen of the trachea.
$S.\ aureus$ can infect many tissues in the human body, including tissues in the gas exchange system.
Vancomycin and penicillin are antibiotics used to treat infectious diseases caused by $S.\ aureus$. Fig. 3.2 shows how vancomycin works.
Vancomycin and penicillin act on the bacterial cell wall. Using Fig. 3.2, describe the similarities and differences between how vancomycin acts and how penicillin acts.
Some strains of $S.\ aureus$ are resistant to vancomycin and penicillin. Describe the steps that can be taken to reduce the effect of antibiotic resistance.