mposition of the cell wall and$/$or cell membrane, as well as ribosomal structure.

See a larger version of Foundation Figure $4\mathrm{.}6$

Part A $-$ The Bacterial Cell Wall

Actually, there is much more to the cell wall than appears in Figure $4\mathrm{.}6.$ There are two fundamental types of bacterial cell walls: Gram$-$positive cell walls, and Gram$-$negative cell walls. These two cell wall$-$types can be differentiated by using a Gram stain, which results in Gram$-$positive bacteria staining a deep purple, and Gram$-$negative organisms staining a pink or red. This difference in cell wall structure results in more than just color differences when bacteria are Gramstained, however. Knowledge of the cell wall type can enable prediction of other characteristics such as sensitivity to certain antibiotics, production of toxins, and susceptibility to disruption by different environmental agents. Understanding such differences begins with knowledge of the structural differences between these two cell wall types.

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plasma membrane

periplasm

thick layer of peptidoglycan

lipopolysaccharide

outer membrane

thin layer of peptidoglycan

lipoprotein

Part B $-$ Do all bacterial cells have the same structures?

There are some structures that are common to all prokaryotic cells, and others that are only found in some bacterial species or Select the structures below that are found in all bacterial cells.

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cytoplasm

ribosomes

pilus $($pili$)$

cell wall

flagella

plasma membrane

capsule

nucleoid

fimbriae

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