sacculus
(noun)
 a small sac
Examples of sacculus in the following topics:
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Shared Features of Bacteria and Archaea- Within prokaryotes, archaeal cell structure is most similar to that of Gram-positive bacteria, largely because both have a single lipid bilayer and usually contain a thick sacculus of varying chemical composition.
 
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The Origins of Archaea and Bacteria- Within prokaryotes, archaeal cell structure is most similar to that of gram-positive bacteria, largely because both have a single lipid bilayer and usually contain a thick sacculus of varying chemical composition.