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Which material forms the cell wall of a bacterium?
APeptidoglycan, a cross-linked polymer
BCellulose, a plant-type wall polymer
CChitin, the wall polymer of fungi
DCholesterol, a membrane sterol lipid
Answer & Solution
Correct answer: A. Peptidoglycan, a cross-linked polymer
1. The bacterial wall is built from peptidoglycan, polysaccharide chains cross-linked by unusual peptides.
2. Those peptides carry both L- and D-amino acids, which is what makes the wall a drug target.
3. Cellulose walls belong to plants, and chitin walls belong to fungi and insects, not to bacteria.
4. Cholesterol is a lipid, so it could never give the wall its rigid cross-linked mesh.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 22 "Prokaryotes: Bacteria and Archaea", section 22.2 Structure of Prokaryotes_
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