NURSING EXAM QUESTIONS
MICROBIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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They are prokaryotes
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They live in extreme environments
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They have peptidoglycan in their cell walls
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None of the above
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Detailed explanation-1: -The cell wall of Archaea comprises substances called polysaccharides. These polysaccharides are proxy substances that are present instead of peptidoglycan. It helps in providing structure and rigidity to the cell and prevents any damages from occurring. Hence, Archaea and bacteria do not have peptidoglycan.
Detailed explanation-2: -Archaea lack peptidoglycan, but they still form rigid cell boundaries that confer resistance to high internal osmotic pressure. To do this, they elaborate protein or glycoprotein coats or reinforce their cytoplasmic membranes. The S-layer glycoproteins are the best characterized glycoproteins of Archaea.
Detailed explanation-3: -For instance, the cell walls of all bacteria contain the chemical peptidoglycan. Archaeal cell walls do not contain this compound, though some species contain a similar one.
Detailed explanation-4: -Answer and Explanation: The correct answer is (d) Chlamydia. Bacteria that belong to the phylum Chlamydia do not have peptidoglycan in their cell wall.
Detailed explanation-5: -Peptidoglycan is absent in archaeans, and it is only present in the bacterial cell wall.