Multiple Choice
In prokaryotic cell architecture, what is the primary structural polymer that makes up most bacterial cell walls?
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1. Overview of Cell Biology
Prokaryotic Cell Architecture
Multiple Choice
In prokaryotic cell architecture, how do the cell walls of archaea and bacteria differ?
A
Archaeal cell walls contain peptidoglycan with N-acetylmuramic acid, whereas bacterial cell walls lack peptidoglycan and rely mainly on S-layers.
B
Archaeal cell walls are composed primarily of cellulose, whereas bacterial cell walls are composed primarily of chitin.
C
Bacterial cell walls typically contain peptidoglycan (murein), whereas archaeal cell walls lack peptidoglycan and may instead have pseudopeptidoglycan or an S-layer of proteins/glycoproteins.
D
Both archaea and bacteria have identical cell walls made of peptidoglycan; they differ mainly in the presence or absence of internal membrane-bound organelles.
Verified step by step guidance1
Step 1: Understand the composition of bacterial cell walls. Bacterial cell walls typically contain peptidoglycan, also known as murein, which is a polymer consisting of sugars and amino acids that provides structural strength and shape to the cell.
Step 2: Examine the composition of archaeal cell walls. Unlike bacteria, archaea do not have peptidoglycan in their cell walls. Instead, they may have pseudopeptidoglycan (also called pseudomurein), which is chemically distinct, or an S-layer composed of proteins or glycoproteins that serves as a protective layer.
Step 3: Compare the chemical differences between peptidoglycan and pseudopeptidoglycan. Peptidoglycan contains N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG), whereas pseudopeptidoglycan contains N-acetyltalosaminuronic acid instead of NAM, making it resistant to certain enzymes like lysozyme.
Step 4: Recognize that the presence or absence of peptidoglycan is a key distinguishing feature between bacterial and archaeal cell walls, which affects their susceptibility to antibiotics and environmental adaptations.
Step 5: Summarize that bacterial cell walls are primarily peptidoglycan-based, while archaeal cell walls lack peptidoglycan and instead rely on pseudopeptidoglycan or proteinaceous S-layers, highlighting a fundamental difference in prokaryotic cell architecture.
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