Anatomy of Prokaryotic Cells: Cell Wall Structure

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Questions and Answers

What is the composition of the bacterial cell wall?

Polypeptide and dissacharide

Peptidoglycan, which consists of N-acetyl glucosamine (NAG) and N-acetyl muramic acid (NAM) (correct)

Lipopolysaccharides and phospholipids

Glycogen and cellulose

How do B-Lactam group antibiotics interfere with the bacterial cell wall?

They inhibit the synthesis of peptidoglycan

They interfere with the bond formation between the disaccharide and the polypeptide, making the cell wall weak and leading to cell lysis (correct)

They prevent the formation of tetrapeptides

They disrupt the lipid bilayer of the cell wall

What is the function of the cross-bridge in gram positive bacteria?

To facilitate entry of nutrients into the cell

To connect one tetrapeptide to another (correct)

To inhibit the action of antibiotics

To provide structural support to the cell wall

What is the significance of the Gram staining procedure in microbiology?

It helps differentiate bacteria based on differences in their cell walls Signup and view all the answers

What allows a lattice-like structure to form in the bacterial cell wall?

The cross-linking of peptidoglycan chains by a tetrapeptide extending off the NAM sugar unit Signup and view all the answers

What is the main structural difference between the cell walls of Gram-positive and Gram-negative bacteria?

Outer membrane composition Signup and view all the answers

How does peptidoglycan contribute to the bacterial cell wall?

It forms long chains that are cross-linked to one another by a tetrapeptide, creating a lattice-like structure Signup and view all the answers

What is the function of teichoic acid in Gram-positive bacteria?

Prevents extensive wall breakdown and possible lysis Signup and view all the answers

In Gram-negative bacteria, what is the function of the outer membrane?

Acts as a barrier to certain antibiotics and enzymes Signup and view all the answers

What is the role of the periplasm in Gram-negative bacteria?

Contains degradative enzymes and transport proteins Signup and view all the answers

Which property distinguishes Gram-positive from Gram-negative bacteria based on the correlation table?

Lipopolysaccharide content Signup and view all the answers

What role does the lipoteichoic acid play in Gram-positive bacteria?

Regulates movement of positive ions Signup and view all the answers

Which feature renders Gram-negative bacteria more susceptible to mechanical breakage?

Thin peptidoglycan layer Signup and view all the answers

What is a key attribute of the peptidoglycan layer in Gram-positive bacteria?

Thinner than in Gram-negative bacteria Signup and view all the answers

What is the primary function of the outer membrane in Gram-negative bacteria?

Prevents extensive wall breakdown and possible lysis Signup and view all the answers

What component is present in the periplasm of Gram-negative bacteria that can neutralize the effect of antibiotics?

Degradative enzymes Signup and view all the answers

Study Notes

Bacterial Cell Wall Composition

The bacterial cell wall is composed of peptidoglycan, also known as murein, a rigid layer that provides structural support and maintains cell shape.

B-Lactam Antibiotics and Cell Wall Interference

B-Lactam antibiotics, such as penicillin, inhibit the cross-linking of peptidoglycan chains, preventing cell wall formation and ultimately leading to cell lysis.

Cross-Bridge Function in Gram-Positive Bacteria

In Gram-positive bacteria, the cross-bridge, a short peptide chain, connects adjacent peptidoglycan strands, providing additional strength to the cell wall.

Gram Staining Procedure Significance

The Gram staining procedure distinguishes between Gram-positive and Gram-negative bacteria based on the composition of their cell walls, particularly the presence of peptidoglycan and outer membrane.

Lattice-Like Structure Formation

A lattice-like structure forms in the bacterial cell wall due to the cross-linking of peptidoglycan strands.

Gram-Positive vs. Gram-Negative Cell Walls

The main structural difference between Gram-positive and Gram-negative cell walls is the thickness of the peptidoglycan layer and the presence of an outer membrane in Gram-negative bacteria.

Peptidoglycan Contribution to Cell Wall

Peptidoglycan provides mechanical strength, maintains cell shape, and prevents osmotic lysis.

Teichoic Acid Function in Gram-Positive Bacteria

Teichoic acids, negatively charged molecules, contribute to the overall negative charge of the Gram-positive bacterial cell surface.

Outer Membrane Function in Gram-Negative Bacteria

The outer membrane of Gram-negative bacteria acts as a permeability barrier, regulating the flow of molecules into and out of the cell.

Periplasm Role in Gram-Negative Bacteria

The periplasm, a region between the cell membrane and outer membrane, contains enzymes involved in various cellular processes, including nutrient uptake and cell wall synthesis.

Gram Staining Correlation

The correlation table distinguishes Gram-positive from Gram-negative bacteria based on the presence of peptidoglycan and outer membrane, as well as the response to Gram staining.

Lipoteichoic Acid Role in Gram-Positive Bacteria

Lipoteichoic acids, negatively charged molecules, contribute to the overall negative charge of the Gram-positive bacterial cell surface.

Susceptibility to Mechanical Breakage

The lack of a rigid peptidoglycan layer makes Gram-negative bacteria more susceptible to mechanical breakage.

Peptidoglycan Layer Attribute in Gram-Positive Bacteria

The peptidoglycan layer in Gram-positive bacteria is thick and rigid, providing structural support and contributing to cell wall strength.

Outer Membrane Primary Function

The primary function of the outer membrane in Gram-negative bacteria is to act as a permeability barrier, regulating the flow of molecules into and out of the cell.

Periplasm Component and Antibiotic Neutralization

The periplasm of Gram-negative bacteria contains beta-lactamase, an enzyme that can neutralize the effect of beta-lactam antibiotics.

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Description

Learn about the composition and structure of the cell wall in prokaryotic cells, including the role of peptidoglycan, disaccharides, and polypeptides. Understand how B-Lactam group antibiotics interfere with the bond formation in the cell wall.