Bacterial Cell Wall Structure

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

To provide structural support to the cell
To facilitate cell division
To act as a site for the attachment of O antigen and endotoxin (correct)
To regulate the passage of nutrients and waste products

What is the main component of the inner leaflet of the outer membrane?

Phospholipid (correct)
Peptidoglycan
Lipopolysaccharide
Teichoic acid

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

It provides structural support to the cell
It is involved in cell division
It acts as a receptor for bacterial viruses
It is the major surface antigen (correct)

What is the function of the cytoplasmic membrane in terms of respiration?

It is responsible for electron transport and oxidative phosphorylation (A) Signup and view all the answers

What is the role of the cell wall in maintaining the shape of bacteria?

It provides structural support to the cell (C) Signup and view all the answers

What is the function of the cell wall in relation to antibiotics?

It is the site of action for many antibiotics (D) Signup and view all the answers

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

An asymmetrical bilayer with phospholipid and lipopolysaccharide (C) Signup and view all the answers

What is the function of the cell wall in relation to bacterial viruses?

It contains receptors for bacterial viruses (D) Signup and view all the answers

What is the main function of the capsule in bacteria?

To protect bacteria against phagocytosis and antibacterial agents (C) Signup and view all the answers

What is the composition of the capsular substance in streptococci?

A protein (A) Signup and view all the answers

How is the capsule demonstrated in a bacterial suspension?

By staining with india ink (C) Signup and view all the answers

What is the percentage of water in the bacterial cytoplasm?

80% (C) Signup and view all the answers

What is the shape of the bacterial nucleoid?

A closed circular thread (A) Signup and view all the answers

What is the function of the ribosome in bacteria?

To synthesize proteins (A) Signup and view all the answers

What is the characteristic of a plasmid?

It is a small circular DNA (C) Signup and view all the answers

What is the characteristic of inclusions in bacteria?

They are not essential or permanent structures (A) Signup and view all the answers

What is the primary component of Gram-positive bacterial cell walls?

Peptidoglycan (A) Signup and view all the answers

What is attached to the N-acetyl muramic acid subunit in peptidoglycan?

Tetra-peptide chains (C) Signup and view all the answers

What is the function of pentapeptide bridges in peptidoglycan?

To cross-link tetra-peptide chains (C) Signup and view all the answers

What is the percentage of peptidoglycan in Gram-negative bacterial cell walls?

5-10% (A) Signup and view all the answers

What is the composition of peptidoglycan?

N-acetyl muramic acid and N-acetyl glucosamine (B) Signup and view all the answers

What is the role of cross-linking in peptidoglycan?

To achieve the rigidity of the bacterial cell wall (A) Signup and view all the answers

What is the difference between Gram-positive and Gram-negative bacterial cell walls?

Gram-positive cell walls have a thicker peptidoglycan layer (B) Signup and view all the answers

What is the component of the Gram-negative cell wall that is not present in Gram-positive cell walls?

Outer membrane (A) Signup and view all the answers