BACTERIAL Cell Structures and Staining

What are the basic shapes of bacterial cells?

Bacterial cells can be classified into shapes such as cocci (spherical), bacilli (rod-shaped), and spirilla (spiral-shaped).

What arrangement does 'Staphylococcus' indicate?

Staphylococcus indicates a cluster arrangement of spherical bacterial cells.

What are the major functions of cell walls in bacteria?

Cell walls provide structural support, protect against osmotic pressure, and determine the shape of the bacteria.

What are the two types of bacterial cell walls?

The two types of bacterial cell walls are Gram-positive and Gram-negative.

How do Gram-positive and Gram-negative cell walls differ in structure?

Gram-positive cell walls have a thick peptidoglycan layer, while Gram-negative cell walls have a thin peptidoglycan layer and an outer membrane containing lipopolysaccharides (LPS).

What is teichoic acid and what is its function?

Teichoic acid is a polymer found in the cell wall of Gram-positive bacteria that helps maintain cell wall structure and regulate ion movement.

What is lipopolysaccharide (LPS) and what is its function?

LPS is a component of the outer membrane of Gram-negative bacteria that can trigger strong immune responses and is considered an endotoxin.

Why is the Gram stain important in medical microbiology?

The Gram stain is important because it helps identify bacterial species and informs treatment decisions based on cell wall structure.

How does penicillin work against bacterial cell walls?

Penicillin inhibits the synthesis of peptidoglycan, which is essential for cell wall integrity, affecting primarily Gram-positive bacteria.

Why can LPS/endotoxin make Gram-negative infections serious?

LPS can trigger severe immune responses, leading to septic shock and other complications in the body.

Describe the structure of the acid-fast cell wall.

The acid-fast cell wall is similar to Gram-positive walls but contains mycolic acids, making it waxy and resistant to staining and disinfection.

How can you identify acid-fast and non-acid-fast bacteria?

Acid-fast bacteria retain the red color after an acid-fast stain, while non-acid-fast bacteria do not.

How does the acid-fast cell wall affect bacterial resistance?

The acid-fast cell wall provides resistance to disinfection, the immune system, and many antibiotics.

How does the immune system handle tuberculosis bacteria?

The immune system may wall off tuberculosis bacteria in granulomas, which can lead to severe complications if untreated.

What are the clinical problems related to treating tuberculosis?

Clinical problems include antibiotic resistance, the lengthy treatment regimen, and the potential for reactivation of the disease.