OIA1010 BACTERIOLOGY

What are the three basic shapes of bacteria?

Cocci (spherical), Bacilli (rod-shaped), and Spirochetes (spiral-shaped).

What structure allows bacteria to adhere to surfaces and form biofilms?

Glycocalyx; specifically, the capsule (organized) or slime layer (unorganized).

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

Gram-positive bacteria have a thick peptidoglycan layer with teichoic acids, while Gram-negative bacteria have a thin peptidoglycan layer and an outer membrane.

Name a bacterium with a kidney-shaped diplococci arrangement.

Neisseria gonorrhoeae.

Which bacterium uses flagella for mobility and is distinguished by its H antigen?

Escherichia coli. (E. coli)

What causes Lyme disease and syphilis, respectively?

Borrelia burgdorferi (Lyme disease) and Treponema pallidum (syphilis).

What is the primary purpose of Gram staining?

To classify bacteria as Gram-positive (purple) or Gram-negative (pink) based on their cell wall structure.

What are the four main steps in Gram staining?

1. Crystal violet application, 2. Gram's iodine, 3. Decolorization with alcohol/acetone, 4. Counterstain with safranin.

How are endospores identified, and why are they significant?

Endospores are identified by their resistance to harsh conditions, formed by genera like Bacillus and Clostridium.

Compare aerobic and anaerobic bacteria.

Aerobes require oxygen, while anaerobes grow without it. Facultative anaerobes can grow in both conditions.

What is the difference between monotrichous and lophotrichous flagella?

Monotrichous: single flagellum; Lophotrichous: tuft of flagella at one end.

What temperature ranges do psychrophiles, mesophiles, and thermophiles prefer?

Psychrophiles: <0°C, Mesophiles: 25-40°C, Thermophiles: >45°C.

What pH range do neutrophiles prefer, and give an example of an acidophile.

Neutrophiles: 5-8; Example: Helicobacter pylori (survives acidic stomach).

Which bacterium causes toxic shock syndrome?

Staphylococcus aureus.

Name a Gram-positive cocci that forms chains and can cause strep throat.

Streptococcus pyogenes.

Which Gram-positive rod causes severe keratitis and panophthalmitis?

Bacillus cereus.

What enzyme do Staphylococcus aureus produce to protect from phagocytosis?

Coagulase.

How do bacteria like Escherichia coli acquire nitrogen?

Through decomposition of proteins or from nitrites/nitrates.

What is the role of siderophores in bacteria?

Siderophores bind to iron and transport it into bacterial cells.

How is bacterial ATP produced?

Through processes in the plasma membrane since bacteria lack mitochondria.