4 Principles of Bacterial Classification

Question 1

What classical methods are used to identify bacteria?

Answer 1

Cell shape, Gram stain, motility, and cell grouping.

Question 2

What are the different bacterial shapes and arrangements?

Answer 2

Rod (bacillus), sphere (coccus), spiral (spirilla/spirochetes), curved rod (vibrio); bacilli in singles or chains; cocci in chains (streptococci) or clusters (staphylococci).

Question 3

What is the difference between Gram-positive and Gram-negative bacteria?

Answer 3

Gram-positive: thick peptidoglycan wall, teichoic acids. Gram-negative: thin wall, outer membrane with lipopolysaccharide (LPS).

Question 4

What are the key components of the bacterial cell wall?

Answer 4

Peptidoglycan, teichoic acids (Gram+), outer membrane and LPS (Gram−).

Question 5

How is motility used in bacterial classification?

Answer 5

Spiral forms are motile; cocci are generally non-motile.

Question 6

How does cell wall structure influence antibiotic targeting?

Answer 6

Cell wall is essential for viability and is a major antibiotic target due to unique structural components.