Question

Staining properties of bacteria - cell wall contains thick peptidoglycan layer with teichoic acid & lipoteichoic acid.

a) Gram-positive
b) Acid-fast
c) Gram-negative
d) Capsulated

Answer 1

The cell wall characteristics provided, including a thick peptidoglycan layer with teichoic acid and lipoteichoic acid, match those of Gram-positive bacteria, which retain the crystal violet stain during Gram staining.

Step-by-step explanation:

The characteristics of the bacterial cell wall outlined in the question, including the presence of a thick peptidoglycan layer with embedded teichoic acid and lipoteichoic acid, are indicative of Gram-positive bacteria. Gram-positive bacteria have a cell wall consisting of a significant amount of peptidoglycan, which retains the primary stain crystal violet during the Gram staining procedure, and most of the wall is composed of acidic substances called teichoic acids. In contrast, Gram-negative bacteria possess a thinner peptidoglycan layer and have an outer membrane that contains lipopolysaccharides. Bacteria that have a waxy mycolic acid layer and require acid-fast staining are neither Gram-positive nor Gram-negative but rather classified as acid-fast, a characteristic of the Mycobacteriaceae family.

Lastly, capsulated bacteria refer to those with a distinct capsule surrounding their cell wall, which is not related to the Gram staining characteristics.

Answer 2

The bacteria being described have thick peptidoglycan layers with teichoic acid and lipoteichoic acid, which are features of Gram-positive bacteria, making (a) Gram-positive the correct classification.

Step-by-step explanation:

When analyzing the staining properties of bacteria, one vital characteristic is the structure of their cell walls. Bacteria that have a thick peptidoglycan layer with embedded teichoic acid and lipoteichoic acid are classified as Gram-positive. This thick layer allows them to retain the crystal violet stain used in the Gram staining method, making them appear purple.

On the other hand, Gram-negative bacteria have a thinner peptidoglycan layer and do not retain the crystal violet stain due to the presence of an outer membrane that contains lipopolysaccharides (LPS). They instead take up the counterstain, safranin, and appear red/pink. Acid-fast bacteria, such as those of the Mycobacteriaceae family, possess a distinctive waxy layer of mycolic acids on their cell wall surface, which necessitates the use of special acid-fast stains. The mentioned characteristics of the bacterial cell wall match with Gram-positive bacteria. Therefore, the correct option to classify bacteria with a thick peptidoglycan layer and teichoic acids would be (a) Gram-positive.