Question

What do gram-positive and gram-negative bacteria secrete?

A) Gram-positive bacteria secrete exotoxins, while gram-negative bacteria secrete endotoxins.
B) Gram-positive bacteria secrete lipopolysaccharides, while gram-negative bacteria secrete teichoic acids.
C) Gram-positive bacteria secrete enzymes like hyaluronidase, facilitating tissue invasion.
D) Gram-negative bacteria secrete enzymes like proteases, breaking down host tissues for nutrient absorption.

Answer 1

Gram-positive bacteria have a thick peptidoglycan cell wall anchored by lipoteichoic acid, while Gram-negative bacteria have a thin peptidoglycan layer with an outer membrane containing lipopolysaccharides, which function as endotoxins.

Step-by-step explanation:

Characteristics of Gram-Positive and Gram-Negative Bacteria

The distinction between Gram-positive and Gram-negative bacteria is based on their cell wall composition and staining properties. Gram-positive bacteria have a thick cell wall composed primarily of peptidoglycan and substances called teichoic acids, which include lipoteichoic acids that anchor the cell wall to the cell membrane. Conversely, Gram-negative bacteria possess a relatively thin layer of peptidoglycan, and their cell wall is surrounded by an outer membrane that contains lipopolysaccharides (LPS) and lipoproteins. LPS acts as an endotoxin which can cause severe symptoms in infections. Additionally, porins are specialized proteins in the outer membrane of Gram-negative bacteria that allow substances to pass through.

Statement A is correct stating that Gram-positive bacteria have a cell wall anchored to the cell membrane by lipoteichoic acid. The other statements present inaccuracies regarding the composition and thickness of the bacterial cell walls.