Question

in gram-negative bacteria, transport across the outer membrane is made possible by the presence of ______.

porin proteins

brauns lipoproteins

lps

teichoic acids

Explanation:

To solve this, we analyze each option:

• Porin proteins: These are channel - like proteins in the outer membrane of Gram - negative bacteria that form pores, allowing the passage of small molecules and facilitating transport across the outer membrane.
• Braun’s lipoproteins: They function to anchor the outer membrane to the peptidoglycan layer, not for transport across the outer membrane.
• LPS (Lipopolysaccharide): It is a major component of the outer membrane, contributing to the structural integrity and pathogenicity, but not directly involved in transport.
• Teichoic acids: These are found in Gram - positive bacteria, not Gram - negative, so they are not relevant here.

Answer:

A. porin proteins