Question

A cell of which of the following genera has an outer membrane composed of unusual lipids that are not found in other genera of bacteria?

Group of answer choices

Staphylococcus

Streptococcus

Streptomyces

Mycobacterium

Lactobacillus

Answer 1

Mycobacterium is a genera of bacterial pathogen responsible for the disease tuberculosis which kills millions of humans every year. They are naturally resistant to commonly used antibiotics, presumably because the cell interior is well protected by the presence of the lipid-rich cell wall, which is thought to exist as a membrane, or the outer membrane. Mycobacterium species, including the human pathogen Mycobacterium tuberculosis, are unique among Gram-positive bacteria in producing a complex cell wall that contains unusual lipids and functions as a permeability barrier. These unusual lipids help the pathogen from the antibiotics.

So, Mycobacterium is the correct answer.

Staphylococcus, Streptococcus, Streptomyces, Lactobacillus all are gram-positive bacteria with a thick cell wall made up of several layers of peptidoglycans but their cell wall lack these unusual lipids.