Which of the Following Prokaryotic Cells Contain an Outer Membrane

Question

Which of the following prokaryotic cells contain an outer membrane?
A) Gram-negative bacteria only
B) Gram-positive bacteria only
C) both Gram-positive and Gram-negative bacteria
D) archaea
E) all prokaryotes

Accepted Answer

Gram-negative bacteria are the only prokaryotes that contain an outer membrane. Gram-positive bacteria have a thick peptidoglycan layer but lack an outer membrane. Archaea have unique cell wall structures that are different from bacteria and do not contain an outer membrane. Therefore, option E, "all prokaryotes," is incorrect.