Which of the following statements correctly describes some aspect of protein secretion from prokaryotic cells?
A) Prokaryotes are unlikely to be able to secrete proteins because they lack an endomembrane system.
B) The mechanism of protein secretion in prokaryotes is probably the same as that in eukaryotes.
C) Proteins that are secreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane.
D) In prokaryotes, the ribosomes that are used for the synthesis of secreted proteins are located outside of the cell.
E) Prokaryotes contain large pores in their plasma membrane that permit the movement of proteins out of the cell.

Question

Quizplus · Accepted Answer

Prokaryotes lack an endomembrane system, but they still have the ability to secrete proteins. Secreted proteins in prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane.

Answer: B
 The mechanism of protein secretion in prokaryotes is not identical to that in eukaryotes, but there are some similarities. For example, both prokaryotes and eukaryotes use signal sequences to direct proteins to their appropriate location.

Answer: D
 Ribosomes that are used for the synthesis of secreted proteins in prokaryotes are located in the cytoplasm. However, some prokaryotes have specialized structures (such as the type III secretion system) that allow them to secrete proteins directly from the cytoplasm into other cells or the external environment.

Answer: E
 Prokaryotes do not have large pores in their plasma membrane. However, some bacteria have specialized structures (such as pili) that allow them to transport proteins across the membrane and into other cells.

Which of the Following Statements Correctly Describes Some Aspect of Protein