Question

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.

Answer 1

Proteins that are secreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane.

Step-by-step explanation:

The correct statement that describes some aspect of protein secretion from prokaryotic cells is option C) Proteins that are secreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane.

In prokaryotes, the process of protein secretion involves partially elongated signal peptides guiding mRNA-bound ribosomes to the cytoplasmic side of the plasma membrane. The ribosomes bind and then pass elongating proteins through the plasma membrane into the space between the cell membrane and wall.

As the protein exits the cell, a bacterial signal peptidase (SPase) cleaves the signal peptide. This mechanism of protein secretion has been conserved and is also used by eukaryotes for packaging proteins into organelles and membranes.