Question

a scientist is comparing ribosomes in a prokaryotic cell and a eukaryotic cell. which is a property of the ribosomes from the eukaryotic cell only and not the prokaryotic cell?
a proteins are assembled on ribosomes.
b some of the ribosomes are attached to the cell membrane.
c some of the ribosomes are located on the endoplasmic reticulum.
d all of the ribosomes are distributed evenly throughout the cytoplasm.
e all of the ribosomes are attached to the cell membrane.

Explanation:

Prokaryotic cells have ribosomes that are free - floating in the cytoplasm. In eukaryotic cells, some ribosomes are attached to the endoplasmic reticulum (rough endoplasmic reticulum). Prokaryotic cells do not have an endoplasmic reticulum.

• Option A: Proteins are assembled on ribosomes in both prokaryotic and eukaryotic cells.
• Option B: In prokaryotic cells, ribosomes are not attached to the cell membrane in this context (they are free - floating in the cytoplasm).
• Option C: Prokaryotic cells do not have an endoplasmic reticulum, so ribosomes attached to the endoplasmic reticulum is a feature of eukaryotic cells only.
• Option D: Ribosomes are not evenly distributed throughout the cytoplasm in the sense that in eukaryotes, some are attached to the endoplasmic reticulum.
• Option E: Ribosomes are not attached to the cell membrane in the way described for eukaryotic cells (attached to endoplasmic reticulum is the relevant membrane - association for eukaryotic ribosomes in this context).

Answer:

C. Some of the ribosomes are located on the endoplasmic reticulum.