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Endoplasmic reticulum may occur with or without small particles that are the actual sites of protein synthesis. What are these particles called?
publish date: 2026/06/15 06:27:3.095052 UTC
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The endoplasmic reticulum comes in two forms: one lined with small particles (rough ER), and one without (smooth ER).
What are these small particles — the actual sites of protein synthesis — called?
Correct Answer
ribosomes
Explanation
Ribosomes are the small particles that line the rough endoplasmic reticulum and are the actual sites of protein synthesis. Besides being found on the ER, ribosomes also occur freely in the cytoplasm (free ribosomes) and can cluster into groups called polysomes or polyribosomes.
Reference
Biology: A Self-Teaching Guide