Which one of the following structures is an organelle within an organelle?
Which one of the following structures is an organelle within an organelle?
Ribosome
Peroxisome
$\mathrm{ER}$
Mesosome
Solution
Ribosomes are smallest known electron microscopic ribonucleoprotein particles attached either to endoplasmic reticulum, floating free in cytoplasm and also found in mitochondria and chloroplast (these are called organeller ribosomes). These are site of protein synthesis.