Ringed sideroblasts are a reflection of iron-laden:

a. Mitochondria
b. Golgi complex
c. Ribosomes
d. Rough endoplasmic reticulum

ANS: A
In the sideroblastic anemias, where ringed sideroblasts are present, plenty of iron is available to developing red cells. However, for one reason or another, the iron cannot be inserted into the protoporphyrin IX ring. Because this is the last step in heme synthesis, and it takes place in the mitochondria, the mitochondria become laden with iron. When these cells are stained with Prussian blue, the iron stains; mitochondria encircle the nucleus of the cell, so that what is seen is a "ring" of stained iron granules encircling the nucleus (hence called a ringed sideroblast).