Prometaphase and Metaphase

During prometaphase the nuclear envelope breaks down, allowing the kinetochore microtubules in the spindle to attach to the chromosomes. Note the absence of staining and irregular border around the chromosomes, an indication that the nuclear envelope is absent. During metaphase the chromosomes are aligned at the equator of the cell midway between the centrosomes. Kinetochore microtubules from both centrosomes have attached to the chromosomes, linking the sister chromatids to opposite poles of the spindle.

Answer: The gonads would be expected to have lots of SER because of their production of estrogen, progesterone, and testosterone.