The chloride cells of fish gills have a high density of mitochondria. How does this characteristic relate to the functional role of chloride cells? Would you expect other epithelial cells involved in ion transport to contain large numbers of mitochondria? Explain

Mitochondria provide the ATP necessary for ion transport against the gradient between sea water and the fish internal fluids

Explanation:

Other epithelial cells with similar functions such as the proximal convoluted tubule epithelium in the kidney also have a high density of mitochondria to provide ATP for ion reabsortion.