Glucose is a fancy name for a specific and common sugar (yup, everything is turned to sugar). Iron stores in the liver are great enough for most people that iron supplements are not usually needed, except in people with iron-deficiency anemia, which is the most common nutritional deficiency worldwide.
The liver also serves as the initial source of glucose when you rush the hot dog stand at half-time (even before you get there) since the sugar in your blood only provides 10 minutes of energy. It then does double-duty to break down the nitrates from that hot dog in the detox function described below.
This, by the way, is the reason why you don't burn fat immediately when you start exercising-it's because your body is using the fuel that's stored as glucose in the liver first.