Why Glycogen?

Notes

Osmotic Pressure

The reason why glucose gets stored as glycogen (one large molecule of glucose) rather than staying as a bunch of glucose molecules comes down to osmotic pressure. 

If there are 55,000 glucose molecules creating tons of osmotic pressure in the cell, water wants to rush in to even out the concentration, which will cause the cell to burst. If instead, all of the glucose molecules were bound together to make only one molecule, then inside of the cell will have only 1 osmotic particle. This does not have a large driving force to push water inside to even out the concentration, which makes it safer for the cell. 

The body can now store large amounts of glucose without affecting the osmotic pressure!