One feature is its compact shape. Starch molecules consists of two components: Amylose and Amylopectin. Amylose is the straight chained part and amylopectin is the branch chained part. Both these structures enable the starch molecule to coil into a compact shape so that it takes the least possible space and is ideal for storage. Another feature is its capacity of easy conversion. Starch molecules can be easily converted back to glucose molecules for use in respiration when it is needed. Also starch is generally insoluble so when it is stored it does not affect the osmotic balance of the cell.