Glucose. Polarised light micrograph of glucose crystals. Glucose is a monosaccharide sugar, widely occurring in nature. It is vital for the energy metabolism of living organisms, being transported in humans by blood, lymph and cerebro- spinal fluid to cells where the energy is released by the process of glycolysis. Glucose is found in the sap of plants, in fruits and in honey. It may also be produced by the digestion of starch. Magnification: x8 at 35mm size.