Glucose has the chemical formula `C_6H_12O_6` and is a 6-carbon sugar. Each of these carbon atoms are connected to an oxygen atom and a hydrogen atom. However, 5 of these carbon atoms are connected to hydroxyl group or OH-. Also, these 5 carbon atoms are part of a ring structure, while the sixth carbon atom has a double bond with oxygen atom. This structure is true for all the configurations of glucose molecules, including alpha and beta glucose. Such a configuration also plays an important role in polymerization of monomers such as glucose.
Glucose is the molecule generated during photosynthesis by green plants (containing chlorophyll) and is the basic food material which is later used on during cellular respiration to generate energy rich ATP (or adenosine triphosphate) molecules in all life forms.
Hope this helps.