Write a brief note on the structure of glucose

Molecular formula of Glucose is ${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6$ Glucose has two kinds of structures i.e., open chain, cyclic structures.
 Evidences in favour of open chain structure :

S.No.	Reaction	Reagent	Product	Conclusion
1)	Acetylation	${\mathrm{Ac}}_2\mathrm{O}/\mathrm{AcOH}$	Penta acetate	Presence of 5–OH groups
2)	With Hydroxyl amine	NH2OH	Oxime	Presence of
3)	Mild oxidation	Br2/ H2O or Gluconic acid Presence of –CHO Tollens reagent or Fehling's sol.	Gluconic acid	Presence of –CHO
4)	Strong oxidation	Conc.HNO3	Saccharic acid	Presence of –CH2OH
5)	Reduction	HI/Red 'P'	n-Hexane	Presence of six carbons in a straight chain

Points in favour of cyclic structure:
1) It doesn't react with schiff's base, ${\mathrm{NH}}_3\&{\mathrm{NaHSO}}_3$
2) It forms two isomeric glucosides
3) It exhibits mutarotation
Conclusions : From all above points and based on other reactions, it is known that glucose in water exist as a mixture of open chain & ring structures in equilibrium i.e.,


Open chain and cyclic structures of $\mathrm{\alpha }$ –D–(+)– glucose :