Why Does the Fischer Projection of Glucose Show Carbon Atoms with Five Bonds?

AI Thread Summary
The discussion centers on the confusion surrounding the Fischer formula representation of D-glucose, particularly regarding the structure and bonding of carbon atoms. The main points of inquiry include the presence of five bonds on the upper carbon atoms in both the left and right formulas, and the origin of an additional hydrogen atom attached to alpha D-glucopyranose. Participants seek clarification on how the aldehyde form of glucose transitions to the beta and alpha forms of D-glucopyranose, expressing frustration with the textbook provided by their biochemistry department. The need for a detailed explanation of the Fischer formula's accuracy and the structural changes during the conversion of glucose forms is emphasized, highlighting the importance of understanding these concepts for exam preparation.
Asmaa Mohammad
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Hello,
my book shows this figure of Fischer formula of D-glucose
onrmf.jpg

I don't understand this figure, and I wonder why the upper carbon atoms in both the right and left formulas have 5 bonds.

And from where comes this hedrogen atom in the upper left side of the figure (attached to alpha, D-glucopyranose).

When turning D-glucose to Fischer formula, it seems there's an additional hydrogen atom, isn't it? Why and how this happens?!

Could some one explain for me how the aldehyde form of glucose (the middle structure) to the beta, D-Glucopyranose and the alpha, D-Glucopyranose?
 

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Burn that book!
 
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@DrDu
Why?! It's the book which the biochemistry department in my college provide, and the book I'm supposed to do my final exam according to it.
Could you please give a further explanation? And hopefully you explain for me where is the correct and wrong parts about Fischer formula of glucose!
 
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