Glycosidic Bonding of Glucose through a Dehydration reaction.

Question

I am taking an honors biology class at my local college and was wondering if anyone could put some light on this topic.

The question was asked: "If 10 glucose (C6H12O6) molecules were linked together by dehydration reactions, what would the chemical formula of the resulting polymer be?"

I first thought they would form a straight chain, with nine bonds, thus resulting in C60H102O51 (Because you would lose 18 H atoms and 9O atoms due to the nine dehydration reactions), however, referencing the back of the book, the answer is C60H100O50, meaning that 10 dehydration reactions have occurred. When this polymer forms, do the glucose rings all form a much larger ring, with the initial molecule bonding with the last one of the "chain"?

Thank you for your time,

Cheers,

Neonomical65

Answer 1

You are correct if the question does not state whether the glucose is beta or alpha glucose, or the structure of the polysaccharide.

Answer 2

Paul B is correct...text books often have mistakes that are perpetuated over several editions. My students and I do proofing of that sort of event on a rather constant basis . You are correct given the conditions you stated above

Answer 3

I think you are right and the book is wrong, unless you are supposed to assume (and you are not told this) that the polymer is cyclic.

It does happen, even in the best textbooks