Following complete hydrolysis of a sample of glycogen and a sample of cellulose,which of the following must be true?
A)The glycogen sample is more soluble than the cellulose sample.
B)The cellulose sample is more soluble than the glycogen sample.
C)Both samples consist of a mixture of $\alpha$-d-glucose and $\beta$-d-glucose.
D)The glycogen sample has a higher ratio of $\alpha$-d-glucose than the cellulose sample.
E)The cellulose sample contains only $\beta$-d-glucose.

Question

Quizplus · Accepted Answer

Both glycogen and cellulose are polysaccharides made up of glucose monomers. However, the linkages present between the glucose units are different. Glycogen has α(1-4) linkages with occasional α(1-6) branches, while cellulose has β(1-4) linkages between the glucose units.

Complete hydrolysis of glycogen and cellulose will break all the linkages between the glucose units, resulting in the formation of individual glucose molecules. Therefore, both samples will consist of a mixture of α-glucose and β-glucose molecules (F1F1F1S1αF1F1F10-d-glucose and F1F1F1S1βF1F1F10-d-glucose), which are the two anomers of glucose. Thus, choice C is the correct answer.

Solubility is not affected by the type of linkages present in the polysaccharides, so choices A and B are incorrect. The ratio of α-glucose to β-glucose in the samples cannot be determined from the information given, so choice D is incorrect. Choice E is also incorrect because cellulose consists only of β-glucose, but after complete hydrolysis, it will also yield α-glucose.

Following Complete Hydrolysis of a Sample of Glycogen and a Sample