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466 Chapter 24 CARBOHYDRATES: POLYFUNCTIONAL COMPOUNDS IN NATURE (d) An example of a "weighted average": = + where X = mole fraction for each component. Let A = pyranose and B = furanose. -92° = (0.68)( 132°) + and = -6°. 54. Reducing: (a), (b), (c), (e), (f), (h), (i), and (j). (All have hemiacetal groups.) 55. Yes. At the lower right of the formula (Section 24-11) is a hemiacetal group. H OH HO OH HO H 56. Trehalose must be (d). the only nonreducing sugar illustrated. Turanose is (c), the only one containing a ketose (the bottom half). Sophorose is (a) (top half is an anomer and bottom half is a ß anomer). Sugar (b) is composed of two aldoses that are epimers of each other at C4. 57. The structure is shown below, with the three carbohydrate units labeled. Redraw each one separately, and then rotate it such that it is presented in a more conventional view that can be compared with monosaccharides you know. A OH HO B HO OH HO 0 OH HO OH HO 0 0 C OH OH HO OH A 0 HO OH CH₂OH rotate 180° OH around horizontal axis is just B-D-glucopyranose. B HO OH HO CH₂OH rotate 120° (1/3 turn) HO OH around vertical axis OH is just again. HO OH OH is also B-D-glucopyranose. Stevioside contains three molecules of glucose in its structure.