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CASE FILES: BIOCHEMISTRY
C O M P R E H E N SIO N Q U E ST IO N S
[25.1] A patient with type I diabetes mellitus has fasting and postprandial
blood glucose levels that are frequently above the normal range despite
good compliance with his insulin therapy. He was referred to a dietician
that specialized in diabetic patients. The patient was recommended to
incorporate foods high in dietary fiber. Which of the following dietary
fibers would be most helpful in maintaining a normal blood glucose
level?
A. Cellulose
B. Hemicellulose
C. Lignins
D. Pectins
[25.2] Some individuals complain of flatulence following a meal plentiful in
beans, peas, soybeans, or other leguminous plants. All legumes contain
the oligosaccharides raffinose and stachyose that contain glycosidic
linkages that are poorly hydrolyzed by intestinal enzymes but are good
sources of energy for intestinal bacteria that convert these sugars to H2.
Which of the following glycosidic bonds are contained in raffinose and
stachyose and are not hydrolyzed by our intestinal enzymes but can be
by intestinal flora?
A. Galactose (a1—6) glucose
B. Galactose (P1 —>4) glucose
C. Glucose (P1——
2) fructose
D. Glucose (a1—4) glucose
E. Glucose (P1 ——
4) glucose
[25.3] Cellulose is the most abundant polysaccharide and is an important
structural component of cell walls. Strict vegetarians consume a large
amount of cellulose, but it is not a source of energy because it is indi-
gestible by the human intestinal tract. Cellulose is indigestible because
it contains which of the following glycosidic bonds?
A. Galactose (P1 ——
4) glucose
B. Galactose (P1——
6) galactose
C. Glucose (a 1—4) glucose
D. Glucose (P1——
2) fructose
E. Glucose (P1 ——
4) glucose
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