Complete Solutions
Which ONE of the following amino acids may be linked
covalently to an oligosaccharide via an O-glycosidic bond?
A. Glc
B. Tyr
C. Thr
D. Asp correct answer: C - Thr has an OH side chain
Which ONE of the following statements is CORRECT regarding
the role of thermodynamics in glycolysis?
A. It is spontaneous in the forward direction due to the cleavage
of glucose into 2 molecules.
B. ATP is required as the pathways is unfavourable under
standard conditions.
C. Thermodynamically favourable reactions are the regulated
steps in the pathway.
D. Free energy is only released under cellular conditions. correct
answer: C
A - it is spontaneous but NOT due to cleavage of glucose
B - ATP is required but the pathway IS favorable under std
conditions
D - free E is also released under std conditions
Which ONE of the following statements is CORRECT regarding
the following molecule?
,A. It is a reducing sugar in H2O.
B. It contains 2 furanose rings.
C. It is a homodisaccharide.
D. It obeys the molecular formula (CH2O)n correct answer: A -
hydroxyl on anomeric C of mono on the right can open up to a
linear chain + be oxidized to reduce CU2+
B - it contains ONE furanose ring
C - HETEROdisaccharide
D - nope, its no longer a simple MONOsaccharide
Which ONE of the following statements is CORRECT regarding
disaccharides?
A. They can be homodimers or heterodimers.
B. They are always connected by their anomeric carbons.
C. Water is required for glycosidic bond formation.
D. They obey the formula (C*H2O)n correct answer: A -
homodimer ex: maltose (2 glucoses), heterodimer ex: lactose
(glucose + galactose)
B - nope, 1,4 linear and 1,6 branching bonds exist
C - water is RELEASED when glycosidic bond forms
(condensation rxn)
D - nope, not simple monosaccharides
Which ONE of the following statements is CORRECT regarding
the breakdown of dietary carbohydrates in humans?
, A. When glycogen is broken down, glucose is removed from the
reducing ends.
B. Only homopolymers can be used for energy.
C. Hydrolases are enzymes that cleave O-glycosidic bonds.
D. Cellulose can be used as a source of free glucose correct
answer: C - uses H2O to cleave bonds
A - NON-reducing end
B - nope, heteropolymers like lactose/sucrose can also be used
in glycolysis (after being broken down to monos)
D- not in humans, because we dont have enzymes specific for b-
1,4 glycosidic bonds
Which ONE of the following enzymes is stimulated by
phosphorylation following epinephrine signalling?
A. Pyruvate kinase
B. Phosphoglucomutase
C. Phosphofructokinase 1
D. Glycogen phosphorylase correct answer: D - by PKA, starts
glycogen phosphorolysis by removing glucose from non-
reducing ends + transferring a P onto glucose to form G1P
A - INactivated
B + C - not phosphorylated by epinephrine signalling
Which ONE of the following is CORRECT regarding a pair of
epimers?
A. Mutarotation allows for their interconversion.