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26 Cards in this Set

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1.) Which of the following monosaccharides is not an aldose?
A) erythrose
B) glucose
C) fructose
D) glyceraldehyde
E) ribose
C) fructose
When two carbohydrates are epimers:
A) one is a pyranose, the other a furanose.
B) one is an aldose, the other a ketose.
C) they differ in length by one carbon.
D) they rotate plane-polarized light in the same direction.
E) they differ only in the configuration around one carbon atom.
E) they differ only in the configuration around one carbon atom.
Which of the following is an epimeric pair?
A) D-glucose and D-glucosamine
B) D-glucose and D-mannose
C) D-glucose and L-glucose
D) D-lactose and D-sucrose
E) L-mannose and L-fructose
B) D-glucose and D-mannose
4.) Which of the following pairs is interconverted in the process of mutarotation?
A) D-glucose and D-fructose
B) D-glucose and D-galactose
C) α-D-glucose and β-D-glucosamine
D) D-glucose and L-glucose
Ε) α-D-glucose and β-D-glucose
Ε) α-D-glucose and β-D-glucose
5.) Which of the following is not a reducing sugar?
A) Fructose
B) Glucose
C) Ribose
D) Sucrose
E) Glyceraldehyde
D) Sucrose
Which of the following statements about starch and glycogen is false?
A) Amylose is unbranched; amylopectin and glycogen contain (α1- 6) branches.
B) Both are homopolymers of glucose.
C) Both serve primarily as structural elements in cell walls.
D) Both starch and glycogen are stored intracellularly as insoluble granules.
E) Glycogen is more extensively branched than starch.
C) Both serve primarily as structural elements in cell walls.
In the favored chair form of beta-D-glucopyranose which of the following is true.
A) All the hydroxyl groups are in the equatorial position and all the hydrogens are in the axial position
B) All the hydrogen atoms are in the equatorial position and all the hydroxyl groups are in the axial position
C) The anomeric hydrogen is always equatorial
D) The hydroxyl group of carbon 6 is also close to the pyranose Oxygen
E) None of the above is true.
A) All the hydroxyl groups are in the equatorial position and all the hydrogens are in the axial position
9.) D-Glucose is called a reducing sugar because it undergoes an oxidation-reduction reaction at the anomeric carbon. One of the products of this reaction is:
A) D-galactose.
B) D-gluconate.
C) D-glucuronate.
D) D-ribose.
E) muramic acid.
2
B) D-gluconate.
When a mixture of glucose 6-phosphate and fructose 6-phosphate is incubated with the enzyme phosphohexoseisomerase (which catalyzes the interconversion of these two compounds) until equilibrium is reached, the final mixture contains twice as much glucose 6-phosphate as fructose 6-phosphate. Which one of the following statements is best applied to this reaction outlined below? (R = 8.315 J/mol·K; T = 298 K)
Glucose 6-phosphate ←→ fructose 6-phosphate
A) ΔG'° is incalculably large and negative.
B) ΔG'° is –1.72 kJ/mol.
C) ΔG'° is zero.
D) ΔG'° is +1.72 kJ/mol
E) ΔG'° is incalculably large and positive.
D) ΔG'° is +1.72 kJ/mol.
The standard free-energy changes for the reactions below are given.
Phosphocreatine → creatine + Pi ΔG'° = –43.0 kJ/mol
ATP → ADP + Pi ΔG'° = –30.5 kJ/mol
What is the overall ΔG'° for the following reaction?
Phosphocreatine + ADP → creatine + ATP
A) –73.5 kJ/mol
B) –12.5 kJ/mol
C) +12.5 kJ/mol
D) +73.5 kJ/mol
E) ΔG'° cannot be calculated without Keq'.
B) –12.5 kJ/mol
Which one of the following compounds does not have a large negative free energy of hydrolysis?
A) 1,3-bis phosphoglycerate
B) ADP
C) Phosphoenolpyruvate
D) Thioesters (e.g. acetyl-CoA)
E) 3-phosphoglycerate
E) 3-phosphoglycerate
The anaerobic conversion of 1 mol of glucose to 2 mol of lactate by fermentation is accompanied by a net gain of:
A) 1 mol of ATP.
B) 1 mol of NADH.
C) 2 mol of ATP.
D) 2 mol of NADH.
E) none of the above.
C) 2 mol of ATP.
If glucose labeled with 14C in C-1 were fed to yeast carrying out the ethanol fermentation, where would the 14C label be in the products?
A) In C-2 (methyl group) of ethanol only
B) In C-1 of ethanol and CO2
C) In C-1 of ethanol only
D) In C-2 of ethanol and CO2
E) In CO2 only
A) In C-2 (methyl group) of ethanol only
The catalytic mechanism of the phosphoglucoseisomerase involves the following enzyme-linked (not covalent) intermediate. What is the intermediate-type?
A) Schiff base
B) thiohemiacetal
C) cis-enediolate
D) trans-enediolate
E) tetrahedral intermediate
C) cis-enediolate
Which statement is true.The glyceraldehyde 3-P dehydrogenase reaction
A) involves formation of a thiohemiacetal that is converted to a thioester.
B) uses ATP as one of its substrates
C) is a highly exergonic reaction
D) is a highly regulated enzyme step in glycolysis
E) is inhibited by citrate
A) involves formation of a thiohemiacetal that is converted to a thioester.
The hydrolysis of phosphoenolpyruvate proceeds with aΔG'° of about –62 kJ/mol. The greatest contributing factors to this reaction are the destabilization of the reactants by electostatic repulsion and stabilization of the product pyruvate by:
A) electrostatic attraction.
B) ionization.
C) polarization.
D) resonance.
E) tautomerization.
E) tautomerization.
In liver, fructose metabolism is initiated with the formation
A) of fructose-6-P and then formation of fructose 1,6-bis-P.
B) of fructose -1-P and then formation of fructose 1,6-bis-P
C) of fructose-6-P and then cleavage to glyceraldehyde-3-P and dihydroxyacetone
D) of fructose-1-P and then cleavage to dihydroxyacetone -P and glyceraldehyde
E) of fructose-6-P and then conversion to glucose-6-P which is metabolized
D) of fructose-1-P and then cleavage to dihydroxyacetone -P and glyceraldehyde
Galactosemia is usually a genetic error of metabolism associated with:
A) deficiency of UDP-glucose: galactose 1-phosphate uridylyltransferase
B) deficiency of galactokinase.
C) deficiency of UDP-glucose.
D) excessive ingestion of galactose.
E) inability to digest lactose.
A) deficiency of UDP-glucose: galactose 1-phosphate uridylyltransferase
In the alcoholic fermentation of glucose by yeast, thiamine pyrophosphate is a
coenzyme required by:
A) aldolase
B) pyruvate decarboxylase
C) hexokinase
D) lactate dehydrogenase
E) transaldolase
B) pyruvate decarboxylase
Which glycolytic enzyme has a Phopsphohistidine residue that is important for its catalytic activity?
A) Phospho-glyceraldehyde dehydrogenase
B) Aldolase
C) Triose-P isomerase
D) Phospho-glyceromutase
E) Phospho-hexoseisomerase
D) Phospho-glyceromutase
In liver, fructose metabolism is initiated with the formation
A. of fructose-6-P and then cleavage to glyceraldehyde-3-P
and dihydroxyacetone
B. of fructose-1-P and then formation of fructose-1,6-bis-P
C. of fructose-6-P and then conversion to glucose-6-P
which is metabolized
D. of fructose-6-P and then formation of fructose-1,6-bis-P.
E. of fructose-1-P and then cleavage to dihydroxyacetone-
P and glyceraldehyde
answer
Galactosemia is usually a genetic error of metabolism associated with:
A. excessive ingestion of glucose
B. inability to digest lactose
C. de ciency of galactokinase
D. de ciency of UDP-glucose:galactose-1-phosphate uridylyltransferase
E. de ciency of UDP-glucose
answer
In the alcoholic fermentation of glucose by yeast, thiamine
pyrophosphate is a coenzyme required by
A. pyruvate decarboxylase
B. aldolase
C. lactate dehydrogenase
D. transaldolase
E. hexokinase
answer
Which glycolytic enzyme has a phosphohistidine residue that
is important for its cataytic activity?
A. triose-P isomerase
B. phospho-hexoseisomerase
C. aldolase
D. phosphoglyceraldehyde dehydrogenase
E. phosphoglyceromutase
answer
In the list of enzymes below, three enzymes are essential and unique for gluconeogenesis. Starting with pyruvate as your
substrate, list those unique enzymes in the sequence of their conversion from pyruvate to glucose. Thus, the rst unique
reaction of pyruvate in gluconeogenesis should be catalyzed by [enzyme #1], the next unique reaction needed for gluconeogenesis
should be catalyzed by [enzyme #2], and the
subsequent unique reaction catalyzed by a gluconeogenic enzyme
should be listed for [enzyme #3].
A fructose-1,6-bisphosphatase
B phosphoglyceromutase
C phosphofructokinase 1
D glyceraldehyde-3-P dehydrogenase
E lactate dehydrogenase
F hexokinase
G PEP carboxykinase
H enolase
I phosphoglucoseisomerase
J pyruvate carboxylase
K None of the above

- Enzyme #3
- Enzyme #2
- Enzyme #1
answer
Below is a scheme of the glycolytic pathway. The numbers indicate the various enzyme-catalyzed reactions. Please identify the names of the enzymes listed in the question by number
{for instance, what number is the phosphoglyceromutase
reaction? The metabolite structures are indicated by letters.

Please identify the metabolites listed in the question by letter
{ for example, what metabolite is letter B?
Choices: A, B, C, D.

A. pyruvate kinase
B. phosphofructokinase I
C. aldolase
D. 3-phosphoglycerate
E. fructose-6-P
F. 3-phosphoglycerate kinase
G. glyceraldehyde-3-P
H. hexokinase
I. 2-phosphoglycerate
J. fructose-1,6-bisphosphate
K. phospho-enol pyruvate
L. enolase
M. phosphohexoseisomerase
N. 1,3-bisphosphoglycerate
O. dihydroxyacetone-phosphate
P. glucose-6-P
Q. triose phosphate isomerase
R. glyceraldehyde-3-P dehydrogenase
S. pyruvate
T. phosphoglyceromutase
answer