Biochemistry Exam 3 Study Guide

Complete the sentence. Glucose and Galactose are my epimers because
A) glucose is a pyranose and galactose is a furanose
B) glucose is an aldose and galactose is a ketose
C) glucose and galactose differ in length by one carbon
D) glucose and galactose differ only in the configuration around one carbon

Complete the sentence. Glucose and Galactose are my epimers because
A) glucose is a pyranose and galactose is a furanose
B) glucose is an aldose and galactose is a ketose
C) glucose and galactose differ in length by one carbon
D) glucose and galactose differ only in the configuration around one carbon

D) glucose and galactose differ only in the configuration around one carbon

What type of bond links the monomers of a polysaccharide?
A) glucotide bond
B) phosphate ester bond
C) peptide bond
D) glycosidic bond

D) glycosidic bond

Which of the following is a heteropolysaccharide?
A) glycogen
B) hyaluronate
C) chitin
D) cellulose

B) hyaluronate

A branched polymer of glucose with a α-(1-6) linkages is
A) amylose
B) chitin
C) amylopectin
D) trehalose

C) amylopectin

Which of the following best describes cellulose?
A) N-acetylglucosamine polymer with α-(1-4) linkages and α (1-6) branches
B) Glucose polymer with β (1-6) branches
C) A disaccharide containing trehalose and lactose connected by a β (1-3) bond
D) Glucose polymer with β (1-4) linkages

D) Glucose polymer with β (1-4) linkages

A storage polysaccharide of plants is
A) starch
B) chitin
C) amylopectin
D) glycogen

A) starch

Which statement is most likely correct with respect to disaccharide?
A) The molecular formula of lactose is C12H22O11
B) More ATP molecules are produced from metabolism of sucrose compared to lactose
C) Humans can't metabolize lactose due to the β glycosidic bond
D) Catabolism of lactose will produce two molecules of glucose 1-phosphate

A) The molecular formula of lactose is C12H22O11

Which of the following is true about chitin, found in insect and crustacean shells?
A) It is a homopolysaccharide composed of N-acetylglucosamine subunits
B) It is a heteropolysaccharide composed of alternating glucose and galactose subunits
C) It contains a dipeptide with two alanine amino acids
D) It contains α (1→4) and α (1→6) branches

A) It is a homopolysaccharide composed of N-acetylglucosamine subunits

Which of the following statements about starch and glycogen is TRUE?
A) Starch contains more branches than glycogen
B) Both are homopolymers of sucrose
C) Glycogen and starch catabolism both require the enzyme phosphoglucomutase
D) Starch is stored in muscle cells while glycogen is stored in liver cells

C) Glycogen and starch catabolism both require the enzyme phosphoglucomutase

A molecule that mediates the immune response to injury is
A) Chitin
B) Lectin
C) Proteoglycan
D) Amylase

B) Lectin

Which of the following amino acid residues is a point of oligosaccharide attachment in glycoproteins?
A) T
B) G
C) W
D) Q

A) T

The biochemical property of glycosaminoglycans that confers their biological effects is their ability to bind to
A) specific oligosaccharides on immune cells
B) water
C) glycosphingolipids on the surface of red blood cells
D) insulin

B) water

Which of the following enzymes is not utilized for the catabolism of sucrose?
A) phophoglucomutase
B) sucrase
C) fructokinase
D) triose kinase

A) phophoglucomutase

The sugar D-ribose is a
A) triose
B) tetrose
C) hexose
D) pentose

D) pentose

Lactose (milk sugar) is a disaccharide made up of which monosaccharides?
A) galactose and glucose
B) two glucose molecules
C) fructose and glucose
D) galactose and fructose

A) galactose and glucose

Which of the following is true about glycogen metabolism?
A) Phosphorolysis produces glucose 1-phosphate
B) Removal of the glucose at the branch point of glycogen produces glucose 6-phosphate
C) Mammals utilize glycogen as a means of excreting unwanted glucose
D) Removal of one glucose from glycogen and conversion to glucose 6-phosphate requires ATP hydrolysis

A) Phosphorolysis produces glucose 1-phosphate

Energy-rich compounds such as ATP, NADH, FADH2 are generated by which process?
A) catabolism
B) glycogen synthesis
C) anabolism
D) gluconeogenesis

A) catabolism

The free energy change for a pathway that consists of a series of 5 reactions
A) is equal to the sum of the free energy changes of the component reactions
B) is equal to the free energy change for the most favorable reactions of the series
C) is equal to the free energy change for the least favorable reaction of the series
D) is always negative

A) is equal to the sum of the free energy changes of the component reactions

Which of the following molecules is produced by cellular catabolism?
A) Proteins
B) Carbon Dioxide (CO2)
C) Adenosine diphosphate (ADP)
D) Oxidized form of nicotinamide adenine dinucleotide (NAD+)

B) Carbon Dioxide (CO2)

The coenzyme nicotinamide adenine dinucleotide, oxidized form, NAD+
A) accepts a proton and one electron
B) donates a proton and two electrons
C) accepts one proton and two electrons
D) accepts two protons and two electrons

C) accepts one proton and two electrons

The coenzyme flavin adenine dinucleotide, fully oxidized form, FAD
A) can accept two protons and one electron
B) can donate a proton and two electrons
C) can accept one proton and two electrons
D) can accept two protons and two electrons

D) can accept two protons and two electrons

The free energy of a favorable reaction can be used to make an unfavorable reaction happen. For conversion of glucose 1-phosphate to glucose 6-phosphate the standard free energy change (∆G°') is equal to -7.3 kJ/mol. For conversion of glucose 6-phosphate to fructose 6-phosphate ∆G°' = +1.7 kJ/mol. For the overall conversion of glucose 1-phosphate to fructose 6-phosphate which of the following statements is true?
A) (∆G°') = +5.6 kJ/mol and the reaction is thermodynamically favorable
B)

C) The thermodynamically favorable reaction glucose 1-phosphate → glucose 6-phosphate makes the conversion of glucose 1-phosphate → fructose 6-phosphate thermodynamically favorable

In a human erythrocyte, what is the approximate actual free energy of hydrolysis of ATP due to the following concentrations of reactants and products? Note: for ATP → ADP + Pi
R = 8.315 J/mol*K T = 37 °C ∆G°' = -30.5 kJ/mol
[ATP] = 2.0 mM [ADP] = 0.5 mM [Pi] = 2.0 mM
A) -32 kJ/mol
B) +11 kJ/mol
C) -11 kJ/mol
D) -50 kJ/mol

D) -50 kJ/mol

Which statement is most likely correct with respect to nicotinamide coenzymes in a human cell?
A) NADH commonly serves as an electron acceptor in catabolic pathways
B) NADH commonly serves as a proton acceptor in anabolic pathways
C) NADH commonly serves as a proton donor in catabolic pathways
D) NADH commonly serves as an electron donor in anabolic pathways

D) NADH commonly serves as an electron donor in anabolic pathways

In the conversion of one molecule of glucose to 1,3-bisphosphoglycerate, how many molecules of ATP are consumed?
A) No ATP are consumed, 2 molecules of ATP are produced
B) 1
C) 2
D) 4

C) 2

Which of the following reactions of glycolysis is near equilibrium?
A) glucose 6-phosphate → fructose 6-phosphate
B) fructose 6-phosphate → fructose 1,6-bisphosphate
C) glucose → glucose 6-phosphate
D) phosphoenolpyruvate → pyruvate

A) glucose 6-phosphate → fructose 6-phosphate

Complete the following sentence by filling in the blanks. In the removal of three glucose molecules from the linear portion of glycogen and conversion of those three glucose molecules to pyruvate, _____ molecules of ATP (net molecules) and ____ molecules of NADH are produced.
A) 6, 6
B) 6, 3
C) 9, 6
D) 4, 2

C) 9, 6

Which of the following molecules, in high concentration, activates the glycolytic enzyme phosphofructokinase-1?
A) pyruvate
B) ATP
C) AMP
D) 2,3-bisphosphoglycerate

C) AMP

The pentose phosphate pathway produces what energy-rich molecule?
A) NADPH
B) NAD+
C) O2
D) ATP

A) NADPH

What are the enzymes of gluconeogenesis that bypass irreversible steps of glycolysis?
A) hexokinase, phosphofructokinase, phosphoglycerate kinase
B) phosphofructokinase, pyruvate phosphatase, glucose decarboxylase
C) pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, glucose 6-phophatase
D) pyruvate kinase, phosphoenolpyruvate dehydrogenase, fructose 6-phosphatase, glucose 6-kinase

C) pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, glucose 6-phophatase

Which of the following pathway(s) in the liver is/are stimulated by glucagon?
A) gluconeogenesis
B) glycogen synthesis
C) glycolysis
D) all of the above

A) gluconeogenesis

An increase in the concentration of which of the following molecules would increase the rate of gluconeogenesis?
A) glucose
B) fructose 2,6-bisphosphate
C) cAMP
D) glycogen

C) cAMP

If a person look a medicine that had the side effect of inhibiting the catalytic activity of pyruvate carboxylase, what is the likely effect on the person's blood glucose levels?
A) In the fed state there would be little to no effect on the blood glucose levels
B) In the fasting state the blood glucose levels would rise
C) In the fasting state there would be little to no effect on the blood glucose levels
D) The blood glucose levels would be high in both the fed and fasting states

A) In the fed state there would be little to no effect on the blood glucose levels

Describe the symptoms you would NOT expect to find in someone with a liver glycogen synthase deficiency?
A) The person would have high blood glucose levels in the fed state
B) The person would have low glycogen levels in the liver
C) The person would have low blood glucose levels in the pasting state
D) The person would have low levels of ATP in liver cells in the fed state

D) The person would have low levels of ATP in liver cells in the fed state

Which clinical symptoms would you NOT expect to find in someone with a liver glycogen synthase kinase deficiency?
A) Low blood glucose levels between meals
B) Fatigue soon after starting exercise
C) Enlarged liver (hepatosplenomegaly) due to excess glycogen synthesis
D) Abnormally high blood glucose levels in the fed state

D) Abnormally high blood glucose levels in the fed state

Which biochemical effect would you expect to find in someone with a liver protein kinase A deficiency?
A) Abnormally high blood glucose in the fed state
B) Low blood glucose in the fasting state
C) Glycogen degradation would occur when insulin is in the bloodstream
D) Lower than normal rate of glycolysis in the fasting state

B) Low blood glucose in the fasting state

Which statement is not true about catabolic pathways?
A) They have a net consumption ATP
B) They have a net release of energy
C) They liberate smaller molecules from larger ones
D) They are regulated

A) They have a net consumption of ATP

The conversion of glucose-1-phosphate to glucose-6-phosphate by the enzyme phosphoglucomutase has a ∆G°' of -7.5 kJ/mol; calculate the Keq for this reaction at 298 K if R = 8.315 J/K*mol
A) 0.003
B) 0.047
C) 1.00
D) 21

D) 21

Which of the following is the approximate molecular weight of an amylose molecule containing 10 glucose residues?
A) 1802 g/mol
B) 1621 g/mol
C) 1649 g/mol
D) 1638 g/mol

D) 1638 g/mol

Which of the following monosaccharides is a ketose?
A) mannose
B) glucose
C) fructose
D) glyceraldehyde
E) ribose

C) Fructose

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) D-glucose and D-glucosamine
D) α-D-glucose and β-D-glucose
E) D-glucose and L-glucose

D) α-D-glucose and β-D-glucose

A storage polysaccharide of plants is:
A) amylase
B) chitin
C) amylopectin
D) glycogen
E) hyaluronate

C) amylopectin

Starch and glycogen are both polymers of:
A) fructose
B) glucose 1-phosphate
C) sucrose
D) β-D-glucose
E) α-D-glucose

E) α-D-glucose

Which of the following amino acid residues is a point of oligosaccharide attachment in glycoproteins?
A) T
B) G
C) W
D) Q
E) H

A) T

Biological oxidation-reduction reactions involve:
A) hydration of CO2
B) formation of water
C) mitochondria
D) formation of H2
E) transfer of electron(s)

E) transfer of electron(s)

Which of the following reactions in glycolysis produces ATP as a product?
A) hexokinase
B) glyceraldehyde 3-phosphate dehydrogenase
C) pyruvate kinase
D) aldolase
E) phosphofructokinase-1

C) pyruvate kinase

Which of the following statements about starch and glycogen are FALSE?
A) Amylase is unbleached; amylopectin and glycogen contain many (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.

Which of the following best describes cellulose?
A) N-acetylglucoseamine polymer with (α1→4) linkages and (α1→6) branches.
B) Glucose polymer with (β1→6) branches.
C) A disaccharide containing trehalose and lactose connected by a (β1→3) bond.
D) Glucose polymer with (β1→4) linkages.
E) Epimer of amylopectin.

D) Glucose polymer with (β1→4) linkages.

Which of the following is correct with respect to chitin?
A) It is a homopolysaccharide composed of N-acetylglucoseamine subunits.
B) It is a heteropolysaccharide composed of alternating glucose and galactose subunits.
C) It contains a dipeptide with two alanine amino acids.
D) It contains (α1→4) linkages and (α1→6) branches.
E) It is a monosaccharide found in insect and crustacean blood.

A) It is a homopolysaccharide composed of N-acetylglucoseamine subunits.

The basic structure of a proteoglycan consists of a core protein and a:
A) glycolipid
B) lipopolysaccharide
C) glycoseaminoglycan
D) lectin
E) peptidoglycan

C) glycoseaminoglycan

Which statement is incorrect with respect to catabolic pathways?
A) They have a net consumption of ATP
B) They have a net release of energy
C) They liberate smaller molecules from larger ones
D) They are regulated
E) They typically occur in the nucleus of a mammalian cell

E) They typically occur in the nucleus of a mammalian cell

The reaction A+B→C has a ΔG'° of -20 kJ/mol at 25°C. Starting under standard conditions, one can predict that:
A) at equilibrium, the concentration of B will exceed the concentration of A.
B) at equilibrium, the concentration of C will be less than the concentration of A.
C) at equilibrium, the concentration of C will be much greater than the concentration of A or B.
D) C will rapidly break down to A+B.
E) when A and B are mixed, the reaction will proceed rapidly toward formation of C.

C) at equilibrium, the concentration of C will be much greater than the concentration of A or B.

For the reaction A→B, the Keq' is 104. IF a reaction mixture originally contains 1 mol of A and no B, which one of the following is most likely true?
A) At equilibrium, there will be far more B than A.
B) The rate of the reaction is very slow.
C) The reaction requires coupling to an exergonic reaction in order to proceed.
D) The reaction will proceed toward B at a very high rate.
E) ΔG'° for the reaction will be large and positive.

A) At equilibrium, there will be far more B than A.

During sugar metabolism, glucose 1-phosphate is converted to fructose 6-phosphate in two successive reactions:
Glucose 1-phosphate → glucose 6-phosphate ΔG'° = -7.1 kJ/mol
Glucose 6-phosphate → fructose 6-phosphate ΔG'° = +1.7 kJ/mol
ΔG'° for the overall reaction is:
A) -8.8 kJ/mol
B) -7.1 kJ/mol
C) +5.4 kJ/mol
D) -5.4 kJ/mol
E) +8.8 kJ/mol

D) -5.4 kJ/mol

Which of the following enzymes in glycolysis requires ATP as a substrate?
A) hexokinase
B) glyceraldehyde 3-phosphate dehydrogenase
C) pyruvate kinase
D) aldolase
E) phosphoglycerate kinase

A) hexokinase

Which of the following enzymes in glycolysis interconverts an aldose and a ketose?
A) enolase
B) phosphohexose isomerase
C) phosphoglycerate mutase
D) aldolase
E) glyceraldehyde 3-phosphate dehydrogenase

B) phosphohexose isomerase

Which of the following is a cofactor in the reaction catalyzed by glyceraldehyde 3-phosphate dehydrogenase?
A) ATP
B) Cu2+
C) heme
D) NAD+
E) NADP+

D) NAD+

In the phosphoglycerate mutate reaction, the side chain of which amino acid in the enzyme is transiently phosphorylated and a part of the reaction?
A) S
B) T
C) Y
D) H
E) R

D) H

Inorganic fluoride inhibits enolase. In an anaerobic system that is metabolizing glucose as a substrate, which of the following compounds would you expect to increase in concentration following the addition of inorganic fluoride?
A) 2-phosphoglycerate
B) glucose
C) glyoxylate
D) phosphoenolpyruvate
E) pyruvate

A) 2-phosphoglycerate

The steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate involve all of the following except:
A) ATP synthesis
B) catalysis of phosphoglycerate kinase
C) oxidation of NADH to NAD+
D) the formation of 1,3-bisphosphoglycerate
E) utilization of inorganic phosphate (Pi)

C) oxidation of NADH to NAD+

During strenuous exercise, the NADH formed in the glyceraldehyde 3-phosphate dehydrogenase reaction in skeletal muscle must be reoxidized to NAD+ if glycolysis is to continue. The most important reaction involved in the reoxidation of NADH is:
A) dihydroxyacetone phosphate → glycerol 3-phosphate
B) glucose 6-phosphate → fructose 6-phosphate
C) isocitrate → α-ketoglutarate
D) oxaloacetate → malate
E) pyruvate → lactate

E) pyruvate → lactate