Unit 1 exam

For an enzyme that displays Michaelis-Menten kinetics, the reaction velocity (as a fraction of Vmax) observed at [S]= 2 Km will be: 0.91 0.09. 0.99 0.67 0.33

0.67

A mutation is most likely to alter the three-dimensional conformation of protein if? A. It places a proline residue in the middle of an a-helix B. There is a substitution of a hydrophobic amino acid for a hydrophilic amino acid C. Valine is substituted for leucine D. It changes the amino acid at the carboxyl-terminus E. It changes the amino acid at the amino-terminus

A . It places a proline residue in the middle of an a-helix

Hydrolysis of the hexapeptide Glys-Arg-Cys-Met-Lys-Ala with the protease trypsin, would produce how many fragments? A. 3 B. 2 C. 1 D. 4 E. None

A. 3

In carbohydrate nomenclature, a triose contains how many carbon atoms? A. 3 B. 6 C 4 D. 2 E. 5

A. 3

Hemoglobin exhibits which of the following structural hierarchies? A. All of the above B. Tertiary C. Primary D. Secondary E. Quartenary

A. All of the above

Which of the following amino acid pairs have side chains that carry a negative charge at pH 7.0? A. Aspartate and Glutamate B. Aspartate and Asparagine C. Glutamate and Glutamine D. Lysine and Arginine E. Alanine and Glycine

A. Aspartate and Glutamate

Standard Watson-Crick base-pairing requires that guanine always pairs with? A. Cytosine B. Uridine C. Adenine D. Thymine E. 5-methylcytosine

A. Cytosine

Which of the following carbohydrates is a ketose sugar? A. Fructose B. Hexose C. Lactose D. Galactose E. Glucose

A. Fructose

Which of the following hemoglobin variants has a quartenary structure comprised of two alpha chains and two beta-2 glucose chains? A. HbA1c B. HbA2 C. HbA D. Hb Gower-2 E. HbF

A. HbA1c

Which of the following amino acids contains an imidazole group? A. Histidine B. Tryptophan C. Glycine D. Asparagine E. Proline

A. Histidine

Which of the following is NOT a common regulatory strategy for controlling the flux through a metabolic pathway? A. Non-Competitive inhibition B. Compartmentation C.Gene regulation D. Covalent modification E. Allosteric regulation

A. Non-Competitive inhibition

Naturally-occurring fatty acids always contain which of the following types of double bonds? A. Only cis B. Only trans C. None of the above D. Mixtures of trans and amides E. Mixtures of trans and cis

A. Only cis

The Edman degration, performed using phenylisothiocyanate, is used to determine which of the following structural heirarchies? A. Primary B. Quaternary C. Tertiary D. Secondary E. None of the above

A. Primary

An example of irreversible regulation of enzyme activities is? A. Proteolytic conversion of digestive enzymes B. Allosteric regulation by substrates C. Dissociation of subunits in oligomeric enzymes D. Inhibition by competitive inhibitors E. Phosphorylation/dephosphorylation by protein kinases/phosphatases

A. Proteolytic conversion of digestive enzymes

Regulation of enzyme activity by covalent modification occurs primarily though that action of protein kinases that phosphorylate specific amino acids such as? A. Serine B. Cysteine C. Lysine D. Proline E. Glutamine

A. Serine

Reducing sugars are oxidized by Fehling's solution to produce a color reaction. Which of the following is NOT a reducing sugar? A. Sucrose B. Lactose C. Glucose D. Galactose E. Fructose

A. Sucrose

Captopril, a competitive inhibitor for angiotensin converting enzyme, can be used as a therapeutic agent for hypertension. Competitive inhibitors change? A. The Km of the reaction B. The substrate specificity of the enzyme C. None of the above D. Both the Vmax and Km of the reaction E. The Vmax of the reaction

A. The Km of the reaction

The Michaelis-Menten constant, Km, for enzyme-catalyzed reaction is? A. The substrate concentration at v=1/2 Vmax B. Equal to 1/2 Vmax C. The equilibrium constant for the dissociation of Es to E+P D. The intercept of the 1/v axis of a Lineweaver-Burk plot E. Not changed by the presence of a noncompetitive inhibitor

A. The substrate concentration at v=1/2 Vmax

Which one of the following correctly describes the expected products obtained when the polypeptide Arg-Gly-Phe-Leu-Met-Lys is treated as indicated? A. Treatment with cyanogen bromide yields two products B. Treatment with HCl at 110 oC yields two products C. Treatment with trypsin gives three products D. Treatment with phenylisothiocyanate followed by mild acidification yields three products E. Treatment with urea gives three products

A. Treatment with cyanogen bromide yields two products

Which of the following mutations is observed in sickle cell hemoglobin? A. b6 Glu -> Val B. a6 Val -> Glu C. b6 Val -> Glu D. b6 Glu -> Lys E. a6 Glu -> Val

A. b6 Glu -> Val

All of the following are branched-chain amino acids EXCEPT? Ala Val Ile Leu None of the above

Ala

Acid hydrolysis of a peptide reveals equimolar amounts of lysine, glycine and alanine. Following trypsin digestion of the peptide, only free glycine and a single dipeptide are observed upon analysis. What is the primary structure of the original peptide? A. Lys-Gly-Ala B. Ala-Lys-Gly C. Ala-Gly-Lys D. Gly-Lys-Ala E. Gly-Lys-Ala-Lys-Gly-Ala

B. Ala-Lys-Gly

Which of the following statements concerning the peptide bond is TRUE? A. The C, O, N and H atoms around the peptide bond are all coplanar B. All of the Above C. Peptide bonds can be cleaved by acid hydrolysis in the presence of concentrated HCL at 110 degrees C D. The peptide bond has partial double bond character

B. All of the Above

Which of the following statements is correct? A. The a-helix can be composed of more than one polypeptide chain B. Amino acid R-groups or side chains point above and below the plane of b-sheets C. Motifs are a type of secondary structure D. b-sheets exist only in the antiparallel form E. The a-helix is stabilized primarily by ionic interactions between the side chains of amino acids

B. Amino acid R-groups or side chains point above and below the plane of b-sheets

In the study of enzymes a sigmoidal plot of substrate concentration {[S]} versus reaction velocity (V) may indicate? A. Myoglobin binding to oxygen B. Cooperative binding C. Competitive inhibition D. Noncompetitive inhibition E. Michaelis-Menten kinetics

B. Cooperative binding

which of the following amino acids in involved in the formation of disulfide bonds? A. Alanine B. Cysteine C. Methionine D. Serine E. Proline

B. Cysteine

Which of the following is true for the double helical structure of DNA? A. The major and minor grooves run in opposite directions B. DNA double helices are more stable than RNA double helices C. The base sequence can only be read by proteins when the helix is opened up into a single-stranded form D. Electrostatic bonds are the primary stabilizing force for the double helix E. each strand of the helix contains unique information

B. DNA double helices are more stable than RNA double helices

Monitoring the formation or levels of HbA1c in a patients blood can be used to diagnose which of the following disease? A. Phenylketouria B. Diabetes mellitus C. Sickle cell disease D. Respiratory acidosis E. b-Thalassemia

B. Diabetes mellitus

Polymerization of glucose units to form glycosides requires the formation of which type of bond? A. Disulfide bond B. Glycosidic bond C. Amide bond D. Hydrogen bonds E. Electrostatic bond

B. Glycosidic bond

All EXCEPT which of the following statements may characterize sickle cell anemia? A. The clinical symptoms are much less severe when the mutation is only on one chromosome B. HbS has the same electrophoretic mobility as normal hemoglobin C. Sickling occurs when there is a high concentration of the deoxygenated form of hemoglobin S D. The disease can be diagnosed by restriction enzyme digestion E. HbS is caused by an alteration of a single amino acid in the b-chain

B. HbS has the same electrophoretic mobility as normal hemoglobin

Protein secondary structure is stabilized by which of the forces? A. Disulfide bonds B. Hydrogen bonds C. Hydrophobic interactions D. Ionic bonds E. van der Waals forces

B. Hydrogen bonds

A purely competitive inhibitor of an enzyme has which of the following kinetic effects? A. Decreases Km without affecting Vmax B. Increases Km without affecting Vmax C. Decreases Vmax without affecting Km D. Increases Vmax without affecting Km E. Decreases both Vmax and Km

B. Increases Km without affecting Vmax

All of the following statements about the a-helix are true EXCEPT? A. It is stabilized by intramolecular hydrogen bonds B. It is stabilized by hydrophobic interactions C. It is one type of secondary structure found in proteins D. Prolyl and glycyl residues tend to interrupt a-helix structure E. It is stabilized by minimizing unfavorable R-group interactions

B. It is stabilized by hydrophobic interactions

Which of the following reactions is an example of an oxidation-reduction reaction? A. Pyruvate + CO2 -> Oxaloacetate B. Lactate + NAD+ -> Pyruvate + NADH + H+ C. Methylmalonyl-CoA -> Succinyl-CoA D. Pyruvate -> Acetaldehyde + CO2 E. Urea + H2O -> CO2 + 2NH3

B. Lactate + NAD+ -> Pyruvate + NADH + H+

Amino acid sequences are read in which direction? A. In any order B. Left to right C. Top to bottom D. Right to left E. Bottom to top

B. Left to right

The Mechaelis constant Km for an enzyme-catalyzed reaction can be determined from? A. The Vmax of the reaction B. Measuring reaction rates at different substrate concentrations C. Measuring reaction rates at different enzyme concentrations D. Knowledge of he molecular weight of the enzyme E. The equilibrium constant of the enzyme-catalyzed reaction

B. Measuring reaction rates at different substrate concentrations

Which of the following statements concerning enzymes is CORRECT? A. Enzymes have only organic compounds as substrates B. None of the above C. All proteins are enzymes D. Enzymes have absolute specificity for their natural substrate E. Enzymes require specific cofactors for activity

B. None of the above

An enzyme that catalyzes the reaction A B changes the? A. Equilibrium constant B. Rate of both the forward and reverse reactions C. Equilibrium concentration of A D. Heat of reaction E. Entropy of the reaction

B. Rate of both the forward and the reverse reactions

Which of the following statements concerning DNA is correct? A. The Z-form of DNA is favored by long stretches of A and T nucleotides B. The B-form of DNA is the predominant natural form C. The two grooves in the DNA double helix are equal in size D. The A-form of DNA is the predominant natural form E. The purine and pyrimidine bases in DNA extend on the outside of the double helix

B. The B-form of DNA is the predominant natural form

Which of the following statements concerning the structure of heme is correct? A. Heme is comprised of two pyrrole rings B. The proximal ligand is a histidine residue C. The fifth coordination position of heme is occupied by a lysine residue D. Hemoglobin and methemoglobin both bind oxygen with equal affinities E. The heme prosthetic group contains a central Cu atom

B. The proximal ligand is a histidine residue

Which of the following statements concerning allosteric regulation of enzyme activity is CORRECT? A. Positive allosteric effectors displace the sigmoidal reaction curve to the left B. All of the above C. Allosteric inhibitors generally have a greater effect on enzyme velocity than competitive inhibitors D. Positive cooperativity occurs when the binding of a ligand at one site increases the affinity at adjacent sites E. The binding of allosteric effectors generally induce a change in the conformation of the enzyme

B. all of the above

In the a-helix the carbonyl oxygen is hydrogen bonded to which amino nitrogen in the linear chain? A. n+3 B. n+4 C. n+5 D. n+1 E. n+2

B. n+4

Which of the following is the correct form of the Michaelis-Menten equation? A. v=Km+S/Vmax [S] B. v=Vmax[S]/Km+[S] C. Vmax=v[S]/Km+[S] D. v=Vmax+S/Km[S] E. v=Vmax[S]/Km-[S]

B. v=Vmax[S]/Km+[S]

Which of the following mutations is observed in sickle cell hemoglobin? A. a6 Glu-> Val B. b6 Glu-> Lys C. b6 Val -> Glu D. a6 Val -> Glu E. b6 Glu-> Val

B6 Glu -> Val

How many a-amino functional groups are present in the pentapeptide Gly-Arg-Lys-Cys-His? A. 2 B. 4 C. 1 D. 5 E. 3

C. 1

Which of the following is an allosteric effector of hemoglobin oxygen binding? A. Carbon monoxide B. Carbonic acid C. 2,3-bisphosphoglycerate D. Hydroxyl anions E. Oxygen

C. 2,3-bisphosphoglycerate

Medium fatty acids contain how many carbon atoms? A. 2-4 B. 12-15 C. 6-10 D. 15-20 E. 4-6

C. 6-10

Because of the abundance of hydroxyl groups, sugar molecules can form several types of carbohydrate derivatives which include? A. Amino sugars B. Deoxy sugars C. All of the above D. Sugar alcohols E. Sugar acids

C. All of the above

Which of the following statements concerning enzymes is correct? A. Enzymes chiefly bind substrates by non-covalent interactions B. Changes in the specificity sub site may change the type of substrate that is bound but not the chemistry that is catalyzed C. All of the above D. Enzyme active sites ensure that two substrates come together in the correct orientation for chemical reaction to occur E. Enzymes use salt bridges and hydrogen bonds to bind ligands specifically

C. All of the above

When lysine has a charge of +1? A. all the ionic groups are protonated B. Only the a-amino group is protonated C. Both amino groups are protonated D. The carboxyl group is protonated E. Only the e-amino group is protonated

C. Both amino groups are protonated

Which one of the following types of bonds or interactions is LEAST important in determining the tertiary structure of proteins? A. Hydrogen bonds B. Hydrophobic interactions C. Coordination bonds (to ligands) D. Electrostatic bonds E. Disulfide bonds

C. Coordination bonds (to ligands)

Which of the following statements concerning denaturation of proteins is CORRECT? A. Denaturation increases the solubility or proteins in aqueous solution B. Denaturation is always irreversible C. Denaturation results in the loss of secondary and tertiary structure D. Denaturation is not produced by high concentration of chaotropes such as urea E. Denaturation results in the cleavage of peptide bonds

C. Denaturation results in the loss of secondary and tertiary structure

Which of the following statements concerning isoenzymes is CORRECT? A. Isoenzymes catalyze different chemical reactions B. Isoenzymes are composed of identical subunits C. Isoenzymes catalyze the same chemical reactions but have different amino acid sequences D. Isoenzymes will have the same kinetic properties, such as Km and Vmax E. All isoenzymes are located in the same tissue or cellular compartment

C. Isoenzymes catalyze the same chemical reactions but have different amino acid sequences

The presence of a noncompetitive inhibitor? A. Leads to an increase in Km without affecting Vmax B. Leads to both an increase in the Vmax of a reaction and an increase in the Km C. Leads to a decrease in the observed Vmax D. Increases the steady-state concentration of ES E. Leads to a decrease in Vmax and Km

C. Leads to a decrease in the observed Vmax

Enzymes as classic catalysts accomplish which of the following energy effects? A. Raise the energy of activation B. Raise the energy level of the reaction products C. Lower the energy of activation D. Decrease the free energy of the reaction E. Lower the energy level of the reaction substrates

C. Lower the energy of activation

Enzymes as classic catalysts accomplish which of the following energy effects? A. Lower the energy level of the reaction substrates B. Raise the energy level of the reaction products C. Lower the energy of activation D. Raise the energy of activation E. Decrease the free energy of the reaction

C. Lower the energy of activation

An amino acid with an ionic, polar side chain is? A. Phenylalanine B. Alanine C. Lysine D. Leucine E. Serine

C. Lysine

Within the a-helix, the R-groups or amino acid side chains lie in which direction A. In no particular angular pattern B. In the center of the helix C. Perpendicular to the direction of propagation of the helix D. Antiparallel to the direction of propagation of the helix E. Parallel to the direction of propagation of the helix

C. Perpendicular to the direction of propagation of the helix

The rate of an enzyme-catalyzed reaction was measured using several substrate concentrations that were much lower than Km. The dependence of reaction velocity on substrate concentration can best be described as? A. A constant fraction of Vmax B. Zero order with respect ot substrate C. Proportional to the substrate concentration D. Independent of enzyme concentration E. Equal to Km

C. Proportional to the substrate concentration

In an intact cell, the free energy change (delta G) associated with an enzyme-catalyzed reaction is frequently different from the standard free energy change (delta Go) of the same reaction because in the intact cell the? A. Reaction may be catalyzed by more than one enzyme B. Enzyme may be regulated allosterically C. Reactants are not at 1M concentrations D. Activation energy is different E. Reaction is always near equilibrium

C. Reactants are not at 1M concentrations

The proteolytic action of the enzyme chymotrypsin is specific to which of the following amino acids? A. Carboxyl terminal amino acid B. Cysteine C. Tyrosine D. Glycine E. Arginine

C. Tyrosine

Which of the following bases is found in RNA? A. Guanine B. Adenine C. Uracil D. Cytosine E. Thymine

C. Uracil

Vmax and Km can be derived from the Lineweaver-Burke plot of the Michaelis-Menten equation. When V is the reaction velocity at substrate concentration S, the x-axis experimental data are expressed as? A. S B. V C. V/S D. 1/S E. 1/V

D. 1/S

What is the difference between an active site and an allosteric site? A. An active site regulates enzyme activity, while catalysis occurs at the allosteric site B. An enzyme can have only one allosteric site, but can have many active sites C. An active site is typically larger than an allosteric site D. An active site binds substrate, while an allosteric site binds a regulatory ligand E. Allosteric sites bind coenzymes, but active sites bind only enzymes

D. An active site binds substrate, while an allosteric site binds a regulatory ligand

Which of the following amino acids has three pK values between pH 2 and 12? A. Threonine B. Glutamine C. Alanine D. Cysteine E. Glycine

D. Cysteine

A purely noncompetitive inhibitor of an enzyme has which of the following kinetic effects? A. Decreases both Vmax and Km B. Increases Vmax without affecting Km C. Decreases Km without affecting Vmax D. Decreases Vmax without affecting Km E. Increase Km without affecting Vmax

D. Decreases Vmax without affecting Km

Which of the following Greek symbols is used to designate the position of double bonds in a fatty acid structure? A. Epsilon B. Alpha C. Gamma D. Delta E. Beta

D. Delta

Which of the following statements concerning the process of denaturation of DNA is correct? A. Denaturation involves an increase in the number of hydrogen bonds between bases B. Denaturation can be achieved by decreasing the solution pH C. Decreasing the temp of a denatured DNA sample does not result in the reforming of the double helix D. Denaturation can be monitored by hyperchromicity (increased absorbance at 260nm) E. The melting curve is steeper for non homogenous DNA samples (non-identical sequences)

D. Denaturation can be monitored by hyperchromicity (increased absorbance at 260nm)

In biochemical energetics and thermodynamics, the change in free energy of a reaction is indicated by the symbol? A. None of the above B. S C. T D. G E. H

D. G

The "sickling" of erythrocytes in sickle cell hemoglobin is due to polymerization of the hemoglobin molecules under conditions of? A. Increased concentrations of the oxygenated form of HbS B. Increased concentrations of HbF C. Decreased pH D. Increased concentrations of the deoxygenated form of HbS E. Increased concentrations of 2,3-bisphosphoglycerate

D. Increased concentrations of the deoxygenated form of HbS

Which of the following fatty acids contains 18 carbon atoms and two double bonds in its structure? A. Linolenic acid B. Stearic acid C. Palmitic acid D. Linoleic acid E. Oleic acid

D. Linoleic acid

The Michaelis constant Km is? A. Dependent on the enzyme concentration B. Independent of pH C. Increased in the presence of a noncompetitive inhibitor D. Numerically equal to the substrate concentration that gives half-maximal velocity E. Numerically equal to 1/2 Vmax

D. Numerically equal to the substrate concentration that gives half-maximal velocity

Which of the following is NOT one of the 6 IUB classes of enzymes? A. Isomerase B. Hydrolase C. Transferase D. Polymerase E. Ligase

D. Polymerase

Which structural hierarchy corresponds to the linear amino acid sequence of a protein? A. Secondary B. None of the above C. Tertiary D. Primary E. Quaternary

D. Primary

A negative allosteric effector such as carbon dioxide acts on the oxygen saturation curve of hemoglobin displacing it in which direction? A. Down B. Up C. Left D. Right E. No Change

D. Right

Cooperativity in the binding of oxygen to hemoglobin compared to myoglobin is indicated by which shape of the oxygen saturation curve? A. Linear B. Exponential C. Hyperbolic D. Sigmoidal E. None of the above

D. Sigmoidal

Which of the following statements concerning nucleotide structure is correct? A. The 4'-carbon position determines whether the nucleotide is a deoxyribonucleotide or a ribonucleotide B. One or more phosphate groups is attached to the 5'-carbon C. A purine or pyrimidine base is attached to the 3'-carbon position D. Nucleotide polymerization proceeds via the 5'-carbon E. A purine or pyrimidine base is attached to the 1'-carbon

E. A purine or pyrimidine base is attached to the 1'-carbon

Which of the following treatments hydrolyzes all the peptide bonds in a protein regardless of specificity? A. Trypsin treatment B. Cyanogen bromide treatment C. Mercaptoethanol treatment D. Chymotrypsin treatment E. Acid hydrolysis

E. Acid hydrolysis

Which of the following statements concerning simplifying assumptions governing Michaelis-Menten enzyme kinetics is correct? A. The enzyme substrate complex ES can break down to enzyme and substrate without reacting B. The enzyme substrate complex (ES) can complete the reaction to from product P C. A single substrate (S) binds reversible to form the enzyme-substrate complex ES D. E+S ES-> E+P E. All of the above

E. All of the above

Which of the following statements concerning enzyme-catalyzed first order reactions is CORRECT? A. Reaction rate is proportional to the concentration of two substrates B. Enzyme is saturated with substrate, no more will bind C. None of the above D. Increasing substrate concentration has no effect on rate of reaction. E. Answer Reaction rate is directly proportional to the amount of substrate added

E. Answer Reaction rate is directly proportional to the amount of substrate added

which of the following amino acids in involved in the formation of disulfide bonds? A. Proline B. Serine C. Alanine D. Methionine E. Cysteine

E. Cysteine

Which of the following is likely to increase the midpoint temp of the melting curve for DNA? A. Decreasing the number of G-C pairs B. None of the above C. The incorporation of unusual bases D. Increasing the degree of homogeneity of the DNA sample E. Decreasing the number of the A-T pairs

E. Decreasing the number of the A-T pairs

Which is NOT a property of enzymes? A. Enzymes accelerate the rate of a reaction B. Enzymes react with only specific substrates C. Enzymes do not get used up in the reaction it catalyzes D. The same enzyme can catalyze both the forward and reverse reaction E. Enzymes alter the reaction equilibrium

E. Enzymes alter the reaction equilibrium

Which of the following amino acids contains an amide group? A. Glycine B. Cysteine C. Tryptophan D. Threonine E. Glutamine

E. Glutamine

Which of the following is NOT an L-amino acid in human proteins? A. Glutamine B. Threonine C. Leucine D. Cysteine E. Glycine

E. Glycine

Similarities between hemoglobin and myoglobin include which of the following? A. Increased acidity reduces the oxygen binding B. Conversion from the "tense" to the "relaxed" conformation occurs when binding oxygen C. They are both located in the red blood cell (erythrocyte) D. 2,3-BPG reduces the oxygen binding capacity E. Heme is a prosthetic group

E. Heme is a prosthetic group

Which of the following will increase the melting point of a fatty acid? A. Decreased chain length B. None of the above C. Increased cis-unsaturation D. Increased unsaturation E. Increased chain length

E. Increased chain length

Which of the following best describes a drug that acts as a noncompetitive inhibitor? A. It increases the steady-state concentration of the ES complex B. It doesn't affect the Lineweaver-Burke plot C. It has a structure similar to a substrate D. It is usually irreversible E. It acts by removing active enzyme from the substrate pool

E. It acts by removing active enzyme from the substrate pool

Which of the following is true of the peptide bond? A. It is always favored in the cis configuration B. It is stabilized in a spiral configuration C. It is readily broken by denaturing agents D. It has both a positive and negative charge at physiologic pH E. It is a type of amide linkage

E. It is a type of amide linkage

Which of the following is true of Lysine (pk1=2.2, pk2=9.0, pk3=10.5) A. It has a charge of +1 when the carboxyl group is protonated B. It has a PI of 5.6 C. It has a phenolic side chain D. It is most likely to be found n the interior of the protein E. It will migrate toward the cathode (negative electrode) during electrophoresis at pH 7.0

E. It will migrate toward the cathode (negative electrode) during electrophoresis at pH 7.0

The chemical cyanogen bromide cleaves peptide chains on the carboxyl side of which amino acid residue? A. Aspartic acid B. Cysteine C. Lysine D. Arginine E. Methionine

E. Methionine

Which of the following is not an enzyme prosthetic group? A. Pyridoxal phosphate B. FAD C. Biotin D. Cu E. NAD+

E. NAD+

The Michaelis constant, Km, is? A. Numerically equal to 1/2 Vmax B. Independent of pH C. Increased in the presence of a noncompetitive inhibitor D. Dependent on the enzyme concentration E. Numerically equal to the substrate concentration that gives half-maximal velocity

E. Numerically equal to the substrate concentration that gives half-maximal velocity

An enzyme that catalyzes the reaction A B changes the? A. Equilibrium concentration of A B. Equilibrium constant C. Heat of reaction D. Entropy of the reaction E. Rate of both the forward and reverse reactions

E. Rate of both the forward and reverse reactions

which of the following sugar alcohols is a derivative of glucose? A. Xylitol B. Glycerol C. None of the above D. Galactitol E. Sorbitol

E. Sorbitol

Which of the following amino acids can exist in four optically-active isomers? A. Glycine B. Alanine C. Glutamine D. Cysteine E. Threonine

E. Threonine

The b-sheet is an example of which type of structure? A. Quartenary B. Primary C. None of the above D. Tertiary E. Secondary

E.Secondary

The imidazole functional group is an important component of buffering intracellular pH of approximately 7.0. The imidazole ring is present in which of the following amino acids? Trp Met His Phe Tyr

His

Which of the following will decrease the melting point of a fatty acid? None of the responses Increased chain length Increased unsaturation Decreased saturation

Increased unsaturation

Which of the following oxygen transport proteins has the greatest affinity for molecular oxygen in human tissue? HbS HbA HbA1c Myoglobin Hb Boston

Myoglobin