BICH test 1
What functional groups are present on this molecule? (A)hydroxyl and ester (B) ether, hydroxyl, and ketone. (C) hydroxyl and aldehyde (D)hydroxyl and carboxylic acid (E) hydroxyl and ketone
A
Which of the following forces in biological systems is usually the strongest? (A)Electrostatic interactions (B) Hydrogen bonds (C) London dispersion forces (D)Van der Waals interactions (E) Dipole-dipole interactions
A
Which of the peptide bonds in the above sequence would be cleaved by chymotrypsin?
Phe-Thr
What three types of amino acid residues are found in high proportion in silk fibroin? (A) Lysine, Glutamate and Proline. (B) Glycine, Proline and 4-hydroxyproline. (C) Phenylalanine, tyrosine and tryptophan. (D) Glycine, Alanine and Serine. (E) Asparagine, Lysine and Serine.
d
Which of the peptide bonds in the above sequence would be cleaved by trypsin?
arg-ala
ATP + H2O <--> ADP + Pi + H+ deltaGo' = -30.5 kJ/mol; T= 25C In an E. coli cell the concentrations of [ATP] = 7.9 mM, [ADP] = 1.04 mM and [Pi] = 7.9 mM, [H2O] = 55.6 M and [H+ ] = 10-7 M. What is the free energy of hydrolysis of ATP in E. coli with these concentrations. (A)-51.8 kJ/mole (B) -7.78 kJ/mole (C) -17.0 kJ/mole (D)-47.5 kJ/mole (E) None of the above.
d
Acetyl phosphate + H2O --> Acetate + Pi + H+ 298 K, deltaG' = -43.3 kJ/mol K'eq equals (A) 0 (B) 0.98 (C) 2.6 X 10-8 (D) 3.9 X 107 (E) None of the above.
d
The folded states of globular proteins in aqueous solutions are stabilized mainly by: (A)peptide bonds (B) phosphodiester bonds (C) ionic bonds (D)hydrophobic interactions (E) Disulfide Bridges
d
The spatial arrangement of protein subunits is called: (A) primary structure. (B) secondary structure. (C) tertiary structure. (D) quaternary structure. (E) none of the above.
d
The structure of silk fibrion consists of (A) two long alpha-helices twisted together in left handed manner. (B) a triple helix with every third residue a glycine facing the interior of the helix. (C) four antiparallel helix bundles (D) antiparallel beta-sheets. (E) alternating alpha helices and beta sheets.
d
Water derives all its special properties from its A.) cohesiveness and adhesiveness. B.) high boiling point and melting point. C.) small degree of ionization. D.) polarity and hydrogen-bonding capacity. E.) high dielectric constant.
d
Which of the above reagents will react with the N-terminal free amino group of peptides? (A) Ammonium Sulfate (B) Iodoacetate (C) beta-mercapto ethanol (D) Phenylisothiocyanate (E) Cyanogen Bromide
d
Which of the above reagents will react with the N-terminal free amino group of peptides? (A)Ammonium Sulfate (B)Iodoacetate (C) Dithiothreitol (D)Dansyl Chloride (E) Guanidinium Chloride
d
Which of the peptide bonds in the above sequence would be cleaved by cyanogen bromide?
met-phe
In a prokaryotic cell the DNA is found in the: (A)Mitochondrian. (B) Cytosol. (C) Nucleus. (D)Endoplasmic Reticulum. (E) Golgi Apparatus.
B
The feature that distinguishes eukaryotic cells from prokaryotic cells is: A.) All eukaryotes are multicellular. B.) All eukaryotes have rigid cell walls. C.) All eukaryotes have a well-defined nucleus within each cell. D.) All eukaryotes all have circular chromosomes E.) All of the above statements are correct.
C
Which of the following organelles is site of eukaryotic DNA transcription? (A)Mitochondrian (B) Golgi Apparatus (C) Nucleus (D)Rough Endoplasmic Reticulum (E) Cytosol
C
2.) Which of the following statements about hydrogen bonds is true? A. A hydrogen bond can be as strong as a covalent bond. B. Water is a weak hydrogen bond donor, but a strong hydrogen bond acceptor. C. Hydrogen bonds occur between nonpolar molecules. D. Hydrogen bonds account for the high boiling point of water. E. Hydrogen bonds form between positively and negatively charged ions
D
Which of the following rank the interactions in order of strength from the lowest to the highest? (A)Hydrogen bonds, ionic interactions, hydrophobic interactions, covalent bonds. (B) Hydrogen bonds, hydrophobic interactions, ionic interactions, covalent bonds (C) Ionic interactions, covalent bonds, hydrogen bonds, hydrophobic interactions. (D) Hydrophobic interactions, hydrogen bonds, ionic interactions, covalent bonds. (E) Covalent bonds, hydrophobic bonds, hydrogen bonds, ionic interactions.
D
Which one of the following statements is correct: A.) Prokaryotes are multicellular. B.) Prokaryotes have organelles. C.) Prokaryotes have a well-defined nucleus within each cell. D.) Prokaryotes have a circular chromosome E.) All of the above statements are correct.
D
Which of the following organelles is the major site of lipid biosynthesis? (A)Mitochondrian (B) Golgi Apparatus (C) Nucleus (D)Rough Endoplasmic Reticulum (E) Smooth Endoplasmic Reticulum
E
Which of the interactions has the weakest energy? (A)Dipole-induced dipole (B) Hydrogen bonds (C) Dipole - dipole interaction (D)Ionic interactions (E) London dispersion forces
E
A clathrate is (A) The extensive hydrogen-bonding network of liquid water molecules around a nonpolar molecule. (B) the measure of hydrophobicity of amino acids. (C) the measure of polarity of amino acids. (D) the rate at which nonpolar solutes intercalate into solution. (E) an amphiphilic molecule.
a
A peptide bond: (A) has partial bond character. (B) is ionized at physiological pH. (C) is cleaved by denaturants such as SDS and urea. (D) is stable to heating with strong acids. (E) occurs in polypeptides predominantly in the cis configuration.
a
ATP + H2O <--> ADP + Pi + H+ deltaGo' = -30.5 kJ/mol; T= 25C In a rat heart muscle cell the concentration of [ATP] = 8.0 mM, [ADP] = 0.9 mM and [Pi] = 8.0 mM, [H2O] = 55.6 M and [H+ ] = 10-7 M. What is the free energy of hydrolysis of ATP in a rat neuron with these concentrations? (A)-47.9 kJ/mole (B) -57.8 kJ/mole (C) -32.0 kJ/mole (D)-30.5 kJ/mole (E) None of the above.
a
At equilibrium: (A)the deltaG = 0 (B) the deltaG0' = 0 (C) the deltaG =deltaG0' (D)the Keq = 1 (E) the Keq = 0
a
At what pH is the side chain of cysteine 75% ionized? (A) 8.8 (B) 8.2 (C) 7.8 (D) 7.7 (E) None of the above
a
For any amino acid with a neutral side chain, at any pH below the pI of the amino acid, the amino acid will (A) have a net positive charge. (B) be neutral without any net charge. (C) have 0 net charge. (D) have a net negative charge. (E) have an equal number of positive and negative charges.
a
Gel filtration chromatography fractionates proteins based on (A) molecular size. (B) hydrophobicity. (C) electrostatic charge. (D) isoelectric point. (E) affinity for an immobilized ligand.
a
Given: Glucose 6-Phosphate > Glucose 1-Phosphate deltaGo' = 7.11 kJ/mol Glucose 6-Phosphate > Fructose 6-Phosphate deltaGo' = -1.67 kJ/mol What is the deltaGo' for the conversion of Glucose 1-Phosphate >Fructose 6- Phosphate? (A) -8.8 kJ/mol (B) -7.1 kJ/mol (C) -5.4 kJ/mol (D) 5.4 kJ/mol (E) None of the above
a
Hair, finger nails, toe nails and horns are composed primarily of (A) alpha-keratin. (B) fibroin. (C) cytochrome C. (D) parallel -sheets. (E) collagen.
a
If a reaction produces heat but is not spontaneous then it is (A) exothermic and endergonic. (B) endothermic and endergonic. (C) exothermic and exergonic. (D) endothermic and exergonic. (E) at equilibrium.
a
In an alpha-helix, The side chains of the amino acid residues: (A) Are found on the outside of the helix spiral. (B) Participate in the hydrogen bonding of the polypeptide backbone that stabilize the helix. (C) Stabilize the helix through electrostatic interaction with the polypeptide backbone. (D) A and B of the above are true. (E) A, B and C are true.
a
The abbreviation of the residue shown in the peptide above is (A) Ala (B) Gly (C) Cys (D) Trp (E) Pro
a
The folded states of globular proteins in aqueous solutions are stabilized mainly by: (A)hydrophobic interactions (B) peptide bonds (C) phosphodiester bonds (D)ionic bonds (E) disulfide bridges.
a
The slowest step of protein folding is (A) the conformational adjustments to optimize the orientation of the side chains. (B) the formation of domains by cooperative interactions of folded nuclei. (C) the hydrophobic collapse of the unfolded protein. (D) the formation of the molten globule (E) the transient formation of short stretches of secondary structure.
a
Which of the above reagents is used to purify proteins by salt fractionation? (A) Ammonium Sulfate (B) Iodoacetate (C) beta-mercapto ethanol (D) Phenylisothiocyanate (E) Cyanogen Bromide
a
Which of the above reagents is used to purify proteins by salt fractionation? (A)Ammonium Sulfate (B)Iodoacetate (C) Dithiothreitol (D)Dansyl Chloride (E) Guanidinium Chloride
a
Which of the following amino acids is most soluble in water at pH 7.0? (A)Glutamate (B) Tryptophan (C) Leucine (D)Tyrosine (E) Phenylalanine
a
Which of the following amino acids would serve as the best buffer at pH 6? (A) H (B) I (C) Y (D) S (E) E
a
Which of the following organelles is the site of eukaryotic oxidative phosphorylation? a. a. Mitochondrian b. Lysosome c. Nucleus d. Rough Endoplasmic Reticulum e. Cytosol
a
Which one of the following statements correctly describes the expected products obtained when the polypeptide Arg-Gly-Phe-Met-Lys is treated as indicated below? (A) Treatment with cyanogen bromide yields two products. (B) Treatment with trypsin gives three products. (C) Treatment with phenylisothiocyanate followed by mild acidification yields three products. (D) Treatment with dithiothreitol gives two products. (E) Treatment with 1 M HCl at 100 o C yields two products
a
Which of the peptide bonds in the above sequence would be cleaved first by carboxypeptidase A?
ala-tyr
ATP + H2O <--> ADP + Pi + H+ deltaGo' = -30.5 kJ/mol; T= 25 o C In a rat liver cell the concentrations of [ATP] = 3.5 mM, [ADP] = 1.7 mM and [Pi] = 4.8 mM, [H2O] = 55.6 M and [H+] = 10-7 M. What is the free energy of hydrolysis of ATP in a rat neuron with these concentrations? (A)-55.5 kJ/mole (B) -45.5 kJ/mole (C) -30.5 kJ/mole (D)-28.4 kJ/mole (E) None of the above.
b
ATP + H2O <-->ADP + Pi + H+ deltaGo' = -30.5 kJ/mol; T= 25C In a rat neuron the concentrations of [ATP] = 2.59 mM, [ADP] = 0.73 mM and the concentration of [Pi] = 2.72 mM, [H2O] = 55.6 M and [H+ ] = 10-7 M. What is the free energy of hydrolysis of ATP in a rat neuron with these concentrations? (A)-58.2 kJ/mole (B) -48.3 kJ/mole (C) -30.5 kJ/mole (D)-12.7 kJ/mole (E) None of the above.
b
Acetyl phosphate + H2O Acetate + Pi + H+ 298 o K, Go ' = -43.3 kJ/mol If the initial concentrations are: [Acetyl phosphate] = 1.43 mM [Acetate] = 2.4 mM [Pi] = 4.8 mM [H2O] = 55.6 M [H+ ] = 10-7 M G = (A) + 38 kJ/mol (B) -55 kJ/mol (C) -38 kJ/mol (D) -65 kJ/mol (E) None of the above.
b
Calculate the pKa of Formic acid, given that when the concentration of formic acid is 0.1 M and the formate ion concentration is 0.018 M, the pH is 3.01. (A)2.26 (B) 3.75 (C) 4.76 (D)5.63 (E) None of the above.
b
Ethanol (l) + 3O2 (g) 2CO2 (g)+ 3H2O (l) H = 1,367 kJ/mol, S = .138 kJ/molo K The reaction is (A) exergonic for all temperature values. (B) exergonic for all temperature values below 9,906 o K. (C) exergonic for all temperature values above 9,906 o K (D) endergonic for all temperature values. (E) None of the above.
b
Given: Sucrose + H2O --> Glucose + Fructose deltaGo' = -29.3 kJ/mol Glucose 1-Phosphate + H2O --> Glucose + Pi deltaGo' = -20.9 kJ/mol What is the deltaGo' for the conversion of Sucrose + Pi --> Glucose 1-Phosphate +Fructose? (A)-50.2 kJ/mol (B) -8.4 kJ/mol (C) 8.4 kJ/mol (D)20.9 kJ/mol (E) None of the above
b
Glycerol-3-phosphate + H2O Glycerol + Pi + H+ At 298 o K, the equilibrium concentrations are [Glycerol-3-phosphate]eq = 2.3 mM [Glycerol]eq = 74.8 mM [Pi]eq = 74.8 mM [H2O] = 55.6 M [H+] = 10-7 M The standard free energy change deltaG' = (A) 0 (B) -2.2 kJ/mol (C) 7.7 kJ/mol (D) -19.3 kJ/mol (E) None of the above.
b
If heat energy is absorbed by the system during a spontaneous chemical reaction, the reaction is said to be (A) exothermic and endergonic. (B) endothermic and exergonic. (C) endothermic and endergonic. (D) exothermic and exergonic. (E) at equilibrium.
b
In an alpha-helix, the hydrogen bonding interaction involves which atoms or groups? (A) The carbonyl C=O of residue number, n, with the amide N-H of residue n + 3. (B) The carbonyl C=O of residue number, n, with the amide N-H of residue n + 4. (C) The amide N-H of residue number, n, with the carbonyl C=O of residue n + 3. (D) The amide N-H of residue number, n, with the carbonyl C=O of residue n + 4. (E) None of the above are correct.
b
NH3 (g) + HCl (g) NH4Cl (s) deltaH = -176 kJ/mol, deltaS = -0.285 kJ/molo K The reaction is (A) exergonic for all temperature values. (B) exergonic for all temperature values below 617.5 o K. (C) exergonic for all temperature values above 617.5 o K (D) endergonic for all temperature values. (E) None of the above.
b
Phosphoglucomutase catalyzes the reaction shown below: Glucose-1-phosphate --> Glucose-6-phosphate At 310 K, the equilibrium concentration of glucose-6-phosphate is 17 times greater than the concentration of glucose-1-phosphate. What is deltaGo' for this reaction? R = 8.3145 J/moleK. (A)+7.3 kJ/mole (B) -7.3 kJ/mole (C) +3.17 kJ/mole (D)-3.17 kJ/mole (E) None of the above are correct.
b
The change in free energy, deltaG, for a protein going from a completely unfolded random state to its native folded state when the temperature is 298 o K, deltaH = -54 kJ/mol and deltaS = 600 J/mol is (A) 178.7 kJ/mol (B) -232.8 kJ/mol (C) -178.9 kJ/mol (D) 124.8 kJ/mol (E) 232.8 kJ/mol
b
The extensive hydrogen-bonding network of liquid water molecules around a nonpolar molecule is called: (A) A micelle. (B) A clathrate. (C) A amphiphile. (D) the rate at which nonpolar solutes intercalate into solution. (E) an amphiphilic molecule.
b
The free energy change, G (A)is directly proportional to the standard free energy change, G0'. (B) is equal to zero at equilibrium (C) can only be calculated when the reactants and products are present at 1 M concentrations. (D)is equal to -RTlnKeq (E) is negative for an endergonic process.
b
The sequence of amino acids in a protein is: (A) Chromatin structure. (B) Primary structure. (C) Secondary structure. (D) Tertiary structure. (E) Quaternary structure.
b
The structure of collagen consists of: (A)two long alpha-helices twisted together in left handed manner. (B) a triple helix with every third residue a glycine residue facing the interior of the helix. (C) four antiparallel helix bundles . (D) antiparallel beta-sheets. (E) alternating alpha helices and beta sheets
b
What is the pH of 10-4 M HCl? (A)0.0001 (B) 4 (C) -4 (D)11 (E) None of the above.
b
What three types of amino acid residues are found in high proportion in collagen? (A) Glycine, Alanine and Serine. (B) Glycine, Proline and 4-hydroxyproline. (C) Phenylalanine, tyrosine and tryptophan. (D) Lysine, Glutamate and Proline. (E) Asparagine, Lysine and Serine.
b
When the pH equals the pKa of a weak acid, then (A) The weak acid is completely ionized. (B) The concentrations of the weak acid and its conjugate base are equal. (C) The weak acid becomes a strong acid. (D) The net charge of the weak acid is zero. (E) The weak acid is completely protonated.
b
Which of the above reagents will alkylate the sulfhydryl group of cysteine residues to prevent reformation of disulfide bonds? (A) Ammonium Sulfate (B) Iodoacetate (C) beta-mercapto ethanol (D) Phenylisothiocyanate (E) Cyanogen Bromide
b
Which of the above reagents will alkylate the sulfhydryl group of cysteine residues to prevent reformation of disulfide bonds? (A)Ammonium Sulfate (B)Iodoacetate (C) Dithiothreitol (D)Dansyl Chloride (E) Guanidinium Chloride
b
Which of the following is not a state function. (A) Pressure (B) Heat (C) Enthalpy (D) Entropy (E) Free Energy
b
You want to study an enzyme reaction at pH 4.0. Which of the following weak acids would make the best buffer solution for this pH based on the given Ka values? (A) Phosphoric Acid Ka = 7.3 X 10-3 (B)Lactic Acid Ka = 1.4 X 10-4 (C)Acetic acid Ka = 1.7 X 10-5 (D)H2PO4- Ka = 6.3 X 10-8 (E) Bicarbonate Ka = 6.3 X 10-11
b
An -helix would be stabilized by: (A) containing two successive charged residues. (B) containing two successive bulky nonpolar residues. (C) containing an arginine and aspartate 3 residues apart. (D) containing a glycine residue. (E) All of the above.
c
At what pH is the side of tyrosine ½ ionized? (A) 11.2 (B) 10.1 (C) 10.5 (D) 13.7 (E) None of the above.
c
Calculate the pKa of a propionic acid solution, given that when the concentration of propionic acid is 0.10 M and the propionate ion concentration is 0.43 M, the pH is 5.50. A. 2.26 B. 3.75 C. 4.87 D. 6.13 E. None of the above
c
Given A > B > Go' = -14.2 kJ/mol C > B > Go' = +23.8 kJ/mol Then the deltaGo' for A > C would be (A) 9.6 kJ/mol (B) -9.6 kJ/mol (C) 38 kJ/mol (D) -38 kJ/mol (E) None are correct. 10.) Under the biochemistry standard conditions: (A)the deltaG = 0 (B) the deltaG0' = 0 (C) the deltaG =deltaG0' (D)the Keq = 1 (E) the Keq = 0
c
If 104 residues form an helix, what is the length of the helix in Å? (A) 103 Å (B) 210 Å (C) 156 Å (D) 246 Å (E) None of the above.
c
If the following polypeptide were folded into an alpha-helix, to which amino acid would the carbonyl of cysteine be hydrogen bonded? Cys-Tyr-Ile-Gln-Asp-His-Ala (A)Tryosine (B) Glutamine (C) Aspartate (D)Histidine (E) Isoleucine
c
In a typical eukaryotic cell the pH is usually around 7.40, What is the hydrogen ion concentration in a typical eukaryotic cell? (A) 0.00000074 M (B) 6.6 M (C) 4 X 10-8 M (D) 23 X 10-9 M (E) 7.4 X 10-5 M
c
Ion exchange chromatography fractionate proteins based on (A) molecular size. (B) hydrophobicity. (C) electrostatic charge. (D) isoelectric point. (E) affinity for an immobilized ligand.
c
NH4Cl (s) NH3 (g) + HCl (g) deltaH = +176 kJ/mol, deltaS = +0.285 kJ/molK The reaction is (A) exergonic for all temperature values. (B) exergonic for all temperature values below 617.5 o K. (C) exergonic for all temperature values above 617.5 o K (D) endergonic for all temperature values. (E) None of the above.
c
The following titration curve corresponds to which amino acid? (A) aspartic acid (B) arginine (C) isoleucine (D) glutamate (E) histidine
c
The standard free energy changes for two reactions are given below: GTP + H2O --> GDP + Pi deltaGo' = -30.5 kJ/mole Succinyl-CoA + H2O --> Succinate + CoA deltaGo ' = -33.4 kJ/mole What would be the standard free change for the following reaction? Succinyl-CoA + GDP + Pi Succinate + CoA + GTP Go ' = ? (A)-63.9 kJ/mole (B) +63.9 kJ/mole (C) -2.9 kJ/mole (D)2.9 kJ/mole (E) None of the above is correct.
c
What is the advantage of adding SDS to gel electrophoresis? (A) SDS colors the proteins for visualization. (B) SDS reduces disulfide bonds. (C) SDS allows proteins to be separated on the basis of approximate mass. (D) SDS fragments the protein into small peptides. (E) None of the above.
c
What is the shortest alpha-helix that will span a 75 Å membrane bilayer? (A)5 amino acids (B) 20 amino acids (C) 50 amino acids (D)100 amino acids (E) 200 amino acids
c
Which of the above reagents will reduce disulfide bonds? (A) Ammonium Sulfate (B) Iodoacetate (C) beta-mercapto ethanol (D) Phenylisothiocyanate (E) Cyanogen Bromide
c
Which of the above reagents will reduce disulfide bonds? (A)Ammonium Sulfate (B)Iodoacetate (C) Dithiothreitol (D)Dansyl Chloride (E) Guanidinium Chloride
c
Which of the following rank the interactions in order of strength from the lowest to the highest? (A)Hydrogen bonds, ionic interactions, hydrophobic interactions, covalent bonds. (B) Hydrogen bonds, hydrophobic interactions, ionic interactions, covalent bonds (C) Ionic interactions, covalent bonds, hydrogen bonds, hydrophobic interactions. (D) Hydrophobic interactions, hydrogen bonds, ionic interactions, covalent bonds. (E) Covalent bonds, hydrophobic bonds, hydrogen bonds, ionic interactions.
d
Which of the following reagents would be most useful in determining the N-terminal residue of a polypeptide? (A) Trypsin (B) Carboxypeptidase A (C) Carboxypeptidase B (D) Phenylisothiocyanate (E) Cyanogen bromide
d
Which of the following statements about hydrogen bonds is true? A. A hydrogen bond can be as strong as a covalent bond. B. Water is a weak hydrogen bond donor, but a strong hydrogen bond acceptor. C. Hydrogen bonds occur between nonpolar molecules. D. Hydrogen bonds account for the high boiling point of water. E. Hydrogen bonds form between positively and negatively charged ions
d
Which of the following statements is correct? (A)The alpha-helix is composed of two antiparallel polypeptide chains. (B) beta-sheets found in biological systems are always antiparallel. (C) The alpha-helix is stabilized by successively charged amino acid residues. (D)Antiparallel beta-sheets are more stable than parallel beta-sheets (E) The side chains of an alpha-helix are found in the inside of the helix.
d
An alpha-helix would be destabilized by (A) containing two successive charged residues. (B) containing two successive bulky nonpolar residues. (C) containing a proline residue. (D) containing a glycine residue. (E) All of the above.
e
At equilibrium, (A) the concentration of reactants and products is 1 M (B) K'eq = 0 (C) K'eq = 1 (D) deltaG'= 0 (E) deltaG'= -RTLnK'eq
e
Bone is composed primarily of: (A) alpha-keratin. (B) fibroin. (C) myogobin. (D) parallel beta-sheets. (E) collagen.
e
The large dipole moment of water is due to : (A) the electronegativity of the Oxygen atom of water. (B) waters bent geometry. (C) the polarity of the O-H bond. (D) A, B and C are all incorrect. (E) A, B, and C are all correct.
e
The second law of thermodynamics states (A) The energy of the universe is constant. (B) The energy of the universe is conserved. (C) The entropy of the universe is constant. (D) At the temperature of absolute zero, the entropy is zero. (E) All spontaneous processes increase the entropy of the universe.
e
The slowest step of protein folding is (A)the formation of domains by cooperative interactions of folded nuclei. (B) the hydrophobic collapse of the unfolded protein. (C) the formation of the molten globule (D)the transient formation of short stretches of secondary structure. (E) the conformational adjustments to optimize the orientation of the side chains.
e
Which of the above organelles is site of prokaryotic DNA replication? a. Mitochondrian b. Lysosome c. Nucleus d. Rough Endoplasmic Reticulum e. Cytosol
e
Which of the following is not a state function? (A)volume (B) entropy (C) free energy (D)internal energy (E) thermal energy
e
Which of the following statements is correct? (A) The alpha-helix is composed of more than one polypeptide chain. (B) beta-Sheets are found in nature only in the antiparallel form. (C) The alpha-helix is stabilized by successively charged amino acids. (D) beta-sheets are stabilized primarily by ionic interactions between the side chains of amino acids. (E) beta-turns often contain proline residues
e
Which of the following statements is correct? (A) The alpha-helix is composed of more than one polypeptide chain. (B) beta-Sheets are found in nature only in the antiparallel form. (C) The alpha-helix is stabilized by successively charged amino acids. (D) beta-sheets are stabilized primarily by ionic interactions between the side chains of amino acids. (E) beta-turns often contain proline residues.
e
Which of the following statements is correct? (A)Parallel -sheets are more stable than antiparallel -sheets. (B) In -sheets,every carbonyl oxygen is hydrogen bonded with an amide hydrogen four residues farther up the polypeptide chain. (C) Only antiparallel -sheets are found in proteins. (D)All -sheets have a left-handed twist. (E) In all -sheets successive side chains of the polypeptide chains occur on opposite planes of the sheet.
e
Which reagent cleaves polypeptides on the C-side of methionine residues? (A) Ammonium Sulfate (B) Iodoacetate (C) beta-mercapto ethanol (D) Phenylisothiocyanate (E) Cyanogen Bromide
e
Which reagent is used to reversibly denature proteins? (A)Ammonium Sulfate (B)Iodoacetate (C) Dithiothreitol (D)Dansyl Chloride (E) Guanidinium Chloride
e
You are trying to separate the following 3 tripeptides by anion exchange chromatography. (a) Gly-Pro-Val, (b) Ser-Asp-Met and (c) Ala-Lys-His. If the pH is 7.0, then (A) All three peptides would elute together. (B) The order of elution would be a-b-c. (C) The order of elution would be c-b-a. (D)The order of elution would be b-a-c (E) The order of elution would be c-a-b.
e
