Biochemistry Testbank 1
Considering a 0.1 M formic acid buffer, what is the concentration of formic acid present in a solution of pH 4.25 if the pKof formic acid is 3.75? A) 0.024 M B) 0.033 M C) 0.067 M D) 0.076 M E) none of the above
A) 0.024 M
What is the resulting pH if 10 millimoles of HCl is added to 1 liter of a 0.1 M phosphate buffer at pH 7.00 (pK=6.82)? A) 6.82 B) 6.98 C) 7.01 D) 7.19 E) cannot be determined
A) 6.82
Which allosteric effector has the greatest ability to stabilize the deoxy state of hemoglobin? A) BPG B) CO 2 C) O 2 D) H + E) all of the above have equal ability
A) BPG
Which of the following is an example of a conservative amino acid substitution? A) Ile >Leu B) Ser > Glu C) Phe >Tyr D) Asp > Gln E) Arg > Cys
A) Ile >Leu
A technique for determining protein structure where the protein is in solution is ___. a) NMR spectroscopy b) X-ray crystallography c) electron crystallography d) mass spectrometry e) none of these choices
A) NMR spectroscopy
The total number of proteins that can be produced from any 10 amino acids is? A) 10^20 B) 20^10 C) 100 D) 200 E) 10^10
B) 20^10
What would be the resulting pH if one drop (0.05 ml) of 1.0 M HCl was added to one liter of pure water (assume pH 7.0)? A) 2.7 B) 4.3 C) 5.0 D) 7.0 (there would be no significant change) E) 9.7
B) 4.3
Hydrogen bonds are approximately _____% of the bond strength of covalent C-C or C-H bonds. A) 1 B) 5 C) 20 D) 50 E) 95
B) 5
What would be the resulting pH if one ml of 1.0 M NaOH was added to one liter of pure water (assume pH 7.0)? A) 1 B) 3 C) 7.3 D) 11 E) 13
D) 11
In an aqueous solution, if the [OH-] is 3.0×10-5M, what is the [H+]? A) 7.0×10^-9 B) 7.0×10^-2 C) 3.3×10^-3 D) 3.3×10^-10 E) none of the above
D) 3.3×10^-10
Given pKavalues of 3.5, 9.0and 3.9 (side chain), what is the pI of aspartic acid? a) 6.5 b) 6.3 c) 5.3 d) 3.7 e) none of these choices
D) 3.7
If 1.0 mL of 1.0 M acetic acid (pK = 4.76, K = 1.74 x 10 -5 ) was added to one liter of pure water, what is the resulting pH? A) 1.0 B) 1.3 C) 3.0 D) 3.9 E) 10.1
D) 3.9
What is the one letter abbreviation for Proline?
P
What is the net charge of the pentapeptide Ala-Cys-Ser-Glu-Asn at pH 7? a) -2 b) -3 c) 0 d) +1 e) none of these choices
b) -3
At pH ___, the pentapeptide Ala-Glu-His-Val-Cys would contain two positively charged groups and one negatively charged group. a) 1 b) 3 c) 5 d) 7 e) 9
b) 3
What are the four major classes of molecules studied in biochemistry (in monomeric form)?
lipids, nucelotides, monosaccharides, amino acids
Amino acids are the building blocks of _________.
proteins
If a phosphate buffer (pK=6.82) was formulated such that its pH was 7.3, it would be best suited to buffer against _____. If instead, it was formulated such that its pH was 6.3, it would be best suited to buffer against _____. A) acid; base B) acid; acid C) base; acid D) base; base E) a buffer with a pH that far from the pK would not be an effective buffer
A) acid; base
Which of the following explains the conversion of hemoglobin subunits from deoxy to oxy state? A) all four subunits switch simultaneously B) each subunit switches only upon oxygen binding to the particular subunit C) both alpha-subunits simultaneously switch first followed by both beta subunits D) both beta subunits simultaneously switch first followed by both alpha subunits E) none of the above
A) all four subunits switch simultaneously
What is the most prevalent secondary structure observed in the proteins of intermediate filaments? A) alpha-helices B) beta-helices C) alpha-sheets D) beta-sheets E) both alpha-helices and beta-helices are observed
A) alpha-helices
Bone and tendons contain _____ while hair and nails contain _____. A) collagen; keratin B) actin; keratin C) tubulin; collagen D) collagen; actin E) tubulin; keratin
A) collagen; keratin
Which of the following would be the strongest acid? A) formic acid, pK=3.75 B) succinic acid, a diprotic acid with pK=4.21 and 5.64 C) acetic acid, pK=4.76 D) ammonium ion, pK=9.25 E) cannot be determined from the given information
A) formic acid, pK=3.75
In aqueous solution, globules of up to several thousand amphiphilic molecules arranged with the hydrophilic groups on the surface and the hydrophobic groups buried in the center are called _____. A) micelles B) vacuoles C) liposomes D) bilayers E) none of the above
A) micelles
The similarity of one organism to another (for example a bacteria versus a human) is most easily done by comparing which biopolymer? A) nucleic acids B) polysaccharides C) proteins D) lipids E) all of the above
A) nucleic acids
Considering the energetics of transferring nonpolar molecules from water to a nonpolar solvent, the factor TdeltaS is generally _____, causing deltaG to be _____. A) positive; negative B) negative; negative C) positive; positive D) positive; positive E) negligible; either positive or negative
A) positive; negative
When a non-polar substance is added to water, how do the molecules of water behave? A) the regular hydrogen bond pattern is disrupted resulting in a decrease of entropy B) the regular hydrogen bond pattern is disrupted resulting in an increase of entropy C) the regular hydrogen bond pattern is disrupted resulting in a decrease of enthalpy D) the regular hydrogen bond pattern is disrupted resulting in an increase of enthalpy E) none of the above
A) the regular hydrogen bond pattern is disrupted resulting in a decrease of entropy
The heads of kinesin bind to _____; the light chains of kinesin bind to _____. A) tubulin; proteins in the membrane of a vesicle B) proteins in the membrane of an organelle; tubulin C) proteins in the membrane of a vesicle; actin D) collagen fibers; proteins in the cell membrane E) none of the above
A) tubulin; proteins in the membrane of a vesicle
At any given moment, a single water molecule participates in _____ strong hydrogen bond(s). The role played by the water molecule is best characterized as _____. A) two ; one H-bond donor, one H-bond acceptor B) two ; two H-bond donor C) two ; two H-bond acceptor D) one; H-bond donor E) one; H-bond acceptor
A) two ; one H-bond donor, one H-bond acceptor
During vigorous exercise, hydrogen ions are produced within cells as a result of increased metabolism. What component of the intracellular buffer would increase as a result of the increased H + production? A) H3 PO4 B) H2 PO4 - C) HPO4 2- D) PO4 3- E) none of the above
B) H2 PO4 -
Which amino acid is critical for crosslinking of collagen trimers? A) Ser B) Lys C) His D) Cys E) Gln
B) Lys
Keratin is classified as which of the following types of protein? A) Enzyme B) Structural C) Movement D) Defense E) Regulatory
B) Structural
Proteins such as hemoglobin are known as _____ proteins since binding of a molecule to one site alter binding to other sites. A) ligand-activated B) allosteric C) induced-fit D) cooperative E) none of the above
B) allosteric
When a peptide bond forms, a(n) ___ reacts with a carboxylate group. a) amide b) amine c) alcohol d) ester e) none of these choices
B) amine
A molecule that has both a polar and nonpolar region is called _____________. A) micelleic B) amphiphilic C) endergonic D) a membrane E) none of the above
B) amphiphilic
Which of the following is the most abundant element in the human body? A) nitrogen B) carbon C) oxygen D) phosphorous E) none of the above
B) carbon
The idea that binding of one molecule of oxygen to hemoglobin enhances further binding of oxygen to hemoglobin is called _____. A) homologous binding B) cooperativity C) fractional saturation D) allosterism E) none of the above
B) cooperativity
Which of the following explains the interactions that occur between the atoms of water molecules and the ions that form when sodium chloride dissolves in water? A) hydrogens interact with the sodium ion, oxygens interact with the chloride ion B) hydrogens interact with the chloride ion, oxygens interact with the sodium ion C) hydrogens interact with the sodium ion and the chloride ion D) oxygens interact with the sodium ion and the chloride ion E) none of the above
B) hydrogens interact with the chloride ion, oxygens interact with the sodium ion
Hemoglobin S, the variant responsible for the misshapen red blood cells characteristic of the disease sickle-cell anemia, is potentially advantageous to heterozygotes because it confers some level of resistance to the disease _____. A) AIDS B) malaria C) polycythemia D) rickets E) cyanosis
B) malaria
Which of the following represents the longest distance traveled by a kinesin-vesicle complex? A) movement of a mitochondria in a cardiac cell B) movement of a neurotransmitter vesicle down the axon of a nerve cell C) movement of a glucose filled vesicle to the membrane of a liver cell D) movement of a lipid-filled vesicle within an intestinal cell E) none of the above
B) movement of a neurotransmitter vesicle down the axon of a nerve cell
Based upon its side chain, how is the amino acid Ser classified? a) non-polar b) polar c) positively charged d) negatively charged e) none of these choices
B) polar
Which of the following biopolymers is correctly paired with the bond that forms between the monomers? A) protein: ester bond B) polysaccharide: glycosidic bond C) DNA: phosphate bond D) RNA: phosphate bondE)all of the above
B) polysaccharide: glycosidic bond
Heme is considered a _____. A) catalyst B) prosthetic group C) coenzyme D) cofactor E) none of the above
B) prosthetic group
In a hydrogen bond between a water molecule and another biomolecule, _____. A) a hydrogen ion on the water molecule forms an ionic bond with a hydride ion on the other molecule B) the hydrogen bond will typically form between a hydrogen atom and either a nitrogen, sulfur, or oxygen atom C) the partial charge on a hydrogen of the water interacts with the partial charge on a hydrogen of the other molecule D) a hydrogen on the water molecule forms a covalent bond to an oxygen or nitrogen atom on the other molecule E) the hydrogen atom is located between an oxygen atom of the water and a carbon atom of the other molecule
B) the hydrogen bond will typically form between a hydrogen atom and either a nitrogen, sulfur, or oxygen atom
Which of the following is true regarding hydrophobic interactions between nonpolar molecules or groups? A) they result from the tendency to maximize waters contact with nonpolar molecules B) they require the presence of surrounding water molecules C) they are the result of strong attractions between nonpolar regions D) they are the result of strong repulsion between water and nonpolar regions E) they depend on strong permanent dipoles in the nonpolar molecules
B) they require the presence of surrounding water molecules
In a muscle cell, what is the name for the bundles of myosin tails? A) cytoskeleton B) thick filaments C) intermediate filaments D) thin filaments E) none of the above
B) thick filaments
At pH 3, how many charged groups are present in the pentapeptide Ala-Asp-His-Ser-Lys? a) 1 b) 2 c) 3 d) 4 e) 5
C) 3
Which of the following is a nonstandard amino acid? A) Glycine B) Cysteine C) 5-Hydroxyproline D) Valine E) Alanine
C) 5-Hydroxyproline
The term protein refers to amino acid polymers with greater than ________ amino acids. A) 10 B) 20 C) 50 D) 70 E) 90
C) 50
What is the [H + ] of an aqueous solution with a pH of 6.2? A) 6.2x10 -6 B) 1.6x10 -8 C) 6.3x10 -7 D) 3. 3x10 -5 E) none of the above
C) 6.3x10 -7
28) If the pK values for phosphoric acid are 2.15, 6.82 and 12.38, at what pH would one observe equal amounts of H 2 PO 4 - and HPO 4 2- ? A) 2.15 B) 4.49 C) 6.82 D) 9.60 E) 12.38
C) 6.82
Which of the following correctly describes the sequence of events in the myosin-actin cycle? A) myosin release from actin, ATP binds to myosin, myosin binds to another actin subunit, release of P i and ADP, stretched myosin returns to original conformation B) myosin release from actin, ATP binds to myosin, myosin binds to another actin subunit, stretched myosin returns to original conformation, release of P i and ADP C) ATP binds to myosin, myosin release from actin, myosin binds to another actin subunit, release of P i and ADP, stretched myosin returns to original conformation D) ATP binds to myosin, myosin release from actin, myosin binds to another actin subunit, stretched myosin returns to original conformation, release of P i and ADP E) myosin release from actin, myosin binds to another actin subunit, ATP binds to myosin, stretched myosin returns to original conformation, release of P i and ADP
C) ATP binds to myosin, myosin release from actin, myosin binds to another actin subunit, release of P i and ADP, stretched myosin returns to original conformation
During the formation of microfilaments, which of the following occurs? A) ATP binds to F-actin B) F-actin polymerizes, becoming G-actin C) ATP hydrolysis is catalyzed by F-actin D) polymerization proceeds quickly at first, then slows after about ten actin monomers have polymerized E) none of the above
C) ATP hydrolysis is catalyzed by F-actin
The central ion of the heme group of hemoglobin is _____. A) Cu+ B) Cu2+ C) Fe2+ D) Fe3+ E) none of the above
C) Fe2+
The central ion of the heme group of hemoglobin is _____. A) Cu+ B) Cu2+ C) Fe2+ D) Fe3+ E) none of the above
C) Fe^2+
During the initial synthesis of collagen molecules, _____ and _____ are most often incorporated into the growing protein. A) Ser; Gly B) Pro; Ala C) Gly; Pro D) Ala; Gly E) Ser; Pro
C) Gly; Pro
What is the conjugate acid of H 2 PO 4 - ? A) HPO4 2- B) H2 PO4 C) H3 PO4 D) PO4 3- E) none of the above
C) H3 PO4
What is the conjugate acid ofH2PO4-? A) HPO4^2- B) H2PO4 C) H3PO4 D) PO4^3- E) none of the above
C) H3PO4
Which of the following explains how cell division is blocked by drugs that prevent proper microtubule function? A) the condensation of chromatin requires a microtubule skeleton B) production of new membranes for organelles and nucleus requires microtubules C) chromosomes separate along a microtubule spindle D) division of organelles between daughter cells requires organelle movement along microtubules E) none of the above
C) chromosomes separate along a microtubule spindle
Hydrogen bonds within liquid water are _________. A) attractions between the protons of the oxygen nuclei B) ion-induced dipole interactions C) dipole-dipole interactions D) attractions between two oxygen atoms E) attractions between the H + and - OH ions of the liquid
C) dipole-dipole interactions
What term is used to describe the exclusion of nonpolar substances from an aqueous solution? A) nonpolar effect B) lipid effect C) hydrophobic effect D) oil droplet effect E) amphiphilic effect
C) hydrophobic effect
A plot of the binding of oxygen to myoglobin as a function of pO2 gives a _____ shape; a similar plot for hemoglobin gives a _____ shape. A) sigmoidal; sigmoidal B) sigmoidal; hyperbolic C) hyperbolic; sigmoidal D) hyperbolic; hyperbolic E) hyperbolic; exponential
C) hyperbolic; sigmoidal
Due to the formation of hydrogen bonds, _____ is highly soluble in water. A) carbon dioxide B) sodium chloride C) methanol D) octane E) cholesterol
C) methanol
Fatty acid anions most commonly assemble into _____ in aqueous solution. A) lipid bilayers B) solvent-filled vesicles C) micelles D) liposomes E) none of the above
C) micelles
Which of the following occurs in hemoglobin upon oxygen binding? A) the heme Fe 2+ is pulled out of the plane of the heme group B) the His coordinated to the heme Fe 2+ is pushed away from the heme group C) the central cavity between the four subunits is decreased in size D) hemoglobin changes from the R state to the T state E) all of the above occur
C) the central cavity between the four subunits is decreased in size
Which of the following amino acids has a thiol group in its side chain? a) Ser b) Asn c) Cys d) Tyr e) Met
C0 Cys
What is the pH of a solution that contains three parts of acetic acid and one part sodium acetate? The pKfor acetic acid is 4.76. A) 5.24 B) 5.06 C) 4.46 D) 4.28 E) cannot be determined from the given information
D) 4.28
Which of the following correctly describes the sequence of events in the kinesin reaction cycle? For simplicity, the two heads are referred to as head 1 and head 2. Head 1 starts as the leading head. A) head 1 releases tubulin, ATP binds to head 1, head 2 swings forward, head 2 binds to tubulin, ADP release from head 2, ATP hydrolysis in head 1 B) ATP binds to head 1, head 2 swings forward, ADP release from head 2, ATP hydrolysis in head 1, head 2 binds to tubulin, head 1 releases tubulin C) ATP binds to head 1, head 2 swings forward, head 2 binds to tubulin, ATP hydrolysis in head 1, ADP release from head 2, head 1 releases tubulin D) ATP binds to head 1, head 2 swings forward, head 2 binds to tubulin, ADP release from head 2, ATP hydrolysis in head 1, head 1 releases tubulin E) none of the above
D) ATP binds to head 1, head 2 swings forward, head 2 binds to tubulin, ADP release from head 2, ATP hydrolysis in head 1, head 1 releases tubulin
How does CO 2 affect hemoglobin-oxygen binding? A) CO 2 binds directly to the oxygen binding site, displacing oxygen and thus promoting the deoxy state B) CO 2 displaces BPG, thus promoting the oxy state C) CO 2 is converted to bicarbonate and H + which promotes the oxy state D) CO 2 is converted to bicarbonate and H + which promotes the deoxy state E) none of the above
D) CO 2 is converted to bicarbonate and H + which promotes the deoxy state
Which of the following best explains the ability for carbon monoxide (CO) to bind to hemoglobin (Hb) despite the relatively low concentrations of CO? A) CO binds to Hb with less affinity than oxygen B) CO binds to Hb with an affinity about the same as oxygen C) CO binds to Hb about 5 times more strongly than oxygen D) CO binds to Hb about 250 times more strongly than oxygen E) none of the above
D) CO binds to Hb about 250 times more strongly than oxygen
Metabolic acidosis often causes increased respiratory rates. What portion of the bloodstream buffer is lost through increased respiration? A) H+ B) HCO3 - C) H2 CO3 D) CO2 E) H2O
D) CO2
How does CO2affect hemoglobin-oxygen binding? A) CO2 binds directly to the oxygen binding site, displacing oxygen and thus promoting the deoxy state B) CO2 displaces BPG, thus promoting the oxy state C) CO2i s converted to bicarbonate and H+which promotes the oxy state D) CO2 is converted to bicarbonate and H+which promotes the deoxy state E) none of the above
D) CO2 is converted to bicarbonate and H+which promotes the deoxy state
Which amino acid is critical for crosslinking of keratin fibers? A) Ser B) Lys C) His D) Cys E) Gln
D) Cys
When oxygen is bound to the heme group of myoglobin, it is coordinated between _____ and _____. A) F8 His; Fe 3+ of heme B) E7 His; Fe 3+ of heme C) F8 His; Fe 2+ of heme D) E7 His; Fe 2+ of heme E) none of the above
D) E7 His; Fe 2+ of heme
Which of the following shows the buffer that is found in the blood stream? A) H3PO4 <----> H2PO4^2-+ H+ B) H2PO4- <----> HPO4^2-+ H+ C) HPO4^2- <----> PO4^3-+ H+ D) H2CO3 <----> HCO3-+ H+ E) HCO^3- <----> CO3^2-+ H+
D) H2CO3 <----> HCO3-+ H+
Each myosin head contains a binding site for _____ and a binding site for _____. A) tubulin; GTP B) another myosin molecule; ATP C) kinesin; GTP D) actin; ATP E) none of the above
D) actin; ATP
What is the N-terminal residue of the peptide AYSDG? a) glutamic acid b) glycine c) aspartic acid d) alanine e) none of these choices
D) alanine
Which of the following functional groups has two hydrogen bond donors and one hydrogen bond acceptor? A) alcohol B) ester C) thiol D) amine E) amide
D) amine
At a pH above its pKa, the R-group of Asp is ___. a) protonated and neutral b) protonated and positively charged c) deprotonated and neutral d) deprotonated and negatively charged e) none of these choices
D) deprotonated and negatively charged
Which of the major types of biomolecules is never found in a polymeric form? A) amino acids B) carbohydrates C) nucleotides D) lipids E) none of the above
D) lipids
Which of the following is an example of an amphipathic molecule? A) adenine, a base found in nucleic acids B) glucose, a monosaccharide C) serine, anamino acid D) palmitic acid, a fatty acid E) none of the above
D) palmitic acid, a fatty acid
Which of the biopolymers is correctly paired with its major function? A) protein: information encoding B) nucleic acids: energy storage C) lipids: information encoding D) polysaccharide: energy storage E) none of the above
D) polysaccharide: energy storage
In a water molecule, hydrogens are partially _____; oxygens are partially _____. A) negative; negative B) negative; positive C) positive; positive D) positive; negative E) none of the above
D) positive; negative
The individual hemoglobin subunits and myoglobin share similar _____ structure but have rather different _____ structure. A) primary; secondary B) secondary; tertiary C) primary; tertiary D) secondary and tertiary; primary E) primary and secondary; tertiary
D) secondary and tertiary; primary
Which of the following explains the attractive forces between hydrophobic molecules in an aqueous solution? A) in an aqueous environment, London dispersion forces between hydrophobic molecules become stronger B) in an aqueous environment, London dispersion forces between hydrophobic molecules and water become stronger C) since nonpolar molecules do not form hydrogen bonds with hydrogen bonds with water, they can form hydrogen bonds with other nonpolar molecules D) there is no increase in attractive forces between nonpolar molecules in an aqueous environment E) none of the above
D) there is no increase in attractive forces between nonpolar molecules in an aqueous
Which of the following explains the attractive forces between hydrophobic molecules in an aqueous solution? A) in an aqueous environment, London dispersion forces between hydrophobic molecules become stronger B) in an aqueous environment, London dispersion forces between hydrophobic molecules and water become stronger C) since nonpolar molecules do not form hydrogen bonds with hydrogen bonds with water, they can form hydrogen bonds with other nonpolar molecules D) there is no increase in attractive forces between nonpolar molecules in an aqueous environment E) none of the above
D) there is no increase in attractive forces between nonpolar molecules in an aqueous environment
The helical structure of collagen contains _____. A) three right-handed helices wound around each other in a right-handed triple helix B) three right-handed helices wound around each other in a left-handed triple helix C) three left-handed helices wound around each other in a left-handed triple helix D) three left-handed helices wound around each other in a right-handed triple helix E) none of the above
D) three left-handed helices wound around each other in a right-handed triple helix
Which of the following amino acids contains a side chain that is polar and uncharged from pH 1-13? a) Phe b) Tyr c) Asp d) Gln e) Ile
D0 Gin
Which of the 20 standard amino acids is optically inactive? a) Arg b) Pro c) Ile d) Gly e) Cys
D0 Gly
What is the one letter abbreviation for Glutamate?
E
Which of the following could be used to formulate 100 mls of a 0.10 M acetate buffer (pK=4.76) at pH 5 if you start with 64 mls of 0.10 M sodium acetate? A) 3.6 mls of 1 M HCl B) 3.6 mls of 1 M NaOH C) 34 mls of 0.10 M HCl D) 34 mls of 0.10 M NaOH E) 34 mls of 0.10 M acetic acid
E) 34 mls of 0.10 M acetic acid
With respect to oxygen saturation, hemoglobin is _____ saturated at the pO 2 of the lungs and _____ saturated at the pO 2 of the tissue A) 20%; 20% B) 25%; 20% C) 50%; 20% D) 50%; between 30 and 70% E) >90%; between 30 and 70%
E) >90%; between 30 and 70%
When not at the terminal of a protein, which of the following amino acids cannot contribute to the pI of a protein? A) Arginine B) Lysine C) Cysteine D) Tyrosine E) Alanine
E) Alanine
If the pK values for phosphoric acid are 2.15, 6.82 and 12.38, _____ would predominate at pH 5 while _____ would predominate at pH 10. A) H3 PO4 ; H2 PO4 - B) H3 PO4 ; HPO4 2- C) H3 PO4 ; PO4 3- D) H2 PO4 - ; PO4 3- E) H2 PO4 - ; HPO4 2-
E) H2 PO4 - ; HPO4 2-
Which of the following interactions does notstabilize tertiary structure? A) Hydrophobic interactions B) Electrostatic interactions C) Hydrogen bonds D) Covalent bonds E) None of the above
E) None of the above
Which of the following could be used to formulate 100 mls of a 0.10 M phosphate buffer (pK=6.82) at pH 7.2? A) 2.9 mmoles of Na2 HPO4 and 7.1 mmoles of NaHPO4 B) 10 mmoles of Na2 HPO4 and 7.1 mmoles of NaOH C) 10 mmoles of NaHPO4 and 7.1 mmoles of HCl D) 10 mmoles of H3 PO4 and 17.1 mmoles of NaOH E) all of the above
E) all of the above
Which of the following fibers is correctly paired with the protein that forms the fiber? A) microfilaments: actin B) microtubule: tubulin C) extracellular support fibers: collagen D) intermediate filaments: keratin E) all of the above
E) all of the above
Which of the following is a physical property of water that results from hydrogen bonding? A) high boiling point relative to molecular weight B) a solid state that is less dense than the liquid state C) high surface tension D) ability to solubilize polar molecules E) all of the above
E) all of the above
Which of the following is an example of the hydrophobic effect? A) the lipid membrane of cells and organelles B) protein folding that places hydrophobic amino acids in the interior of the protein C) the separation of salad dressing D) oil sheens seen on the ocean following an oil spill E) all of the above
E) all of the above
Which of the following molecules would be prevented from readily crossing a lipid bilayer? A) glucose B) sodium ions C) potassium ions D) water E) all of the above
E) all of the above
What is the prominent type of secondary structure observed in myoglobin? A) beta-helices B) alpha-bends C) parallel beta-sheets D) antiparallel beta.sheets E) alpha-helices
E) alpha-helices
Ascorbic acid is required for the production of _____ in collagen. A) hydroxylysine B) y-carboxyglutamic acid C) desmosine D) aspartate beta-semialdehyde E) hydroxyproline
E) hydroxyproline
The strongest non-covalent interactions are _____. A) van der Waals interactions B) London dispersion forces C) hydrogen bonds D) dipole-dipole interactions E) ionic interactions
E) ionic interactions
Each kinesin head contains a binding site for _____ and a binding site for _____. A) tubulin; GTP B) another kinesin molecule; GTP C) myosin; ATP D) actin; ATP E) tubulin; ATP
E) tubulin; ATP
The central ion of the heme group of hemoglobin is ________.
Fe^2+
What is the three letter abbreviation for Glycine?
GLY
What is the one letter abbreviation for Lysine?
K
Lysine can form a salt bridge by interacting with the side chain of ___. a) Glu b) Gly c) Asn d) Ser e) Pro
a) Glu
48) A technique for determining protein structure where the protein is in solution is ___. a) NMR spectroscopy b) X-ray crystallography c) electron crystallography d) mass spectrometry e) none of these choices
a) NMR spectroscopy
The amino acid ___ is commonly phosphorylated. a) Ser b) Asp c) Asn d) His e) none of these choices
a) Ser
What level of protein structure is characterized by the amino acid sequence? a) primary b) secondary c) tertiary d) quaternary e) none of these choices
a) primary
Myosin works with which protein to produce movement?
actin
If a protein underwent a mutation such that a Glu residue was changed to another amino acid, which of the following amino acids would least likely result in a change in the overall structure of the protein? a) Ser b) Asp c) Gln d) Lys e) Ala
b) Asp
The side chain of serine could interact with the side chain of ___ using a(n) ___. a) Val; hydrophobic interaction b) His; hydrogen bond c) Gln; hydrophobic interaction d) Asn; electrostatic interaction e) none of these choices
b) His; hydrogen bond
Which of the following amino acids has a nonpolar side chain? a) Ser b) Val c) Lys d) Asn e) none of these choices
b) Val
A technique for determining protein structure that requires crystals of the protein is ___. a) NMR spectroscopy b) X-ray crystallography c) electron crystallography d) mass spectrometry e) none of these choices
b) X-ray crystallography
When a peptide bond forms, a(n) ___ reacts with a carboxylate group. a) amide b) amine c) alcohol d) ester e) none of these choices
b) amine
The predominant non-covalent interaction seen in alpha-helices and beta-sheets is ___. a) electrostatic interactions b) hydrogen bonds c) dipole-dipole interactions d) hydrophobic interactions e) all of these choices
b) hydrogen bonds
Which of the following is most critical for maintaining the tertiary structure of a protein? a) hydrogen bonds b) hydrophobic interactions c) disulfide bonds d) salt bridges e) none of these choices
b) hydrophobic interactions
Based upon its side chain, how is the amino acid Ser classified? a) non-polar b) polar c) positively charged d) negatively charged e) none of these choices
b) polar
At a pH above its pKa, the epsilon-amino group of lysine is ___. a) protonated and neutral b) protonated and positively charged c) deprotonated and neutral d) deprotonated and negatively charged e) none of these choices
b) protonated and positively charged
alpha-helices and beta-sheets comprise ___ structure. a) primary b) secondary c) tertiary d) quaternary e) none of these choices
b) secondary
Molecular chaperones assist proteins in the formation of ___. a) aggregates b) tertiary structure c) peptide bonds d) primary structure e) none of these choices
b) tertiary structure
At physiological pH, all amino acids have at least ___ charged groups. a) 0 b) 1 c) 2 d) 3 e) cannot be determined
c) 2
If an alpha-helical region of a protein contained 18 amino acid residues, how many helical turns would be present? a) 3.33 b) 4 c) 5 d) 6 e) none of these choices
c) 5
Given pKa values of 2.3 and 9.7, what is the pI of alanine? a) 12 b) 7.4 c) 6 d) 4.2 e) none of these choices
c) 6
Which of the following amino acids has a thiol group in its side chain? a) Ser b) Asn c) Cys d) Tyr e) Met
c) Cys
For a globular protein that is found in the cytosol, ___ would most likely be found in the proteins interior while ___ would most likely be found on the surface. a) Val; Phe b) Leu; Ile c) Leu; Ser d) Thr; His e) none of these choices
c) Leu; Ser
Which of the following amino acids has a positively charged side chain at pH 7.4? a) Glu b) Ala c) Lys d) Leu e) His
c) Lys
Which of the following best describes the peptide backbone in a beta-sheet? a) coiled b) compacted c) highly extended d) rigid e) none of these choices
c) highly extended
What level of protein structure is characterized by the three dimensional structure of an entire polypeptide including all amino acid side chains? a) primary b) secondary c) tertiary d) quaternary e) none of these choices
c) tertiary
Polymers of sugars are __________.
carbohydrates
The idea that binding of one molecule of oxygen to hemoglobin enhances further binding of oxygen to hemoglobin is called ____________.
cooperativity
Since there are 20 standard amino acids, the number of possible linear polypeptides of length N can be expressed as ___. a) 20 x 10^N b) N 20 c) N x 10 ^20 d) 20^N e) N x 20
d) 20^N
Given pKa values of 2.1, 9.8 and 3.9 (side chain), what is the pI of aspartic acid? a) 6.0 b) 6.9 c) 5.3 d) 3.0 e) none of these choices
d) 3.0
At pH 3, how many charged groups are present in the pentapeptide Ala-Asp-His-Ser-Lys? a) 1 b) 2 c) 3 d) 4 e) 5
d) 4
Which of the following amino acids contains a side chain that is polar and uncharged from pH 1-13? a) Phe b) Tyr c) Asp d) Gln e) Ile
d) Gln
Which of the 20 standard amino acids is optically inactive? a) Arg b) Pro c) Ile d) Gly e) Cys
d) Gly
Which of the following amino acids is generally absent from an alpha-helix? a) Trp b) Ser c) Ile d) Pro e) none of these choices
d) Pro
What is the N-terminal residue of the peptide AYSDG? a) glutamic acid b) glycine c) aspartic acid d) alanine e) none of these choices
d) alanine
At a pH above its pKa, the R-group of Asp is ___. a) protonated and neutral b) protonated and positively charged c) deprotonated and neutral d) deprotonated and negatively charged e) none of these choices
d) deprotonated and negatively charged
At a pH above its pKa, the phenolic group of tyrosine is ___. a) protonated and neutral b) protonated and positively charged c) deprotonated and neutral d) deprotonated and negatively charged e) none of these choices
d) deprotonated and negatively charged
If the following mixture of proteins was applied to a size-exclusion chromatography column, what would be the order of elution? Proteins with molecular weights: myoglobin (17.7 kDa) , hemoglobin (64.5 kDa) , lysozyme (14.3 kDa) and triose phosphate isomerase (57.4 kDa) a) lysozyme, myoglobin, triose phosphate isomerase, hemoglobin b) triose phosphate isomerase, hemoglobin, lysozyme, myoglobin c) hemoglobin, myoglobin, lysozyme, triose phosphate isomerase d) hemoglobin, triose phosphate isomerase, myoglobin, lysozyme, e) cannot be determined
d) hemoglobin, triose phosphate isomerase, myoglobin, lysozyme,
18) The formation of a dipeptide from two amino acids requires ___. a) reduction of the -carboxyl group b) protonation of the -amine group c) interaction of the two side-chains d) loss of water e) none of these choices
d) loss of water
Disulfide bonds form between two residues of which amino acid? a) Met b) Ser c) Asn d) Thr e) Cys
e) Cys
What is the C-terminal amino acid in the pentapeptide Val-Leu-Arg-Ser-Gly? a) Val b) Leu c) Arg d) Ser e) Gly
e) Gly
Which of the following interactions would be involved in quaternary structure? a) hydrogen bonds b) hydrophobic interactions c) disulfide bonds d) salt bridges e) all of these choices
e) all of these choices
Which protein associates with microtubules to transport cargo within a cell?
kinesin
Name the amino acid with the following side chain: -CH2-CH2-S-CH3
methionine
look at 26 chap 4 test bank and type ok
ok
look at 32 and 33 chap 4 test bank and type ok
ok
look at 7, 12, 17 chap 4 test bank type ok
ok
look at chap 2 test bank 33 and 34 and type ok
ok
What is the Henderson-Hasselbalch equation?
pH = pKa + log([A-]/[HA])
Name the amino acid with the following side chain: -CH2-OH
serine
[HA] is the _____________ and [A-] is the ____________.
tris acid (HCl), tris base
