Advanced Biochem Final

If an inhibitor changes the slope of the Lineweaver-Burk graph, but not the y-intercept, it is this type of inhibition:
a. Competitive.
b. Non-competitive.
c. Mixed Inhibition (uncompetitive inhibition).
d. You cannot tell from the data given. e. More than one answer is correct.
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If an inhibitor changes the slope of the Lineweaver-Burk graph, but not the y-intercept, it is this type of inhibition:
a. Competitive.
b. Non-competitive.
c. Mixed Inhibition (uncompetitive inhibition).
d. You cannot tell from the data given. e. More than one answer is correct.
a. Competitive.
Zymogens are
a. inactive precursors of enzymes which can be activated by the irreversible cleavage of covalent bonds.
b. inactive forms of enzymes which require phosphorylation by a kinase to become active.
c. allosteric enzymes that are always in the R state. d. allosteric enzymes that are always in the T state.
a. inactive precursors of enzymes which can be activated by the irreversible cleavage of covalent bonds.
Allosteric enzymes must exhibit which of the following?
a. feedback inhibition b.
a phosphorylation site
c. general acid-base catalysis
d. a quaternary structure
e. none of these must be exhibited
d. a quaternary structure
What is the function of protein spikes on a virus?
a. They protect the genome.
b. They are involved with incorporation of the genome into that of host (lysogeny).
c. They transcribe the RNA genome into a DNA copy.
d. They help the virus attach to the host
d. They help the virus attach to the host
A virus life cycle that involves the incorporation of the viral DNA into the host chromosome is
a. lysogeny.
b. lytic.
c. oncogenic.
d. non-existent.
a. lysogeny.
What happens to the DNA copy of the retroviral RNA genome after it is produced?
a. It is incorporated into the host's DNA.
b. It is transcribed to produce mRNAs.
c. It is wrapped in a capsid for export from the cell.
d. It is replicated as a plasmid.
a. It is incorporated into the host's DNA.
Which of the following is not a feature common to all retroviruses?
a. Reverse Transcriptase (RT)
b. Retroviral Coat Protein (CP)
c. Retroviral Envelope Protein (EP)
d. Sarcoma Oncogenes
d. Sarcoma Oncogenes
What causes Cystic Fibrosis
a. Mutation to a gene
b. Malfunctioning Na/Cl ion pumps
c. Both A + B
d. None of the above
c. Both A + B
Nitrification is the conversion of
a. nitrogen gas to nitrate.
b. nitrogen gas to ammonia.
c. nitrate to ammonia.
d. nitrate to nitrogen gas.
e. ammonia to nitrogen gas.
b. nitrogen gas to ammonia.
Which of the following are all essential amino acids in humans?
a. leucine, lysine, valine
b. methionine, threonine, serine
c. arginine, histidine, cysteine
d. glutamate, glutamine, arginine
e. valine, isoleucine, glycine
a. leucine, lysine, valine
18. The urea cycle is linked to the citric acid cycle by a. arginine b. citrulline c. fumarate d. ornithinec. fumarateMyoglobin is tertiary as hemoglobin is to a. primary b. Secondary c. Tertiary d. quaternaryd. quaternary3. Which of the following amino acids are ketogenic? a. Glycine. b. Alanine. c. Aspartic Acid. d. Leucine.d. Leucine.The overall folding of a single protein subunit is called: a. primary structure b. secondary structure c. tertiary structure d. quaternary structurec. tertiary structureWhich of the following is often found connecting the strands of an antiparallel β- sheet? a. β-bulge b. reverse turn c. α-helix d. prosthetic groupb. reverse turnThe protein myoglobin a. contains a high degree of β-pleated sheet structure b. carries oxygen in the bloodstream c. contains no histidine d. contains a heme groupd. contains a heme groupWhich of the following is not a characteristic of most fatty acids? a. Presence of trans double bonds. b. Even number of carbon atoms. c. Only one carboxyl (−COOH) group. d. Absence of conjugated double bonds.a. Presence of trans double bondsWhat kinds of bonds do lipase break in order to release fatty acids from triacylglycerols? a. esters b. carbon-carbon single bonds c. carbon-carbon double bonds d. There are no fatty acids in triacylglycerols to release.a. estersHow does the presence of cis double bonds in fatty acids affect membrane fluidity? a. They tend to increase the fluidity. b. They tend to decrease the fluidity. c. They don't have any specific effect on fluidity. d. fatty acids don't have cis double bondsa. They tend to increase the fluidity.Membranes are generally symmetrical, i.e., the outer face is composed of the same number and types of phospholipids as the inner face. a. True b. Falseb. FalseThe serine in the active site of chymotrypsin functions as a. a Lewis acid. b. a metal ion. c. an electrophile. d. a nucleophiled. a nucleophileA function of aspartic acid in the active site of HIV protease is a. Acid base catalysis b. a metal ion induced catalysis c. an electrophile d. a nucleophilea. Acid base catalysisThe carrier molecule which transports fatty acids through the inner mitochondrial membrane is a. ATP. b. Carnitine. c. Coenzyme A. d. Lipoic Acid. e. none of theseb. Carnitine.Which of the following statements concerning β-oxidation of fatty acids is false? a. Initiation occurs at the methyl end of the fatty acid. b. β-oxidation is the primary route for degradation of fatty acids. c. β-oxidation takes place in the mitochondrial matrix. d. Two-carbon units are successively eliminated with each rounda. Initiation occurs at the methyl end of the fatty acid.Which group of small molecules best fit the boxes associated with the reaction shown (C-OH-> C=O)? 1) ATP + ADP 2) NAD+ + NADPH 3) NADP+ + NADPH 4) FAD + FADH2 a. I b. II c. III d. IVb. IIThe oxidation of unsaturated fatty acids specifically requires a. a cis-trans isomerase and a reductase. b. a cis-trans isomerase and a dehydrogenase. c. a dehydrogenase and a reductase. d. a dehydrogenase and a hydrase.a. a cis-trans isomerase and a reductase.The addition of two-carbon units to a growing fatty acid chain is directly driven by a. reduction of NADP+ b. oxidation of NADPH c. decarboxylation of malonyl-CoA d. hydrolysis of ATPc. decarboxylation of malonyl-CoAThe enzyme activity catalyzing the reaction shown (C-OH -> C=C) is best termed a a. reductase b. ketothiolase c. transferase d. Dehydratased. DehydrataseIn the induced-fit model of substrate binding to enzymes a. the substrate changes its conformation to fit the active site b. the active site changes its conformation to fit the substrate c. there is a conformational change in the enzyme when the substrate binds d. there is aggregation of several enzyme molecules when the substrate bindsc. there is a conformational change in the enzyme when the substrate bindsA transition-state analog is likely to bind to an enzyme a. more tightly than the substrate. b. less tightly than the substrate. c. about as tightly as the substrate. d. at a site other than the catalytic site.a. more tightly than the substrate.The active site of an enzyme a. is frequently located in a cleft in the enzyme. b. is the portion of the enzyme to which the substrate binds. c. contains the reactive groups that catalyze the reaction. d. all of these are correctd. all of these are correctAbzymes a. invariably bind to pyridoxal phosphate. b. are antibodies with catalytic activity. c. differ markedly from transition states in enzymatic reactions. d. have proline as part of their structure.b. are antibodies with catalytic activity.Which of the following is true? a. Phosphorylation always increases enzyme activity b. Kinases often use AMP as a co-substrate in their phosphorylation reactions c. Some enzymes are activated by phosphorylation while others are inhibited d. ADP is the most common substrate for a kinase reactionc. Some enzymes are activated by phosphorylation while others are inhibitedThe initial bond formation in the covalent intermediate in the reaction catalyzed by chymotrypsin is between a. serine and the carbonyl carbon in the peptide backbone b. serine and the nitrogen in the peptide backbone c. histidine and the carbonyl carbon in the peptide backbone d. histidine and the nitrogen in the peptide backbonea. serine and the carbonyl carbon in the peptide backbonePhospholipases break down fats by a. adding a phosphate group to them. b. reducing the double bonds to single bonds. c. hydrolyzing them. d. removing acetyl-CoA units.c. hydrolyzing them.The metabolically activated form of a fatty acid is a. an ester b. a Schiff base c. a phosphate ester d. a thioesterd. a thioesterHow many cycles of β-oxidation are required to convert 20 carbon saturated Fatty acid to 10 acetyl-CoAs? a. 6 b. 8 c. 9 d. 18c. 9Unsaturated fatty acids usually have ____ double bonds. a. cis b. trans c. no d. seven or eighta. cisWhich of the following four fatty acids has the highest melting point? 1. CH3CH2CH2CH2CH2COOH 2. CH3CH2CH2CH2CH2CH2CH2CH 2CH2COOH 3.CH3CH2CH2CH2CH2CH2CH2COOH 4. CH3CH=CHCH2CH2COOH a. 1 b. 2 c. 3 d. 4b. 2A key intermediate in the catabolism of fatty acids with uneven numbers of carbon atoms is a. malonyl-CoA b. propionyl-CoA c. oxaloacetate d. phosphoenolpyruvateb. propionyl-CoAThe β-oxidation of unsaturated fatty acids requires additional enzymes to isomerize the double bonds. a. True b. Falsea. TrueWhich level of structural organization is the double helix of DNA? a. primary b. secondary c. tertiary d. Quaternaryb. secondaryWhich of the following nucleobases is a purine? a. adenine b. cytosine c. thymine d. Uracilb. cytosineRecombination: a. occurs randomly throughout a chromosome b. occurs more often in areas called hot spots c. is a process that only happens under controlled laboratory conditions d. is a spontaneous process that requires no enzymesb. occurs more often in areas called hot spotsCholesterol is a precursor of all of the following except a. cortisone b. testosterone c. progesterone d. Lanosterold. LanosterolWhere in the cell does fatty acid synthesis occur? a. Cytoplasm. b. Outer mitochondrial membrane. c. Mitochondrial intermembrane space. d. Inner mitochondrial membrane.b. Outer mitochondrial membrane.Reduction reactions during fatty acid synthesis utilize a. FADH2. b. NADH. c. NADPH. d. FADH2 and NADH.c. NADPH.Synthesis of fatty acids involves simple reversal of the β-oxidation cycle. a. True b. Falseb. FalseWhat is the requirement for a template strand in DNA replication? a. It serves as a guide in determining the next nucleotide to be added according to the Watson- Crick base pairing scheme. b. It serves as the start point for the new DNA strand. c. It allows the DNA polymerase to move along it easily. d. It is a substrate for the 3'−5' exonuclease activity.a. It serves as a guide in determining the next nucleotide to be added according to the Watson- Crick base pairing scheme.Semiconservative replication implies that a. each of the new double stranded DNA molecules contains one of the original intact strands and one completely new strand. b. one of the new double stranded DNA molecules contains both of the original strands, while the other contains two new strands. c. each of the new double stranded DNA molecules contains strands that are composed of segments of original and newly synthesized material. d. None of these.a. each of the new double stranded DNA molecules contains one of the original intact strands and one completely new strand.DNA replication is a challenging process because: a. DNA strands must be separated b. New DNA is always synthesized from the 5' → 3' direction but the two template strands run in opposite directions c. The cell must guard against replication errors d. All of thesed. All of theseThe direction of synthesis of a DNA strand is a. from the 5' end to the 3' end on both strands. b. from the 3' end to the 5' end on both strands. c. from the 5' end to the 3' end on one strand and from the 3' end to the 5' end on the other strand. d. none of the above.a. from the 5' end to the 3' end on both strands.Which of the following is not a function of DNA Polymerase III? a. Polymerization. b. Ligating the final products. c. Proofreading. d. Clamping on to the template.b. Ligating the final products.Which of the following enzymes is used to create AP sites? a. primase b. helicase c. ligase d. Glycosylased. GlycosylaseWhich of the following repair mechanisms would most likely be used to repair a G in DNA damaged by oxidation? a. Base Excision: b. Nucleotide Excision c. Pol III Proofreading d. Mismatch Repaira. Base Excision:_____ is an enzyme that introduces supercoiling into closed circular DNA. a. Primase b. DNA ligase c. Helicase d. DNA gyrased. DNA gyraseIn addition to all the other problems, why can a person get fat from overdrinking alcohol? a. Alcohol inhibits carnitine palmitoyltransferase I b. Ethanol is converted to acetate and then to acetyl-CoA which makes lipids c. Ethanol converts carbohydrates into lipids d. none of theseb. Ethanol is converted to acetate and then to acetyl-CoA which makes lipidsWhat distinguishes nucleotides from nucleosides? a. Nucleosides lack the phosphate group. b. Nucleosides lack the sugar group. c. Nucleosides lack a nitrogenous base. d. The two words are synonymousa. Nucleosides lack the phosphate group.Which of the following statements is true for double-stranded DNA? a. The amount of A is the same as the amount of T, and the amount of G is the same as the amount of C. b. The amount of A is the same as the amount of G, and the amount of T is the same as the amount of C. c. The amount of A is the same as the amount of C, and the amount of G is the same as the amount of T. d. More than one of the above is true.a. The amount of A is the same as the amount of T, and the amount of G is the same as the amount of C.Which of the following fats are linked with high cholesterol and heart disease? a. saturated fats b. monounsaturated fats c. polyunsaturated fats d. all fats, regardless of saturationa. saturated fatsWhich of the following is not a typical structure for a hormone? a. steroid b. carbohydrate c. amino Acid derivative d. protein or polypeptide e. All of these structures are seen as hormones.b. carbohydrateA second messenger is a. a substance that brings about a desired effect in a cell as a result of a hormone binding to its receptor on the cell surface b. a hormone that acts on a target cell, not one of the releasing factors or trophic hormones that act on specific endocrine glands c. a hormone that affects the DNA of the target cell d. a specialized form of mRNAa. a substance that brings about a desired effect in a cell as a result of a hormone binding to its receptor on the cell surfaceWhich of the following best describes protein kinases? a. Protein kinases act by transferring a phosphate from a protein to ADP to make ATP. b. Protein kinases act by transferring a phosphate from a donor molecule, like ATP, to a protein molecule, thereby changing its activity c. Protein kinases phosphorylate enzymes and activate them d. Protein kinases phosphorylate key tyrosine residues on receptorsb. Protein kinases act by transferring a phosphate from a donor molecule, like ATP, to a protein molecule, thereby changing its activityAn important process in the synthesis of new DNA is a. proofreading and repair. b. unwinding of the double helix. c. protection of single-stranded regions from nuclease action. d. all of thesed. all of theseThe primer for in vivo DNA replication is: a. The 3' hydroxyl of the preceding Okazaki fragment. b. A short piece of RNA. c. A nick made in the DNA template. d. A primer is not always required for DNA replication.b. A short piece of RNA.The mechanism of breakage and reunion of DNA strands during recombination was proposed by: a. Messelson and Stahl b. Messelson and Weigle c. Robin Holliday d. Francis Crickc. Robin Holliday