BioChem Final Exam

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4. Identify the stabilizing forces for protein tertiary structure in the figure below. A- B- C- D-

A- hydrophobic interaction B- disulfide bond C- hydrogen bond D- electrostatic interaction

______ are proteins that bind to specific carbohydrate structures.

Lectins

_______ is the amino acid that contains a sulfur atom and is consider hydrophobic.

Methionine

_______, ______ is the class of glycoproteins with predominantly Nacetylgalactosamine moieties.

Mucoprotein, peptidoglycan

_______ gels are often used as the media for electrophoretic techniques such as SDS-PAGE and isoelectric focusing.

Polyacrylamide

Sedimentation coefficients are described as _____ units

Svedberg

The enzyme that catalyzes the formation of a phosphodiester linkage at a break in a DNA strand is _____

DNA ligase

Which of the following amino acid has a nonpolar side chain?

Which of the following is the anomer of β-D-glucopyranose?

Which tripeptide structure best represents Met-leu-Asp at pH 7?

Which of the following is not an example of column chromatography? a) ammonium sulfate fractionation b) ion-exchange separation c) high pressure liquid chromatography d) affinity separation

a) ammonium sulfate fractionation

Which of the following molecule(s) is (are) a nucleotide? Check all that applied.

a, d, and e

What is the charged group(s) present in Ile at a pH of 1? a. -NH3 + b. -COO- c. -NH2 + d. -NH3 + and -COO-

a. -NH3 +

What is the approximate overall charge on the peptide Glu-Lys-Thr-Tyr at pH 7? a. 0 b. -1 c. +2 d. +1 e. -2

a. 0

Approximately what percentage of the human genome encodes for proteins? a. 3% b. 10% c. 50% d. 90% e. None of these

a. 3%

Approximately what percentage of the human genome encodes for proteins? a. 3% b. 10% c. 50% d. 90% e. None of these

a. 3%

How many chiral carbons are there for an aldohexose? ___. How many stereoisomers are possible for an aldohexose? ____ a. 4, 16 b. 3, 8 c. 3, 6 d. 4, 8 e. 4, 32

a. 4, 16

Using the Henderson-Hasselbach equation, calculate the pH of a buffer solution made from 0.05 M CH3COOH and 0.04 M CH3COOthat has pKa= 4.7. a. 4.6 b. 2.5 c. 4.8 d. 5.4

a. 4.6

In a DNA microarray, how many different oligonucleotides can be produced if each oligonucleotide is 20 nucleotides long? a. 4^20 b. 20^4 c. 80 d. 20

a. 4^20

What statement about plasmids is false? a. A bacterial cells always has plasmids b. They are circular double-stranded DNA molecules. c. Plasmids can replicate independently of the host chromosome. d. Plasmids carry genes for the inactivation of antibiotics.

a. A bacterial cells always has plasmids

Insulin is a polypeptide hormone that contains two short polypeptide chains linked by two interstrand disulfide bonds. The most logical order of events to perform in order to sequence this protein would be: A- the peptides are reduced with mercaptoethanol. B- the peptides are sequenced using Edman chemistry. C- the peptides are separated by chromatography techniques. D- the peptides are alkylated with iodoacetamide. a. A, D, C, B b. C, A, D, B c. C, B, A, D d. A, B, C, D e. A, C, D, B

a. A, D, C, B

Insulin is a polypeptide hormone that contains two short polypeptide chains linked by two interstrand disulfide bonds. The most logical order of events to perform in order to sequence this protein would be: A: the peptides are reduced with mercaptoethanol. B: the peptides are sequenced using Edman chemistry. C: the peptides are separated by chromatography techniques. D: the peptides are alkylated with iodoacetamide. a. A, D, C, B b. C, A, D, B c. C, B, A, D d. A, B, C, D e. A, C, D, B

a. A, D, C, B

Which statements about the components of cartilage are TRUE? a. Aggrecan cushions compressive forces. b. Collagen has three globular domains with an extended region for glycosaminoglycan attachment. c. Dermatan sulfate filaments form a network by linking together. d. Water does not bind to glycosaminoglycans due to a lack of negative charges.

a. Aggrecan cushions compressive forces.

Which of the following functional groups are not commonly seen in biomolecules? a. Alkyl halides b. Carboxylic acids c. Amides d. Ethers e. Phosphate esters

a. Alkyl halides

Which of the following is true? (select all that apply) a. Allosteric enzymes are important in the regulation of metabolic pathways. b. Michaelis-Menten kinetics describe the reactions of allosteric enzymes c. Allosteric enzymes have a hyperbolic plot of reaction rate vs. substrate concentration d. Enzymes that obey Michaelis-Menten kinetics have a hyperbolic plot of reaction rate vs. substrate concentration

a. Allosteric enzymes are important in the regulation of metabolic pathways. d. Enzymes that obey Michaelis-Menten kinetics have a hyperbolic plot of reaction rate vs. substrate concentration

If the substrate contained a negative charge, which of the following amino acids would most likely be present in the active site to provide electrostatic stabilization of the ES complex? a. Asp b. Ser c. Gln d. Val e. Arg

a. Asp

The amino and carboxyl groups of amino acids are bonded to which carbon? a. Both are bonded to the α-carbon. b. Both are bonded to the β-carbon. c. The amino is bonded to the β-carbon, and the carboxyl is bonded to the α-carbon. d. The amino is bonded to the α-carbon, and the carboxyl is bonded to the β-carbon

a. Both are bonded to the α-carbon.

Glucose molecules form an intramolecular hemiacetal through the interaction of the: a. C-5 hydroxyl group and the C-1 carbon of the aldehyde group. b. C-4 hydroxyl group and the C-1 carbon of the aldehyde group. c. C-3 hydroxyl group and the C-1 carbon of the aldehyde group. d. C-2 hydroxyl group and the C-5 hydroxyl group. e. C-3 hydroxyl group and the C-6 hydroxyl group.

a. C-5 hydroxyl group and the C-1 carbon of the aldehyde group.

What is the sequence of the template strand obtained from the autoradiogram shown below: a. CGCTCAGACTT b. AAGTCTGAGCG c. GCGAGTCTGAA d. TTCAGACTCGC

a. CGCTCAGACTT

Which of the following molecules will not form hydrogen bonds? a. CH4 b. NH3 c. H2O d. HF

a. CH4

Which statement about CRISPR-cas9 system is false? a. Cas9, CRISPR Associated Protein 9, is a polymerase that synthesizes DNA b. With CRISPR, researchers can permanently modify genes in any living cells and organisms. c. CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. It is a prokaryotic immune system that confers resistance to foreign genetic elements. d. With CRISPR, it may be possible to correct mutations at precise locations in the human genome to treat genetic causes of disease.

a. Cas9, CRISPR Associated Protein 9, is a polymerase that synthesizes DNA

Which of the following groups is not present in a phosphatidic acid? a. Choline b. Fatty acids c. Glycerol d. Phosphate

a. Choline

The "c" in cDNA stands for a. Complementary b. Complimentary c. Chromosomal d. Complete

a. Complementary

The enzyme that catalyzes the formation of a phosphodiester linkage at a break in a DNA strand is a. DNA ligase. b. topoisomerase. c. restriction enzyme. d. DNA polymerase I.

a. DNA ligase.

What is the underlying cause of I-cell disease? a. Degradation enzymes are improperly addressed and delivered because a mannose lacks a phosphate. b. Degradation enzymes aggressively and rapidly digest glycosaminoglycans and glycolipids. c. Degradation enzymes exist only in their inactive zymogen forms. d. Degradation enzyme synthesis is up-regulated at the level of transcription. e. Degradation enzyme synthesis is down-regulated at the level of translation.

a. Degradation enzymes are improperly addressed and delivered because a mannose lacks a phosphate.

Leucine zipper in which a. Every seven amino acid residue in each α-helix is leucine with leucine on the same side of the helix b. Every seven amino acid residue in each α-helix is leucine with leucine on the opposite side of the helix c. Every seven amino acid residue in each β-strand is leucine, as a result 2 strands are hold together by van der Waals interactions between the leucine residues.

a. Every seven amino acid residue in each α-helix is leucine with leucine on the same side of the helix

Leucine zipper in which a. Every seven amino acid residue in each α-helix is leucine with leucine on the same side of the helix b. Every seven amino acid residue in each α-helix is leucine with leucine on the same opposite side of the helix c. Every seven amino acid residue in each β-strand is leucine, as a result 2 strands are hold together by van der Waals interactions between the leucine residues.

a. Every seven amino acid residue in each α-helix is leucine with leucine on the same side of the helix

Chain termination DNA sequencing method was developed by a. Frederick Sanger b. Kary Mullis c. James Watson d. Francis Crick

a. Frederick Sanger

The first three bases of the 6-base recognition cleavage site of EcoR V are GAT. What is the complete sequence of this 6 bp site? a. GATATC. b. GATGAT. c. GATTAG. d. GATCTA.

a. GATATC.

Which of the following DNA sequences contains a palindromic site (note: only one strand is shown)? a. GGATCC b. CAGTCC c. GCATCG d. GAGAGA

a. GGATCC

Which of the following sets of amino acid residues would be most likely find on the surface of a globular protein at physiological pH? a. Glu, Asp, Thr. b. Ser, Ala, Trp. c. Trp, Gly, Phe. d. Met, Val, Leu.

a. Glu, Asp, Thr.

______ have molecular formula of Cn(H2O)n. Select all that apply a. Glucose b. fructose c. sucrose d. lactose

a. Glucose b. fructose

In a sample consisting of Lysine, Leucine, and Glutamic acid, which will be eluted last from an anion exchange resin at pH 7? a. Glutamic acid b. Lysine c. Leucine d. all three will be eluted at the same time

a. Glutamic acid

Which of the following molecules have the highest degree of α-[1, 6] branching linkages a. Glycogen b. Amylopectin c. Amylose d. Starch e. All of these have the same degree of branching

a. Glycogen

Phosphoric acid has three pKas as shown At the physiological pH which two species are predominant? a. H2PO4 - and HPO4 2- b. H3PO4 and H2PO4 - c. H2PO4 - and PO4 3- d. HPO4 2- and PO4 3-

a. H2PO4 - and HPO4 2-

Which peptide is expected to have the highest absorbance at 280 nm? a. HWFY b. FYAN c. FAND d. YMEH

a. HWFY

Which of the following acids would serve as a good buffer for a reaction at pH = 4.0? a. I b. II c. III d. IV

a. I

In uncompetitive inhibition: a. I combines only with ES. b. I combines only with E. c. I combines with E and ES. d. I combines with EP. e. none of these.

a. I combines only with ES.

What is the role of the variable number of tandem repeats (VNTR) region in mucin? a. It facilitates glycosylation. b. It facilitates polymerization of molecules. c. It forms a region for bacterial cells adhesion. d. It is responsible for the formation of long fibers. e. It provides for the high activity of the molecule.

a. It facilitates glycosylation.

Which statement is correct about the Michaelis-Menten constant, KM, for the kinetic mechanism below? a. It is numerically equal to the substrate concentration required to achieve one half the maximum velocity. b. Its defined as KM = k1/(k-1 + k2). c. It is approximately equal to the dissociation constant for the enzyme-substrate complex to E + P. d. The value of KM is constant for an enzyme regardless of the specific substrate molecule used to determine it. e. Its numeric value has the units of moles-1 .

a. It is numerically equal to the substrate concentration required to achieve one half the maximum velocity.

This is a map of pBR322 plasmid If a recombinant plasmid were obtained inserting DNA into the BamHI site, the recombinant plasmid would have which of the following properties? Check all that apply. a. It would replicate autonomously. b. It would be resistant to the antibiotic tetracycline. c. It would be resistant to the antibiotic ampicillin. d. It would be resistant to both ampicillin and tetracycline.

a. It would replicate autonomously. c. It would be resistant to the antibiotic ampicillin.

D-glucose may undergo mutarotation to all of the following forms EXCEPT: a. L-glucopyranose. b. α-anomer. c. free aldehyde. d. β-anomer.

a. L-glucopyranose.

What technique has become a valuable tool in forensics and legal medicine? a. PCR b. pyrosequencing c. controlled termination of replication d. genomic library screening

a. PCR

Reaction of the peptide, met-ala-lys-ser, with Edman reagent at pH 8.0 followed by mild acidification (first cycle of Edman method) would release: a. PTH-met and the peptide ala-lys-ser b. PTH-ser and the peptide met-ala-lys c. PTH-met, PTH-ala, PTH-lys and PTH-ser d. the labeled peptide met-ala-lys-ser-PTH

a. PTH-met and the peptide ala-lys-ser

For a mixture of proteins shown in the Table, predict the order of emergence when subjected to a gel filtration column with a fractionation range of 1-100 kDa at pH 7? a. Protein 3, Protein 1, Protein 2 b. Protein 2, Protein 3, Protein 1 c. Protein 2, Protein 1, Protein 3 d. Protein 1, Protein 3, Protein 2

a. Protein 3, Protein 1, Protein 2

What type of molecule is in the diagram below? The question mark in the box marked which end of the molecule? a. Protein, N-terminus b. Protein, C-terminus c. DNA 5' end d. DNA 3' endec. impossible to determine

a. Protein, N-terminus

What is NOT a key property that enable proteins to participate in a wide range of functions? a. Proteins have a high molecular weight. b. Proteins contain different functional groups. c. Some proteins are quite rigid, whereas others display considerable flexibility. d. Proteins are linear polymers built of different amino acids. e. Proteins can interact with one another and with other biological macromolecules to form complex assemblies.

a. Proteins have a high molecular weight.

In pyrosequencing, following complementary binding of an activated nucleotide to the template strand a. Pyrophosphate is release b. adenosine 5' phosphosulfate degrades c. photons of light are release d. Luciferin is converted to oxyluciferin

a. Pyrophosphate is release

In O-linked glycoproteins, the carbohydrate portion is attached to which residue in the protein? Select all that apply. a. Ser b. Thr c. Asp d. Asn e. Tyr

a. Ser b. Thr

What are the consequences of sugar phosphorylation? a. Sugars gain a negative charge. b. Sugars gain a positive charge. c. Phosphorylation creates intermediates that are less available for metabolic reactions. d. The gained charge causes sugars to leave the cell by crossing the lipid bilayer membrane.

a. Sugars gain a negative charge.

What happen when sugars become phosphorylated? Select all that apply. a. Sugars gain a negative charge. b. Sugars gain a positive charge. c. The gained charge causes sugars to stay in the cell. d. Phosphorylation creates intermediates that are less available for metabolic reactions. e. The gained charge causes sugars to leave the cell by crossing the lipid bilayer membrane.

a. Sugars gain a negative charge. c. The gained charge causes sugars to stay in the cell.

Which of the following is true under the following conditions: the enzyme concentration is 10 nM, the substrate concentration is 10 mM, and the KM is 10 µM? a. The enzyme is saturated with substrate. b. Most of the enzyme does not have substrate bound. c. There is more enzyme than substrate. d. All of the answers are correct. e. None of the answers is correct.

a. The enzyme is saturated with substrate.

Inhibitor I is a competitive inhibitor. Which statement is false? a. The inhibitor binds a site other than the active site. b. The inhibitor is structurally similar to the substrate. c. EI does not give rise to E + P. d. For a given [I], V decreases. e. As [S] increases, at some point, S can displace all of I on E.

a. The inhibitor binds a site other than the active site.

How do the membranes of archaea differ from bacteria and eukaryotes? Select all that apply. a. The lipids have an ether link to the glycerol instead of a carboxylic acid ester. b. The alkyl chains are branched. c. The membrane is a solid structure. d. The membrane always consists of one layer of lipids.

a. The lipids have an ether link to the glycerol instead of a carboxylic acid ester. b. The alkyl chains are branched.

Which of the following is/are characteristic of the Watson-Crick DNA double helix? (select all that apply) a. The two polynucleotide chains are coiled about a common axis b. hydrogen bonds between A and T and between C and G hold the two chains together c. the purines and pyrimidines are on the outside of the helix and the sugar phosphate backbones are on the inside. d. base composition analyses of DNA duplexes isolated from many organisms have shown that the amount of A and C are equal, as the amounts of G and T.

a. The two polynucleotide chains are coiled about a common axis b. hydrogen bonds between A and T and between C and G hold the two chains together

Hydrogen bonds can only form when the hydrogen atom is involved in a polar bond. a. True b. False

a. True

One advantage of cis double bonds (as opposed to trans double bonds) in fatty acids is that they increase membrane fluidity. a. True b. False

a. True

The side chain of ser can hydrogen bond to other residues. a. True b. False

a. True

α-Keratin is referred to as a coiled-coil protein a. Two α helices wind around one another to form a stable double helix b. Two β-strands form a stable β sheet c. Two protein chains form random coiled-coil d. None of these are true

a. Two α helices wind around one another to form a stable double helix

Most sugars are attached to which molecule prior to transfer? a. UDP b. GTP c. ATP d. ADP e. UTP

a. UDP

Which peptide is expected to have the highest absorbance at 280 nm? a. YWH b. FAN c. AND d. YME

a. YWH

Examples of cofactors include: (Select all that apply). a. Zn2+, Mg2+, and Ni2+ . b. biotin pyrophosphate. c. pyridoxal phosphate. d. coenzyme A. e. thiamine pyrophosphate.

a. Zn2+, Mg2+, and Ni2+ . b. biotin pyrophosphate. c. pyridoxal phosphate. d. coenzyme A. e. thiamine pyrophosphate.

A genomic DNA library consists of a. a set of cloned fragments that collectively represent the genes of a particular organism. b. an alphabetical list of all the genes in an organism c. a set of reference books on genetics d. a collection of short fragments from nuclear DNA digestion. e. arrays of synthetic oligonucleotides used to select for a specific DNA.

a. a set of cloned fragments that collectively represent the genes of a particular organism.

This molecule is a a. adenine b. cytosine c. guanine d. thymine e. uracil

a. adenine

A genomic DNA library consists of a. all the DNA of an organism divided up and cloned in suitable vectors b. an alphabetical list of all the genes in an organism c. a set of reference books on genetics d. none of these

a. all the DNA of an organism divided up and cloned in suitable vectors

Proteins that are not catalysts are often probed or assayed using a. antibody binding assays b. genomic analysis c. catalytic activity d. none of these e. all of these

a. antibody binding assays

What do the amino acids Tyr, Phe, and Trp have in common? a. aromatic rings b. negatively charged at pH 7.0 c. positively charged at pH 7.0 d. polar e. nonpolar

a. aromatic rings

Liposomes are a. artificial membrane-bounded structures used to deliver medications. b. single-layered membranes. c. mixed micelles involved in cholesterol transport among cells. d. bilayers with the hydrophobic regions on the outside.

a. artificial membrane-bounded structures used to deliver medications.

Which group consists only of amino acids with acidic side chains? a. aspartate, glutamate b. aspartate, glutamine c. histidine, asparagine, glutamine d. asparagine, glutamate

a. aspartate, glutamate

This fatty acid (select all that apply) a. can be represented as 18:2 b. can be represented as 17:2 c. can be represented as 18:0 d. is an omega 3 fatty acid e. is an omega 6 fatty acid f. is an omega 9 fatty acid

a. can be represented as 18:2 e. is an omega 6 fatty acid

Protein databases a. can identify proteins from small stretches of amino acid sequences. b. are not useful in proteomics studies due to the complexities of the proteome c. are determined from sequence data only, never deduced from genomic data d. none of these e. all of these

a. can identify proteins from small stretches of amino acid sequences.

Which method can be used to desalt a protein solution? a. dialysis b. centrifugation c. fractionation d. gel electrophoresis e. salting out

a. dialysis

Monosaccharides that are non-superimposable mirror image stereoisomers are called a. enantiomers b. epimers c. anomers d. diastereomers

a. enantiomers

Where does protein glycosylation take place in the cell? Select all that apply. a. endoplasmic reticulum b. mitochondria c. cytosol d. Golgi complex e. nucleus

a. endoplasmic reticulum d. Golgi complex

Another name for an antigenic determinant is _____. a. epitope b. epimer c. epinephrine d. epidemic

a. epitope

Where in the cell are glycoproteins and glycolipids commonly located? a. external surface of the plasma membrane b. Golgi complex c. lumen of the ER d. inner surface of the plasma membrane e. ER membrane

a. external surface of the plasma membrane

Generally speaking, this type of protein is not water-soluble: a. fibrous. b. globular. c. both fibrous and globular proteins are usually water-soluble d. neither fibrous nor globular proteins are usually water-soluble e. you cannot generalize about the solubility of fibrous or globular proteins

a. fibrous.

Current DNA sequencing commonly uses ____ base analogues a. fluorescent b. radioactive c. phosphorescent d. cross-linked e. photoreactive

a. fluorescent

Current DNA sequencing commonly uses ____ base analogues. a. fluorescent b. radioactive c. phosphorescent d. cross-linked e. photoreactive

a. fluorescent

Every 3rd residue in the protein collagen is a. glycine b. proline c. hydroxyproline d. lysine

a. glycine

The storage form of glucose in animals is a. glycogen b. starch c. cellulose d. chitin

a. glycogen

Which substance would you expect to be eluted first from a gel filtration chromatographic column with a suitable degree of crosslinking? a. hemoglobin b. 2,3-bisphosphoglycerate c. myoglobin d. all would elute at the same rate

a. hemoglobin

What term describes an enzyme with its cofactor? a. holoenzyme b. coenzyme c. apoenzyme d. inactive enzyme

a. holoenzyme

What property is used to determine the probability that a segment of a protein will be found embedded in a membrane? a. hydropathy b. polarity c. acidity d. entropy e. solvation

a. hydropathy

Membrane lipids in a lipid bilayer are held together by a. hydrophobic interactions b. hydrogen bonds c. electrostatic forces d. covalent bonds

a. hydrophobic interactions

Cell membranes have all of the following properties EXCEPT: a. identical protein and lipid composition in the major organelles b. spontaneous assemblies resulting from hydrophobic interactions c. define boundaries of cellular components d. supramolecular assemblies e. none, all are true

a. identical protein and lipid composition in the major organelles

Which statement about pyrosequencing is correct? Select all that apply. a. it is a next generation sequencing method that enables rapid determination of a complete genome sequence b. it is based on the dideoxy chain termination method. c. Light is produced only when the nucleotide complementary to the template is incorporated and releasing pyrophosphate.

a. it is a next generation sequencing method that enables rapid determination of a complete genome sequence c. Light is produced only when the nucleotide complementary to the template is incorporated and releasing pyrophosphate.

Which of the following is NOT a homodisaccharide? Select all that apply. a. lactose. b. maltose. c. isomaltose. d. cellobiose. e. sucrose

a. lactose. e. sucrose

Which characteristics affect the sedimentation rate of a particle? Select all that apply. a. mass b. shape c. the density of the solution d. pI e. pH

a. mass b. shape c. the density of the solution

_____ is used to determine protein primary structure a. mass spectrometry b. x-ray crystallography c. FTIR spectroscopy d. NMR spectroscopy

a. mass spectrometry

SDS-PAGE is used to determine the ___ of a protein a. molecular weight b. isoelectric point c. amino acid composition d. specific activity

a. molecular weight

Which type of the multiple substrate reaction is shown? a. ordered sequential reaction b. random sequential reaction c. double-displacement reaction d. ordered displacement reaction e. double sequential reaction

a. ordered sequential reaction

Most covalent catalysis is carried out by enzymes using a: a. ping-pong kinetic mechanism. b. sequential bisubstrate kinetic mechanism. c. random bisubstrate kinetic mechanism. d. simple unimolecular kinetic mechanism. e. none of these.

a. ping-pong kinetic mechanism.

If DNA fragments of about 3 kb are to be cloned, which vector would be most useful? a. plasmid b. cosmid c. YACs (yeast artificial chromosomes) d. bacteriophage lambda e. E. coli chromosome

a. plasmid

If atoms with differing electronegativities between 0.4 and 1.6 form a bond, that bond will be a. polar b. nonpolar c. amphipathic d. acidic e. ionic

a. polar

What is the predominant form of the amino acid K at pH 7? a. positive. b. neutral. c. negative

a. positive.

All of the amino acids EXCEPT ____ have both free α-amino and free α-carboxyl groups. a. proline b. glycine c. phenylalanine d. lysine e. histidine

a. proline

Mass spectrometric techniques are critical in _____research because it is possible to analyze constituents of large macromolecular assemblies. a. proteomics b. genomics c. chromatography d. transcriptomics

a. proteomics

Which of the following best describes the following molecule? a. a component of sphingolipid b. a component of diacylglycerol c. a component of monoacylglycerol d. a component of phosphoacylglycerol

a. sphingolipid

The Gibbs free energy of activation is the difference between the: a. substrate and the transition state. b. substrate and the product. c. product and the transition state. d. substrate and the final state. e. final and initial states.

a. substrate and the transition state.

What is the term for the combination helix-turn-helix? a. supersecondary structure b. supertetriary structure c. globular protein d. domain e. tertiary structure

a. supersecondary structure

What can be used to add nucleotides to the 3' end of DNA? a. terminal transferase b. reverse transcriptase c. telomeres d. pseudogenes

a. terminal transferase

Natural occurring carbohydrates exist as: a. the D isomer. b. the L isomer. c. both D and L. d. neither D nor L.

a. the D isomer.

The original development of PCR did not use the Taq polymerase. What is the reason that the Taq polymerase is currently used? (check all that apply) a. the DNA melting step at 94°C would cause denaturation of most DNA polymerases from other organisms. b. the Taq polymerase is one of the most rapid DNA polymerase enzymes known and is therefore extremely useful for PCR. c. the original method of PCR required that DNA polymerase be added prior to each round of elongation, something that is not suitable for automation. d. the Taq polymerase is the only DNA polymerase that will allow production of 2n amounts of DNA (n=number of cycles).

a. the DNA melting step at 94°C would cause denaturation of most DNA polymerases from other organisms. c. the original method of PCR required that DNA polymerase be added prior to each round of elongation, something that is not suitable for automation.

Expression libraries are most often made from a. the mRNA found with a given cell or tissue. b. the genome of a given cell or tissue. c. the promoters of a given cell or tissue. d. the DNA of a single chromosome from cell type or tissue.

a. the mRNA found with a given cell or tissue.

The main difference, on the surface of a red blood cell, between the A-B-O major blood groups depends on a. the presence or absence of a certain sugar b. the presence or absence of a certain protein sequence c. the presence or absence of an acetyl group on a sugar d. all of these

a. the presence or absence of a certain sugar

The Second Law of Thermodynamics states a. the total entropy of a system and its surroundings always increases for a spontaneous process. b. temperatures will always decrease in a spontaneous process. c. the total energy of a system and its surroundings is constant. d. diversity is the result of gradual evolution. e. None of the answers is correct.

a. the total entropy of a system and its surroundings always increases for a spontaneous process.

A plot of 1/V vs. 1/[S] for an enzyme catalyzed reaction gave a line with an equation of y = 0.6x + 0.3. The same enzyme with an inhibitor present gave a line with an equation of y = 1.3x + 0.3. Which of the following statements is true? a. the type of inhibition is competitive b. the type of inhibition is noncompetitive c. the type of inhibition is uncompetitive d. the Vmax with the inhibitor present has decreased e. the Km with the inhibitor present has decreased

a. the type of inhibition is competitive

The carbohydrate moiety of glycoproteins can be linked to protein through which amino acid side chains? a. threonine, asparagine b. glycine, proline c. tyrosine, tryptophan d. cysteine, methionine

a. threonine, asparagine

Several methods of cleavage (such as proteolytic enzymes) are used in determining the primary structure of a protein a. to give overlapping peptides, which can be compared to obtain a complete sequence b. to use less material in each experiment c. so that results from different laboratories can be compared d. to distinguish between the N-terminal and C-terminal amino acids of the protein

a. to give overlapping peptides, which can be compared to obtain a complete sequence

The most important and the most used type of restriction enzymes in molecular biology is a. type IIP b. type IIS c. type III d. type IV

a. type IIP

Proteins are marked for degradation by attaching to a. ubiquitin b. proteasome c. chaperone protein d. Intrinsically unstructured proteins

a. ubiquitin

The distribution of lipids in membranes is a. uneven, with bulkier molecules on the exterior b. characterized by even distribution of molecules c. distinguished by the absence of cholesterol d. not well understood

a. uneven, with bulkier molecules on the exterior

When every enzyme's active site in a reaction mixture is saturated by substrate, the kinetics of the reaction become ____-order, and the velocity is ____. a. zero; Vmax b. first; Vmax c. second; Vmax/2 d. zero; Vmax/2 e. first; Vmax/2

a. zero; Vmax

A system is at equilibrium when a. ΔG for the system is zero. b. ΔG for the system is negative. c. ΔG for the system is positive. d. ΔH for the system is zero. e. ΔH for the system is negative

a. ΔG for the system is zero.

pUC plasmids are useful for screening cells that contain recombinant DNA because they contain the _____ gene. a. β-galactosidase b. tetracycline resistance c. green fluorescent protein d. luciferase

a. β-galactosidase

Which structure depicts β-D-ribofuranose?

Which tripeptide structure best represents Met-leu-Asp at pH 1?

Which of the following molecule(s) is (are) a nucleoside? Select all that apply.

b and c

Which of the following molecule(s) is/are used as a chain terminator in DNA sequencing?

b and d

The KM expression is equal to a. (k1 + k2) / k-1 b. (k-1 + k2) / k1 c. (k1 + k-1) / k2 d. k-1 / k1

b. (k-1 + k2) / k1

The standard conditions for ΔGº are: a. 1.0 atm, [reactants] 1.0 M, [OH- ] 10-5 M, 25ºC. b. 1.0 atm, [reactants] 1.0 M, [H+ ] 10-7 M, 25ºC. c. 1.0 atm, [products] 1.0 M, [OH- ] 10-1 M, 20ºC. d. 1.0 atm, [reactants] 1.0 M, [OH- ] 10-7 M, 0ºC. e. 1.0 atm, [products] 1.0 M, [H+ ] 10-1 M, 25ºC.

b. 1.0 atm, [reactants] 1.0 M, [H+ ] 10-7 M, 25ºC.

Which of the following four fatty acids has the lowest melting point? 1 - CH3CH2CH2CH2CH2COOH 2 - CH3CH=CHCH2CH2COOH 3 -CH3CH2CH2CH2CH2CH2CH2CH2CH2COOH 4 -CH3CH2CH2CH2CH2CH2CH2COOH a. 1 b. 2 c. 3 d. 4

b. 2

At pH 6, what percent of histidine has a neutral charge (the side chain pKa = 6)? a. 9% b. 50% c. 91% d. 100%

b. 50%

At pH 6, what percent of histidine has a neutral charge (the side chain pKa = 6)? a. 9% b. 50% c. 91% d. 100%

b. 50%

A buffer solution at pH 8 has a ratio of [A-]/[HA] of 10. What is the pKa of the acid? a. 6 b. 7 c. 8 d. 9 e. 10

b. 7

Two-dimensional gel electrophoresis is the workhorse for proteomics. You have extracted a subset of proteins from the kidney of a kidney cancer patient and the same subset from a normal individual. To analyze the differences of the two protein samples you have performed a 2-D gel electrophoresis experiment using the same amount of total protein from each sample. To estimate molecular weight, you have run an SDS-PAGE and used a MW marker containing proteins with 20, 35, 50, 90, 150, and 250 kDa. The results of your experiment are shown below. What is the MW and pI of a protein that is expressed only in the diseased tissue? a. 28 kDa, 8.0 b. 75 kDa, 8.0 c. 45 kDa, 5.0 d. 48 kDa, 8.0 e. 60 kDa, 9.0

b. 75 kDa, 8.0

Which would be best to separate a protein that binds strongly to its substrate? a. Gel filtration b. Affinity chromatography c. Cation exchange d. Anion exchange e. Cation or anion exchange

b. Affinity chromatography

Which of the peptides would absorb light at 280 nm? a. Thr-Val-Ile b. Ala-Met-Trp c. Val-Pro-Leu d. Gly-Lys-His e. Ser-Gly-Asp

b. Ala-Met-Trp

How does an expression vector differ from a regular cloning vector? a. An expression vector does not have an origin of replication. b. An expression vector has the ability to have the inserted DNA be transcribed. c. An expression vector is always a linear molecule, while a cloning vector may be circular. d. An expression vector must be of viral origin, so that it can infect a cell naturally

b. An expression vector has the ability to have the inserted DNA be transcribed.

Which statement about biological diversity is true? (Select all that apply) a. No species can live in seemingly hostile environments such as hot springs and glaciers. b. Animal kingdom species range from nearly microscopic to very large. c. Organisms such as protozoa, yeast, and bacteria are present with great diversity in water and soil. d. Microscopic organisms can only live within larger organisms.

b. Animal kingdom species range from nearly microscopic to very large. c. Organisms such as protozoa, yeast, and bacteria are present with great diversity in water and soil.

In N-linked glycoproteins, the carbohydrate portion is attached to which residue in the protein? a. Asp b. Asn c. Thr d. Ser e. Tyr

b. Asn

How do some viruses gain entry into specific cells? a. By attaching to ion channels b. By binding to glycoproteins on the cell surface that are unique to specific cells c. By cleaving the glycosidic bonds and altering protein shapes d. By passive diffusion

b. By binding to glycoproteins on the cell surface that are unique to specific cells

Amino acid analysis of an oligopeptide seven residues long gave Asp, Glu, Leu, Arg, Met, Tyr and Trp. Trypsin treatment had no apparent effect on the oligopeptide. Which of the following is true? a. C-terminal residue is Lys b. C-terminal residue is Arg c. N-terminal residue is Arg d. C-terminal residue is Trp e. N-terminal residue is Met

b. C-terminal residue is Arg

These are found in tendons, cartilage and other connective tissue. a. Heparin; chondroitins b. Chondroitins; keratin sulfate c. Keratin sulfate, dermatan sulfate d. Hyaluronate, keratin sulfate

b. Chondroitins; keratin sulfate

Which of the following correctly lists the isoelectric pH's of Asn, Asp, and Arg from lowest to highest? a. E Q K b. D N R c. A D R d. N D R e. S P R f. R N D

b. D N R

Determination of the sequence of amino acids in a peptide can be done by (check all that apply) a. x-ray crystallography b. Edman degradation c. treatment with cyanogen bromide d. trypsin hydrolysis e. tandem mass spectrometry

b. Edman degradation e. tandem mass spectrometry

In the Three Domain classification system, Escherichia coli would be considered a. Archaebacteria. b. Eubacteria. c. Eukarya.

b. Eubacteria.

A buffer is a solution which maintains a solution at a neutral pH a. True b. False

b. False

A non-polar molecule cannot have any polar bonds. a. True. b. False

b. False

What is the sequence of the template strand obtained from the autoradiogram of DNA sequencing using a dideoxy method? a. ACAGTTCGAG b. GAGCTTGACA c. CTCGAACTGT d. TGTCAAGCTC

b. GAGCTTGACA

Which of the following acids would serve as a good buffer for a reaction at pH = 7? a. I b. II c. III d. IV

b. II

The backbone of nucleic acids consists of a. a phosphodiester bond between the 2' and 5' hydroxyl groups of neighboring sugars b. a phosphodiester bond between the 3' and 5' hydroxyl groups of neighboring sugars c. a glycosidic bond between a pyrimidine and a sugar d. a glycosidic bond between a purine and a sugar

b. a phosphodiester bond between the 3' and 5' hydroxyl groups of neighboring sugars

The probe used to isolate a gene from a genomic library is often a. the ligand that binds to the protein b. a portion of the mRNA of the gene c. the protein produced by the gene d. its telomere region e. its promoter region

b. a portion of the mRNA of the gene

Glucose most commonly forms which of the following structures? a. a pyranose using the hydroxyl group on carbon 4 b. a pyranose using the hydroxyl group on carbon 5 c. a pyranose using the hydroxyl group on carbon 6 d. a furanose using the hydroxyl group on carbon 3 e. a furanose using the hydroxyl group on carbon 4

b. a pyranose using the hydroxyl group on carbon 5

How does RNA interference work? a. siRNA binds to genes and prevents transcription. b. a single strand of the siRNA binds to the gene transcript, promoting degradation thus preventing translation. c. siRNA is produced by RNA polymerase. d. siRNA binds to RNA polymerase preventing mRNA production.

b. a single strand of the siRNA binds to the gene transcript, promoting degradation thus preventing translation.

Which treatment would be most useful in separating an integral membrane protein from the lipid component of a cell membrane? a. add a salt b. add a mixture of proteases c. change the pH d. none of these. You cant separate an integral membrane protein from the lipid e. add a detergent

b. add a detergent

When designing primers for PCR, scientists often compare the primer sequence to database sequence. This is to ensure that the sequence a. aligns with several different sequences b. aligns with a single sequence c. has a maximum number of homologous sequences d. absents from the database

b. aligns with a single sequence

Carbohydrate residues attached to the membrane lipids are a. always positioned on the inside center of the bilayer b. always positioned on the extracellular side of the membrane c. also covalently attached to membrane proteins d. always positioned on the intracellular side of the membrane e. always positioned equally on both sides of the membrane

b. always positioned on the extracellular side of the membrane

The fatty acid described as 20:4 is a. palmitic acid b. arachidonic acid c. lauric acid d. linoleic acid

b. arachidonic acid

Which of the following is a metabolic precursor of prostaglandins & leukotrienes? a. vitamin A. b. arachidonic acid. c. sphingomyelin. d. cholesterol.

b. arachidonic acid.

Glycoproteins a. are involved in the metabolism of sugars b. are proteins to which sugars are covalently bonded c. occur in the bloodstream of diabetics d. have not been found in nature, but have been synthesized in the laboratory

b. are proteins to which sugars are covalently bonded

Ribosomes a. are never bound to membranes b. are the site of protein synthesis c. are the site of photosynthesis d. cannot be seen in the electron microscope

b. are the site of protein synthesis

Selectins are proteins that a. aid in selection of proteins bound for the Golgi complex b. bind immune-system cells as part of the inflammatory response c. selectively bind proteins destined for lysozomes d. All of these e. None of these

b. bind immune-system cells as part of the inflammatory response

Sucrose is not a reducing sugar because: a. the primary hydroxyl groups are oxidized to carboxylic acids. b. both anomeric carbons are involved in formation of the glycosidic bond. c. the glycosidic bond is in the α configuration. d. it is composed of a furanose and a pyranose.

b. both anomeric carbons are involved in formation of the glycosidic bond.

If mRNA is converted to DNA and cloned into suitable vectors, the resultant library is called a. DNA library b. cDNA library c. mRNA library d. none of these

b. cDNA library

If mRNA is converted to DNA and cloned into suitable vectors, the resultant library is called a a. DNA library b. cDNA library c. mRNA library d. none of these

b. cDNA library

What does an α-amino acid consist of? a. carbonyl group, α carbon, amino group, oxygen atom, distinctive R group b. carboxylic acid group, α carbon, amino group, hydrogen atom, distinctive R group c. carboxylic acid group, ε carbon, nitro group, hydrogen atom d. alcohol group, α carbon, amino group, nitrogen atom, distinctive R group, hydrogen atom e. carboxylic acid group, δ carbon, imine radical, hydrogen atom, distinctive R group

b. carboxylic acid group, α carbon, amino group, hydrogen atom, distinctive R group

When enzymes are purified, the assay is often based on a. light absorbance b. catalytic activity c. temperature changes d. mRNA levels e. pH.

b. catalytic activity

What do the amino acids cysteine and methionine have in common? a. form disulfide bonds b. contain sulfur c. polar d. nonpolar

b. contain sulfur

The Cα-N (Φ) and Cα-CO (Ψ) are single bonds and can rotate freely. a. true b. false

b. false

Generally speaking, this type of protein is water-soluble: a. fibrous. b. globular. c. both fibrous and globular proteins are usually not water-soluble d. neither fibrous nor globular proteins are usually not water-soluble e. you cannot generalize about the solubility of fibrous or globular proteins

b. globular.

The amino acid with a side-chain pKa near neutrality and which therefore plays an important role as proton donor and acceptor in many enzyme catalyzed reactions is: a. cysteine b. histidine c. proline d. serine e. methionine

b. histidine

Domains are a. the α-helical portions of proteins b. independently folded regions of proteins c. the β-pleated regions of proteins d. all of these are true

b. independently folded regions of proteins

Which statement is false about peptide mass fingerprinting? a. it is a high throughput protein identification technique b. it depends on protein sequencing for identification c. it uses mass spectrometry to generate a peak list of proteolytic fragments d. it requires database to have similar protein that is already characterized

b. it depends on protein sequencing for identification

A multiple cloning site contains a. links for antibiotic resistance. b. many closely spaced restriction enzyme sites. c. sequences allowing linkage to mRNA. d. All of these. e. None of these.

b. many closely spaced restriction enzyme sites.

The graph shows the saturation of hemoglobin and myoglobin with oxygen. Which statement is false? a. myoglobin binding of oxygen follows Michaelis-Menten kinetics b. myoglobin has a lower binding affinity for oxygen than hemoglobin at various pressure c. hemoglobin binds oxygen in an allosteric manner d. hemoglobin binds oxygen in a cooperative manner

b. myoglobin has a lower binding affinity for oxygen than hemoglobin at various pressure

If atoms with differing electronegativities less than 0.4 form a bond, that bond will be a. polar b. nonpolar c. amphipathic d. acidic e. ionic

b. nonpolar

In an enzyme catalyzed reaction that obeys Michaelis-Menten kinetics, which pair of graphs would illustrate competitive inhibition? a. plots 1 &3 b. plots 1 & 4 c. plots 2 & 3 d. plots 2 & 4 e. unable to determine from the information provided

b. plots 1 & 4

The information needed for the structure of a protein is contained in a. amino acid composition b. primary structure c. secondary structure d. tertiary structure e. quaternary structure

b. primary structure

The "natural" function of restriction endonucleases is to a. help bacteriophages infect cells. b. protect bacterial cells from invasion by viruses (bacteriophages). c. regulate gene expression from specific promoters. d. remove chromatin from histones.

b. protect bacterial cells from invasion by viruses (bacteriophages).

Proteoglycans are a group of macromolecules formed from: a. proteases and monosaccharides. b. proteins and glycosaminoglycans. c. proteins and polysaccharides. d. proteases and glycosaminoglycans. e. proteins and glycogen.

b. proteins and glycosaminoglycans.

What is the first step in analysis of any cellular protein? a. digestion of proteins b. purification proteins c. identification of proteins d. affinity chromatography e. gel electrophoresis

b. purification proteins

Which statement is false about ELISA? (check all that apply) a. primary antibody binds directly to the target protein b. secondary antibody binds directly to the target protein c. the ELISA enzyme is linked to the secondary antibody d. the ELISA enzyme is linked to the primary antibody

b. secondary antibody binds directly to the target protein d. the ELISA enzyme is linked to the primary antibody

Hydrogen bonds are most important in this type of structure in proteins: a. primary structure b. secondary structure c. tertiary structure d. quaternary structure e. All of these

b. secondary structure

Which group consists only of amino acids with polar side chains? a. cysteine, threonine, and phenylalanine b. serine, threonine, and tyrosine c. histidine, threonine, and methionine d. serine, threonine, and isoleucine

b. serine, threonine, and tyrosine

The main difference between Western blotting and ELISA is: a. enzyme is linked to primary antibody in Western blotting but to secondary antibody in ELISA b. substrate is water soluble in ELISA but not in Western blotting c. enzyme is linked to secondary antibody in Western blotting but to first antibody in ELISA d. substrate is water soluble in Western blotting but not ELISA

b. substrate is water soluble in ELISA but not in Western blotting

Which statement about solid phase peptide synthesis is false? a. the desired product is bound to beads and excess reagents can be easily removed at each step. b. synthesis starts from N-terminus. c. there is limitation on the length of peptide chain. d. amino acid's carboxyl group must be activated with dicyclohexylcarbodiimide to facilitate peptide bond formation.

b. synthesis starts from N-terminus.

The rate of a reaction is most directly related to a. the free energy change b. the activation energy c. the enthalpy change d. the entropy change

b. the activation energy

When electrophoretic separations are done based on molecular weight, the distance that a molecule moves can be graphed as a straight line when compared to: a. the MW of the proteins b. the log of the MW of the proteins c. the negative of the MW of the proteins d. none of these

b. the log of the MW of the proteins

All are true for cDNA libraries EXCEPT: a. reverse transcriptase synthesizes a DNA strand complement of the mRNA templates. b. the original RNA strands are broken down by treating with acid c. mRNA templates are isolated using oligo (dT)-cellulose chromatography. d. the cDNA are copies from mRNA templates.

b. the original RNA strands are broken down by treating with acid

The main difference, on the surface of a red blood cell, between the A-B-O major blood groups depends on a. the presence or absence of a certain protein sequence b. the presence or absence of a certain sugar c. the presence or absence of an acetyl group on a sugar d). all of these

b. the presence or absence of a certain sugar

The initial rate of an enzymatic reaction is usually determined in order to assure that a. the enzyme is active b. there is no reverse reaction of product to the enzyme-substrate complex c. the substrate is not used up d. the experiment can be completed quickly

b. there is no reverse reaction of product to the enzyme-substrate complex

Drug A acts by competing with substrate S of the target enzyme. Drug B acts by binding only to the ES complex to form ESB (inactive). If the levels of A and B are fixed, an increase in level S (select all that apply) a. will increase the degree of inhibition by drug A. b. will decrease the degree of inhibition by drug A. c. will decrease the degree of inhibition by drug B. d. will increase the degree of inhibition by drug B.

b. will decrease the degree of inhibition by drug A. d. will increase the degree of inhibition by drug B.

In transforming the Michaelis-Menten equation into a straight line equation, y = mx + b, the Lineweaver-Burk double reciprocal plot, which of the following is NOT a true representation? a. slope = KM/Vmax b. x-intercept is 1/KM c. y axis is 1/V d. y-intercept is 1/Vmax e. x axis is 1/[S]

b. x-intercept is 1/KM

In an enzyme catalyzed reaction, if [S] >> KM , the reaction is most likely to be: a. first order with a maximum rate. b. zero order with a maximum rate. c. second order, independent of the substrate concentration. d. zero order with a minimal rate. e. pseudo-first order, independent of the substrate concentration.

b. zero order with a maximum rate.

When substrate concentration is much greater than KM, the reaction is: a. first order with a maximum rate. b. zero order with a maximum rate. c. second order, independent of the substrate concentration. d. zero order with a minimal rate. e. pseudo-first order, independent of the substrate concentration.

b. zero order with a maximum rate.

What technique would be used to separate proteins with different sedimentation coefficients? a. MALDI-TOF mass spectrometry b. zonal centrifugation c. HPLC d. gel-filtration chromatography e. All of these

b. zonal centrifugation

Chitin, which forms the exoskeletons of insects, is composed of a. α-(1, 4) linked N-acetylglucosamine residues b. β-(1, 4) linked N-acetylglucosamine residues c. α-(1, 4) linked glucose residues d. β-(1, 4) linked glucose residues

b. β-(1, 4) linked N-acetylglucosamine residues

Which of the following amino acid has a side chain that can make hydrogen bonds to other molecules?

Which of the following amino acid has a side chain that can make hydrogen bonds to other molecules? (select all that apply)

Which of the following would be the correct Haworth projection for the sugar shown below?

Which of the following amino acid has a polar side chain? (select all that apply)

c and d

Where C(alpha) is the alpha-carbon, N represents the amide nitrogen and Co is the carbonyl carbon of amino acids in a peptide, the peptide backbone of a protein consists of the repeated sequence. a. -Co-Calpha-N- b. -N-Co-Calpha c. -N-Calpha-Co- d. -Calpha-N-Co- e. none of these

c. -N-Calpha-Co-

What is the approximate overall charge on the peptide Gly-Arg-Tyr-Asp at pH 7? a. +2 b. -1 c. 0 d. +1 e. -2

c. 0

A buffer solution at pH 9 has a ratio of [HA]/[A-] of 10. What is the pKa of the acid? a. 8 b. 9 c. 10 d. 11 e. 12

c. 10

If the rate constant for the enzyme catalyzed reaction is 2x10^5/sec and the rate constant for the uncatalyzed reaction is 2x10^-6/sec, the catalytic power of the enzyme is: a. 2x10^11 b. 10^-1 c. 10^11 d. 2x10^-1 e. 2x10^-11

c. 10^11

How many fragments will result from trypsin cleavage of the following peptide? Asp-Leu-Gln-Arg-Ile-Ala-Met-Trp-Phe-Lys-Gln-Met-Asp-Arg a. 1 b. 2 c. 3 d. 4

c. 3

What is the number of hydrogen bonds formed between G and C nucleotides? a. 1 b. 2 c. 3 d. 4 e. 5

c. 3

If an enzyme has a Vmax of 20 mM/min, what is the velocity if the substrate is present at 1/4 of the KM? a. 12 mM/min b. 6 mM/min c. 4 mM/min d. 2.5 mM/min e. cannot be determined from given information

c. 4 mM/min

Which amino acid substitutions are most likely to affect structure/function of the protein? a. Lys-->Arg b. Ser--> Thr c. Arg--> Glu d. Leu --> Ile

c. Arg--> Glu

Which amino acid is most likely to have a net positive charge at a pH of 7.0 a. Aspartic acid b. Glutamine c. Arginine d. Histidine

c. Arginine

Molecules which contain both hydrophilic and hydrophobic regions are: a. Amphipathic. b. Able to form micelles. c. Both of these. d. none of these

c. Both of these

Which of the following molecules has polar bonds but is itself not polar? a. H2O b. CH4 c. CO2 d. NH3

c. CO2

Which statement is true about restriction fragment length polymorphism? a. Can correlate a DNA mutation with the occurrence of a disease b. Can only detect mutation occurs at restriction enzyme cleavage site c. Can detect mutation that occurs either at restriction enzyme cleavage site or outside restriction enzyme cleavage site

c. Can detect mutation that occurs either at restriction enzyme cleavage site or outside restriction enzyme cleavage site

Select the monosaccharide that is correctly paired with its description. a. D-glucose - ketohexose b. D-galactose - aldopentose c. D-fructose - ketohexose d. D-ribulose - ketotetrose e. D-ribose - ketopentose

c. D-fructose - ketohexose

Living systems a. Violate the second law of thermodynamics b. Violate the first law of thermodynamics c. Decrease their entropy while increasing the entropy of the universe d. Are examples of a closed system

c. Decrease their entropy while increasing the entropy of the universe

Which of the following statements regarding enzymes is true? a. Enzymes shift the equilibrium of a chemical reaction. b. Enzymes increase the number of products of a chemical reaction. c. Enzymes increase the rate of a chemical reaction. d. Enzymes decrease the free energy of reactants. e. Enzymes decrease the rate of a chemical reaction.

c. Enzymes increase the rate of a chemical reaction.

Which statement about enzymes is correct? a. Enzymes shift the equilibrium of a chemical reaction. b. Enzymes increase the number of products of a chemical reaction. c. Enzymes increase the rate of a chemical reaction. d. Enzymes decrease the free energy of reactants. e. Enzymes decrease the rate of a chemical reaction.

c. Enzymes increase the rate of a chemical reaction.

In the Three Domain classification system, yeast would be considered a. Archaebacteria. b. Eubacteria. c. Eukarya.

c. Eukarya

Which of the following is a correct listing of electronegativity values, from low to high? a. C, H, O, N b. N, H, O, C c. H, C, N, O d. H, C, O, N

c. H, C, N, O

Which of the following is a correct listing of electronegativity values, from low to high? a. C, H, O, N b. N, H, O, C c. H, C, N, O d. O, N, C, H

c. H, C, N, O

A cloning vector map is shown below. Which restriction site is best for inserting a DNA fragment for selection of chimeric plasmid containing colonies? a. BamHI b. EcoRI c. HindIII d. They're all equally good.

c. HindIII

Which of the following is true? a. Both serine and homoserine are building blocks of proteins. b. Serine has one additional methylene (-CH2-) group than homoserine. c. Homoserine is less desirable than serine in a protein because it could result in peptide-bond cleavage. d. Homoserine has one additional amine group than serine

c. Homoserine is less desirable than serine in a protein because it could result in peptide-bond cleavage.

Which of the following statements concerning active transport is false? a. It takes place in the opposite direction as a concentration gradient. t b. It requires expenditure of energy by the cell. t c. It can be compared to water running downhill. d. A membrane-associate protein must be involved.

c. It can be compared to water running downhill.

How does the binding of epinephrine to its receptor set a response in action? a. It causes G proteins to produce cGMP b. It causes the release of insulin c. It causes an exchange of GTP for the G protein bound GDP d. It causes a pore to open, allowing proton-ion exchange e. It causes G protein to come off the membrane

c. It causes an exchange of GTP for the G protein bound GDP

What did Watson and Crick suggest to be significant about the base pairing found in the helix? a. It allowed the DNA to twist in a helix. b. The DNA could be circular. c. It was a mechanism for copying. d. All of the answers are correct. e. None of the answers is correct.

c. It was a mechanism for copying.

In the following peptide, which amino acid retains its α-carboxyl group? Asp-Glu-Arg-Lys a. Asp b. Glu c. Lys d. Arg e. none of these

c. Lys

Which of the following groups is not present in a cerebroside? a. Sphingosine b. Fatty acid c. Phosphate d. Sugar

c. Phosphate

If a protein with the sequence QPAKSFRYCIG is treated with trypsin, what will the products be? a. QPAK SFRYCIG b. QPAKSFR YCIG c. QPAK SFR YCIG d. QPAKSF RY CIG

c. QPAK SFR YCIG

Coronavirus is a type of ____ virus. The genome can be detected by ____. a. RNA, PCR b. DNA, PCR c. RNA, RT-PCR (Reverse transcription PCR) d. DNA, RT-PCR

c. RNA, RT-PCR (Reverse transcription PCR)

Coronavirus's genomic material composed of ____. In host cells, the genomic materials must be ____ into ____ before viral proteins can be produced. a. DNA, translated, proteins b. RNA, translated, proteins c. RNA, reverse-transcribed, DNA d. DNA, reverse-transcribed, RNA e. RNA, reverse-transcribed, RNA

c. RNA, reverse-transcribed, DNA

What type of plot allows one to investigate the likely phi and psi angles of the peptide backbone? a. Hill b. Lineweaver-Burk c. Ramachandran d. Michaelis-Menten

c. Ramachandran

In chain termination method of DNA sequencing in what direction do you read the nucleotide sequence why? a. Reading the gel from the top to the bottom gives the sequence in the 5' to 3' direction; shorter fragments that were terminated early in polymerization move faster down the gel. b. Reading the gel from the top to the bottom gives the sequence in the 5' to 3' direction; longer fragments that were terminated early in polymerization move faster down the gel. c. Reading the gel from the bottom to the top gives the sequence in the 5' to 3' direction; shorter fragments that were terminated early in polymerization move faster down the gel. d. Reading the gel from the bottom to the top gives the sequence in the 5' to 3' direction; longer fragments that were terminated later in polymerization move faster down the gel. e. Reading the gel from the bottom to the top gives the sequence in the 3' to 5' direction; shorter fragments that were terminated early in polymerization move faster down the gel.

c. Reading the gel from the bottom to the top gives the sequence in the 5' to 3' direction; shorter fragments that were terminated early in polymerization move faster down the gel.

Advantages of the Polymerase Chain Reaction include all of these, except: a. The reaction is specific for certain sequences in the DNA. b. Only small amounts of template are needed. c. Results can only be obtained with freshly isolated DNA. d. Virtually all the products from a specific part of the DNA will be the same size

c. Results can only be obtained with freshly isolated DNA.

To which amino acid residues in glycoproteins are the sugars commonly linked? a. Tyrosine and asparagine b. Serine and threonine c. Serine, threonine, and asparagine d. Serine, tyrosine, and asparagine

c. Serine, threonine, and asparagine

Sequencing DNA using a dideoxy method can be done by putting fluorescent tags on the ddNTPs, and then separating the DNA fragments by size using electrophoresis. A short segment is sequenced using ddNTPs tagged as shown in the Table ddNTP color ddATP ddCTP ddGTP ddTTP Green Blue Yellow red The resulting electrophoresis gel is displayed below. What is the DNA sequence of the template strand? a. AGTCCA b. TCAGGT c. TGGACT d. ACCTGA

c. TGGACT

The free energy of activation is defined as: a. The average free energy of the product formed. b. The rate of a chemical reaction in relationship to the concentration of reactant molecules. c. The energy required to raise the average energy of reactant to the transition state energy. d. The amount of energy released by a spontaneous reaction. e. The lowest point on a free energy diagram.

c. The energy required to raise the average energy of reactant to the transition state energy.

Which of the following best describes the state of a protein whose pI = 9.5, when in a solution whose pH = 7? a. The protein will have no net charge. b. The protein will have a net negative charge. c. The protein will have a net positive charge. d. The side chains of the protein's acidic residues will mostly be in their unprotonated states. e. The side chains of the protein's basic residues will mostly be in their uncharged states.

c. The protein will have a net positive charge.

What happens to nonpolar molecules in water? a. They precipitate. b. They dissolve independently. c. They aggregate together. d. All of these are correct.

c. They aggregate together.

All of the following are properties of a coenzyme EXCEPT: a. They are usually actively involved in the catalytic reaction of the enzyme. b. They can serve as intermediate carriers of functional groups. c. They are protein components. d. They may contain vitamins as part of their structure.

c. They are protein components.

All are characteristic of allosteric enzymes EXCEPT: a. Effectors may show stimulatory or inhibitory activity. b. They have multiple subunits. c. They obey Michaelis-Menten kinetics. d. The regulatory effect is by altering conformation and interaction of subunits. e. Binding one subunit impacts binding of substrate to other subunits.

c. They obey Michaelis-Menten kinetics.

Which of the following are related for a given enzyme? a. Vmax, KM, and percentage of α-helix b. Vmax, kcat, and percentage of β-sheet c. Vmax, kcat, and turnover number d. Vmax, KM, and molecular weight

c. Vmax, kcat, and turnover number

To determine if cancer cells express protein A. Which technique would be most useful? a. Northern blotting b. Southern blotting c. Western blotting d. Lowry protein assay e. UV/Vis spectroscopy

c. Western blotting

All are characteristics of yeast artificial chromosomes (YACs) EXCEPT: a. YACs must include telomeres b. YACs must include centromere c. YACs must include operon d. YACs must include cloning site e. YACs can successfully propagate DNA molecules of 2 megabase pairs in length.

c. YACs must include operon

If a reaction has a negative DeltaG, is it likely to occur? a. Not unless energy is added to the system b. Yes, if it is coupled to another reaction c. Yes, it is spontaneous. d. No, it is not spontaneous. e. Yes, as long as the temperature increases

c. Yes, it is spontaneous.

If a reaction has a negative ΔG, is it likely to occur? a. Not unless energy is added to the system b. Yes, if it is coupled to another reaction c. Yes, it is spontaneous. d. No, it is not spontaneous. e. Yes, as long as the temperature increases

c. Yes, it is spontaneous.

Molecules of a given protein have all EXCEPT: a. a fixed amino acid composition b. a defined amino acid sequence c. a sequence read from C-terminal end to N-terminal end d. an invariant molecular weight e. a nucleotide sequence from which they are encoded

c. a sequence read from C-terminal end to N-terminal end

Glycoforms refers to a. glycoproteins from the same gene family b. a common core of sugars that can be found on many different proteins c. a single protein type that can have forms that vary in glycosylation d. all of these e. none of these

c. a single protein type that can have forms that vary in glycosylation

A single clone of interest can be distinguished from others in a mixture of clones by a. testing the clones for antibiotic resistance. b. mobility of the clones in gel electrophoresis. c. a specific probe, usually a labeled complementary DNA. d. resistance to damage by ultraviolet light.

c. a specific probe, usually a labeled complementary DNA.

A single clone of interest can be distinguished from others in a mixture of clones by a. testing the clones for antibiotic resistance. b.mobility of the clones in gel electrophoresis. c. a specific probe, usually a labeled complementary DNA. d. resistance to damage by ultraviolet light.

c. a specific probe, usually a labeled complementary DNA.

All are distinctive features of enzymes EXCEPT: a. regulation. b. catalytic activity. c. ability to change ΔG. d. specificity.

c. ability to change ΔG.

What type of enzymes often display sigmoidal plots of activity versus substrate concentration? a. holoenzymes b. monomeric enzymes c. allosteric enzymes d. Michaelis-Menten enzymes e. isozymes

c. allosteric enzymes

Lactose intolerance a. depends on a deficiency of lactose in the diet. b. is based on the composition of lactose, consisting glucose and fructose in glycosidic linkage. c. arises from inability to metabolize the disaccharide lactose. d. arises because lactose is a dimer of galactose

c. arises from inability to metabolize the disaccharide lactose.

Glycosidic linkages between monosaccharide units may vary based on a. the anomeric form of the cyclic structure, i.e., α or β. b. which -OH group is involved. c. both of these. d. none of these.

c. both of these.

Which papain property allows using it as a meat-tenderizer? a. high substrate specificity b. absolute substrate specificity c. broad substrate specificity d. broad stereochemical specificity

c. broad substrate specificity

Carbonic anhydrase is reported to: (Select all that apply). a. catalyze the hydration of carbonic acid. b. add a water molecule to carbonic acid. c. catalyze the hydration of carbon dioxide. d. catalyze carbonic acid synthesis. e. add a phosphate group to carbonic dioxide.

c. catalyze the hydration of carbon dioxide. d. catalyze carbonic acid synthesis.

Prosthetic groups are referred to as: a. apoenzymes. b. holoenzymes. c. coenzymes. d. active sites. e. inhibitors.

c. coenzymes.

Which of the following treatments results in a polypeptide fragment with a homoserine lactone at the C-terminal end? a. trypsin b. chymotrypsin c. cyanogen bromide d. Edman method

c. cyanogen bromide

The fatty acid synthesis occurs in ____, and the fatty acid degradation occurs in the ____. a. endoplasmic reticulum, mitochondria b. mitochondria, mitochondria c. cytoplasm, mitochondria d. cytoplasm, Golgi complex e. mitochondria, cytoplasm

c. cytoplasm, mitochondria

What technique is used to locate disulfide bonds in protein? a. HPLC b. SDS-PAGE c. diagonal electrophoresis d. protein sequencing e. mass spectrometry

c. diagonal electrophoresis

What technique is used to locate disulfide bonds in protein? a. HPLC b. SDS-PAGE c. diagonal electrophoresis d. protein sequencing e. mass spectrometry

c. diagonal electrophoresis

The ΔG of a reaction depends only on the: a. free energy of activation. b. molecular mechanism of the transformation. c. difference in free energy between the final and initial states. d. nature of the reactants. e. nature of the products.

c. difference in free energy between the final and initial states.

A non-spontaneous reaction is a. at equilibrium. b. exergonic. c. endergonic. d. none of these

c. endergonic.

A nonspontaneous reaction is a. at equilibrium. b. exergonic. c. endergonic. d. none of these.

c. endergonic.

A pattern of DNA fragments can serve as a ____ of a particular DNA molecule a. template b. primer c. fingerprint d. vector e scaffold

c. fingerprint

Which of the following techniques is most useful for fractionating a heterogeneous protein mixture by size? a. affinity chromatography b. Edman degradation c. gel-filtration chromatography d. ion-exchange chromatography e. isoelectric focusing

c. gel-filtration chromatography

Cellulose is homopolysaccharide composed of ______ linked together by ______ glycosidic bonds. a. galactose; β-(1-4). b. galactose; α-(1-4). c. glucose; β-(1-4). d. glucose; α-(1-4).

c. glucose; β-(1-4).

RNA is more susceptible to alkaline hydrolysis than DNA because RNA a. contains U instead of T b. forms hairpin c. has a 2'-OH group d. lacks a 2'-OH group

c. has a 2'-OH group

When the pH is below pI, proteins a. have no net charge b. precipitate c. have a net positive charge d. have a net negative charge e. impossible to predict

c. have a net positive charge

The typical order for the major steps of enzyme isolation would be (from first to last): a. homogenization, salt fractionation, electrophoresis, column chromatography b. salt fractionation, homogenization, electrophoresis, column chromatography c. homogenization, salt fractionation, column chromatography, electrophoresis d. homogenization, column chromatography, salt fractionation, electrophoresis e. homogenization, electrophoresis, salt fractionation, column chromatography

c. homogenization, salt fractionation, column chromatography, electrophoresis

What releases a peptide from beads after solid-phase synthesis? a. trifluoroacetic acid b. dicyclohexylcarbodiimide c. hydrofluoric acid d. fluoroacetic acid e. water

c. hydrofluoric acid

Facilitated diffusion of membrane transport a. is an endergonic process b. requires coupling to ATP hydrolysis c. is driven by a difference in solute concentration d. requires that the solute be uncharged e. requires a carrier protein

c. is driven by a difference in solute concentration e. requires a carrier protein

Why is the peptide bond planar? a. bulky side chains prevent free rotation around the bond b. hydrogen bonding between the NH and C=O groups from the peptide backbone limits movement c. it contains partial double-bond character, preventing rotation d. all of these are true

c. it contains partial double-bond character, preventing rotation

What happens when a protein is denatured? a. it is broken apart into its constituent amino acids. b. its primary structure is disrupted but its secondary and tertiary structures remain intact. c. its secondary and tertiary structures are disrupted but its primary structure remains intact. d. it becomes all β-sheets.

c. its secondary and tertiary structures are disrupted but its primary structure remains intact.

Enzymes work by: a. providing an alternate reaction pathway b. increasing the spontaneity (ΔG) of the reaction c. lowering the activation energy of the reaction d. altering the concentration of the reactants to achieve a favorable ΔG e. proceeding in only one direction, from reactants to products

c. lowering the activation energy of the reaction

All are true for cDNA libraries EXCEPT: a. reverse transcriptase synthesizes a DNA strand complement of the mRNA templates. b. the original RNA strands are broken down by treating with alkaline c. mRNA templates are isolated using oligo (dA)-cellulose chromatography. d. the cDNA are copies from mRNA templates.

c. mRNA templates are isolated using oligo (dA)-cellulose chromatography.

What parameter of the molecule can be determined based on time it takes for the ion of that molecule to pass through the chamber of the TOF mass analyzer? a. structure b. shape c. mass d. pI e. pH

c. mass

Glycosidic bonds from sugars a. always link to the other molecule through a nitrogen atom. b. always link to the other molecule through an oxygen atom. c. may link to the other molecule through either an oxygen or a nitrogen atom. d. none of these.

c. may link to the other molecule through either an oxygen or a nitrogen atom.

Two-dimensional electrophoresis usually exploits these 2 different properties of proteins: a. molecular weight and shape b. molecular weight and net charge c. molecular weight and isoelectric point d. isoelectric point and net charge e. isoelectric point and shape

c. molecular weight and isoelectric point

Migration of linear DNA during electrophoresis is based a. mostly on the charge of the molecule, since the ratio of charge to mass is approximately the same, no matter how large the DNA is. b. mostly on the charge-to-mass ratio since this can vary greatly among pieces of DNA. c. mostly on the size of the molecule, since the ratio of charge to mass is approximately the same, no matter how large the DNA is. d. on parameters not understood well.

c. mostly on the size of the molecule, since the ratio of charge to mass is approximately the same, no matter how large the DNA is.

The pH optimum of an enzyme is: (Select all that apply) a. always between pH 6-8. b. nearly the same for all enzymes. c. often dependent upon the amino acids that form the active site. d. occurs when there is optimum secondary and tertiary structure in the active site of the enzyme.

c. often dependent upon the amino acids that form the active site. d. occurs when there is optimum secondary and tertiary structure in the active site of the enzyme.

The yeast artificial chromosomes (YACs) do not have a(n): a. pair of telomeres b. centromere c. operon d. cloning site e. autonomously replicating sequence

c. operon

Which molecule is used in Edman degradation to label the N-terminal amino acid of a polypeptide? a. cyanogen bromide b. O-iodosobenzoate c. phenyl isothiocyanate d. hydroxylamine e. 2-nitro-5-thiocyanobenzoate

c. phenyl isothiocyanate

An ELISA can be used for a. protein sequencing b. size analysis c. quantitative analysis d. protein conformation analysis e. three-dimensional structure analysis

c. quantitative analysis

All are steps used for construction of a chimeric plasmid EXCEPT: a. annealing the ends of the vector and foreign DNA. b. cutting the source of the foreign DNA with a restriction endonuclease. c. reannealing the ends of the vector back together. d. cutting the vector plasmid with the same restriction endonuclease.

c. reannealing the ends of the vector back together.

What is not included in the PCR mixture? a. the target sequence b. the primers c. reverse transcription d. dNTPs e. DNA polymerase

c. reverse transcription

What characteristic is most used to define lipids? a. ionic charge b. melting point c. solubility d. ability to bind metal ions

c. solubility

The purity of an enzyme at various stages of purification is best measured by a. total protein. b. total enzyme activity. c. specific activity of the enzyme. d. percent recovery of the protein. e. percent recovery of the enzyme.

c. specific activity of the enzyme.

Penicillin is an example of a mechanism-based enzyme inactivator and is a(n): a. competitive inhibitor. b. noncompetitive inhibitor. c. suicide substrate. d. uncompetitive inhibitor. e. none of the above.

c. suicide substrate.

The specificity or stringency of a PCR reaction can be controlled by altering the reaction a. target sequence b. volume c. temperature and salt concentration d. All of these e. None of these

c. temperature and salt concentration

The degree of animal membrane fluidity depends on a. the percentage of cholesterol b the percentage of fatty acids c. the percentage of unsaturated fatty acids d. the percentage of cholesterol and unsaturated fatty acids e. all of these

c. the percentage of unsaturated fatty acids

In the SDS-PAGE method, separation takes place on the basis of a. charge only, because all particles have different charges, but the same mass. b. the sieving action of the gel, because all particles have the same charge, but different masses. c. the sieving action of the gel, because all particles have approximately the same charge/mass ratio, but different masses. d. the chemical nature of the buffer used as the electrolyte.

c. the sieving action of the gel, because all particles have approximately the same charge/mass ratio, but different masses.

Explain the existence of the hydrophobic effect a. the tendency of water molecules to make a bond with hydrophobic proteins b. the tendency of polar molecules to self-associate in the presence of an aqueous solution c. the tendency of nonpolar molecules to self-associate in the presence of an aqueous solution d. the inability of charged molecules to dissolve in water e. the property of nucleic acids to dissolve in water

c. the tendency of nonpolar molecules to self-associate in the presence of an aqueous solution

Which statement about solid phase peptide synthesis is false? a. the desired product is bound to beads and excess reagents can be easily removed at each step. b. synthesis starts from C-terminus. c. there is no limit on the length of peptide chain. d. amino acid's carboxyl group must be activated with dicyclohexylcarbodiimide to facilitate peptide bond formation.

c. there is no limit on the length of peptide chain.

What does the N-linked oligosaccharide core include? a. three mannose, two glucose, and two N-acetylgalactosamine residues b. three mannose and two N-acetylglucosamine residues c. three mannose, two N-acetylglucosamine, and one fucose residue d. two N-acetylglucosamine and one fucose residue e. two N-acetylglucosamine residues only

c. three mannose, two N-acetylglucosamine, and one fucose residue

Which reagent enzymatically cleaves proteins? Select all that apply. a. cyanogen bromide b. O-iodosobenzoate c. thrombin d. hydroxylamine e. trypsin

c. thrombin e. trypsin

What possesses the highest free energy? a. reactant b. product c. transition state d. final state e. initial state

c. transition state

Which of the following is not membrane lipid? a. cholesterol b. phosphoglycerides c. triacylglycerol d. glycolipids

c. triacylglycerol

Given the rate law, rate = k[A][B], the overall reaction order is a. zero b. one c. two d. cannot be determined

c. two

The typical order of differential centrifugation for organelles is (from slowest speed/lowest g to fastest speed/highest g): a. nuclei, microsomes, mitochondria & chloroplasts, cytosol, whole cells b. whole cells, cytosol, microsomes, nuclei, mitochondria & chloroplasts c. whole cells, nuclei, mitochondria & chloroplasts, microsomes, cytosol d. nuclei, mitochondria & chloroplasts, whole cells, cytosol, microsomes e. cytosol, microsomes, nuclei, mitochondria & chloroplasts, whole cells

c. whole cells, nuclei, mitochondria & chloroplasts, microsomes, cytosol

Liquid water consists of H2O molecules: a. held in a rigid three-dimensional network b. with local prefernce for linear geometry c. with large numbers of broken hydrogen bonds d. all are true e. which do not switch H-bonds readily

c. with large numbers of broken hydrogen bonds

In transforming the Michaelis-Menten equation into a straight-line equation, y = mx + b, the Lineweaver-Burk double reciprocal plot, which of the following is NOT a true representation? a. slope = KM/Vmax b. y-intercept is 1/Vmax c. x-intercept is 1/KM d. y = 1/V e. x = 1/[S]

c. x-intercept is 1/KM

Which of the following best describes the glycosidic bond in the disaccharide shown? a. α(1-4). b. β(1-4). c. α(2-4). d. β(2-4). e. None of the above.

c. α(2-4).

Maltose is a disaccharide composed of: a. α-D-glucopyranose and β-D-fructofuranose. b. α-D-galactopyranose and α-D-glucopyranose. c. α-D-glucopyranose and α-D-glucopyranose. d. β-D-fructofuranose and α-D-galactopyranose. e. β-D-glucopyranose and β-D-fructofuranose.

c. α-D-glucopyranose and α-D-glucopyranose.

The glycosidic linkage of the disaccharide shown is a. α-1,4 b. α-1,6 c. β-1,4 d. β-1,6

c. β-1,4

What compounds are used to reduce disulfide bonds? Select all that apply a. sodium dodecyl sulfate b. polyacrylamide c. β-mercaptoethanol d. dithiothreitol e. polyampholytes

c. β-mercaptoethanol d. dithiothreitol

The "c" in cDNA stands for _____

complementary

What is the charged group(s) present in valine at a pH of 7? a. -NH3 + b. -COO- c. -NH2 + d. -NH3 + and -COO- e. All the charged groups are present.

d. -NH3 + and -COO-

Four KM values are given for the binding of substrates to a particular enzyme. Which has the strongest affinity when k-1 is greater than k2? a. 150 mM b. 0.15 mM c. 150 µM d. 1.5 nM

d. 1.5 nM

When did life on Earth begin and when did human beings emerge, respectively? a. 3 billion years ago and 1 billion years ago b. 3.5 billion years ago and 0.5 billion years ago c. 3.5 billion years ago and 0.2 billion years ago d. 3.5 billion years ago and less than 0.1 billion years ago e. 3.5 billion years ago and 0.1 billion years ago

d. 3.5 billion years ago and less than 0.1 billion years ago

At pH 6.9 H+ concentration is ____ times greater than at pH 7.4 and results in severe acidosis. a. 5 b. 0.5 c. 50 d. 4 e. 3.2

d. 4

The following steps are all involved in genetic recombination: 1- Screening for cells that contain the recombined gene. 2- Cutting the vector with restriction enzyme. 3- Mixing the gene of interest with the vector. 4- Isolating the gene of interest from its original source. 5- Ligating the gene of interest and the vector together. The following sequence of these five steps would be typical: a. 1 → 2 → 3 → 4 → 5 b. 2 → 3 → 5 → 1 → 4 c. 5 → 4 → 3 → 2 → 1 d. 4 → 2 → 3 → 5 → 1 e. 2 → 3 → 5 → 4 → 1

d. 4 → 2 → 3 → 5 → 1

Which of the DNA compositions would have the lowest melting temperature? a. 40% G b. 30% C c. 20% A d. 40% T

d. 40% T

Using the Henderson-Hasselbach equation, calculate the pH of a buffer solution made from 0.04 M CH3COOH and 0.2 M CH3COOthat has pKa= 4.7. a. 4 b. 2.5 c. 4.5 d. 5.4

d. 5.4

What type(s) of inhibition can be reversed? a. competitive b. noncompetitive c. mixed d. All of the answers are correct. e. None of the answers is correct.

d. All of the answers are correct.

Which of the following function of an enzyme is false: a. Enzymes help to catalyze virtually every metabolic reaction. b. Enzymes mediate the rates of cellular reaction in proportion to cellular requirements. c. Enzymes are sensitive to temperature, pH, and concentration changes. d. An increased activity of an enzyme increases the amount of energy produced. e. Enzymes are used as a catalyst to increase reaction rates many orders of magnitude.

d. An increased activity of an enzyme increases the amount of energy produced.

In the following peptide, which amino acid is the C-terminus? Phe-Ala-Gly-Arg a. Ala b. Phe c. Phe and Arg d. Arg e. Gly

d. Arg

The correct sequence of procedures in the Southern blotting technique is: A- hybridization with radioactive probe. B- agarose gel electrophoresis and visualize bands. C- transfer (blot) to nitrocellulose filter. D- digest DNA with restriction nucleases. E- expose filter to X-ray film, develop and observe. a. B, A, C, E, D b. D, C, B, A, E c. C, D, B, E, A d. D, B, C, A, E e. A, B, C, D, E

d. D, B, C, A, E

Methods for breaking proteins into smaller peptides include all of the following except: a. digestion with chymotrypsin b. cyanogen bromide treatment c. digestion with trypsin d. Edman degradation

d. Edman degradation

The simplest way to depict stereochemistry is to use a. ball-and-stick models. b. ribbon diagrams. c. space-filling models. d. Fisher projections. e. None of the answers is correct.

d. Fisher projections.

Riboflavin is a water-soluble organic substance that is not synthesized by humans. Metabolically, it is chemically converted into a substance called flavin adenine dinucleotide, which is required by succinate dehydrogenase. Which of the following statements is MOST accurate? a. Riboflavin is a coenzyme. b. Flavin adenine dinucleotide is a vitamin. c. Succinate dehydrogenase is a coenzyme. d. Flavin adenine dinucleotide is a coenzyme. e. Succinate dehydrogenase is a vitamin

d. Flavin adenine dinucleotide is a coenzyme.

The Beta-pleated sheet secondary structure of proteins is primarily stabilized by a. optimum ionin strength b. optimum pH c. interacton between amino acid R-groups d. H-bonds between peptide backbone groups e. disulfide bonds

d. H-bonds between peptide backbone groups

Which of the following mutations would probably be most likely to impact the function of the protein? a. Lys to Arg b. Leu to Ile c. Thr to Ser d. His to Pro e. Glu to Asp

d. His to Pro

Which arrow identifies the reducing end of the sugar? a. I b. II c. III d. IV

d. IV

What statement about membranes is false? a. Membranes are lipid bilayers. b. Membrane consists of peptides and lipids. c. Many membranes are electrically polarized. d. Membrane is an absolutely solid formation. e. Membrane lipids have both hydrophobic and hydrophilic properties.

d. Membrane is an absolutely solid formation.

Which of the following molecules is polar? a. CCl4 b. CH4 c. CO2 d. NH3

d. NH3

Amylose and glycogen are both polymers of glucose. What is an important difference between them? a. One is made with D-glucose and the other with L-glucose. b. One is used as a structural polymer in insects; the other for energy in plants. c. One contains α glycosidic bonds while the other contains β glycosidic bonds. d. One is a linear polymer while the other is highly branched. e. none of the above explain the difference between amylose and glycogen.

d. One is a linear polymer while the other is highly branched.

This is a map of pBR322 plasmid If a recombinant plasmid were obtained inserting DNA into the BamHI site, screening for the recombinant plasmid can be done by the following technique. a. Plate on nutrient agar plates that contain ampicillin. b. Plate on nutrient agar plates that contain tetracycline. c. Plate on nutrient agar plates that contain both ampicillin and tetracycline. d. Plate on nutrient agar plates that contain ampicillin, followed by replica plating on tetracycline. e. Plate on nutrient agar plates that contain tetracycline, followed by replica plating on ampicillin.

d. Plate on nutrient agar plates that contain ampicillin, followed by replica plating on tetracycline.

Which peptide is most likely to be found in the interior of a globular protein? a. PMDCAN b. FKITSA c. FTWIL d. REPYDG

d. REPYDG

The following item was the most important one for the development of PCR as a commercially successful and widely-used procedure: a. Heat-resistant DNA. b. Heat-resistant primers for DNA synthesis. c. Heat-resistant nucleoside triphosphate substrates. d. Taq DNA Polymerase

d. Taq DNA Polymerase

Cells that contain a "blue/white screening" plasmid that has an added gene are recognized by the method: a. Ability to grow on ampicillin. b. Inability to grow on ampicillin. c. The colonies have a blue color. d. The colonies lack a blue color. e. More than one of these choices indicates that the plasmid contains recombined DNA.

d. The colonies lack a blue color.

What statement is consistent with the structure of biological membranes? a. All membrane proteins are integral and associate with the hydrophobic region of the membrane. b. Both proteins and lipids readily undergo transverse ("flip-flop") diffusion. c. Membranes are symmetric. d. The membrane lipids self-assemble to form the lipid bilayer. e. A biological membrane consists of proteins sandwiched between two layers of lipids.

d. The membrane lipids self-assemble to form the lipid bilayer.

The steady state of an enzyme reaction is the following: a. The rate observed just after mixing the enzyme and substrate. b. The rate observed and Vmax. c. The rate of product formation. d. The state which exists when E-S complex is forming as fast as it is breaking down. e. The state which exists when substrate concentration equals KM.

d. The state which exists when E-S complex is forming as fast as it is breaking down.

The Michaelis constant is a. related to the molecular weight of the enzyme b. a measure of the resistance of the enzyme to denaturation c. a reflection of the percentage of polar amino acids in the enzyme d. a measure of how tightly the substrate is bound to the enzyme

d. a measure of how tightly the substrate is bound to the enzyme

The formation of cyclic structures in sugars with creation of an additional asymmetric center results from an alcohol reacting with a(n): a. secondary alcohol. b. phosphate group. c. thiol group. d. aldehyde or ketone. e. primary alcohol.

d. aldehyde or ketone.

In the β-pleated sheet conformation a. there are hydrogen bonds perpendicular to the direction of the polypeptide chain. b. the polypeptide chain is almost fully extended. c. the polypeptide chains may be hydrogen bonded together in a parallel or antiparallel orientation. d. all of these

d. all of these

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

d. all of these

The peptide bond a. is planar b. can be written as a resonance hybrid c. is the basis of protein structure. d. all of these

d. all of these

Recombinant DNA technology can aid in protein purification because a. Large quantities of proteins can be expressed, allowing for extensive characterization of the protein. b. Affinity tags can be fused to the protein to aid in purification by affinity chromatography. c. Mature proteins that have already been modified can be generated. d. all of these are true.

d. all of these are true.

Which of the following is true about the ABO blood groups? a. type O blood is the universal donor because it has an α-L-fucose group b. type A blood has a β-N-acetylgalactosamine group c. type AB blood is the universal donor d. all three of the blood groups have an α-L-fucose group attached

d. all three of the blood groups have an α-L-fucose group attached

Amino acids are linked in a head-to-tail fashion. elimination water, and forming a covalent ____ linkage typically referred to as a(n) ____ bond. a. anhydride, phosphoanhydride b. ester, aromatic c. dehydration, hydrogen d. amide, peptide e. none of these

d. amide, peptide

Which of the following function(s) of an enzyme is (are) false: a. Enzymes help to catalyze virtually every metabolic reaction b. Enzymes are sensitive to temperature, pH, and concentration changes c. Enzymes mediate the rates of cellular reaction in proportion to cellular requirements d. an increased activity of an enzyme increases the amount of energy produced e. enzymes are used as a catalyst to increase reaction rates many orders of magnitude

d. an increased activity of an enzyme increases the amount of energy produced

If DNA fragments of about 20 kb are to be cloned, which vector would be most useful? a. plasmid b. cosmid c. YACs (yeast artificial chromosomes) d. bacteriophage lambda e. E. coli chromosome

d. bacteriophage lambda

Which of the following is not characteristic of the Watson-Crick DNA double helix? a. The two polynucleotide chains are coiled about a common axis b. hydrogen bonds between A and T and between C and G hold the two chains together c. the purines and pyrimidines are on the inside of the helix and the sugar phosphate backbones are on the outside. d. base composition analyses of DNA duplexes isolated from many organisms have shown that the amount of A and U are equal, as the amounts of G and C.

d. base composition analyses of DNA duplexes isolated from many organisms have shown that the amount of A and U are equal, as the amounts of G and C.

The active site of an enzyme: a. is a three-dimensional cavity, formed by a coenzyme. b. occupies a significant part of an enzyme. c. consists of unique microenvironments formed by water molecules. d. binds to the substrate by multiple weak attractions. e. binds to the substrate after a prolonged contact.

d. binds to the substrate by multiple weak attractions.

On the quantitative PCR diagram, CT shows the a. number of copies of the original cDNA template b. fluorescence intensity c. number of copies of the original template d. cycle number at which fluorescence becomes detectable e. starting quantity of DNA

d. cycle number at which fluorescence becomes detectable

The chain terminator used in Sanger's DNA sequencing is _______. It works due to ______. a. dNTP; lack of 2'OH b. ddNTP; lack of 2'OH c. dNTP; lack of 3'OH d. ddNTP; lack of 3'OH

d. ddNTP; lack of 3'OH

What monosaccharide lacks an asymmetric carbon atom? a. fructose b. mannose c. galactose d. dihydroxyacetone

d. dihydroxyacetone

What is shown in the figure? a. plasmid pUC18 b. cloning vector c. lambda phage d. expression vector e. cosmid

d. expression vector

A cyclic hemiacetal with a five-membered oxygen-containing ring is referred to as a(n): a. aldehyde. b. pyranose. c. ketopentose. d. furanose. e. sorbitol.

d. furanose.

Which of the following is not a commonly used technique for protein isolation and purification? a. electrophoresis b. ion exchange chromatography c. affinity chromatography d. gas chromatography e. solubility ("salting in" or "salting out")

d. gas chromatography

Sucrose is composed of ___________ linked via ______ bond. a. galactose and glucose; α(1-4) glycosidic. b. glucose and fructose; α(1-4) glycosidic. c. glucose and fructose; α(1-2) glycosidic. d. glucose and fructose; α-1, β-2 glycosidic. e. galactose and glucose; α(1-2) glycosidic.

d. glucose and fructose; α-1, β-2 glycosidic.

Whether a segment of a protein may be found embedded in a membrane can be predicted by a. polarity b. acidity c. entropy d. hydropathy plot e. Ramachandran map

d. hydropathy plot

Salting out with ammonium sulfate is based upon proteins interacting with other proteins via a. disulfide bonds b. hydrogen bonds c. ionic bonds d. hydrophobic interactions

d. hydrophobic interactions

The process of converting analytes into gas-phase ions is called a. polymerization b. isoelectric focusing c. ion-exchange chromatography d. ionization e. electrophoresis

d. ionization

The Golgi apparatus a. occurs in prokaryotes b. is site of lipid synthesis c. is part of the chloroplast d. is involved in sorting of proteins in the cell

d. is involved in sorting of proteins in the cell

Which statement is false about peptide mass fingerprinting? a. it is a high throughput protein identification technique b. it does not depend on protein sequencing for identification c. it uses mass spectrometry to generate a peak list of proteolytic fragments d. it does not require database to have similar protein that is already characterized

d. it does not require database to have similar protein that is already characterized

What proteins facilitate cell-to-cell recognition by binding to specific carbohydrate structures? a. mucoproteins b. glycosaminoglycans c. glycoproteins d. lectins e. proteoglycans

d. lectins

Which of the following would be a possible amino acid sequence for an oligopeptide given the experimental data below? 1. The amino acid composition is found to be [val, lys, phe, met, cys, plus some decomposition products]. 2. the peptide has a molecular weight about 700 Da and absorbs at 280 nm 3. treatment with carboxypeptidase results in tryptophan and a peptide 4. CNBr treatment yields two tripeptides 5. trypsin digestion produces an amino acid and a pentapeptide with cys on the amino end 6. chymotrypsin digestion produces a tetrapeptide and a dipeptide a. trp-lys-met-cys-met-val b. lys-val-cys-phe-met-trp c. trp-val-phe-cys-met-lys d. lys-cys-met-phe-val-trp e. lys-met-cys-val-phe-trp

d. lys-cys-met-phe-val-trp

Matrix-Assisted Laser Desorption Ionization is a type of _______ technique. a. electrophoresis b. ion exchange chromatography c. affinity chromatography d. mass spectrometry

d. mass spectrometry

The substrate-enzyme (E-S) complex a. always proceeds to form the products rapidly. b. always breaks down to form free enzyme and substrate. c. always breaks down to form free enzyme and product. d. may break down to form free enzyme and substrate, or free enzyme and product.

d. may break down to form free enzyme and substrate, or free enzyme and product.

In vitro ____ makes it possible to alter the nucleotide sequence of a cloned gene systematically. a. protein synthesis b. mRNA synthesis c. hybridization d. mutagenesis

d. mutagenesis

Where are Ω and β turns and loops often found? a. in a hydrophobic pocket b. on the interior cleft c. at the protein interface with ligand d. on the surface of proteins

d. on the surface of proteins

The MOST fluid membrane would be a bilayer made of lipids with: a. polyunsaturated 18-carbon fatty acids. b. saturated 18-carbon fatty acids. c. saturated 16-carbon fatty acids. d. polyunsaturated 16-carbon fatty acids. e. polyunsaturated 20-carbon fatty acids.

d. polyunsaturated 16-carbon fatty acids.

A protein mixture (shown in the Table) was separated using a size exclusion chromatography with fractionation range 1-100 kDa at pH 7. Predict the order of emergence from the column. a. protein B, protein C, protein A b. protein B, protein A, protein C c. protein C, protein A, protein B d. protein A, protein C, protein B

d. protein A, protein C, protein B

What types of molecules can serve as antigens? a. proteins b. polysaccharides c. metal ions d. proteins and polysaccharides

d. proteins and polysaccharides

The arrangement of the two alpha and two beta polypeptide chains in hemoglobin is an example of a. primary structure of a protein b. secondary structure of a protein c. tertiary structure of a protein d. quaternary structure of a protein

d. quaternary structure of a protein

The DNA fragment was inserted into a specific plasmid. What do the plasmid and the DNA fragment have in common? a. both act as vectors b. identical restriction sites c. same molecular weight d. same sticky ends

d. same sticky ends

Which of the following atoms IS NOT contained within the amide plane of the peptide backbone? a. Cα-carbon b. amide nitrogen c. carbonyl carbon d. side chain carbons

d. side chain carbons

Which of the following atoms IS NOT contained within the amide plane of the peptide backbone? a. α-carbon b. amide nitrogen c. carbonyl carbon d. side chain carbons

d. side chain carbons

Which carbon of the Fischer projection of a sugar becomes the anomeric carbon in the Haworth projection? a. the highest numbered carbon. b. the highest numbered chiral center. c. It depends on the individual sugar. d. the carbonyl carbon.

d. the carbonyl carbon.

Which groups of a pair of amino acids must react to form a peptide bond? a. the two carboxyls b. the two aminos c. the two R-groups d. the carboxyl of one and the amino of the other

d. the carboxyl of one and the amino of the other

Which of the following happens as a protein is purified? a. the percent recovery and the fold purification both increase b. the percent recovery increases and the fold purification decreases c. the percent recovery and the fold purification both decrease d. the percent recovery decreases and the fold purification increases

d. the percent recovery decreases and the fold purification increases

The degree of separation in molecular sieve chromatography depends on a. the polarity of the mobile phase b. the pKa of the buffer material in the mobile phase c. the chemical nature of the sieve material d. the size of the pores in the sieve material

d. the size of the pores in the sieve material

The entropy of a reaction refers to a. the effect of the temperature on the rate of the reaction b. the energy of the transition state. c. the heat given off by the reaction d. the tendency of the system to move toward maximal randomness

d. the tendency of the system to move toward maximal randomness

The entropy of a reaction refers to a. the effect of the temperature on the rate of the reaction. b. the energy of the transition state. c. the heat given off by the reaction d. the tendency of the system to move toward maximal randomness

d. the tendency of the system to move toward maximal randomness

What gives proteins such a dominant role in biochemistry? a. the rigidity of the peptide backbone b. the ability to act as a blueprint c. their ability to self-replicate d. their ability to spontaneously fold into complex three-dimensional structures e. All of these

d. their ability to spontaneously fold into complex three-dimensional structures

In 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 aggregation of several enzyme molecules when the substrate binds. d. there is a conformational change in the enzyme when the substrate binds.

d. there is a conformational change in the enzyme when the substrate binds.

The configuration of most peptide bonds in a protein is _____. a. cis b. circular c. parallel d. trans e. perpendicular

d. trans

The predominance of protein sequence information is now derived from: a. chemical sequencing (Edman method). b. mass spectrometry. c. tandem mass spectrometry. d. translating the nucleotide sequence of genes into codons, and thus amino acid sequence.

d. translating the nucleotide sequence of genes into codons, and thus amino acid sequence.

A term that describes a molecule that contains both positive and negative charges but overall has a neutral charge is _____. a. enantiomer b. amino acid c. racemate d. zwitterion e. amphipath

d. zwitterion

Disulfide bonds in proteins can be reduced to free sulfhydryl groups by reagents such as a. Urea b. guanidine hydrochloride c. detergent d. β-mercaptoethanol

d. β-mercaptoethanol

How many fragments will result from CNBr cleavage of the following peptide? Asp-Met-Gln-Phe-Ile-Ala-Trp-Phe-Lys-Gln-Met-Asp-Glu a. 1 b. 2 c. 3 d. 4 e. 5

d.4

Which pair of carbohydrates is epimeric at C-2?

If the pH of a solution is 6, then the [H+ ] in that solution is: a. 6 M. b. 60 M. c. 1x106 M. d. 6x10-6 M e. 1x10-6 M

e. 1x10-6 M

If the rate constant for the enzyme catalyzed reaction is 3 x 106 /sec and the rate constant for the uncatalyzed reaction is 1 x 10-7 /sec, the catalytic power of the enzyme is: a. 10^13 b. 3 x 10^-13 c. 10^-13 d. 10^-1 e. 3 x 10^13

e. 3 x 10^13

If carbon 1 is the carbonyl group of an aldohexose, which carbon determines if the sugar is a D- or L- stereoisomer? a. 1 b. 2 c. 3 d. 4 e. 5 f. 6

e. 5

If 1.0 moles Na2HPO4 and 0.1 moles of NaH2PO4 are mixed in water, what is the resulting pH? The pKa values for phosphoric acid are 2.1, 7.2, 12.4. a. 2.1 b. 12.4 c. 8.2 d. 3.1 e. 7.2 f. 6.2

e. 7.2

Which of the following correctly describes peptide bonds? a. They are special type of amide bond. b. They are a very stable bonds. c. They are formed when water is split out from an amino group and a carboxylic acid. d. They are a bond which displays resonance. e. All of these

e. All of these

Which statement about glycosylation is true? a. Glycosyltransferases catalyze the formation of glycosidic bonds. b. Dolichol phosphate is a lipid molecule located in the membrane of the endoplasmic reticulum. c. O-linked glycosylation takes place in the Golgi complex. d. N-linked glycosylation begins in the endoplasmic reticulum and continues in the Golgi complex. e. All of these are true.

e. All of these are true.

Which of the following are methods by which cells can be induced to take up recombinant DNA molecules? a. liposome. b. DNA "guns" which spray the DNA at very high speeds. c. Electroporation. d. Phage or virus infection. e. All of these are used.

e. All of these are used.

Which of the following are methods used to determine where the DNA bands are located on an electrophoresis gel? a. Radioactivity b. Fluorescence c. Dyes which bind to DNA d. Luminescence e. All of these can visualize the DNA

e. All of these can visualize the DNA

Restriction enzymes are especially useful for genetic recombination work for which of the following reasons? a. They cut DNA at specific sequences. b. They cut DNA independent of the source of the DNA. c. They often generate single stranded tails or "sticky ends". d. There are a large variety of them commercially available. e. All of these traits make restriction enzymes useful.

e. All of these traits make restriction enzymes useful.

Using an anion exchange resin, a mixture of four amino acids is separated using an elution gradient of increasing NaCl solution. What would be the correct elution sequence? a. Ser, Asp, Lys, Arg b. Arg, Lys, Ser, Asp c. Lys, Arg, Asp, Ser d. Asp, Arg, Ser, Lys e. Asp, Ser, Lys, Arg

e. Asp, Ser, Lys, Arg

. All the following bonds are important in biomolecules, except: a. C-N b. C-H c. O-H d. O-P e. C-Cl

e. C-Cl

All the following bonds are important in biomolecules, except: a. C-N b. C-H c. O-H d. O-P e. C-Cl

e. C-Cl

The method pf protein detection based on the linking of an enzyme to a specific antibody is a. NMR b. SDS-PAGE c. HPLC d. MALDI e. ELISA

e. ELISA

Which statement about enzymes is correct? a. Enzymes force reactions to proceed in only one direction. b. Enzymes alter the equilibrium of the reaction. c. Enzymes alter the standard free energy of the reaction. d. All known enzymes are proteins. e. Enzymes accelerate reactions by factors of as much as a million or more.

e. Enzymes accelerate reactions by factors of as much as a million or more.

Which is a correct pair of abbreviations for an amino acid? a. Asp / P b. Tyr / T c. Lys / L d. Glu / Q e. Gln / Q

e. Gln / Q

Assuming the oligopeptide DTEASRTENT forms one continuous α-helix, the carbonyl oxygen of the alanine residue is hydrogen bonded to the amide nitrogen of a. Aspartic acid b. Asparagine c. Threonine d. Arginine e. Glutamic acid

e. Glutamic acid

How does zanamivir, an anti-influenza agent, help treat influenza infection? a. It blocks viral RNA synthesis. b. It makes glycoproteins and glycolipids on the cell surface invisible to the virus. c. It makes the virus weaker but still active. d. It destroys the capsid right after virus ingestion. e. It inhibits viral neuraminidase.

e. It inhibits viral neuraminidase

The method that reveals the atomic structure of proteins in a solution is: a. MALDI b. electrophoresis c. x-ray crystallography d. ion-exchange chromatography e. NMR

e. NMR

Which of the following is classified as a neutral polar amino acid? a. His b. Asp c. Leu d. Met e. Ser

e. Ser

What is not a step in cassette mutagenesis? a. DNA is cleaved at a pair of unique restriction sites b. The short segment is removed from the plasmid c. the cassette is ligated into the plasmid d. in the end, we get the desired mutation e. The short segment connects with the cassette

e. The short segment connects with the cassette

Assuming the oligopeptide TEASRTEYNT forms one continuous α-helix, the carbonyl oxygen of the serine residue is hydrogen bonded to the amide nitrogen of a. Aspartic acid b. Asparagine c. Threonine d. Arginine e. Tyrosine

e. Tyrosine

which statements are true for kcat: a. referred to as the molecular activity of the enzyme. b. called the turnover number of the enzyme. c. measures the maximal catalytic activity. d. defines the number of substrate molecules converted into product/enzyme active site/unit of time when the enzyme is saturated with substrate. e. all are true.

e. all are true.

Solid-phase DNA synthesis can be used to prepare a. DNA probes b. primers for PCR c. gene codes for novel peptide d. primers for DNA sequencing e. all of these

e. all of these

The use of synthetic peptides includes a. use as antigens for making antibodies b. drugs c. "hooks" used in purification d. a and c e. all of these

e. all of these

Due to what mechanism do many genes encode more than one protein? a. adenylation b. mutagenesis c. translation d. transcription e. alternative splicing

e. alternative splicing

Which type of interaction does not exist between the substrate does and the active site of an enzyme? a. electrostatic interactions. b. hydrogen bonds. c. van der Waals forces. d. hydrophobic interactions. e. covalent interactions.

e. covalent interactions.

Which amino acid can form disulfide bonds? a. histidine b. methionine c. proline d. serine e. cysteine

e. cysteine

Someone with uncontrolled diabetes mellitus may have ____ levels of blood ____ so they test their blood for ____. a. elevated; fructose; gluconic acid. b. depressed; glucose; oxidizing sugars. c. elevated; glucose; fructose. d. depressed; gluconic acid; reducing sugars. e. elevated; glucose; reducing sugars.

e. elevated; glucose; reducing sugars.

Which type of reaction requires an input of energy to proceed? a. reversible reaction. b. irreversible reaction. c. catalyzed reaction. d. exergonic reaction. e. endergonic reaction.

e. endergonic reaction.

Which statement about gene disruption is false? a. gene disruption can be used to determine the function of a gene. b. gene disruption can be achieved by RNA interference. c. gene disruption can be achieved by CRISPR-Cas9 system. d. gene disruption is also known as gene knockout. e. gene disruption cannot be done at a precise location

e. gene disruption cannot be done at a precise location

Which of the following membrane components contain carbohydrates? a. lipid-linked proteins b. cholesterol c. integral membrane proteins in contact with the cytoplasm d. phosphatidylserine e. glycolipids

e. glycolipids

What is the name for a mixture of disrupted cells or tissues? a. supernatant b. proteome c. precipitate d. solution e. homogenate

e. homogenate

A β sheet is formed by linking two or more β strands lying next to one another through: a. nitrogen bonds. b. oxygen bonds. c. ionic bonds. d. disulfide bridges. e. hydrogen bonds.

e. hydrogen bonds.

Cartilage-matrix proteoglycan has all of the following properties EXCEPT: a. responsible for the flexibility and resiliency of cartilage. b. has a hyaluronic acid binding domain. c. has reversible hydration-dehydration properties. d. contains both N-linked and O-linked oligosaccharides. e. is an integral transmembrane protein.

e. is an integral transmembrane protein.

Which of the following binds most tightly to enzyme's active site? a. an activator b. the transition state of the reaction c. a competitive inhibitor d. its product e. its substrate

e. its substrate

The main difference between prokaryotic and eukaryotic cells is the existence of ________ in eukaryotes. a. cell membrane b. ribosomes. c. DNA. d. RNA. e. nucleus.

e. nucleus.

The point with the highest free energy on an activation energy profile represents the a. Vmax b. kinetic energy c. transition state d. catalytic energy e. standard free energy change for the reaction

e. standard free energy change for the reaction

Which property accounts for the wide range functions of carbohydrate? a. involvement in metabolism. b. stability of molecules. c. hydrophobic property. d. hydrophilic property. e. structural diversity

e. structural diversity

Another name for an antigenic determinant is _____

epitope

If a peptide has a pI of 4.2, ____ might be present while ____ would probably be absent. a. Arg/His b. Glu/Lys c. His/Ser d. Asp/Gly 5. Cys/Tyr

glu/lys

A given protein with several potential glycosylation sites can give many different glycosylated structures is known as ______

glycoforms

Which membrane components contain carbohydrates? a. glycolipids b. cholesterol c. lipoproteins d. integral membrane proteins in contact with the cytoplasm e. phosphatidylserine

glycolipids

Which amino acid has a side-chain pKa near neutrality and plays an important role as proton donor and acceptor in many enzyme catalyzed reactions? a. proline b. methionine c. histidine d. cysteine e. serine

histidine

Due to its highly polar nature, water is an excellent solvent for polar substances, but NOT for: a. alcohols and amines b. hydrocarbons c. aldehydes and ketones d. salts e. sugars

hydrocarbons

What enzyme is used to create DNA from RNA?

reverse transcriptase

The influenza virus recognizes ______ residues of glycoproteins present on cell surface.

sialic acid

The ratio of enzyme activity relative to total protein is called ______

specific activity

The amino acid sequence of the tripeptide in the image below is _____

val-thr-cys

A term that describes a molecule that contains both positive and negative charges but overall has a neutral charge is ______

zwitterion

The term _____ is used to indicate Gibbs free energy change.

∆G

______ are enzymes that synthesize oligosaccharides.

Glycosyltransferases

Facilitated diffusion requires a. a channel protein through which the transported substance passes without binding b. a carrier protein to which the transported substance binds c. a receptor protein d. expenditure of energy by the cell

b. a carrier protein to which the transported substance binds not the select all question

What is the main difference in the lock-and-key and induced-fit models of enzyme- substrate binding? a. In the lock-and-key model, the active site has a free structure. In the induced-fit model, the active site has a rigid structure. b. In the lock-and-key model, the active site is complementary in shape to the substrate. In the induced-fit model, the active site forms a shape complementary to the substrate only after the substrate has been bound. c. In the lock-and-key model, the active site binds to the substrate to form a transition state. In the induced-fit model, the active site binds to the substrate to form a final state. d. In the lock-and-key model, several conformations of the active site are complementary to the substrate. In the induced-fit model, the only certain conformation of the active site is complementary to the substrate. e. In to the lock-and-key model, an enzyme increases a reaction by decreasing the activation energy. In the induced-fit model, an enzyme increases a reaction by facilitating the formation of the transition state.

b. In the lock-and-key model, the active site is complementary in shape to the substrate. In the induced-fit model, the active site forms a shape complementary to the substrate only after the substrate has been bound.

Which of the following statement about noncompetitive inhibition is false: a. The inhibitor can interact with the enzyme as well as the enzyme-substrate complex. b. Increasing the concentration of [S] can overcome the inhibition. c. The Vmax value is different from an un-inhibited reaction. d. The inhibitor can cause a conformational change in the enzyme. e. The inhibitor binds to a different site than does the substrate.

b. Increasing the concentration of [S] can overcome the inhibition.

What is the role of the calcium ion in the activity of C-type lectins? a. It is responsible for carbohydrate binding. b. It binds two glutamate residues in the protein with the sugar. c. It is responsible for nerve impulse conduction. d. It provides for lectin solubility. e. It initiates posttranslational modification of the lectin molecule.

b. It binds two glutamate residues in the protein with the sugar.

Which of the following is false concerning the molecule pictured? a. It would give a negative reaction in a Tollen's silver mirror test. b. It is a reducing sugar because the anomeric hydroxyl is methylated. c. It is not a reducing sugar because the anomeric hydroxyl is methylated.

b. It is a reducing sugar because the anomeric hydroxyl is methylated.

Which of the following statement is false about the relationships between [S], KM and Vmax : a. As the [S] is increased, V approaches the limiting value, Vmax. b. KM = Vmax/2. c. The initial rate of the reaction, V, follows a first order rate equation. d. The rate of product formed, V, is at Vmax when [S] >> KM. e. KM and Vmax assist in finding the rate of the enzyme catalyzed reaction only if the reaction is irreversible

b. KM = Vmax/2.

Which of the following is most often found in proteins? a. D-amino acids b. L-amino acids c. an equal amount of D- and L-amino acids d. amino acids with the alpha-carbon exclusively having an R absolute configuration e. amino acids with the alpha-carbon exclusively having an S absolute configuration

b. L-amino acids

If the pI of a peptide is 8.9, _ might be present while would probably be absent. a. Cys/Thr b. Lys/Asp c. His/Ser d. Glu/Lys e. Lys/Gln

b. Lys/Asp

In a sample consisting of Lysine, Glycine, and Glutamic acid, which will be eluted first from an anion exchange resin at pH 7? a. Glutamic acid b. Lysine c. Glycine d. all three will be eluted at the same time

b. Lysine

Which cell component contains many hydrolytic enzymes? a. Nucleus b. Lysosome c. Chloroplast d. Mitochondrion e. Rough Endoplasmic Reticulum

b. Lysosome

In the following peptide, which amino acid retains its α-amino group? Phe-His-Gly-Tyr a. His b. Phe c. Phe and Tyr d. Tyr e. Gly

b. Phe

Which of the following is NOT a Functional Group a. Amino group b. Protein c. Alcohol group d. Carbonyl group

b. Protein

For a mixture of proteins shown in the Table, predict the order of emergence when subjected to a cation-exchange chromatography at pH 7? a. Protein 3, Protein 1, Protein 2 b. Protein 2, Protein 3, Protein 1 c. Protein 2, Protein 1, Protein 3 d. Protein 1, Protein 3, Protein 2

b. Protein 2, Protein 3, Protein 1

Identify the restriction enzyme that would produce a "blunt end" cut. (The enzyme name is given followed by the recognition sequence. The "/" shows the cut point) a. Bgl II A/GATCT b. Scal I AGT/ACT c. Sac II CCGC/GG d. Xba I T/CTAGA

b. Scal I AGT/ACT

Which of the following best describes the state of a protein whose pI = 6, when in a solution whose pH = 9? a. The protein will have no net charge. b. The protein will have a net negative charge. c. The protein will have a net positive charge. d. The side chains of the protein's acidic residues will mostly be in their unprotonated states. e. The side chains of the protein's basic residues will mostly be in their uncharged states.

b. The protein will have a net negative charge.

What is a characteristic of monoclonal antibodies? a. They are produced by different antibody-producing cells and are specific for different epitopes of antigen. b. They are produced by a single antibody-producing cell and are specific for one epitope of antigen. c. They are produced by a single antibody-producing cell and are specific for different epitopes of antigen. d. They are produced by different antibody-producing cells and are specific for one epitope of antigen. e. They are precursors of polyclonal antibodies.

b. They are produced by a single antibody-producing cell and are specific for one epitope of antigen.

Why are met and trp often used to design DNA probes from amino acid sequences? a. Met is the first amino acid in the protein chain. b. They have single codons. c. Both are used often in proteins. d. All of these. e. None of these.

b. They have single codons.

Which amino acid side chain can hydrogen bond to other residues? a. Met b. Tyr c. Phe d. Pro e. Trp

b. Tyr e. Trp

What is the amino acid sequence of this tripeptide? a. Val-Cys-Phe b. Val-Cys-Tyr c. Leu-Met-Phe d. Leu-Cys-Tyr e. Ile-Cys-Phe

b. Val-Cys-Tyr

A technique used to identify proteins after gel electrophoresis, which employs antibodies in the detection process. a. Southern Blot b. Western Blot c. Northern Blot d. Southwestern Blot e. ELISA

b. Western Blot

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