BSC476 Final
Polar covalent bonds: a. Can result in molecules having an electric dipole moment. b. Can result in molecules having separated positive and negative charges. c. Will not be present in nonpolar molecules. d. Occur when the electrons in the bond are shared between the atoms but biased toward one atom in the bond. e. All of these choices are correct.
e
Which of the following types of electromagnetic radiation are used for nuclear magnetic resonance? a. Gamma b. X-ray c. Ultraviolet d. Visible e. Radio
e
Which of the following statements about activation energy is NOT true? a. The activation energy of a reaction is lowered by enzymes. b. The activation energy is the difference between the energy level of the ground state and the transition state. c. The activation energy is the difference between the free energy of the product of the catalyzed and uncatalyzed reaction. d. The activation energy represents an energy barrier to the transition from substrate to product. e. Activation energy is related to the rate of the reaction.
c
Which of the following statements regarding transcription only applies to eukaryotes and not to prokaryotes? a. A single RNA polymerase transcribes genes that encode mRNAs, tRNAs, and rRNA b. Sigma subunit detaches from RNA polymerase shortly after transcription has initiated c. The C-terminal domain of the polymerase is phosphorylated after transcription has initiated d. RNA synthesis is inhibited by actinomycin D e. RNA synthesis is inhibited by rifampicin
c
Which of the following is NOT usually involved I the processing of primary mRNA transcripts? a. Addition of multiple adenosines to the 3' end b. Covalent joining of exons c. Methylation of nucleotides at the 5' end d. Insertion of intron sequences
d
Which of the following is a characteristic of the set of genes in an operon that is NOT true of a regulon? a. Transcription can produce long polycistronic mRNA that contains multiple genes in each transcript b. Each gene of the set usually contains its own Shine-Delgarno sequence c. Regulation of gene expression can occur through activation or repression mechanisms d. All of the genes in the set are controlled by a single promoter
d
Which of the following mechanisms is used by retrotransporters? a. Cut-and-paste transposition b. Replicative transposition c. Bacterial transduction d. Transposition via an mRNA intermediate e. Lysogeny
d
Which one of the following characteristics of steroid hormone is NOT shared by nonsteroid hormones? a. Hormones activate the transcription of particular genes in response to system requirements b. Hormones bind to hormone receptors c. Responsiveness to hormones can be cell- or tissue-specific d. The hormone crosses the plasma membrane
d
Why are nuclear localization sequences (NLS) NOT removed after nuclear proteins are transported to the nucleus? a. It is too energetically costly for the cell. b. An NLS may be located almost anywhere along the primary sequence of the protein. c. mRNA molecules are synthesized in the nucleus. d. The nuclear envelope breaks down with each cell division.
d
X-ray crystallography yields all of the following EXCEPT: a. A 2-dimensional diffraction pattern/ b. An initial protein model with the location of amino acid residues. c. A model structure created through refinement. d. Information about the protein structure when in solution. e. Information on the structure of the majority of characterized proteins.
d
Chemical reactions: a. Only break chemical bonds or form them but never in the same reaction. b. Are written with the product on the left and the reactant on the right with an arrow to indicate the direction of the reaction. c. Proceed spontaneously through a low-energy transition state to product. d. Proceed spontaneously if the free energy of the product is greater than that of the reactant. e. Require collisions between the reactants, therefore the reaction rate increases when the concentration of the reactants is greater.
e
DNA genotyping by analyzing short tandem repeats has been used to do all of the following EXCEPT: a. Identify criminals using blood samples. b. Identify the father of a child. c. Disprove a mother's claim to a child. d. Acquit an accused rapist. e. Determine a newborn's chance for genetic disease.
e
Poliovirus is an RNA virus that uses host cell ribosomes to synthesize a polyprotein immediately after entering the cell. In order for functional viral protein to be produced, one would expect to observe the mechanism of: a. Phosphorylation. b. Protein methylation. c. Autoinhibition. d. ADP-ribosylation. e. Proteolytic cleavage.
e
The maximum number of bonds that can be formed by an atom: a. Is dependent on the valence of that atom. b. Is dependent on the number of unpaired electrons in its outer shell. c. Can be made up of a combination of single and double bonds. d. Is atom specific; for example, carbon can form 4 bonds, whereas oxygen forms 2. e. All of these choices are correct.
e
Which of the following are CORRECT pairings of histone variants and their functions? a. H3.3 stabilizes the open state (transcriptionally active) b. CENPA maintains kinetochore attachment c. H2AX DNA repair d. macroH2A X chromosome inactivation e. all of these choices are correct.
e
Which of the following is a function of RNA that is dependent on its 3-dimensional structure? a. Catalytic role in translation and splicing b. Transient carrier of genetic information c. Carrier of amino acids to the site of protein synthesis d. Information storage as double-stranded RNA helices in viral genomes e. All of these functions of RNA are dependent on its 3-dimensional structure.
e
Which of the following statements about probes used in hybridization methods is TRUE? a. The probe could be a gene from another species. b. They are usually radiolabeled or conjugated with a fluorescent tag so they can be visualized. c. They can be synthetic DNA sequences based on known amino acid sequences. d. They can be based on DNA sequence information from a sequence database. e. All of these statements about hybridization probes are true.
e
Which of the following statements is TRUE of bacterial polysomes? a. Translation can initiate with an mRNA before transcription of that mRNA is complete. b. A single ribosome can translate multiple mRNA molecules at the same time. c. Polysome formation ensures that only one polypeptide is translated per mRNA molecule. d. Polysomes are membrane-bound compartments where translation occurs.
a
Which of the following is LEAST likely to be the result of a mutation in the promoter of a gene? a. The level of expression of that gene increases b. The level of expression of that gene decreases c. The protein sequence of the gene product is altered d. The level of expression of that gene remains the same
c
Which of the following is NOT a common posttranscriptional modification of tRNA molecules? a. Removal of nucleotides from the 5' and 3' ends b. Methylation and deamination of specific bases c. Addition of a 5' cap d. Attachment of the C-5 of uracil to the ribose at specific sequences
c
Which of the following is TRUE about the chemical bonds found in proteins and nucleic acids? a. Covalent bond result when an electron is completely transferred to another atom such that the atoms are drawn together by electrostatic charges. b. Ionic bonds result when 2 atoms share electrons equally. c. Atoms having a small difference between their electronegativities are more likely to form covalent bonds. d. Ionic bonds are most likely to form between 2 metal atoms. e. The strength of a covalent bond can vary with the salt concentration of the environment.
c
Eukaryotic proteins do NOT require a targeting signal if they are destined to function in the: a. Nucleus. b. Lysosome. c. Plasma membrane. d. Cytoplasm.
d
A polylinker is a: a. Synthetic DNA fragment that contains multiple restriction enzyme sites. b. Synthetic DNA fragment inserted into a vector that allows replication of the vector in the host cell. c. DNA sequence that allows for selection of cells that contain the vector. d. Molecule used to ligate DNA fragments together. e. Synthetic DNA fragment used in a colony hybridization to visualize colonies that contain the DNA of interest.
a
Hydrophobic interactions: a. Arise from the tendency of nonpolar molecules to exclude water in solution. b. Destabilize proteins. c. Destabilize the base-stacking interactions of DNA helices. d. Occur between molecules having partial charges e. Are a function of the repulsive forces generated when atoms are closer than their van der Waals radii.
a
How can a fusion protein be formed? a. By removing a portion of the gene, forming a shorter gene and therefore a shorter protein. b. By site-directed mutagenesis, where a fragment is replaced with a synthetic sequence containing the altered DNA sequence. c. By ligating together the sequences of 2 different genes, creating a new hybrid gene. When expressed, the new gene product is a fusion of the 2 gene products. d. By the recombination of 2 proteins in a bacterial cell to form a new hybrid protein. e. By using oligonucleotide-directed mutagenesis to introduce mutations that cause the expressed protein to fuse to other proteins.
c
The "high-mobility" of HMG proteins refers to their: a. Rapid movement from DNA sequence to DNA sequence b. Rapid electrophoretic mobility in polyacrylamide gels c. Abundant occupancy in chromatin d. Structural role in chromatin remodeling
b
The effector for the Lac repressor protein is: a. Lactose b. Allolactose c. Glucose d. B-galactosidase
b
The function of the Rev protein encoded by the HIV genome is to: a. Reverse transcribe its RNA genome to DNA b. Ensure that HIV gene transcripts containing introns are transported to the cytoplasm c. Integrate the HIV genome into the host genome d. None of the above are correct
b
The process of imprinting of gene: a. Ensures that both alleles of a particular gene contribute to the phenotype b. Is a mechanism to completely shut down the expression of an allele derived from one parent in a diploid cell c. Relies on the DNA sequence alone d. All of the choices are correct
b
The sequence of a promoter constitutes the most basic mechanism of transcription regulation because: a. Promoters are always bound by activators b. RNA polymerase has differential affinities for different sequences that correlate with the efficiency of transcription c. Promoters are always bound by repressors d. The expression levels of different housekeeping genes are always identical
b
The sites of mRNA decapping and degradation in yeast are __ bodies. a. M b. P c. DD d. Y
b
Watson and Crick proposed that during DNA replication the double helix is unwound and each parental DNA strand is used as a template to generate a new daughter strand. What is this mode of replication called? a. Conservative replication b. Semiconservative replication c. Dispersive replication d. Discontinuous replication e. Continuous replication
b
Which of the following is NOT a characteristic of the transcriptional ground state in higher eukaryotes? a. Gene promoters are essentially inactive in the absence of regulatory proteins b. RNA polymerase initiates efficient transcription in the absence of repressors c. Access to promoters is restricted by the structure of chromatin d. Virtually every gene requires activation
b
Which of the following is NOT a mechanism for regulating gene expression before the mature RNA transcript is produced? a. mRNA splicing b. protein degradation c. attenuation of transcription elongation d. modification of mRNA termini
b
Which of the following is NOT a way chromatin remodeling complexes affect nucleosomes? a. They can slide a nucleosome to a different location. b. They can modify the N-terminal tails of histones. c. They can eject a nucleosome from the DNA. d. They can replace the nucleosome with a new nucleosome that contains a variant histone. e. All of these choices are correct.
b
Which of the following is NOT true of human immunodeficiency virus (HIV)? a. It is the causative agent of acquired immune deficiency syndrome (AIDS) b. It targets the B cells of the immune system c. It binds to the cell surface receptor CD4 d. It kills many of the cells it infects but can integrate into the host genome e. It has the most error-prone of all reverse transcriptases, which results in a high mutation rate
b
Which of the following is the result of external mutagens? a. Template slippage during replication b. Addition of bulky adducts to the DNA c. Depurination d. Recombination errors e. Replication errors
b
Which of the following methods is used to amplify RNA sequences? a. PCR with RNA primers that anneal to repetitive DNA sequences. b. Reverse transcriptase-PCR using DNA primers. c. Quantitative PCR using RNA primers. d. RNA polymerase I with DNA primers. e. All of these choices are correct.
b
Why are chemotherapeutic agents effective against cancer cells and yet less effective at killing normal cells? a. These agents are actually toxic to normal cells that are not actively dividing. b. These agents are toxic to cancer cells because they are actively dividing to form a tumor, whereas normal cells are not dividing or are dividing slowly. c. Many cancer drugs destroy telomeres, making the cancer cell mortal. d. These agents are toxic to cancer cells that are not actively dividing. e. None of the explanations given is true.
b
mRNAs with a short half-life may have a(n): a. 5me-G cap b. AU-rich region c. IRE structure in the 5' UTR d. GM-CSF coding region
b
Domains of a protein can BEST be described as: a. The unique sequences of each participating protomer. b. Functional components of a protein. c. Independently folding units of a polypeptide chain. d. None of the answers provided is correct. e. All of the answers provided are correct.
c
In 1979, a group at Cambridge discovered that in human mitochondria, UGA is not a stop codon but instead during translation results in the delivery of the amino acid tryptophan. It was extremely unexpected to discover that one organism could have two different genetic codes, and that the genetic code was not universal - it is mostly or nearly universal. The evolutionary history of the genetic code is an area of robust debate. Which of the following statements about the evolution of the genetic code is most likely TRUE? a. There is no chemical correspondence between codons and amino acids - the code is arbitrary in its origin b. The presence of genetic code alternatives directly challenges the concept of a common ancestor for humans c. Life arose twice as independent events d. The genetic code has a small number of alternative states but these differences cannot be used like nucleotide differences in the genome to infer phylogenies (relationships)
a
In general, repressor proteins that act to inhibit eukaryotic gene expression: a. Interfere with communication between Pol II and DNA-binding transactivators b. Block Pol II-mediated polymerization of ribonucleotides c. Bind to the C-terminal domain of Pol II d. Disrupt HMG protein-DNA interactions
a
Proteins that bind to acetylated lysine residues in the histone tail contain: a. Bromodomains. b. DNA-binding domains. c. Chromodomains. d. Kinase domains. e. Histone-fold motifs.
a
The enzyme adenosine deaminase acting on RNA (ADAR) catalyzes which of the following nucleotide conversions? a. Adenosine to inosine b. Adenosine to cytidine c. Adenosine to guanosine d. Thymidine to uridine
a
The function of DNA ligase is to: a. Catalyze the formation of covalent bonds between adjacent nucleotides. b. Unwind the double-stranded DNA prior to replication. c. Keep the single strands of DNA apart during replication. d. Facilitate base pairing between single stranded molecules of DNA. e. Catalyze the formation of hydrogen bonds between adjacent nucleotides.
a
The packaging of eukaryotic DNA into chromatin renders most promoters inaccessible to RNA polymerases and activator proteins. Under these conditions, MOST eukaryotic genes are: a. Constitutively repressed b. Constitutively activated c. Globally expressed d. Insulated by nucleosome binding
a
Which of the following alternate forms of nucleic acids is NOT known to be biologically important? a. G tetraplex structures can form and act as recognition sites for enzymes that cleave DNA. b. Inverted repeats can form hairpins that are important for slowing or preventing protein synthesis. c. Palindromic sequences can act as recognition sites for enzymes that cleave DNA. d. Sequence-induced bending of the DNA can act as a binding site for transcription factors. e. Cruciform structures are formed during recombination.
a
Which of the following amino acids is a target for phosphorylation by a protein kinase? a. Tyr b. Ala c. Arg d. Gly
a
Which of the following is NOT a function of the RNA-induced silencing complex (RISC)? a. Primary miRNA transcript conversion to precursor miRNA b. Cleavage of precursor miRNA to short duplex miRNAs c. Facilitation of base pairing between mature miRNA and its complementary sequence in an mRNA d. Cleavage of the mRNA transcript targeted by siRNA
a
Which of the following is NOT affected by DNA supercoiling? a. Translation b. Transcription c. Replication d. DNA repair e. Neither replication or DNA repair are affected by supercoiling.
a
Which of the following is NOT an example of the relationship between structure and function in proteins and nucleic acids? a. Glycosylation of RNA can be important for cell-surface differentiation between "self" and "non-self." b. Methylation of DNA is important for accurate DNA replication. c. Modification of RNA bases can be important for biological activity. d. Modification of amino acids can be important for binding of proteins to other molecules. e. Phosphorylation of amino acids can be important for biological activity of proteins.
a
Which of the following is NOT true of gene regulation by DNA looping? a. The precise distance between the regulatory sequence and the promoter is important b. It can result in gene repression c. It can result in gene activation d. It can result in the regulation of a gene even thousands of base pairs away from the regulatory site
a
Which of the following is NOT true of the imprinting of the mammalian gene for insulin growth factor-2 (IGF-2)? a. CTCF binds to the methylated IGF2 gene insulator b. IGF2 gene is activated when the insulator is methylated c. The maternally inherited copy of IGF2 is normally repressed in egg cells d. The insulator of both the paternal and maternal IGF2 alleles lies between the promoter and the enhancer
a
Which of the following is TRUE about the geometry of a chemical bond? a. Single bonds permit free rotation around the bond resulting in more geometric possibilities. b. Double bonds share 2 pairs of electrons giving rise to even greater variability. c. Planar bonds have no rotation and therefore give rise to greater geometric possibilities. d. The degree of rotation around a bond determines whether the bond will be single or double. e. The 2 single bonds of an oxygen atom form a tetrahedron.
a
Each branch point or node of a phylogenetic tree represents: a. An environmental pressure for evolution. b. A mutational event that leads to two species. c. Common ancestor to 2 connected branches. d. The beginning of a new domain. e. The point when life started on earth.
b
H1 binding to DNA is different than that of the other 4 histones because H1 binds: a. To the major groove of the DNA only. b. To the DNA as it comes off both sides of the nucleosome. c. As a component of the octamer; however, unlike H2A, H3, and H4, H1 lacks the histone tail. d. To one strand of the linker DNA as it comes off the nucleosome and binds a second site in the central region of the DNA supercoil. e. To the DNA as a homotetramer.
b
How are the epigenetic marks of a particular chromatin state preserved during cell division? a. Parental, marked H2A-H2B dimers stay associated with strands after replication and recruit new H3-H4 tetramers. b. H2A-H2B dimers and H3-H4 tetramers come off during replication and assemble with umarked histones. These new octamers then rebind to the newly replicated DNA to form nucleosomes. c. Parental, marked H3-H4 tetramers stay associated with strands after replication and recruit new H2A-H2B dimers d. Histone chaperones make sure that at least one component of each new nucleosome is marked. e. None of these choices are correct.
b
Overexpression of proteins using bacteria: a. Makes subsequence purification of the recombinant DNA harder. b. Requires bacterial promoters to be present in the bacterial vector. c. Requires eukaryotic promoters to be present in the bacterial vector. d. Requires eukaryotic ribosome binding sites to be present in the bacterial vector. e. Results in a properly folded, active protein.
b
Proteins that act by bridging activators and RNA polymerase are called: a. Enhancers b. Coactivators c. Corepressors d. Insulators
b
Tetrads are: a. Composed of a pair of nonhomologous chromosomes. b. Composed of 2 pairs of sister chromatids. c. Formed in prophase II of meiosis. d. Lined up along the cell axis during metaphase II. e. Formed during DNA synthesis.
b
In SDS-polyacrylamide gel electrophoresis proteins are partially denatures and separated entirely as a function of their mass. Histones are an exception; they migrate more slowly than they should, as though they are much larger than they actually are. Why does this occur? a. Histones form dimers and tetramers, making them appear larger. b. Histones are heavily glycosylated, greatly adding to their mass. c. Histones have a large number of positively charged amino acid residues. The binding of SDS to the histones is not sufficient to mask these charges, resulting in slower migration, d. Histones have an affinity for polyacrylamide. e. Histones are somewhat insoluble, which slows their passage through the gel.
c
In meiosis, the complexity of DNA (amount of information encoded) per cell is essentially halved as compared to the original cell. This reduction in information occurs immediately after: a. Metaphase I. b. Metaphase II. c. Telophase I. d. Telophase II.
c
In response to the presence of extracellular antigen, B cells rapidly proliferate and the immunoglobulin M (IgM) proteins produced are soluble rather than anchored in the membrane. This change in IgM protein state is due to: a. The cleavage of several hydrophobic amino acid residues from the IgM protein b. The differential expression of two different IgM genes c. The predominant use of the first 3' end cleavage site of the IgM pre-mRNA d. Inclusion of the M exon in mature IgM mRNA
c
Insertions and deletions of three base pairs: a. Change one codon and, therefore, only one amino acid in the protein sequence b. Do not disrupt the reading frame so the protein ends up completely normal c. Do not disrupt the reading frame so the protein will usually retain some degree of function. d. Cause frameshifts that will change the reading frame and, therefore, the sequence of the protein e. Usually result in the expression of a truncated protein
c
Intrinsically unstructured proteins: a. Have no function because they are unstructured. b. Only function in membranes. c. Are capable of binding to several different sites on different partners. d. Are more common in bacteria than in humans. e. Are only observed in diseased cells.
c
Ligation reactions occur most efficiently between DNA fragments: a. That have sticky ends. b. That have blunt ends. c. That have complementary sticky ends. d. That are cleaved with different restriction enzymes. e. Where one fragment has a sticky end and the other has a blunt end.
c
Mg2+ is a _____ for DNA polymerase, while nicotinamide adenine dinucleotide (NAD) is a _____ for salicylate hydroxylase, which is called a(n) _____ if NAD is not bound. a. Cofactor; coenzyme; holoenzyme b. Coenzyme; cofactor; holoenzyme c. Cofactor; coenzyme; apoenzyme d. Coenzyme; cofactor; apoenzyme e. None of these choices are correct
c
RNA processing that leads to mRNAs in which exon sequences are derived from different primary transcripts is called: a. Alternative splicing b. Poly(A) site choice c. Trans-splicing d. Group I self-splicing
c
The frameshift of an entire coding region of an mRNA is most likely to be caused by a: a. Nonsense mutation. b. Transition mutation. c. Single nucleotide deletion. d. Double nucleotide mutation of an insertion and a deletion.
c
The higher order structure of chromatin contains topologically constrained loops. What would happen if a single loop was cleaved? a. The entire chromosome would unravel. b. The genes of that loop could not be transcribed. c. Only that loop would relax because each loop is separately constrained by proteins. d. The genes in the cleaved loop could not be replicated. e. Supercoiling in the cleaved loop would not be affected.
c
What helical forms are adopted by double-stranded RNA? a. There is evidence for B-form RNA in viruses. b. There is no evidence that A-form RNA occurs in cells. c. The A form is the only form found for double-stranded RNA in cells and in viruses. d. There is evidence that Z-form RNA occurs in cells under certain conditions. e. The A form occurs only in the laboratory.
c
What observation by Thomas Hunt Morgan led to the understanding that genes were on chromosomes? a. The white-eyed trait was recessive and disappeared in the F1 generation. b. In a cross of a red-eyed female and a white-eyed male, only females in the F2 generation were white-eyed. c. The inheritance of the white-eyed trait in fruit flies followed the same pattern of inheritance as that of the X chromosome. d. The inheritance of the white-eyed trait in fruit flies followed the same pattern of inheritance as that of the Y chromosome. e. Inheritance of the white-eyed trait was the same for female and male flies.
c
When chromosomes fail to segregate properly, it can result in: a. Sister chromatids that are no longer identical b. Gene conversion c. Aneuploidy d. Mating type conversion e. Recombination
c
When considering alleles of a gene, DNA is to genotype as ____ is/are to phenotype. a. RNA b. Mutation c. Proteins d. Lipids e. Nucleotides
c
Which of the following eukaryotic RNA processing events does NOT occur in the nucleus? a. Intron splicing b. Polyadenylation c. Degradation of mRNA d. RNA editing
c
Which of the following is TRUE of bacterial translation termination? a. The ribosome continues to synthesize protein until it reaches the 3' end of the mRNA. b. Termination requires the degradation of the ribosome. c. Termination is signaled by the presence of a stop codon in the mRNA.
c
Which of the following is generally NOT involved in gene inactivation by histone modification? a. Modification leads to chromatin condensation b. The RNA polymerase associated with the gene dissociates from DNA when HDACs bind to the corepressor c. Increased acetylation of the nucleosomes occurs in the vicinity of the gene d. Increased methylation of the nucleosomes occurs in the vicinity of the gene
c
Which of the following methods can be used to determine the position of nucleosomes in the genome? a. RNA-Seq b. Western blotting c. ChIP-Seq d. Immunogluorescence
c
Which of the following processes is primarily responsible for the fact that mammals are NOT capable of parthenogenesis? a. Dosage compensation b. Gene slicing c. Imprinting d. Barr body formation
c
Why is the formation of a BCR-ABL fusion gene a carcinogenic event? a. The tyrosine kinase activity of the ABL gene becomes inactive. b. The tyrosine kinase activity of the ABL gene is now controlled by a weak promoter resulting in less tyrosine kinase activity. c. The tyrosine kinase activity of the ABL gene becomes unregulated leading to uncontrollable cell division. d. The tyrosine kinase activity of the ABL gene is reduced due to truncation of the protein product. e. The tyrosine kinase activity of the BCR gene is increased in the fusion protein product.
c
A northern blot could be used BEST to monitor control of gene expression at which of the following steps? a. DNA methylation b. Nucleosome acetylation c. Protein ubiquitination d. Transcription
d
A woman has breast cancer. Evaluating the tumor cells' transcriptome may reveal: a. Her prognosis. b. Her response to specific therapies. c. Changes in rRNA as the tumor grows. d. Both her prognosis and response to specific therapies. e. Both her response to specific therapies and changes in rRNA as the tumor grows.
d
Artificial chromosomes that will be stable in human cells must include: a. A yeast centromere. b. Human telomeres. c. A multiple cloning site. d. Human centromeres, telomeres, and origins of replication. e. Yeast centromeres and telomeres, as well as human origins of replication.
d
Choose the INCORRECT statement regarding chaperone-assisted protein folding in bacteria. a. The DnaJ/DnaK complex requires ATP to facilitate protein folding. b. DnaJ and DnaK will both bind the unfolded protein. c. A single DnaJ/DnaK complex is rarely sufficient for complete protein folding. d. GrpE stimulates binding of ATP to DnaJ. e. DnaJ prevents aggregation of unfolded polypeptides.
d
Chromatin is composed of: a. DNA. b. Protein. c. DNA and RNA. d. DNA and protein. e. RNA and protein.
d
Enantiomers are a pair of stereoisomers that are mirror images of each other. Which of the following would also be TRUE of this pair of structures? a. They will have different melting points. b. They will have different densities. c. They will have superimposable structures. d. They will have the same molecular weight. e. If basic molecules, they will have the same pKa.
d
LUCA, the last universal common ancestor, is: a. A prehistoric protozoan cell. b. An embryonic cell (in fetus). c. The simplest bacterial cell. d. A cell from which all organisms descended.
d
Matsumara et al. showed that disulfide bonds create a more stable mutant T4 lysozyme. They inserted pairs of Cys residues into the T4 lysozyme sequence and observed that the: a. Reduction of cysteine residues created a protein that denatures at lower temperatures than wild-type lysozyme. b. Reduction of cysteine residues created a protein that was stable at higher temperatures than wild-type lysozyme. c. Oxidation of cysteine residues created a protein that denatured at lower temperatures than wild-type lysozyme. d. Oxidation of cysteine residues created a protein that was stable at higher temperatures than wild-type lysozyme. e. None of these choices are correct.
d
Point mutations in the DNA sequence do NOT cause ____ mutations. a. Silent b. Missense c. Nonsense d. Frameshift e. Transversion
d
Researchers would like to create HIV protease inhibitors that will not become ineffective due to viral strain resistance. One approach is to design a: a. Protease with no aspartate residues. b. Protease inhibitor and treat all patients in a community simultaneously. c. Protease inhibitor that will not be mutated in the aspartate region. d. Protease inhibitor that binds to highly conserved protease sequences. e. Random screening program that tests hundreds of drug candidates.
d
Synteny can be described as the: a. Degree of conservation between sequences. b. Evolution of orthogs. c. Evolution of paralogs. d. Conserved gene order between 2 organisms. e. Conserved number of chromosomes between 2 organisms.
d
The RNA World hypothesis is directly supported by all the following EXCEPT: a. Catalytic RNAs. b. Ribozymes showing diverse function. c. Ribosome structure. d. Micelle to vesicle formation.
d
What structures solve the end replication problem for linear chromosomes? a. Telomerases b. Centromeres c. Origins of replication d. Telomeres e. Euchromatin
d
Which of the following enzymes unwinds the DNA helix during replication in E. coli? a. Primase b. DNA Pol I c. Gyrase d. Helicase e. SSB
d
Which of the following is NOT true of eukaryotic signal transduction pathways that result in the regulation of gene expression? a. The pathway frequently begins with a signal molecule binding to a cell surface receptor b. The signal is transduced to the nucleus c. They generally involve the localization of a protein d. Signal molecules are always transported into the target cellular compartment
d