Sample Multiple Choice Questions
T/F: Homologous chromosomes carry the same genes and the same versions of those genes
False
T/F: The classic X shaped chromosome is always present and visible with a microscope in the nucleus of eukaryotic cells
False
T/F: The expression of the lac operon is only influenced by the environmental signal lactose.
False
T/F: The leading strand is always on the bottom and the lagging strand is always on the top
False
T/F: When DNA polymerase makes a phosphodiester bond, one phosphate molecule is released
False
T/F: The disaccharide lactose is serving as the environmental signal that is inducing expression.
True
Which of the following facts about eukaryotic gene regulation is TRUE? a. Mediators are protein complexes involved in regulating transcription rates. b. The eukaryotic regulatory promoters are highly conserved with the same consensus sequences throughout the genome. c. Eukaryotic enhancers are a part of basal transcription apparatus. d. The transcriptional repressors always bind to the insulator elements. e. Transcriptional activator proteins bind to the DNA in non specific manner.
a. Mediators are protein complexes involved in regulating transcription rates.
Which of the following correctly describes nonsense mutations? a. They convert a codon for a particular amino acid within a gene into a stop codon. b. They change the nucleotide sequence of a gene but do not change the sequence of the resulting protein. c. They cause a nonfunctional amino acid to replace a functional amino acid. d. They cannot revert or back mutate to wild type. e. They result in the insertion or deletion of a small number of nucleotides to the DNA.
a. They convert a codon for a particular amino acid within a gene into a stop codon.
The cluster of genes that are part of the operon (multiple answers) a. each code for a different protein b. each code for the same protein c. each code for different proteins that are involved in the same biochemical pathway d. each code for different proteins that are involved in different biochemical pathways
a. each code for a different protein c. each code for different proteins that are involved in the same biochemical pathway
The type of mutation that reverses the effects of a frameshift mutation without changing the frameshift and occurs with the same gene as the frameshift is called a(n) a. intragenic suppressor mutation b. nonsense mutation c. silent mutation d. intergenic suppressor mutation e. missense mutation
a. intragenic suppressor mutation
A regulatory element is usually a. made of protein b. made of DNA c. made of carbohydrate d. made of lipid
a. made of protein
DNA replication forks (multiple answers) a. move due to the action of helicase b. move in the same direction c. will each be associated with a helicase, gyrase, and primase d. seal back together after replication is complete
a. move due to the action of helicase c. will each be associated with a helicase, gyrase, and primase
If the dispersive model were correct, Meselson and Stahl should have observed (multiple answers) a. one medium weight band of DNA in the middle of the gradient after one round of replication b. one heavy weight band of DNA towards the bottom of the gradient and one light weight band towards the top of the gradient after one round of replication c. one medium weight band of DNA in the middle of the gradient and one band of light weight DNA towards the top of the gradient after two rounds of replication d. one band of DNA that gets lighter and lighter with each round of replication, moving up the gradient
a. one medium weight band of DNA in the middle of the gradient after one round of replication d. one band of DNA that gets lighter and lighter with each round of replication, moving up the gradient
Spontaneous causes of mutation would include (multiple answers) a. segments of DNA that randomly insert themselves at various places along the chromosome b. reactions of nitrogenous bases with water that alter the base pairing rules for the molecule c. exposure to uv light d. mistakes that occur during replication due to wobble pairing between nitrogenous bases e. exposure to x rays or other forms of radiation f. strand slippage that occurs when a repeated sequence of nucleotides gets replicated g. exposure to nitrous acid
a. segments of DNA that randomly insert themselves at various places along the chromosome b. reactions of nitrogenous bases with water that alter the base pairing rules for the molecule d. mistakes that occur during replication due to wobble pairing between nitrogenous bases f. strand slippage that occurs when a repeated sequence of nucleotides gets replicated
During prophase (multiple answers) a. the chromosomes compact themselves into their tightest heterochromatin form b. the nuclear membrane remains intact c. the spindle fibers begin to develop d. the centrosomes get closer together e. the replicated chromosomes pair with their homologous partner
a. the chromosomes compact themselves into their tightest heterochromatin form c. the spindle fibers begin to develop
In order for high levels of transcriptional initiation to take place a. repressor proteins must interact with the basal transcriptional apparatus b. activators and coactivators may need to interact with the basal transcriptional apparatus c. enhancer sequences must interact with the basal transcriptional apparatus. d. the inducing environmental signal must interact with the basal transcriptional apparatus
b. activators and coactivators may need to interact with the basal transcriptional apparatus
Frameshift mutations (multiple answers) a. are caused by UV light b. change many codons c. occur when DNA polymerase makes a mistake when copying long stretches of the same nucleotide d. usually produce nonfunctional proteins
b. change many codons c. occur when DNA polymerase makes a mistake when copying long stretches of the same nucleotide d. usually produce nonfunctional proteins
A eukaryotic DNA sequence that affects transcription at distant promoters is called a(n) a. insulator. b. enhancer. c. repressor. d. mediator. e. silencer.
b. enhancer.
This protein binds to the ori in order to bring about the separation of the two strands of DNA. a. primase b. initiator protein c. helicase d. single stranded binding protein
b. initiator protein
Riboswitches a. involve the production of a small piece of RNA that is the reverse complement of the mRNA whose translation is being regulated. b. involves the interaction of a second molecule, due to an environmental signal, with the 5' UTR c. involves the interaction of a second molecule, due to an environmental signal, with the 3' UTR d. involves the interaction of a second molecule, due to an environmental signal, with the promoter
b. involves the interaction of a second molecule, due to an environmental signal, with the 5' UTR
Antisense regulation of gene expression (multiple answers) a. involves the binding of a protein to the 5'UTR of a mRNA being regulated b. involves the specific elimination of double stranded RNA c. involves the binding of a regulatory protein to a cis element sequence d. involves the binding of a small piece of RNA to a mRNA in a complementary fashion
b. involves the specific elimination of double stranded RNA d. involves the binding of a small piece of RNA to a mRNA in a complementary fashion
If gene expression turns off when a regulatory product binds to the regulatory element, this would be an example of a. positive control b. negative control c. inducible control d. repressible control
b. negative control
The end of the chromosome problem exists because a. replication always follows the helicase. b. no 3' OH exists upstream for polymerase I to link nucleotides to as it is removing the last primer c. DNA polymerase lacks 3' to 5' exonuclease activity d. the two replication forks are moving on opposite directions on linear eukaryotic chromosomes
b. no 3' OH exists upstream for polymerase I to link nucleotides to as it is removing the last primer
The protein Gal4 activates the expression of genes involved in galactose metabolism by making physical contact with the mediator complex. This only happens when galactose is present in the cell. This is an example of a. negative repressible b. positive inducible c. negative inducible d. positive repressible
b. positive inducible
DNA replication was demonstrated to be a. conservative b. semiconservative c. dispersive d. none of the above are correct
b. semiconservative
If a gene is regulated in a negative repressible manner, the expression of the gene when a. the environmental signal is not present causing the regulatory product to bind to the element b. the environmental signal is not present causing the regulatory product to release from the element c. the environmental signal is present causing the regulatory product to bind to the element d. the environmental signal is present causing the regulatory product to release from the element
b. the environmental signal is not present causing the regulatory product to release from the element
Each time the DNA polymerase makes a jump, a new primer must be synthesized on ______ a. the leading strand b. the lagging strand c. the DNA template d. the replication fork
b. the lagging strand
Prokaryotes regulate the expression of their genes depending upon a. what type of tissue the cell is a part of b. the presence of an environmental signal c. the developmental stage of the organism
b. the presence of an environmental signal
Meiosis is used (multiple answers) a. to produce daughter cells that are genetically identical to each other and the parent cell b. to produce daughter cells that are genetically different than each other and different than the parent cell c. to produce cells for sexual reproduction d. to produce cells allowing growth of the organism and repair of tissues e. to produce cells involved in asexual reproduction.
b. to produce daughter cells that are genetically different than each other and different than the parent cell c. to produce cells for sexual reproduction
Mitosis is used (multiple answers) a. to produce cells for sexual reproduction b. to produce daughter cells that are genetically identical to each other and the parent cell c. to produce daughter cells that are genetically different than each other and different than the parent cell d. to produce cells for growth and repair of tissues e. to produce cells for asexual reproduction
b. to produce daughter cells that are genetically identical to each other and the parent cell d. to produce cells for growth and repair of tissues e. to produce cells for asexual reproduction
The protein coded by lac I is involved in negative control because a. when it binds to the regulatory element it turns expression on b. when it binds to the regulatory element it turns expression off c. this protein always turns expression of the operon off d. this protein always turns expression of the operon on
b. when it binds to the regulatory element it turns expression off
The enzyme responsible for most of the DNA synthesis is a. DNA polymerase I b. DNA polymerase II c. DNA polymerase III d. primase
c. DNA polymerase III
What is the function of DNA glycosylases? a. Reattach the two parts of DNA that result from double-strand breaks b. Recognize and cleave phosphodiester bonds in DNA c. Recognize and remove modified bases from the sugar component of DNA d. Prevent strand slippage during DNA replication e. Remove pyrimidine dimers from DNA of E. coli that result from exposure to UV light
c. Recognize and remove modified bases from the sugar component of DNA
The replication of DNA occurs during a. G1 b. G2 c. S d. M phase
c. S
RNA molecules that are complementary to particular sequence on mRNA are called a. ribozymes b. complementary RNA c. antisense RNA d. riboswitches e. sense RNA
c. antisense RNA
Genes that are regulated in a negative repressible manner a. are expressed when a regulatory product does not bind to a regulatory element when an environmental signal is present b. are expressed when a regulatory product binds to a regulatory element when an environmental signal is present c. are expressed when a regulatory product does not bind to a regulatory element when an environmental signal is absent d. are expressed when a regulatory product binds to a regulatory element when an environmental signal is absent
c. are expressed when a regulatory product does not bind to a regulatory element when an environmental signal is absent
If DNA is composed of two strands, both of which carry newly synthesized material and original genetic material, this would be a. the conservative model b. the semiconservative model c. the dispersive model d. none of these are correct
c. the dispersive model
A gene is regulated in a positive inducible manner. The gene is not expressed when a. the environmental signal is not present, causing the regulatory product to bind to the element b. the environmental signal is present causing the regulatory product to bind to the element c. there is no environmental signal present causing the regulatory product to not bind to the element d. the environmental signal is absent causing the regulatory element to bind to the element
c. there is no environmental signal present causing the regulatory product to not bind to the element
One way to relax chromatin structure is a. to degrade the histone proteins b. degrade the scaffold proteins c. to chemically modify a histone protein so it will not bind to the DNA as tightly d. to cut the DNA away from the nucleosome
c. to chemically modify a histone protein so it will not bind to the DNA as tightly
Which of the following is not a mechanism used by eukaryotes to regulate the expression of their genes. a. Controlling initiation of transcription b. Controlling the stability of the mRNA c. Controlling access to the promoter by influencing chromatin structure d. Allowing several related genes to share the same regulatory element e. Controlling the splicing of exons during processing
d. Allowing several related genes to share the same regulatory element
Which of the following types of mutations does NOT lead to a change in the amino acid sequence of the gene product? a. Neutral b. Loss-of-function c. Nonsense d. Silent e. Missense
d. Silent
A technique that allows you to measure the amount of a specific protein in a sample is a. Southern Hybridization b. Northern Hybridization c. Southwestern Hybridization d. Western Hybridization
d. Western Hybridization
Operons are a. single genes with a regulatory element controlled by a regulatory product b. a single gene with a regulatory product controlling a regulatory element c. a cluster of genes sharing one regulatory product controlling multiple regulatory elements d. a cluster of genes with a single regulatory element controlled by a regulatory product
d. a cluster of genes with a single regulatory element controlled by a regulatory product
When ligase seals the nick it a. synthesizes a new segment of DNA b. removes the RNA primer c. synthesizes an RNA primer d. makes a phosphodiester bond between adjacent nucleotides
d. makes a phosphodiester bond between adjacent nucleotides
T/F: During metaphase, the replicated chromosomes line up in a single file line in the middle of the cell
True
All DNA polymerases synthesize new DNA by adding nucleotides to the _____ of the growing DNA chain. a. 3' OH b. 3' Phosphate c. 5' OH d. 5' Phosphate
a. 3' OH
Which of the following is an advantage of gene regulation? a. All are correct b. Efficiency, only make the proteins that are needed c. Specialization, make the proteins that will be used in that tissue. d. Development, only make proteins in certain stages of development
a. All are correct
What type of synthesis occurs on the leading strand? a. Continuous b. Discontinuous c. Dispersive d. Conservative e. Recombinant
a. Continuous
Which of the following is true of deamination (multiple answers) a. Occurs spontaneously in an aqueous environment b. It creates frameshift mutations c. It involves the removal of NH2 from a nitrogenous base d. It creates an AP site e. It is responsible for the conversion of cytosine to uracil
a. Occurs spontaneously in an aqueous environment c. It involves the removal of NH2 from a nitrogenous base e. It is responsible for the conversion of cytosine to uracil
If an individual has the following genotype of the lac operon: I+P+O+Z+Y-/Is, with the / representing separation of the genetic element to a different chromosome, which of the following statements are correct: a. The repressor protein will always be bound to the operator, when lactose is present and absent. b. Transcription will not occur if lactose is absent in the cell c. The repressor protein will bind to allolactose if it is present. d. Transcription will occur if lactose is present in the cell e. mRNA coding for permease will be present if lactose is not present in the cell f. The cell will produce functional beta galactosidase enzyme when lactose is present in the cell
a. The repressor protein will always be bound to the operator, when lactose is present and absent. b. Transcription will not occur if lactose is absent in the cell
In a double stranded DNA molecule a G is paired with a T. Which of the following statements are true (multiple answers) a. This could be corrected by DNA polymerase proofreading b. This could be corrected by Mismatch Repair if the DNA is hemimethylated c. This could be due to DNA polymerase making a mistake during replication d. This could be due to a thymine dimer e. This could be due to the deamination of a methylated cytosine. f. This could be corrected by Mismatch Repair if the DNA is fully methylated. g. There is nothing abnormal about this
a. This could be corrected by DNA polymerase proofreading b. This could be corrected by Mismatch Repair if the DNA is hemimethylated c. This could be due to DNA polymerase making a mistake during replication e. This could be due to the deamination of a methylated cytosine.
Expression of a gene can be regulated in eukaryotes (multiple answers) a. by controlling access to the 5' and 3' splice site b. destabilizing the mRNA by removing its 5' cap or polyA tail c. using one copy of a regulatory element to control multiple genes expression d. binding the mRNA with a small RNA that leads to the degradation of both e. making chemical changes to the polypeptide after translation has been completed
a. by controlling access to the 5' and 3' splice site b. destabilizing the mRNA by removing its 5' cap or polyA tail d. binding the mRNA with a small RNA that leads to the degradation of both e. making chemical changes to the polypeptide after translation has been completed
Mutagens (multiple answers) a. cause the rate of mutation to go above the spontaneous rate b. can change the ability of a nitrogenous base to pair with other molecules c. are substances that cause mutations d. include the substance water e. include ultra violet light
a. cause the rate of mutation to go above the spontaneous rate b. can change the ability of a nitrogenous base to pair with other molecules c. are substances that cause mutations e. include ultra violet light
Microarrays allow the researcher to a. compare the relative abundance of transcripts from two different samples for hundreds if not thousands of genes simultaneously b. compare the relative abundance of proteins from two different samples c. compare the relative abundance of transcripts from two different samples for one gene at a time d. compare the relative abundance of DNA from two different samples
a. compare the relative abundance of transcripts from two different samples for hundreds if not thousands of genes simultaneously
In the example of FLC a. expression is turned off by causing the histones to bind tighter to the DNA b. expression is turned on by causing the histones to bind tighter to the DNA c. expression is turned on by modifying the histones after exposure to low temperatures in order to bind tighter to the DNA
a. expression is turned off by causing the histones to bind tighter to the DNA
In order to test which of the models of replication were correct, Meselson and Stahl (multiple answers) a. grew bacteria in the presence of heavy nitrogen in order to saturate the DNA b. used microscopy to visualize the DNA during replication c. grew the bacteria in the presence of radioactive sulfur and phosphate to label DNA and proteins d. transferred the cells to media containing light nitrogen for one round of replication e. used density gradient centrifugation to determine the density of synthesized DNA molecules
a. grew bacteria in the presence of heavy nitrogen in order to saturate the DNA d. transferred the cells to media containing light nitrogen for one round of replication e. used density gradient centrifugation to determine the density of synthesized DNA molecules
During prophase I (multiple answers) a. the replicated chromosomes compact themselves into their densest chromatin form b. the nuclear envelope remains intact c. the centrosomes begin to migrate to the poles d. homologous pairs of chromosomes pair together during synapsis e. the spindle fibers are broken down
a. the replicated chromosomes compact themselves into their densest chromatin form c. the centrosomes begin to migrate to the poles d. homologous pairs of chromosomes pair together during synapsis
Given the following genotype of the lac operon, which of the following statements are true? (multiple answers) I- P+ O+ Z+ Y+ a. when allolactose is present in the cell, the enzyme necessary for the break down of allolactose will be present b. the repressor protein will always be bound to the operator, and therefore no gene expression will occur c. when allolactose is absent in the cell, mRNA for permease will be made d. the repressor protein will never bind to the operatory and therefore gene expression will occur all the time e. when allolactose is absent in the cell, the transporter protein that is needed to move lactose across the plasma membrane will be abundant f. when allolactose is present in the cell, mRNA for Beta galactosidase will be made
a. when allolactose is present in the cell, the enzyme necessary for the break down of allolactose will be present c. when allolactose is absent in the cell, mRNA for permease will be made d. the repressor protein will never bind to the operatory and therefore gene expression will occur all the time e. when allolactose is absent in the cell, the transporter protein that is needed to move lactose across the plasma membrane will be abundant f. when allolactose is present in the cell, mRNA for Beta galactosidase will be made
Substances that are mutagenic (multiple answers) a. would generate more his+ revertants growing on minimal media in an Ames Test b. may alter the ability of a base to pair with another base in the opposite DNA strand c. cause spontaneous mutations d. are very uncommon e. are more likely to cause cancer
a. would generate more his+ revertants growing on minimal media in an Ames Test b. may alter the ability of a base to pair with another base in the opposite DNA strand e. are more likely to cause cancer
Which of the following kinds of mutations is most likely to be null loss-of-function? a. Induced b. Frameshift c. Transition d. Missense
b. Frameshift
Which of the following DNA repair systems does not involve the activity of a DNA polymerase? a. Base-excision repair in E. coli b. Photoreactivation in E. coli c. All of the above in the activity of a DNA polymerase d. Mismatch repair in humans e. Nucleotide-excision repair in yeast
b. Photoreactivation in E. coli
Select all of the true statements about the expression of a normal copy of the lac operon when lactose is present in the cell. a. The repressor protein will be bound to the operator b. The repressor protein will bind to the lactose (or allolactose) c. Expression will be off d. Messenger RNA coding for permease will be produced e. The cell will be synthesizing Beta Galactosidase enzyme
b. The repressor protein will bind to the lactose (or allolactose) d. Messenger RNA coding for permease will be produced e. The cell will be synthesizing Beta Galactosidase enzyme
What do alkylating agents do? a. They can do all of these activities. b. They add methyl or ethyl groups to bases. c. They deaminate cytosine d. They oxidize guanine. e. They cause pyrimidine dimers.
b. They add methyl or ethyl groups to bases.
What modification neutralizes the charge of histones that promote ionic interaction with DNA molecules? a. deacetylation b. acetylation c. phosphorylation d. dephosphorylation
b. acetylation
On a microarray, if a spot does not fluoresce at all, while other spots are fluorescing, this indicates that the gene represented by the spot a. is not present in the organism b. is not expressed in either of the two samples under those environmental conditions c. is expressed in one sample but not the other d. is expressed equally in both samples
b. is not expressed in either of the two samples under those environmental conditions
Lagging strand synthesis a. progresses in the same direction as helicase is moving b. progresses in the opposite direction that helicase is moving c. is continuous d. is discontinuous e. occurs on opposite strands for the two replication forks
b. progresses in the opposite direction that helicase is moving d. is discontinuous e. occurs on opposite strands for the two replication forks
A small effector molecule that enhances transcription binds to a regulatory protein and causes it to not bind to the DNA. The regulatory protein is a a. either an activator or repressor b. repressor c. activator d. neither an activator or repressor
b. repressor
Telomerase a. shortens linear eukaryotic chromosomes b. restores linear eukaryotic chromosomes to their original length c. cut off single stranded DNA d. synthesize segments of RNA
b. restores linear eukaryotic chromosomes to their original length
Labelled antibodies are used to detect a. the presence of protein on a northern blot b. the presence of proteins on a Western blot c. the presence of RNA on a northern blot d. the presence of DNA on a Southern blot
b. the presence of proteins on a Western blot
Heterozygotes exhibit the dominant phenotype because a. none of the copies of the gene are producing functional proteins b. they still have one one copy of the gene producing a functional protein c. all copies of the gene are producing functional proteins d. the dominant allele overpowers the recessive allele
b. they still have one one copy of the gene producing a functional protein
The following microarray data are shown for four human genes. Two samples were hybridized to the microarray in this experiment. One sample was cDNA generated from mRNA of a tissue culture cell line that was originally derived from a B-cell leukemia. The other sample was cDNA generated from normal, mature neural tissue. • Vertical stripes mean hybridization to cancerous B-cell cDNA only. • Horizontal stripes mean hybridization to normal neural cell cDNA only. • Completely filled in means hybridization to both cDNA types. • Blank means hybridization to neither cell's cDNA. One spot on the microarray contains sequences unique to a gene for an RNA polymerase subunit. One spot contains sequences unique to the skeletal muscle myosin gene. Which spot would be expected to contain the RNA polymerase gene sequences? a. Spot 4 b. Spot 2 c. Spot 1 d. None of the spots e. Spot 3
c. Spot 1
Which of the following statements about RNA polymerase and DNA polymerase are not correct (multiple answers) a. They both make phosphodiester bonds b. They both add nucleotides to the 3' end of a growing chain of nucleic acid c. They are both able to lay down the first nucleotide in the chain being synthesized without any other molecules being present d. They both use NTP as their substrate
c. They are both able to lay down the first nucleotide in the chain being synthesized without any other molecules being present d. They both use NTP as their substrate
Which of the following is not a mechanism used in eukaryotes to regulate gene expression: a. allowing contact between proteins bound to the regulatory promoter and the mediator b. regulating access of the ribosome to the 5' UTR c. all of the options are mechanisms used in eukaryotes d. regulating the acetylation of histones e. regulating the movement of the mRNA out of the nucleus f. regulating the splicing of exons
c. all of the options are mechanisms used in eukaryotes
The sister chromatids are pulled apart from each other during ____ of mitosis. a. prophase b. metaphase c. anaphase d. telophase e. cytokinesis
c. anaphase
When activated, CAP (multiple answers) a. binds to the operator b. binds to Beta Galactosidase c. binds to the CAP site d. interacts with RNA polymerase to make it easier to initiate transcription e. interacts with RNA polymerase to make it more difficult to initiate transcription.
c. binds to the CAP site d. interacts with RNA polymerase to make it easier to initiate transcription
Regulation of translation in prokaryotes often involves a. blocking the A site of the ribosome b. restricting the activity of EF-G c. controlling the small ribosomal subunits access to the ribosomal binding site d. eliminating the ribosomal RNA that is needed to form a ribosome
c. controlling the small ribosomal subunits access to the ribosomal binding site
The expression of genes responsible for galactose metabolism turn on when galactose is present. This is an example of a. positive control b. negative control c. inducible control d. repressible control
c. inducible control
After DNA polymerase III has completed its synthesis on the lagging strand, DNA polymerase I must eliminate the primer and resynthesize DNA in its place. It can do this because a. it has 5' to 3' polymerase activity which polymerase III does not b. it has 3' to 5' exonuclease activity which polymerase III does not c. it has 5' to 3' exonuclease activity which polymerase III does not d. it has endonuclease activity which polymerase III does not
c. it has 5' to 3' exonuclease activity which polymerase III does not.
Recessive alleles of genes are usually due to a. point mutations b. gain of function mutations c. loss of function mutations d. silent mutations
c. loss of function mutations
In order to identify the levels of one protein, westerns rely upon the use of (multiple answers) a. single stranded DNA probes b. single stranded RNA probes c. primary antibodies d. secondary antibodies e. enzymes conjugated to an antibody
c. primary antibodies d. secondary antibodies e. enzymes conjugated to an antibody
The two identical halves of a replicated chromosome are called a. daughter chromosomes b. daughter chromatids c. sister chromatids d. sister chromosomes
c. sister chromatids
The darker the spot on the exposed X ray image from Northern hybridization indicates a. the amount of primary antibody that has bound to the nucleic acid sample b. the amount of secondary antibody that has bound due to the amount of primary antibody that has bound to the nucleic acid sample c. the amount of radioactive single stranded DNA that has bound in a complementary manner to the nucleic acid on the blot d. the amount of radioactive single stranded RNA that has bound in a complementary manner to the nucleic acid on the blot
c. the amount of radioactive single stranded DNA that has bound in a complementary manner to the nucleic acid on the blot
Okazaki fragments are a. the pieces of template DNA copied during replication b. the enzyme responsible for unwinding the DNA c. the discontinuous fragments of newly replicated DNA on the lagging strand d. the discontinuous fragments of DNA found on the leading strand
c. the discontinuous fragments of newly replicated DNA on the lagging strand
The use of a reporter gene assumes a. that all genes are expressed throughout the body of an organism b. that the sequence of the amino acids in the protein determine which tissues in which expression will occur c. the promoter, especially components of the regulatory element, determine where expression will occur d. the location of expression of a gene is random
c. the promoter, especially components of the regulatory element, determine where expression will occur
The conservative model of DNA replication suggests that a. double stranded DNA molecules will be composed of one entire strand of newly synthesized DNA and one strand of the original DNA template b. double stranded DNA will be composed of chunks of newly synthesized DNA and the original DNA template on both strands c. will be composed of some molecules where both strands are newly synthesized and some molecules that contain two strands of the original DNA template d. none of these are correct
c. will be composed of some molecules where both strands are newly synthesized and some molecules that contain two strands of the original DNA template
Which of the following statements about replication forks is not correct? a. Replication forks form when the two strands of DNA are separated at the origin b. There are two replication forks for each origin and they move in opposite directions c. Prokaryotes have one origin of replication and will move in opposite directions around the circular chromosome d. Eukaryotes have one origin of replication and will move in the same direction down a linear chromosome
d. Eukaryotes have one origin of replication and will move in the same direction down a linear chromosome
The mutation I^s, results in a. a defective Beta galactosidase enzyme b. an operon that is always turned on c. an operon that is constantly going through transcription d. a repressor protein that always binds on to the operator, turning expression off
d. a repressor protein that always binds on to the operator, turning expression off
A common reporter gene that is used is Beta Galactosidase. When expressed the enzyme will interact with a substrate called X Gal, resulting in a _____ product a. red b. fluorescent c. chemiluminescent d. blue
d. blue
Gal3 is involved in turning expression on, even though it doesn't bind to any of the DNA elements. It would be classified as a a. activator b. repressor c. regulatory element d. coactivator
d. coactivator
CAP goes through a confirmation change to assume its active form when (multiple answers) a. lactose levels are high b. lactose levels are low c. glucose levels are high d. glucose levels are low e. cAMP levels are low f. cAMP levels are high
d. glucose levels are low f. cAMP levels are high
If DNA replication was conservative, Meselson and Stahl should have observed a. one band of medium wight DNA in the middle of the gradient after one round of replication b. a band of medium weight DNA in the middle of the gradient and one band of light weight DNA higher in the gradient after one round of replication c. a band of medium weight DNA in the middle of the gradient that slowly moves up the gradient with each round of replication d. one band of heavy DNA towards the bottom of the gradient and one band of light DNA towards the top of the gradient after one round of replication
d. one band of heavy DNA towards the bottom of the gradient and one band of light DNA towards the top of the gradient after one round of replication
Two pieces of RNA will be synthesized to serve as a. origins of replication b. initiation factors c. replication holoenzymes d. primers
d. primers
Northern hybridization allows a researcher to measure a. the amount of DNA from a cellular sample b. the amount of a specific protein from various cellular samples c. the amount of RNA transcript of many genes simultaneously d. the amount of RNA transcript produced by different samples, one gene at a time
d. the amount of RNA transcript produced by different samples, one gene at a time
G1 can be distinguished from G2 by a. which organelles are accumulating b. how much growth is taking place c. the rate of cellular growth d. the synthesis of specific proteins during one stage that are not synthesized during the other
d. the synthesis of specific proteins during one stage that are not synthesized during the other
Assume that you have discovered a new chemical mutagen that modifies guanine so that is mispairs with adenine when adenine is in the template DNA strand during DNA replication. However, this mispairing is limited to when the modified guanine is being added to the newly replicating DNA strand. When the modified guanine is in the template DNA strand it always pairs normally with cytosine being added to the growing newly synthesized strand. What type of mutation would you predict would be caused by the new chemical mutagen? a. A-to-T base substitutions b. G-to-T base substitutions c. A-to-G base substitutions d. A-to-G and A-to-C base substitutions e. A-to-C base substitutions
e. A-to-C base substitutions
After translation, eukaryotic proteins can be modified by a. the addition of phosphate groups. b. the removal of amino acids. c. the addition of methyl groups. d. acetylation. e. All of the above
e. All of the above
When a structural gene is under positive repressible control, what would be the result of a mutation that eliminates the repressor protein? a. The transcription of structural gene will not be affected, as a repressor is not required. b. The structural gene to be constitutively expressed due to the lack of inducible control. c. The mutation will lead to activation of an activator upon the lack of a repressor protein, which will stimulate transcription. d. More cAMP will be produced in a cell to compensate for the lack of an activator protein. e. As the transcription does not require a repressor protein, the transcription will be turned on constitutively.
e. As the transcription does not require a repressor protein, the transcription will be turned on constitutively.
When a structural gene is under positive inducible control, what would be the result of a mutation that eliminates the activator protein? a. More cAMP will be produced in a cell to compensate for the lack of an activator protein. b. The mutation will lead to activation of a repressor upon the lack of an activator protein, which will block transcription. c. The structural gene to be constitutively expressed due to the lack of inducible control. d. The transcription of structural gene will not be affected, as an activator is not required. e. As the transcription will require an activator protein, the transcription will be turned off.
e. As the transcription will require an activator protein, the transcription will be turned off.
How do germ-line mutations differ from somatic mutations? a. Germ-line mutations involve small changes to DNA such as base-pair substitutions, while somatic mutations usually involve large deletions. b. Germ-line mutations result in cancers, while somatic mutations do not. c. Germ-line mutations are reversible, while somatic mutations are not. d. Germ-line mutations occur during DNA replication, while somatic mutations do not. e. Germ-line mutations result in mutant gametes, while somatic mutations do not.
e. Germ-line mutations result in mutant gametes, while somatic mutations do not.
Given the following genotype of the lac operon, which of the following statements are true? Is P+ O+ Z+ Y+ a. when allolactose is present in the cell, the transporter protein that is needed to move lactose across the plasma membrane will be abundant b. when allolactose is absent in the cell, mRNA for permease will be made c. the repressor protein will never bind to the operatory and therefore gene expression will occur all the time d. when allolactose is present in the cell, mRNA for Beta galactosidase will be made e. when allolactose is present in the cell, the enzyme necessary for the break down of allolactose will be present f. the repressor protein will always be bound to the operator, and therefore no gene expression will occur
f. the repressor protein will always be bound to the operator, and therefore no gene expression will occur
