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WorksheetsMic 7
Total questions: 87
Worksheet time: 44mins
1)The report that genes direct the synthesis of proteins was first made by
Lederberg
B) Watson and Crick.
C) Beadle and Tatum.
Mendel
2) The phrase "one gene-one enzyme" is associated with the work of
A. Lederberg.B. Watson and Crick.
C. Beadle and Tatum.
Mendel
2)The two strands of DNA are bonded to one another by
A) covalent bonds.
B) oxygen bonds.
C) hydrogen bonds.
D) carbon bonds.
3)Which pairing is incorrect?
A) A:T
D) A:G
C) A:U
E) C:G
4)What structure is indicated by: 10A, 15T, 3G, 7C?
A) Double-stranded DNA
B) Double-stranded RNA
C) Single-stranded DNA
D) Single-stranded RNA
5)Without changing the sequence or the orientation of the sequence(s), which is/are complementary to the sequence 5' AGGCUAAC 3'?
A) 5' TCCGATTG 3'
B) 3' TCCGATTG 5'
C) 5' CTTAGCCT 3'
D) 3' TAAGCTTA 5'
6)GCCCAAAG is a molecule of
A) RNA.
C) protein.
D) DNA OR lipid
E) Cannot tell as written.
7)Which may be or is an RNA molecule?
A) AGCCTAC andGGGCCCA
B) GGGCCCA andAAATTTA
C) GGGCCCA and GCCCUUA
D) GCCCUUA and AAATTTA
8)RNA is characterized by which one of the following features?
Deoxyribose
Thymine
C) Ribose
D) Double-stranded
9)DNA is characterized by which of the following feature(s)?
A) Ribose AND single-stranded
B) Single-stranded AND uracil
D) Deoxyribose AND thymine
E) Thymine AND uracil
10)Which is not true of RNA?
A) It is usually single-stranded.
B) It contains both uracil and thymine.
C) It functions in the cytoplasm.
D) It contains ribose.
11)The 3' end of DNA
A) has a hydroxyl group attached to the number 3 carbon of deoxyribose.
B) attaches to the 3' phosphate group of the incoming nucleotide.
C) always has thymine and uracil attached to it.
D) usually has guanine and guanine attached to it.
12)Which of the following is/are true of DNA replication?
A) It starts at the origin of duplication.
B) Nucleotides are added to the 3' end.
C) It requires a DNA primer to get started.
D) It is carried out by transcriptases.
13)DNA replication is
A) conservative.
B) interspersive.
C) semiconservative.
redundant
14)Which is true about DNA replication?
A) It is semiconservative.
B) It starts at an origin of replication.
C) It is bidirectional.
E) All of the choices are correct.
15)The term antiparallel
A) refers to thestructure of single-stranded RNA.
B) is synonymous with semiconservative.
C) refers to the opposite orientation of the two strands in DNA.
D) refers to a type of prokaryotic replication.
16)The lagging strand
A) is another name for any single-stranded DNA foundin slowly dividing cells.
B) is formed duringRNA replication because of the nature ofthe enzymes involved in it.
C) is formed during DNAreplicationbecause oftheantiparallel nature of DNA.
D) is always the bottom strand of DNA or RNA during the replication process.
17)Which is FALSE about the RNA transcript?
A) It is formed using the DNA minus strand as a template.
B) It has the same 5'–3' orientation as the DNA positive strand.
C) It is made in short fragments that are then stitched together.
D) The template starts at the promoter region.
18)Which is true about prokaryotic (bacterial) RNA polymerase?
A) It is used during transcription.
B) It requires a primer.
C) It has a detachable subunit, alpha factor, which recognizes the promoter.
D) It reads the template in the 5'-3' direction.
19)The specific sequence of nucleotides in the DNA to which the RNA polymerase binds is the
A) regulatory region.
B) promoter region.
C) sigma region.
D) core region.
20)The transcription terminator
A) results in a hairpin loop structure in RNA, AND stops DNA polymerase.
B) results in a hairpin loop structure in RNA, AND results in the polymerase falling off the DNA template.
C) stops DNApolymerase, ANDresults in the polymerase falling off the DNA template.
D) stops DNA polymerase, AND adds a terminator nucleotide to the RNA.
21)How many nucleotides are in a codon?
A) 1
B) 2
C) 3
D) 4
22)There are ______ codons to code for the 20 possible amino acids.
A) 20
B) 30
C) 61
D) 64
23)The genetic code has more than one codon for some amino acids. This is an example of
A) evolution.
B) stringency.
C) redundancy.
D) translation.
24)Which molecule carries an anticodon?
A) DNA
B) mRNA
C) rRNA
D) tRNA
25)AUG
A) is only used as the start codon.
C) determines the reading frame.
D) is one of the stop codons.
E) codes for methionine AND determines the reading frame.
26)The amino acid that is placed first during translation in bacteria, mitochondria, and chloroplasts is
A) methionine.
B) N-formyl-methionine.
C) glycine.
D) N-formyl-glycine.
27)The placement of the amino acid during translation is determined by the
A) DNase, which transcribes both molecules.
B) complementarity of the codon-anticodon.
C) sequence of nucleotides at the 5' end of the tRNA.
D) secondary structure of the newly forming protein.
28)What is the number of tRNA molecules that may be associated with translation?
A) 20
B) Fewer than 20
C) 64
D) Fewer than 64
29)The P-site
A) is found on the polymerase enzyme.
B) is an allosteric site on an enzyme.
C) is a promoter site on the ribosome.
D) is the peptidyl site on the ribosome.
30)The E-site
A) is found on the RNA polymerase enzyme.
B) is responsible for the release of the tRNA.
C) is found on the 35S polysome.
D) is the aminoacyl site on the ribosome.
31)A stop codon
A) codes for the stop amino acid s-methyl-methionine.
B) forms a hairpin loop forcing the ribosome to fall off.
C) codes for no amino acid.
D) enhances the binding of the e-polymerase.
32)Post-translational modification may include
A) formation of exons and introns.
B) folding of the protein, often with the aid of chaperones.
C) removal of the signal sequence.
E) folding of the protein, often with the aid of chaperones, AND removal of the signal sequence.
33)The ribosomes
A) move along the tRNA in a 3'–5' direction AND provide a platform that brings the amino acids into a favorable position for joining.
C) move along the mRNA in a 5'–3' direction AND provide a platform that brings the amino acids into a favorable position for joining.
D) move along the DNA in a 5'–3' directionANDprovide a platform that brings the amino acids into a favorable position for joining.
E) move along the DNA in a 3'–5' directionANDprovide a platform that brings the amino acids into a favorable position for joining.
34)All of the following are true about DNA sequence analysis EXCEPT
A) the (−) strand of DNA is used.
B) the start codon is ATG.
C) ORFs are searched for.
D) codon usage is a helpful indicator for protein coding areas.
35)Some segments of the precursor mRNA in eukaryotes are non-coding and are called
A) exons.
B) introns.
integrans
uselessans
36)Bacteria use ______ attached to the polymerase to direct RNA polymerase to promoters; eukaryotic cells use ______ that attach directly to the DNA first instead.
A) sigma factors;transcription factors
B) transcriptionfactors; sigma factors
C) ribosomes; sigmafactors
D) tRNA; rRNA
Ribozymes
A) are complexes of ribosomes and RNA.
B) are self-catalytic RNA.
C) suggest that nucleic acids evolved before proteins.
E) are self-catalytic RNA AND suggest that nucleic acids evolved before proteins.
38)The scientists responsible for the idea that RNA can act as a catalyst were
A) Watson and Crick.
B) Beadle and Tatum.
C) Altman and Cech.
D) Lederberg and Stanley.
39)Signal transduction
A) is the relay of information about conditions outside a cell to inside the cell.
B) often relies on a four component system.
C) never involves phosphorylation of various molecules.
D) is used by certain pathogens to sense high magnesium conditions.
40)Quorum sensing
A) is used by bacteria to sense the density of cellswithin their population AND is used by eukaryotes to sense the presence of bacteria in their environment.
B) involves the production and monitoring of signaling moleculesAND is used by eukaryotes to sense the presence of bacteriawithin their population.
C) is used by bacteria to limit the density of cells in a populationANDis used by eukaryotes to sense the presence of bacteriawithin their environment.
D) involves the production and monitoring of signaling moleculesANDis used by bacteria to sense the density of cells within their population.
41)Gene regulation may entail
A) turning on genes only when needed.
B) turning off genes when not needed.
C) turning on or off entire groups of genes.
D) All of the answer choices are correct.
42)The regulatory protein
A) binds to the promoter region of DNA.
B) may inhibit or enhance transcription.
C) may control translation of the operon.
D) affects the activity of the DNA polymerase.
43)Operon(s) in bacteria
A) refers to a group of genes that are controlled in a coordinated manner AND involve monocistronic mRNA.
B) refers to a group of genes that are controlled in a coordinated manner AND involve both monocistronic and polycistronic DNA.
D) refers to a group of genes that are controlled in a coordinated manner AND involve polycistronic DNA.
E) refers to a group of genes that are controlled in a coordinated manner AND involve polycistronic mRNA
44)The set of genes in bacteria that are linked together and transcribed as a single unit is referred to as a(n)
A) operon.
B) regulon.
D) repressor.
operator
45)The DNA site to which the repressor protein binds is the
operon
regulon
operator
repressor
46)The molecules that bind to a repressor and cause it to no longer bind to the operator are called
A) activators.
B) repressors.
C) introns.
D) inducers.
47)Repressors
A) bind or do not bind to the operator depending on their shape (conformation) AND are involved in positive control.
B) bind or do not bind to the operator depending on their shape (conformation) AND are involved in negative control.
C) always bind to the promoter ANDare involved in positive control.
D) always bind to the promoter AND are involved in negative control.
48)Activators
A) are involved in negative control AND bind to the terminator.
B) are involved in positive control AND bind to the terminator.
C) are allosteric proteins ANDare involved in positive control.
D) are allosteric proteins AND are involved in negative control.
49)Negative control means a regulator molecule is
A) bound, and transcription starts.
B) removed, and transcription is inhibited.
C) bound, and transcription is inhibited.
E) bound, and transcription is inhibited OR removed, and transcription starts.
50)In the lac operon, glucose
A) is preferentially used over lactose in E. coli as a result of catabolite repression AND levels are correlated with cAMP levels.
B) is preferentially used over sucrose in E. coli as a result of catabolite repression AND levels are directly sensed via catabolite repression.
C) is preferentially used over lactose in E. coli as a result of catabolite repression AND glucose levels are the inverse of cAMP levels.
D) is preferentially used over lactose in E. coli as a result of catabolite repression ANDlevels directly affect the production of lactose dehydrogenase.
51)The lac operon
A) positively regulated by the presence of lactose
B) positively regulated by the presence of glucose
C) negatively regulated by the presence of lactose
D) negatively regulated by the absence of glucose
52)CAP
A) is involved in positive control AND stands for cyclic amp protein.
B) is involved in positive control AND works in conjunction with cAMP.
C) stands for cyclic amp protein AND is a regulon.
D) stands for cyclic amp protein AND works in conjunction with cAMP.
53)RNAi
A) is the form of mRNA that initiates translation in most pathogenic bacteria.
C) is a mechanism of genetic regulation found in all prokaryotes.
D) is any chemical that inhibits transcription.
E) uses short pieces of single-stranded RNA to direct the degradation of specific RNA transcripts
54)A drug that inhibits the activity of bacterial DNA gyrase ______ be a good antibiotic because ______.
A) would; it wouldinhibit all DNA synthesis
B) would NOT; it would inhibit all DNA synthesis, even our own cell's DNA synthesis
C) would; it would selectively inhibit bacterial DNA synthesis due to differences between bacterial/human gyrase
D) would NOT; the DNAreplication machinery could still function, even with impaired DNA gyraseenzyme
55)Why is it beneficial for a bacterial cell to be able to use glucose FIRST as an energy source (until it is depleted), THEN switch to lactose?
A) Lactose can onlybe used by a small number of bacteriaas an energy source AND for conservation of energy:why use the energy to make the enzymes for breaking down lactose when glucose doesn't need any extra enzymes for breakdown?
B) For conservation of energy:why use the energy to make the enzymes for breaking down lactose when glucose doesn't need any extra enzymes for breakdown AND because breakdown of lactose produces inhibitory compounds.
C) Glucose is aneasier compound to break down and obtain energy from than lactose AND for conservation of energy:why use the energy to make the enzymes for breaking down lactose when glucose doesn't need any extra enzymes for breakdown?
D) Glucose provides 10x as much energy when broken down as lactose AND for conservation of energy:why use the energy to make the enzymes for breaking down lactose when glucose doesn't need any extra enzymes for breakdown?
56)Does the presence of introns/exons in eukaryotic cells provide more potential diversity in gene products (proteins) than is possible in prokaryotic cells?
A) It doesn't. There is the same potential for gene products (proteins) in a bacterium with 1,000 genes as there is in a eukaryotic cell with 1,000 genes.
B) It does. Each exon and each intron could be used individually and discretely to make a gene product (protein). Since bacteria lack these, they will have less ability to create different proteins.
C) It does. Exons/introns can be spliced together in different ways post-transcription to yield different mRNAs (and therefore, different proteins). Bacteria lack this system.
D) It does. Exons/introns can be spliced together in different ways at the DNA level to eventually yield different mRNAs (and therefore, different proteins). Bacteria lack this system.
57)A graduate student is trying to isolate bacterial mRNA for an enzyme that will degrade trinitrotoluene (TNT). She's frustrated to find that the enzyme isn't produced when the bacterium in question is grown on nutrient agar. What might she do to solve the problem and obtain the mRNA?
A) Add nitrogen and toluene to the agar which willdrive up synthesis of TNT, leading to production of the mRNA the student is looking for.
B) Add TNT to the agar—this will drive synthesis of the enzyme to degrade it, leading to production of the mRNA the student is looking for.
C) Remove glucose from the agar—this will cause the bacteria to shift to other compounds for their energy purposes.
D) Remove nitrogen and toluene fromthe agar whichwill lead todrivingup synthesis of TNT,leading to production of the mRNA the student is looking for.
58)Cells are often ground up with abrasive to get to their internal enzymes/molecules, followed by removal of the abrasives. Here are two situations and two outcomes. What is the correct interpretation of the results?
In situation #1, radioactive amino acids are mixed with ground-up cell material. Radioactive proteins are produced.
In situation #2, radioactive amino acids AND the enzyme RNAse (an enzyme that degrades RNA) are mixed with ground-up cell material. No radioactive proteins are produced
A) The mRNA from thecell can be used to make proteins with the radioactive amino acids in the firstsituation. In the second situation, the mRNA is destroyed by the RNAsebefore it can be translated into protein containing the radioactive aminoacids.
B) The DNA from thecell can be translated into protein using the radioactive amino acids in thefirst situation. The RNAse in the second situation degrades the ribosomalRNA (rRNA), preventing ribosomes from forming and making proteins with theradioactive amino acids.
C) The radioactivityin the amino acids corrupts the tRNA molecules, leading to no proteinproduction in the second scenario.
D) The radioactivity in the medium causes the DNA of the bacteria to mutate. This causes a malfunction of all the enzymes of that cell.
59)Cells are often ground up with abrasive to get to their internal enzymes/molecules, followed by removal of the abrasives. Here are three situations and three outcomes. What is the correct interpretation of the results? In situation #1, radioactive amino acids are added to cell material, and radioactive proteins are produced. In situation #2, radioactive amino acids, cell material, and the enzyme DNAse (degrades DNA) are added together. Radioactive proteins are still produced. In situation #3, the ground-up cell material is allowed to sit for 24 hours before radioactive amino acids and DNAse are added to it. No radioactive protein is produced. What is the most likely interpretation?
A) RNA polymerase has no activity after 24 hours, so no mRNA is transcribed and translated into radioactive proteins in the last scenario.
B) The radioactivityin the amino acids is altering/degrading the tRNA molecules, leading to noprotein production in the last scenario.
C) Natural RNAses present in the ground-up material will degrade any existing mRNAs in that 24-hour interval. Added DNAses break down DNA so that new RNAs are not synthesized. This will lead to a loss of capability to translate protein in the last scenario.
D) The radioactivity in the amino acids completely disappears within 24 hours. Transcription and translation occur as usual, but there is no radioactivity left in the system, so proteins are untagged.
60)Transcription begins at the ______ and ends at the ______, while translation begins at the ______ and ends at the ______.
A) start codon; stop codon; promoter; terminator
B) promoter; stop codon; terminator; stop codon
C) promoter; start codon; terminator; stop codon
D) promoter; terminator; start codon; stop codon
61)Which tasks must a bacterial cell accomplish in order to multiply?
A) Replication, translation, protein synthesis which
B) DNA duplication, RNA synthesis, protein synthesis
C) Protein synthesis, mitosis, capsule formation
D) Mitosis, gene expression, apoptosis
62)Which of the following is INCORRECT?
A) Transcription is the conversion of DNA into RNA.
B) Replication is the process of duplicating a DNA molecule.
C) Binary fission is the process of bacterial cell division. of bacterial cell division.
D) Transcription is the process of copying mRNA from DNA.
63)DNA polymerases
A) add nucleotides to the 3' end of RNA during transcription.
B) generate short stretches of RNA called primers to initiate replication.
C) unwind the DNA template at the replication fork.
D) move in a 3' to 5' direction on the template DNA.
64)Which pair is INCORRECT?
A) Okazaki fragments—generated on the lagging strand during DNA replication.
B) Splicing—removal of introns from prokaryote mRNA following transcription.
C) Signal transduction—transmission of information from outside a cell to inside the cell.
D) Constitutive enzymes—enzymes that are constantly produced by a cell.
65)Which of the following is an example of phase variation?
A) N. gonorrhoeaeexpressing different types of pilinprotein.
B) Influenza virus expressing variations of glycoprotein HA and NA spikes.
C) S. pyogenes producing a capsule of hyaluronic acid, which is also ahost component.
D) E. coli producing pilifor attachment to epithelial cells.
66)How can some bacteria sense the density of cells in an environment?
A) Detecting the concentration of a signaling molecule.
B) Quantifying the accumulation of waste products.
C) Measuring the depletion of oxygen in the environment.
D) Sensing the depletion of water in the environment.
67)The simultaneous regulation of many bacterial genes is
A) quorum sensing.
regulon
C) local control.
E) global control.
68)A regulatory protein binds to the operator in a strand of DNA, blocking transcription. The protein is
A) a repressor.
B) an inducer.
C) an operon.
D) a terminator.
69)If a DNA triplet is AGT, the mRNAcodonwould be ______ and the tRNA anticodon would be ______.
A) TCA; AGU
B) UCA; AGU
C) TGA; serine
D) UCA; stop
70)For synthesis of an inducible enzyme to occur,
A) a compound must bind to the repressor.
B) a compound must bind to the operator.
C) a product must bind to the terminator.
D) a corepressor must bind to the start codon.
71)When E. coli is grown in medium containing both glucose and lactose,
A) the cells growth fastest after lactose is used up.
B) the cells use lactose first, then glucose.
C) the cells grow fastest initially when glucose is available.
D) the cells use the glucose and then stop growing.
72)When E. coli is placed in a medium containing both glucose and lactose, why does cell growth stop temporarily when the glucose is used up?
A) Once glucose is depleted, the cell must use the lactose; before it can do this, it must express the lac operon and synthesize the enzymes needed to use lactose, which takes time.
B) Once lactose is depleted, the cell must use the glucose; before it can do this, it must express the lac operon and synthesize the enzymes needed to use lactose, which takes time.
C) Once glucose is depleted, the cell must use the lactose; before it can do this, it must express the lac operon—it can only do this if the culture medium is placed in the dark at 22 oC.
D) Glucose is the preferred medium of the cells—when it is available, they grow extremely fast, and this depletes all the energy in the cell which must be replaced before it can use lactose.
73)Why is the position of the first AUG after the ribosome binding site critical?
A) Every polypeptide must start with methionine.
B) It initiates transcription.
C) Every polypeptide must start with arginine.
D) It establishes the reading frame.
74)What does semiconservative mean with respect to DNA replication?
A) In the two new DNA molecules generated, one has two new strands and one has two original strands.
B) In the two new molecules generated, each has one new DNA strand and one original RNA strand.
C) In the two new DNA molecules generated, each has one new strand and one original strand.
D) In the two new DNA molecules generated, one has a single strand and the other has a double strand.
75)Select the CORRECT statement regarding regulation by a repressor and regulation by an activator.
A) Repressors bind to the operator, blocking the progress of RNA polymerase. Activators bind to the activator-binding site, facilitating the progress of RNA polymerase.
B) Repressors bind to the activator-binding site, blocking the progress of RNA polymerase. Activators bind to the operator, facilitating the progress of RNA polymerase.
C) Repressors bind to the activator-binding site, blocking the progress of DNA polymerase. Activators bind to the operator, facilitating the progress of DNA polymerase.
D) Repressors bind to the operator, blocking the progress of DNA polymerase. Activators bind to the activator-binding site, facilitating the progress of DNA polymerase.
76)Which of the following is NOT involved in transcription?
A) Ribosome
Uracil
C) Promotor
D) Polymerase
77)Which of the following statements about gene expression in prokaryotes is FALSE?
A) More than one RNA polymerase can be transcribing a specific gene at a given time.
B) More than one ribosome can be translating a specific transcript at a given time.
C) Translation begins at a site called a promoter.
D) Transcription stops at a site called a terminator.
78)If a 100 base-pair double-stranded DNA fragment has 40 cytosines, how many adenines does it contain?
A) 60
B) 40
C) 30
D) 20
79)In replication, synthesis of which strand requires the repeated action of DNA ligase?
A) The lagging strand
B) The leading strand
C) Both the leading AND the lagging strand
D) The top strand
80)How do activators facilitate transcription?
A) They bind to DNA, thereby making it easier for RNA polymerase to initiate transcription.
B) They bind to RNA, thereby making it easier for DNA polymerase to initiate transcription.
C) They bind to DNA, thereby making it easier for DNA polymerase to initiate transcription.
D) They bind to DNA, thereby making it easier for RNA polymerase to initiate translation.
81)Which of the following is NOT found in DNA?
A) Peptide bond
Thymine
C) Hydrogen bond
D) Complementary base pairing
82)Select the INCORRECT statement regarding DNA structure.
A) Thymine base pairs with cytosine.
B) Purines base pair with pyrimidines.
C) The two strands are held together by hydrogen bonds.
D) The two strands are antiparallel.
83)Which of the following may use RNA as its genome?
A) Virus
B) Bacterium
C) Protozoan
D) Prion
84)Under which of the following conditions will transcription of the lac operon occur?
A) Lactose present/glucose present
B) Lactose present/glucose absent
C) Lactose absent/glucose present
D) Lactose absent/glucose absent
85)Which of the following statements about repressors is TRUE?
A) A repressor is a protein that binds to an operator site on DNA and prevents transcription.
B) A repressor is a protein that binds to an operator site on RNA and prevents transcription.
C) A repressor is a carbohydrate that binds to an operator site on DNA and prevents transcription.
D) A repressor is a protein that binds to an activator-binding site and prevents transcription.
The source of variation among microorganisms that were once identical is
mutation.
antibiotic resistance.
sigma factors.
virulence factors.mutation.
