Term
Answer: A
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
1) For a couple of decades, biologists knew the nucleus contained DNA and proteins. The
prevailing opinion was that the genetic material was proteins, and not DNA. The reason for this
belief was that proteins are more complex than DNA. What was the basis of this thinking?
A) Proteins have a greater variety of three-dimensional forms than does DNA.
B) Proteins have two different levels of structural organization; DNA has four.
C) Proteins are made of 40 amino acids and DNA is made of four nucleotides.
D) Some viruses only transmit proteins.
E) A and B are correct. |
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Term
Answer: B
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
2) In his transformation experiments, what did Griffith observe?
A) Mutant mice were resistant to bacterial infections.
B) Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can
convert some of the living cells into the pathogenic form.
C) Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes
the pathogenic strain nonpathogenic.
D) Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic
strains.
E) Mice infected with a pathogenic strain of bacteria can spread the infection to other mice. |
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Term
Answer: E
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
3) What does transformation involve in bacteria?
A) the creation of a strand of DNA from an RNA molecule
B) the creation of a strand of RNA from a DNA molecule
C) the infection of cells by a phage DNA molecule
D) the type of semiconservative replication shown by DNA
E) assimilation of external DNA into a cell |
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Term
Answer: B
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
4) The following scientists made significant contributions to our understanding of the structure
and function of DNA. Place the scientists' names in the correct chronological order, starting with
the first scientist(s) to make a contribution.
2
I. Avery, McCarty, and MacLeod
II. Griffith
III. Hershey and Chase
IV. Meselson and Stahl
V. Watson and Crick
A) V, IV, II, I, III
B) II, I, III, V, IV
C) I, II, III, V, IV
D) I, II, V, IV, III
E) II, III, IV, V, I |
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Term
Answer: D
Topic: Concept 16.1
Skill: Synthesis/Evaluation |
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Definition
5) After mixing a heat-killed, phosphorescent strain of bacteria with a living non-phosphorescent
strain, you discover that some of the living cells are now phosphorescent. Which observations
would provide the best evidence that the ability to fluoresce is a heritable trait?
A) DNA passed from the heat-killed strain to the living strain.
B) Protein passed from the heat-killed strain to the living strain.
C) The phosphorescence in the living strain is especially bright.
D) Descendants of the living cells are also phosphorescent.
E) Both DNA and protein passed from the heat-killed strain to the living strain. |
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Term
Answer: B
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
6) In trying to determine whether DNA or protein is the genetic material, Hershey and Chase
made use of which of the following facts?
A) DNA contains sulfur, whereas protein does not.
B) DNA contains phosphorus, but protein does not.
C) DNA contains nitrogen, whereas protein does not.
D) DNA contains purines, whereas protein includes pyrimidines.
E) RNA includes ribose, while DNA includes deoxyribose sugars. |
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Term
Answer: E
Topic: Concept 16.1
Skill: Application/Analysis |
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Definition
7) For a science fair project, two students decided to repeat the Hershey and Chase experiment,
with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate.
They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus,
labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why won't
this experiment work?
A) There is no radioactive isotope of nitrogen.
B) Radioactive nitrogen has a half-life of 100,000 years, and the material would be too
dangerous for too long.
3
C) Avery et al. have already concluded that this experiment showed inconclusive results.
D) Although there are more nitrogens in a nucleotide, labeled phosphates actually have 16 extra
neutrons; therefore, they are more radioactive.
E) Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not
distinguish between DNA and proteins. |
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Term
Answer: C
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
8) Which of the following investigators was/were responsible for the following discovery?
Chemicals from heat-killed S cells were purified. The chemicals were tested for the ability to
transform live R cells. The transforming agent was found to be DNA.
A) Frederick Griffith
B) Alfred Hershey and Martha Chase
C) Oswald Avery, Maclyn McCarty, and Colin MacLeod
D) Erwin Chargaff
E) Matthew Meselson and Franklin Stahl |
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Term
Answer: B
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
9) Which of the following investigators was/were responsible for the following discovery?
Phage with labeled proteins or DNA was allowed to infect bacteria. It was shown that the DNA,
but not the protein, entered the bacterial cells, and was therefore concluded to be the genetic
material.
A) Frederick Griffith
B) Alfred Hershey and Martha Chase
C) Oswald Avery, Maclyn McCarty, and Colin MacLeod
D) Erwin Chargaff
E) Matthew Meselson and Franklin Stahl |
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Term
Answer: D
Topic: Concept 16.1
4
Skill: Knowledge/Comprehension |
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Definition
10) Which of the following investigators was/were responsible for the following discovery?
In DNA from any species, the amount of adenine equals the amount of thymine, and the amount
of guanine equals the amount of cytosine.
A) Frederick Griffith
B) Alfred Hershey and Martha Chase
C) Oswald Avery, Maclyn McCarty, and Colin MacLeod
D) Erwin Chargaff
E) Matthew Meselson and Franklin Stahl |
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Term
Answer: B
Topic: Concept 16.1
Skill: Application/Analysis |
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Definition
11) When T2 phages infect bacteria and make more viruses in the presence of radioactive sulfur,
what is the result?
A) The viral DNA will be radioactive.
B) The viral proteins will be radioactive.
C) The bacterial DNA will be radioactive.
D) both A and B
E) both A and C |
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Term
Answer: A
Topic: Concept 16.1
Skill: Application/Analysis |
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Definition
12) Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism.
Approximately what percentage of the nucleotides in this sample will be thymine?
A) 12
B) 24
C) 31
D) 38
E) It cannot be determined from the information provided. |
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Term
Answer: C
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
13) Chargaff's analysis of the relative base composition of DNA was significant because he was
able to show that
A) the relative proportion of each of the four bases differs within individuals of a species.
B) the human genome is more complex than that of other species.
C) the amount of A is always equivalent to T, and C to G.
D) the amount of ribose is always equivalent to deoxyribose.
E) transformation causes protein to be brought into the cell. |
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Term
Answer: A
Topic: Concept 16.1
5
Skill: Knowledge/Comprehension |
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Definition
14) Which of the following can be determined directly from X-ray diffraction photographs of
crystallized DNA?
A) the diameter of the helix
B) the rate of replication
C) the sequence of nucleotides
D) the bond angles of the subunits
E) the frequency of A vs. T nucleotides |
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Term
Answer: A
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
15) Why does the DNA double helix have a uniform diameter?
A) Purines pair with pyrimidines.
B) C nucleotides pair with A nucleotides.
C) Deoxyribose sugars bind with ribose sugars.
D) Nucleotides bind with nucleosides.
E) Nucleotides bind with nucleoside triphosphates. |
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Term
Answer: A
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
16) What kind of chemical bond is found between paired bases of the DNA double helix?
A) hydrogen
B) ionic
C) covalent
D) sulfhydryl
E) phosphate |
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Term
Answer: A
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
17) It became apparent to Watson and Crick after completion of their model that the DNA
molecule could carry a vast amount of hereditary information in which of the following?
A) sequence of bases
B) phosphate-sugar backbones
C) complementary pairing of bases
D) side groups of nitrogenous bases
E) different five-carbon sugars |
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Term
Answer: C
Topic: Concept 16.1
Skill: Application/Analysis |
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Definition
18) In an analysis of the nucleotide composition of DNA, which of the following will be found?
A) A = C
B) A = G and C = T
C) A + C = G + T
D) G + C = T + A |
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Term
Answer: A
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
19) Mendel and Morgan did not know about the structure of DNA; however, which of the
following of their contributions was (were) necessary to Watson and Crick?
6
A) the particulate nature of the hereditary material
B) dominance vs. recessiveness
C) sex-linkage
D) genetic distance and mapping
E) the usefulness of peas and Drosophila |
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Term
Answer: B
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
20) Replication in prokaryotes differs from replication in eukaryotes for which of these reasons?
A) The prokaryotic chromosome has histones, whereas eukaryotic chromosomes do not.
B) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic
chromosomes have many.
C) The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes.
D) Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not.
E) Prokaryotes have telomeres, and eukaryotes do not. |
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Term
Answer: B
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
21) What is meant by the description "antiparallel" regarding the strands that make up DNA?
A) The twisting nature of DNA creates nonparallel strands.
B) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.
C) Base pairings create unequal spacing between the two DNA strands.
D) One strand is positively charged and the other is negatively charged.
E) One strand contains only purines and the other contains only pyrimidines. |
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Term
Answer: E
Topic: Concept 16.2
Skill: Application/Analysis |
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Definition
22) Suppose you are provided with an actively dividing culture of E. coli bacteria to which
radioactive thymine has been added. What would happen if a cell replicates once in the presence
of this radioactive base?
A) One of the daughter cells, but not the other, would have radioactive DNA.
B) Neither of the two daughter cells would be radioactive.
C) All four bases of the DNA would be radioactive.
D) Radioactive thymine would pair with nonradioactive guanine.
E) DNA in both daughter cells would be radioactive. |
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Term
Answer: D
Topic: Concept 16.2
Skill: Application/Analysis |
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Definition
23) In the late 1950s, Meselson and Stahl grew bacteria in a medium containing "heavy" nitrogen
(15N) and then transferred them to a medium containing 14N. Which of the results in Figure
16.1 would be expected after one round of DNA replication in the presence of 14N? |
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Term
Answer: B
Topic: Concept 16.2
Skill: Application/Analysis |
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Definition
24) A space probe returns with a culture of a microorganism found on a distant planet. Analysis
shows that it is a carbon-based life-form that has DNA. You grow the cells in 15N medium for
several generations and then transfer them to 14N medium. Which pattern in Figure 16.1 would
you expect if the DNA was replicated in a conservative manner? |
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Term
Answer: D
Topic: Concept 16.1
Skill: Knowledge/Comprehension |
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Definition
25) Once the pattern found after one round of replication was observed, Meselson and Stahl
could be confident of which of the following conclusions?
A) Replication is semi-conservative.
B) Replication is not dispersive.
C) Replication is not semi-conservative.
D) Replication is not conservative.
E) Replication is neither dispersive nor conservative. |
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Term
Answer: C
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
26) An Okazaki fragment has which of the following arrangements?
A) primase, polymerase, ligase
B) 3' RNA nucleotides, DNA nucleotides 5'
C) 5' RNA nucleotides, DNA nucleotides 3'
D) DNA polymerase I, DNA polymerase III
E) 5' DNA to 3' |
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Term
Answer: B
Topic: Concept 16.2
Skill: Application/Analysis |
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Definition
27) In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts
at the origin. Which of the following would you expect as a result of this mutation?
A) No proofreading will occur.
B) No replication fork will be formed.
C) The DNA will supercoil.
D) Replication will occur via RNA polymerase alone.
E) Replication will require a DNA template from another source. |
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Term
Answer: C
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
28) Which enzyme catalyzes the elongation of a DNA strand in the 5' 3' direction?
A) primase
B) DNA ligase
C) DNA polymerase III
D) topoisomerase
E) helicase |
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Term
Answer: C
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
29) What determines the nucleotide sequence of the newly synthesized strand during DNA
replication?
A) the particular DNA polymerase catalyzing the reaction
B) the relative amounts of the four nucleoside triphosphates in the cell
C) the nucleotide sequence of the template strand
D) the primase used in the reaction
E) the arrangement of histones in the sugar phosphate backbone |
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Term
Answer: C
Topic: Concept 16.2
Skill: Synthesis/Evaluation |
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Definition
30) Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a
consequence of which of the following?
A) The evolution of telomerase enzyme
B) DNA polymerase that cannot replicate the leading strand template to its 5' end
C) Gaps left at the 5' end of the lagging strand because of the need for a 3' onto which
nucleotides can attach
D) Gaps left at the 3' end of the lagging strand because of the need for a primer
E) The "no ends" of a circular chromosome |
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Term
Answer: D
Topic: Concept 16.2
Skill: Application/Analysis |
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Definition
31) The enzyme telomerase solves the problem of replication at the ends of linear chromosomes
by which method?
A) adding a single 5' cap structure that resists degradation by nucleases
B) causing specific double strand DNA breaks that result in blunt ends on both strands
C) causing linear ends of the newly replicated DNA to circularize
D) adding numerous short DNA sequences such as TTAGGG, which form a hairpin turn
E) adding numerous GC pairs which resist hydrolysis and maintain chromosome integrity |
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Term
Answer: E
Topic: Concept 16.2
Skill: Synthesis/Evaluation |
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Definition
32) The DNA of telomeres has been found to be highly conserved throughout the evolution of
eukaryotes. What does this most probably reflect?
A) the inactivity of this DNA
B) the low frequency of mutations occurring in this DNA
C) that new evolution of telomeres continues
D) that mutations in telomeres are relatively advantageous
E) that the critical function of telomeres must be maintained |
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Term
Answer: A
Topic: Concept 16.2
Skill: Synthesis/Evaluation |
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Definition
33) In an experiment, DNA is allowed to replicate in an environment with all necessary
enzymes, dATP, dCTP, dGTP, and radioactively labeled dTTP (3H thymidine) for several
minutes and then switched to nonradioactive medium. It is then viewed by electron microscopy
and autoradiography. The drawing below represents the results.
Grains represent radioactive material within the replicating eye.
Figure 16.2
Which is the most likely interpretation?
A) There are two replication forks going in opposite directions.
B) Thymidine is only being added where the DNA strands are furthest apart.
C) Thymidine is only added at the very beginning of replication.
D) Replication proceeds in one direction only. |
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Term
Answer: D
Topic: Concept 16.2
Skill: Synthesis/Evaluation |
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Definition
34) At a specific area of a chromosome, the sequence of nucleotides below is present where the
chain opens to form a replication fork:
3' C C T A G G C T G C A A T C C 5'
An RNA primer is formed starting at the underlined T (T) of the template. Which of the
following represents the primer sequence?
A) 5' G C C T A G G 3'
B) 3' G C C T A G G 5'
C) 5' A C G T T A G G 3'
D) 5' A C G U U A G G 3'
E) 5' G C C U A G G 3' |
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Term
Answer: B
Topic: Concept 16.2
Skill: Application/Analysis |
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Definition
35) Polytene chromosomes of Drosophila salivary glands each consist of multiple identical DNA
strands that are aligned in parallel arrays. How could these arise?
A) replication followed by mitosis
B) replication without separation
C) meiosis followed by mitosis
D) fertilization by multiple sperm
E) special association with histone proteins |
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Term
Answer: E
Topic: Concept 16.2
Skill: Application/Analysis |
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Definition
36) To repair a thymine dimmer by nucleotide excision repair, in which order do the necessary
enzymes act?
A) exonuclease, DNA polymerase III, RNA primase
B) helicase, DNA polymerase I, DNA ligase
C) DNA ligase, nuclease, helicase
D) DNA polymerase I, DNA polymerase III, DNA ligase
E) endonuclease, DNA polymerase I, DNA ligase |
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Term
Answer: C
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
37) What is the function of DNA polymerase III?
A) to unwind the DNA helix during replication
B) to seal together the broken ends of DNA strands
C) to add nucleotides to the end of a growing DNA strand
11
D) to degrade damaged DNA molecules
E) to rejoin the two DNA strands (one new and one old) after replication |
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Term
Answer: A
Topic: Concept 16.2
Skill: Application/Analysis |
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Definition
38) You briefly expose bacteria undergoing DNA replication to radioactively labeled
nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into
two classes. One class of labeled DNA includes very large molecules (thousands or even
millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a
few thousand nucleotides in length). These two classes of DNA probably represent
A) leading strands and Okazaki fragments.
B) lagging strands and Okazaki fragments.
C) Okazaki fragments and RNA primers.
D) leading strands and RNA primers.
E) RNA primers and mitochondrial DNA. |
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Term
Answer: D
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
39) Which of the following removes the RNA nucleotides from the primer and adds equivalent
DNA nucleotides to the 3' end of Okazaki fragments?
A) helicase
B) DNA polymerase III
C) ligase
D) DNA polymerase I
E) primase |
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Term
Answer: A
Topic: Concept 16.2
Skill: Inowledge/Comprehension |
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Definition
40) Which of the following separates the DNA strands during replication?
A) helicasa
B) DNA polymerase II
C) ligase
D) DNA polymerase H
E) primase |
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Term
Answer: C
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
41) Which of the following covalently connects segments of DNA?
A) helicase
B) DNA polymerase III
12
C) ligase
D) DNA polymerase I
E) primasa |
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Term
Answer: E
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
42) Which of the following synthesi:es short segments of RNA?
A) helicase
B) DNA polymerase III
C) ligase
D) DNA polymerase I
E) primase |
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Term
Answer: A
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
43) The difference between ATP and the nucleoside triphosphates used during DNA synthesis is
that
A) the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose.
B) the nucleoside triphosphates have two phosphate groups; ATP has three phosphate groups.
C) ATP contains three high-energy bonds; the nucleoside triphosphates have two.
D) ATP is found only in human cells; the nucleoside triphosphates are found in all animal and
plant cells.
E) triphosphate monomers are active in the nucleoside triphosphates, but not in ATP. |
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Term
Answer: A
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
44) The leading and the lagging strands differ in that
A) the leading strand is synthesized in the same direction as the movement of the replication
fork, and the lagginc strand is synthesized in the opposhte direction.
B) dhe leading strand is synthe3ized by adding nucleotides to the 3' end of the growing strajd,
and the lagging strand is synthesized by adding nucleotides to the 5' end.
C) the lagging strand is synthesized continuously, whereas the leading strand is synthesized in
short fragments that are ultimately stitched together.
D) the leading strand is synthesized at twice the rate of the lagging strand. |
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Term
Answer: B
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
45) Which of the following best describes the addition of nucleotides to a growing DNA chain?
A) A nucleoside triphosphate is added to the 5' end of the DNA, releasing a molecule of
pyrophosphate.
13
B) A nucleoside triphosphate is added to the 3' end of the DNA, releasing a molecule of
pyrophosphate.
C) A nucleoside diphosphate is added to the 5' end of the DNA, releasing a molecule of
phosphate.
D) A nucleoside diphosphate is added to the 3' end of the DNA, releasing a molecule of
phosphate.
E) A nucleoside monophosphate is added to the 5' end of the DNA. |
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Term
Answer: E
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
46) A new DNA strand elongates only in the 5' to 3' direction because
A) DNA polymerase begins adding nucleotides at the 5' end of the template.
B) Okazaki fragments prevent elongation in the 3' to 5' direction.
C) the polarity of the DNA molecule prevents addition of nucleotides at the 3' end.
D) replication must progress toward the replication fork.
E) DNA polymerase can only add nucleotides to the free 3' end. |
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Term
Answer: A
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
47) What is the function of topoisomerase?
A) relieving strain in the DNA ahead of the replication fork
B) elongation of new DNA at a replication fork by addition of nucleotides to the existing chain
C) the addition of methyl groups to bases of DNA
D) unwinding of the double helix
E) stabilizing single-stranded DNA at the replication fork |
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Term
Answer: C
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
48) What is the role of DNA ligase in the elongation of the lagging strand during DNA
replication?
A) synthesize RNA nucleotides to make a primer
B) catalyze the lengthening of telomeres
C) join Okazaki fragments together
D) unwind the parental double helix
E) stabilize the unwound parental DNA |
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Term
Answer: D
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
49) Which of the following help to hold the DNA strands apart while they are being replicated?
A) primase
14
B) ligase
C) DNA polymerase
D) single-strand binding proteins
E) exonuclease |
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Term
Answer: D
Topic: Concept 16.2
Skill: Knowledge/Comprehension |
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Definition
50) Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight. This
occurs because their cells have which impaired ability?
A) They cannot replicate DNA.
B) They cannot undergo mitosis.
C) They cannot exchange DNA with other cells.
D) They cannot repair thymine dimers.
E) They do not recombine homologous chromosomes during meiosis. |
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Term
Answer: D
Topic: Concept 16.2
Skill: Application/Analysis |
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Definition
51) Which would you expect of a eukaryotic cell lacking telomerase?
A) a high probability of becoming cancerous
B) production of Okazaki fragments
C) inability to repair thymine dimers
D) a reduction in chromosome length
E) high sensitivity to sunlight |
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Term
Answer: A
Topic: Concepts 16.2 and 16.3
Skill: Application/Analysis |
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Definition
52) Which of the following sets of materials are required by both eukaryotes and prokaryotes for
replication?
A) double-stranded DNA, 4 kinds of dNTPs, primers, origins
B) topoisomerases, telomerase, polymerases
C) G-C rich regions, polymerases, chromosome nicks
D) nucleosome loosening, 4 dNTPs, 4 rNTPs
E) ligase, primers, nucleases |
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Term
Answer: B
Topic: Concept 16.3
Skill: Knowledge/Comprehension |
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Definition
53) A typical bacterial chromosome has ~4.6 million nucleotides. This supports approximately
how many genes?
A) 4.6 million
B) 4.4 thousand
15
C) 45 thousand
D) about 400 |
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Term
Answer: B
Topic: Concept 16.3
Skill: Synthesis/Evaluation |
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Definition
54) Studies of nucleosomes have shown that histones (except H1) exist in each nucleosome as
two kinds of tetramers: one of 2 H2A molecules and 2 H2B molecules, and the other as 2 H3 and
2 H4 molecules. Which of the following is supported by this data?
A) DNA can wind itself around either of the two kinds of tetramers.
B) The two types of tetramers associate to form an octamer.
C) DNA has to associate with individual histones before they form tetramers.
D) Only H2A can form associations with DNA molecules.
E) The structure of H3 and H4 molecules is not basic like that of the other histones. |
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Term
Answer: B
Topic: Concept 16.3
Skill: Application/Analysis |
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Definition
55) When DNA is compacted by histones into 10 nm and 30 nm fibers, the DNA is unable to
interact with proteins required for gene expression. Therefore, to allow for these proteins to act,
the chromatin must constantly alter its structure. Which processes contribute to this dynamic
activity?
A) DNA supercoiling at or around H1
B) methylation and phosphorylation of histone tails
C) hydrolysis of DNA molecules where they are wrapped around the nucleosome core
D) accessibility of heterochromatin to phosphorylating enzymes
E) nucleotide excision and reconstruction |
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Term
Answer: C
Topic: Concept 16.3
Skill: Application/Analysis |
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Definition
56) About how many more genes are there in the haploid human genome than in a typical
bacterial genome?
A) 10 X
B) 100 X
C) 1000 X
D) 10,000 X
E) 100,000 X |
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Term
Answer: D
Topic: Concept 16.3
Skill: Synthesis/Evaluation |
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Definition
57) In prophase I of meiosis in female Drosophila, studies have shown that there is
phosphorylation of an amino acid in the tails of histones. A mutation in flies that interferes with
this process results in sterility. Which of the following is the most likely hypothesis?
A) These oocytes have no histones.
B) Any mutation during oogenesis results in sterility.
C) Phosphorylation of all proteins in the cell must result.
D) Histone tail phosphorylation prohibits chromosome condensation.
E) Histone tails must be removed from the rest of the histones. |
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Term
Answer: D
Topic: Concept 16.3
Skill: Knowledge/Comprehension |
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Definition
58) In a linear eukaryotic chromatin sample, which of the following strands is looped into
domains by scaffolding?
A) DNA without attached histones
B) DNA with H1 only
C) the 10 nm chromatin fiber
D) the 30 nm chromatin fiber
E) the metaphase chromosome |
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Term
Answer: D
Topic: Concept 16.3
Skill: Knowledge/Comprehension |
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Definition
59) Which of the following statements describes the eukaryotic chromosome?
A) It is composed of DNA alone.
B) The nucleosome is its most basic functional subunit.
C) The number of genes on each chromosome is different in different cell types of an organism.
D) It consists of a single linear molecule of double-stranded DNA.
E) Active transcription occurs on heterochromatin. |
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Term
Answer: B
Topic: Concept 16.3
Skill: Synthesis/Evaluation |
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Definition
60) If a cell were unable to produce histone proteins, which of the following would be a likely
effect?
A) There would be an increase in the amount of "satellite" DNA produced during centrifugation.
B) The cell's DNA couldn't be packed into its nucleus.
C) Spindle fibers would not form during prophase.
D) Amplification of other genes would compensate for the lack of histones.
E) Pseudogenes would be transcribed to compensate for the decreased protein in the cell. |
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Term
Answer: B
Topic: Concept 16.3
Skill: Knowledge/Comprehension |
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Definition
61) Which of the following statements describes histones?
A) Each nucleosome consists of two molecules of histone H1.
B) Histone H1 is not present in the nucleosome bead; instead it is involved in the formation of
higher-level chromatin structures.
C) The carboxyl end of each histone extends outward from the nucleosome and is called a
"histone tail."
D) Histones are found in mammals, but not in other animals or in plants.
E) The mass of histone in chromatin is approximately nine times the mass of DNA. |
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Term
Answer: A
Topic: Concept 16.3
Skill: Knowledge/Comprehension |
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Definition
62) Why do histones bind tightly to DNA?
A) Histones are positively charged, and DNA is negatively charged.
B) Histones are negatively charged, and DNA is positively charged.
C) Both histones and DNA are strongly hydrophobic.
D) Histones are covalently linked to the DNA.
E) Histones are highly hydrophobic, and DNA is hydrophilic. |
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Term
Answer: A
Topic: Concept 16.3
Skill: Knowledge/Comprehension |
|
Definition
63) Which of the following represents the order of increasingly higher levels of organization of
chromatin?
A) nucleosome, 30-nm chromatin fiber, looped domain
B) looped domain, 30-nm chromatin fiber, nucleosome
C) looped domain, nucleosome, 30-nm chromatin fiber
D) nucleosome, looped domain, 30-nm chromatin fiber
E) 30-nm chromatin fiber, nucleosome, looped domain |
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Term
Answer: C
Topic: Concept 16.3
Skill: Knowledge/Comprehension |
|
Definition
64) Which of the following statements is true of chromatin?
A) Heterochromatin is composed of DNA, whereas euchromatin is made of DNA and RNA.
B) Both heterochromatin and euchromatin are found in the cytoplasm.
C) Heterochromatin is highly condensed, whereas euchromatin is less compact.
D) Euchromatin is not transcribed, whereas heterochromatin is transcribed.
E) Only euchromatin is visible under the light microscope. |
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Term
|
Definition
1) In his work with pneumonia-causing bacteria and mice, Griffith found that
A) the protein coat from pathogenic cells was able to transform nonpathogenic cells.
B) heat-killed pathogenic cells caused pneumonia.
C) some substance from pathogenic cells was transferred to nonpathogenic cells, making them
pathogenic.
D) the polysaccharide coat of bacteria caused pneumonia.
E) bacteriophages injected DNA into bacteria. |
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Term
|
Definition
2) E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for
two more generations (two rounds of DNA replication). DNA extracted from these cells is
centrifuged. What density distribution of DNA would you expect in this experiment?
A) one high-density and one low-density band
B) one intermediate-density band
C) one high-density and one intermediate-density band
D) one low-density and one intermediate-density band
E) one low-density band |
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Term
|
Definition
3) A biochemist isolates and purifies various molecules needed for DNA replication. When she
adds some DNA, replication occurs, but each DNA molecule consists of a normal strand paired
with numerous segments of DNA a few hundred nucleotides long. What has she probably left out
of the mixture?
A) DNA polymerase
B) DNA ligase
C) nucleotides
D) Okazaki fragments
E) primase |
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Term
|
Definition
4) What is the basis for the difference in how the leading and lagging strands of DNA molecules
are synthesized?
A) The origins of replication occur only at the 5' end.
B) Helicases and single-strand binding proteins work at the 5' end.
C) DNA polymerase can join new nucleotides only to the 3' end of a growing strand.
D) DNA ligase works only in the 3' 5' direction.
E) Polymerase can work on only one strand at a time. |
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Term
|
Definition
5) In analyzing the number of different bases in a DNA sample, which result would be consistent
with the base-pairing rules?
A) A = G
B) A + G = C + T
19
C) A + T = G + T
D) A = C
E) G = T |
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Term
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Definition
6) The elongation of the leading strand during DNA synthesis
A) progresses away from the replication fork.
B) occurs in the 3' 5' direction.
C) produces Okazaki fragments.
D) depends on the action of DNA polymerase.
E) does not require a template strand. |
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Term
|
Definition
7) The spontaneous loss of amino groups from adenine results in hypoxanthine, an uncommon
base, opposite thymine in DNA. What combination of molecules could repair such damage?
A) nuclease, DNA polymerase, DNA ligase
B) telomerase, primase, DNA polymerase
C) telomerase, helicase, single-strand binding protein
D) DNA ligase, replication fork proteins, adenylyl cyclase
E) nuclease, telomerase, primase |
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Term
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Definition
8) In a nucleosome, the DNA is wrapped around
A) polymerase molecules.
B) ribosomes.
C) histones.
D) a thymine dimer.
E) satellite DNA. |
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Term
Answer: A
Topic: Concept 17.1
Skill: Knowledge/Comprehension |
|
Definition
1) Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because
A) genes dictate the production of specific enzymes, and affected individuals have genetic
defects that cause them to lack certain enzymes.
B) enzymes are made of DNA, and affected individuals lack DNA polymerase.
C) many metabolic enzymes use DNA as a cofactor, and affected individuals have mutations that
prevent their enzymes from interacting efficiently with DNA.
D) certain metabolic reactions are carried out by ribozymes, and affected individuals lack key
splicing factors.
E) metabolic enzymes require vitamin cofactors, and affected individuals have significant
nutritional deficiencies. |
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Term
Answer: C
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
Figure 17.1
2) According to Beadle and Tatum's hypothesis, how many genes are necessary for this
pathway?
A) 0
B) 1
C) 2
D) 3
E) It cannot be determined from the pathway. |
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Term
Answer: A
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
3) A mutation results in a defective enzyme A. Which of the following would be a consequence
of that mutation?
A) an accumulation of A and no production of B and C
B) an accumulation of A and B and no production of C
C) an accumulation of B and no production of A and C
D) an accumulation of B and C and no production of A
E) an accumulation of C and no production of A and B |
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Term
Answer: C
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
4) If A, B, and C are all required for growth, a strain that is mutant for the gene encoding enzyme
A would be able to grow on which of the following media?
A) minimal medium
B) minimal medium supplemented with nutrient "A" only
C) minimal medium supplemented with nutrient "B" only
D) minimal medium supplemented with nutrient "C" only
E) minimal medium supplemented with nutrients "A" and "C" |
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Term
Answer: D
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
5) If A, B, and C are all required for growth, a strain mutant for the gene encoding enzyme B
would be capable of growing on which of the following media?
A) minimal medium
B) minimal medium supplemented with "A" only
C) minimal medium supplemented with "B" only
D) minimal medium supplemented with "C" only
E) minimal medium supplemented with nutrients "A" and "B" |
|
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Term
Answer: C
Topic: Concept 17.1
Skill: Knowledge/Comprehension |
|
Definition
6) The nitrogenous base adenine is found in all members of which group?
A) proteins, triglycerides, and testosterone
B) proteins, ATP, and DNA
C) ATP, RNA, and DNA
D) alpha glucose, ATP, and DNA
E) proteins, carbohydrates, and ATP |
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Term
Answer: B
Topic: Concept 17.1
Skill: Knowledge/Comprehension |
|
Definition
7) Using RNA as a template for protein synthesis instead of translating proteins directly from the
DNA is advantageous for the cell because
A) RNA is much more stable than DNA.
B) RNA acts as an expendable copy of the genetic material.
C) only one mRNA molecule can be transcribed from a single gene, lowering the potential rate
of gene expression.
D) tRNA, rRNA and others are not transcribed.
E) mRNA molecules are subject to mutation but DNA is not. |
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Term
Answer: B
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
8) If proteins were composed of only 12 different kinds of amino acids, what would be the
smallest possible codon size in a genetic system with four different nucleotides?
A) 1
B) 2
C) 3
D) 4
E) 12 |
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Term
Answer: C
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
9) The enzyme polynucleotide phosphorylase randomly assembles nucleotides into a
polynucleotide polymer. You add polynucleotide phosphorylase to a solution of adenosine
triphosphate and guanosine triphosphate. How many artificial mRNA 3 nucleotide codons would
be possible?
A) 3
B) 4
C) 8
D) 16
E) 64 |
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Term
Answer: A
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
10) A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding
codon for the mRNA transcribed is
A) 3' UCA 5'.
B) 3' UGA 5'.
C) 5' TCA 3'.
D) 3'ACU 5'.
E) either UCA or TCA, depending on wobble in the first base. |
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Term
Answer: E
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
Figure 17.2
11) A possible sequence of nucleotides in the template strand of DNA that would code for the
polypeptide sequence phe-leu-ile-val would be
A) 5' TTG-CTA-CAG-TAG 3'.
B) 3' AAC-GAC-GUC-AUA 5'.
C) 5' AUG-CTG-CAG-TAT 3'.
D) 3' AAA-AAT-ATA-ACA 5'.
E) 3' AAA-GAA-TAA-CAA 5'. |
|
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Term
Answer: D
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
12) What amino acid sequence will be generated, based on the following mRNA codon
sequence?
5' AUG-UCU-UCG-UUA-UCC-UUG 3'
A) met-arg-glu-arg-glu-arg
B) met-glu-arg-arg-gln-leu
5
C) met-ser-leu-ser-leu-ser
D) met-ser-ser-leu-ser-leu
E) met-leu-phe-arg-glu-glu |
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Term
Answer: C
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
13) A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following
sequences in the coding strand of the DNA could code for this peptide?
A) 3' UUU-CCC-AAA-GGG-UUU-CCC
B) 3' AUG-AAA-GGG-TTT-CCC-AAA-GGG
C) 5' TTT-CCC-AAA-GGG-TTT-CCC
D) 5' GGG-AAA-TTT-AAA-CCC-ACT-GGG
E) 5' ACT-TAC-CAT-AAA-CAT-TAC-UGA |
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Term
Answer: E
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
14) What is the sequence of a peptide based on the following mRNA sequence?
5' . . . UUUUCUUAUUGUCUU 3'
A) leu-cys-tyr-ser-phe
B) cyc-phe-tyr-cys-leu
C) phe-leu-ile-met-val
D) leu-pro-asp-lys-gly
E) phe-ser-tyr-cys-leu |
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Term
Answer: C
Topic: Concept 17.1
Skill: Synthesis/Evaluation |
|
Definition
15) The genetic code is essentially the same for all organisms. From this, one can logically
assume all of the following except
A) a gene from an organism could theoretically be expressed by any other organism.
B) all organisms have a common ancestor.
C) DNA was the first genetic material.
D) the same codons in different organisms usually translate into the same amino acids.
E) different organisms have the same number of different types of amino acids. |
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Term
Answer: A
Topic: Concept 17.1
Skill: Synthesis/Evaluation |
|
Definition
16) The "universal" genetic code is now known to have exceptions. Evidence for this could be
found if which of the following is true?
A) If UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually
coded for by UGG only).
6
B) If one stop codon, such as UGA, is found to have a different effect on translation than another
stop codon, such as UAA.
C) If prokaryotic organisms are able to translate a eukaryotic mRNA and produce the same
polypeptide.
D) If several codons are found to translate to the same amino acid, such as serine.
E) If a single mRNA molecule is found to translate to more than one polypeptide when there are
two or more AUG sites. |
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Term
Answer: D
Topic: Concept 17.1
Skill: Application/Analysis |
|
Definition
17) Which of the following nucleotide triplets best represents a codon?
A) a triplet separated spatially from other triplets
B) a triplet that has no corresponding amino acid
C) a triplet at the opposite end of tRNA from the attachment site of the amino acid
D) a triplet in the same reading frame as an upstream AUG
E) a sequence in tRNA at the 3' end |
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Term
Answer: C
Topic: Concept 17.2
Skill: Knowledge/Comprehension |
|
Definition
18) Which of the following is true for both prokaryotic and eukaryotic gene expression?
A) After transcription, a 3' poly-A tail and a 5' cap are added to mRNA.
B) Translation of mRNA can begin before transcription is complete.
C) RNA polymerase binds to the promoter region to begin transcription.
D) mRNA is synthesized in the 3' 5' direction.
E) The mRNA transcript is the exact complement of the gene from which it was copied. |
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Term
Answer: D
Topic: Concept 17.2
Skill: Knowledge/Comprehension |
|
Definition
19) In which of the following actions does RNA polymerase differ from DNA polymerase?
A) RNA polymerase uses RNA as a template, and DNA polymerase uses a DNA template.
B) RNA polymerase binds to single-stranded DNA, and DNA polymerase binds to doublestranded
DNA.
C) RNA polymerase is much more accurate than DNA polymerase.
D) RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to
initiate DNA synthesis.
E) RNA polymerase does not need to separate the two strands of DNA in order to synthesize an
RNA copy, whereas DNA polymerase must unwind the double helix before it can replicate the
DNA. |
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Term
Answer: B
Topic: Concept 17.2
Skill: Knowledge/Comprehension |
|
Definition
20) Which of the following statements best describes the termination of transcription in
prokaryotes?
A) RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate
with the transcript and cut it free from the polymerase.
B) RNA polymerase transcribes through the terminator sequence, causing the polymerase to fall
off the DNA and release the transcript.
C) RNA polymerase transcribes through an intron, and the snRNPs cause the polymerase to let
go of the transcript.
D) Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the
chromosome.
E) RNA polymerase transcribes through a stop codon, causing the polymerase to stop advancing
through the gene and release the mRNA. |
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Term
Answer: A
Topic: Concept 17.2
Skill: Knowledge/Comprehension |
|
Definition
21) RNA polymerase moves in which direction along the DNA?
A) 3' 5' along the template strand
B) 3' 5' along the coding (sense) strand
C) 5' 3' along the template strand
D) 3' 5' along the coding strand
E) 5' 3' along the double-stranded DNA |
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Term
Answer: B
Topic: Concept 17.2
Skill: Synthesis/Evaluation |
|
Definition
22) RNA polymerase in a prokaryote is composed of several subunits. Most of these subunits are
the same for the transcription of any gene, but one, known as sigma, varies considerably. Which
of the following is the most probable advantage for the organism of such sigma switching?
A) It might allow the transcription process to vary from one cell to another.
B) It might allow the polymerase to recognize different promoters under certain environmental
conditions.
C) It could allow the polymerase to react differently to each stop codon.
D) It could allow ribosomal subunits to assemble at faster rates.
E) It could alter the rate of translation and of exon splicing. |
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Term
Answer: B
Topic: Concept 17.2
Skill: Knowledge/Comprehension |
|
Definition
23) Which of these is the function of a poly (A) signal sequence?
A) It adds the poly (A) tail to the 3' end of the mRNA.
B) It codes for a sequence in eukaryotic transcripts that signals enzymatic cleavage ~10—35
nucleotides away.
C) It allows the 3' end of the mRNA to attach to the ribosome.
8
D) It is a sequence that codes for the hydrolysis of the RNA polymerase.
E) It adds a 7-methylguanosine cap to the 3' end of the mRNA. |
|
|
Term
Answer: C
Topic: Concept 17.2
Skill: Knowledge/Comprehension |
|
Definition
24) In eukaryotes there are several different types of RNA polymerase. Which type is involved in
transcription of mRNA for a globin protein?
A) ligase
B) RNA polymerase I
C) RNA polymerase II
D) RNA polymerase III
E) primase |
|
|
Term
Answer: D
Topic: Concept 17.2
Skill: Knowledge/Comprehension |
|
Definition
25) Transcription in eukaryotes requires which of the following in addition to RNA polymerase?
A) the protein product of the promoter
B) start and stop codons
C) ribosomes and tRNA
D) several transcription factors (TFs)
E) aminoacyl synthetase |
|
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Term
Answer: C
Topic: Concept 17.2
Skill: Synthesis/Evaluation |
|
Definition
26) A part of the promoter, called the TATA box, is said to be highly conserved in evolution.
Which might this illustrate?
A) The sequence evolves very rapidly.
B) The sequence does not mutate.
C) Any mutation in the sequence is selected against.
D) The sequence is found in many but not all promoters.
E) The sequence is transcribed at the start of every gene. |
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Term
Answer: A
Topic: Concept 17.2
Skill: Synthesis/Evaluation |
|
Definition
27) The TATA sequence is found only several nucleotides away from the start site of
transcription. This most probably relates to which of the following?
A) the number of hydrogen bonds between A and T in DNA
B) the triplet nature of the codon
C) the ability of this sequence to bind to the start site
D) the supercoiling of the DNA near the start site
9
E) the 3-dimensional shape of a DNA molecule |
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Term
Answer: C
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
28) Which of the following help(s) to stabilize mRNA by inhibiting its degradation?
A) TATA box
B) spliceosomes
C) 5' cap and poly (A) tail
D) introns
E) RNA polymerase |
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Term
Answer: B
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
29) What is a ribozyme?
A) an enzyme that uses RNA as a substrate
B) an RNA with enzymatic activity
C) an enzyme that catalyzes the association between the large and small ribosomal subunits
D) an enzyme that synthesizes RNA as part of the transcription process
E) an enzyme that synthesizes RNA primers during DNA replication |
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Term
Answer: B
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
30) What are the coding segments of a stretch of eukaryotic DNA called?
A) introns
B) exons
C) codons
D) replicons
E) transposons |
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Term
Answer: A
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
31) A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a
protein consisting of approximately 400 amino acids. This is best explained by the fact that
A) many noncoding stretches of nucleotides are present in mRNA.
B) there is redundancy and ambiguity in the genetic code.
C) many nucleotides are needed to code for each amino acid.
D) nucleotides break off and are lost during the transcription process.
E) there are termination exons near the beginning of mRNA. |
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Term
Answer: D
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
32) Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes
A) union with ribosomes.
B) fusion into circular forms known as plasmids.
C) linkage to histone molecules.
D) excision of introns.
E) fusion with other newly transcribed mRNA. |
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Term
Answer: A
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
33) Introns are significant to biological evolution because
A) their presence allows exons to be shuffled.
B) they protect the mRNA from degeneration.
C) they are translated into essential amino acids.
D) they maintain the genetic code by preventing incorrect DNA base pairings.
E) they correct enzymatic alterations of DNA bases. |
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Term
Answer: B
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
34) A mutation in which of the following parts of a gene is likely to be most damaging to a cell?
A) intron
B) exon
C) 5' UTR
D) 3' UTR
E) All would be equally damaging. |
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Term
Answer: C
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
35) Which of the following is (are) true of snRNPs?
A) They are made up of both DNA and RNA.
B) They bind to splice sites at each end of the exon.
C) They join together to form a large structure called the spliceosome.
D) They act only in the cytosol.
E) They attach introns to exons in the correct order. |
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Term
Answer: C
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
36) During splicing, which molecular component of the spliceosome catalyzes the excision
reaction?
A) protein
B) DNA
C) RNA
D) lipid
E) sugar |
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|
Term
Answer: B
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
37) Alternative RNA splicing
A) is a mechanism for increasing the rate of transcription.
B) can allow the production of proteins of different sizes from a single mRNA.
C) can allow the production of similar proteins from different RNAs.
D) increases the rate of transcription.
E) is due to the presence or absence of particular snRNPs. |
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Term
Answer: C
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
38) In the structural organization of many eukaryotic genes, individual exons may be related to
which of the following?
A) the sequence of the intron that immediately precedes each exon
B) the number of polypeptides making up the functional protein
C) the various domains of the polypeptide product
D) the number of restriction enzyme cutting sites
E) the number of start sites for transcription |
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Term
Answer: B
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
39) Each eukaryotic mRNA, even after post-transcriptional modification, includes 5' and 3'
UTRs. Which are these?
A) the cap and tail at each end of the mRNA
B) the untranslated regions at either end of the coding sequence
C) the U attachment sites for the tRNAs
D) the U translation sites that signal the beginning of translation
E) the U — A pairs that are found in high frequency at the ends |
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Term
Answer: D
Topic: Concept 17.3
Skill: Synthesis/Evaluation |
|
Definition
40) In an experimental situation, a student researcher inserts an mRNA molecule into a
eukaryotic cell after he has removed its 5' cap and poly(A) tail. Which of the following would
you expect him to find?
A) The mRNA could not exit the nucleus to be translated.
B) The cell recognizes the absence of the tail and polyadenylates the mRNA.
C) The molecule is digested by restriction enzymes in the nucleus.
D) The molecule is digested by exonucleases since it is no longer protected at the 5' end.
E) The molecule attaches to a ribosome and is translated, but more slowly. |
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Term
Answer: C
Topic: Concept 17.4
Skill: Application/Analysis |
|
Definition
41) A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the
tRNA that binds the mRNA codon is
A) TTT.
B) UUA.
C) UUU.
D) AAA.
E) either UAA or TAA, depending on first base wobble. |
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Term
Answer: E
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
42) Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on
specificity in the
A) binding of ribosomes to mRNA.
B) shape of the A and P sites of ribosomes.
C) bonding of the anticodon to the codon.
D) attachment of amino acids to tRNAs.
E) both C and D |
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|
Term
Answer: B
Topic: Concept 17.4
Skill: Application/Analysis |
|
Definition
12
40) In an experimental situation, a student researcher inserts an mRNA molecule into a
eukaryotic cell after he has removed its 5' cap and poly(A) tail. Which of the following would
you expect him to find?
A) The mRNA could not exit the nucleus to be translated.
B) The cell recognizes the absence of the tail and polyadenylates the mRNA.
C) The molecule is digested by restriction enzymes in the nucleus.
D) The molecule is digested by exonucleases since it is no longer protected at the 5' end.
E) The molecule attaches to a ribosome and is translated, but more slowly.
Answer: D
Topic: Concept 17.3
Skill: Synthesis/Evaluation
41) A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the
tRNA that binds the mRNA codon is
A) TTT.
B) UUA.
C) UUU.
D) AAA.
E) either UAA or TAA, depending on first base wobble.
Answer: C
Topic: Concept 17.4
Skill: Application/Analysis
42) Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on
specificity in the
A) binding of ribosomes to mRNA.
B) shape of the A and P sites of ribosomes.
C) bonding of the anticodon to the codon.
D) attachment of amino acids to tRNAs.
E) both C and D
Answer: E
Topic: Concept 17.4
Skill: Knowledge/Comprehension
43) A part of an mRNA molecule with the following sequence is being read by a ribosome: 5'
CCG-ACG 3' (mRNA). The following charged transfer RNA molecules (with their anticodons
shown in the 3' to 5' direction) are available. Two of them can correctly match the mRNA so that
a dipeptide can form.
13
Figure 17.3
The dipeptide that will form will be
A) cysteine-alanine.
B) proline-threonine.
C) glycine-cysteine.
D) alanine-alanine.
E) threonine-glycine. |
|
|
Term
Answer: C
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
44) What type of bonding is responsible for maintaining the shape of the tRNA molecule?
A) covalent bonding between sulfur atoms
B) ionic bonding between phosphates
C) hydrogen bonding between base pairs
D) van der Waals interactions between hydrogen atoms
E) peptide bonding between amino acids |
|
|
Term
Answer: D
Topic: Concept 17.4
Skill: Application/Analysis |
|
Definition
Figure 17.4
14
45) Figure 17.4 represents tRNA that recognizes and binds a particular amino acid (in this
instance, phenylalanine). Which codon on the mRNA strand codes for this amino acid?
A) UGG
B) GUG
C) GUA
D) UUC
E) CAU |
|
|
Term
Answer: B
Topic: Concept 17.3
Skill: Knowledge/Comprehension |
|
Definition
46) The tRNA shown in Figure 17.4 has its 3' end projecting beyond its 5' end. What will occur
at this 3' end?
A) The codon and anticodon complement one another.
B) The amino acid binds covalently.
C) The excess nucleotides (ACCA) will be cleaved off at the ribosome.
D) The small and large subunits of the ribosome will attach to it.
E) The 5' cap of the mRNA will become covalently bound. |
|
|
Term
Answer: B
Topic: Concept 17.4
Skill: Application/Analysis |
|
Definition
47) A mutant bacterial cell has a defective aminoacyl synthetase that attaches a lysine to tRNAs
with the anticodon AAA instead of a phenylalanine. The consequence of this for the cell will be
that
A) none of the proteins in the cell will contain phenylalanine.
B) proteins in the cell will include lysine instead of phenylalanine at amino acid positions
specified by the codon UUU.
C) the cell will compensate for the defect by attaching phenylalanine to tRNAs with lysinespecifying
anticodons.
D) the ribosome will skip a codon every time a UUU is encountered.
E) None of the above will occur; the cell will recognize the error and destroy the tRNA. |
|
|
Term
Answer: B
15
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
48) There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best
explained by the fact that
A) some tRNAs have anticodons that recognize four or more different codons.
B) the rules for base pairing between the third base of a codon and tRNA are flexible.
C) many codons are never used, so the tRNAs that recognize them are dispensable.
D) the DNA codes for all 61 tRNAs but some are then destroyed.
E) competitive exclusion forces some tRNAs to be destroyed by nucleases. |
|
|
Term
Answer: C
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
49) What is the most abundant type of RNA?
A) mRNA
B) tRNA
C) rRNA
D) pre-mRNA
E) hnRNA |
|
|
Term
Answer: E
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
50) From the following list, which is the first event in translation in eukaryotes?
A) elongation of the polypeptide
B) base pairing of activated methionine-tRNA to AUG of the messenger RNA
C) the larger ribosomal subunit binds to smaller ribosomal subunits
D) covalent bonding between the first two amino acids
E) the small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA |
|
|
Term
Answer: B
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
51) Choose the answer that has these events of protein synthesis in the proper sequence.
1. An aminoacyl-tRNA binds to the A site.
2. A peptide bond forms between the new amino acid and a polypeptide chain.
3. tRNA leaves the P site, and the P site remains vacant.
4. A small ribosomal subunit binds with mRNA.
5. tRNA translocates to the P site.
A) 1, 3, 2, 4, 5
B) 4, 1, 2, 5, 3
C) 5, 4, 3, 2, 1
D) 4, 1, 3, 2, 5
E) 2, 4, 5, 1, 3 |
|
|
Term
Answer: A
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
52) As a ribosome translocates along an mRNA molecule by one codon, which of the following
occurs?
A) The tRNA that was in the A site moves into the P site.
B) The tRNA that was in the P site moves into the A site.
C) The tRNA that was in the A site moves to the E site and is released.
D) The tRNA that was in the A site departs from the ribosome via a tunnel.
E) The polypeptide enters the E site. |
|
|
Term
Answer: A
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
53) What are polyribosomes?
A) groups of ribosomes reading a single mRNA simultaneously
B) ribosomes containing more than two subunits
C) multiple copies of ribosomes associated with giant chromosomes
D) aggregations of vesicles containing ribosomal RNA
E) ribosomes associated with more than one tRNA |
|
|
Term
Answer: D
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
54) Which of the following is a function of a signal peptide?
A) to direct an mRNA molecule into the cisternal space of the ER
B) to bind RNA polymerase to DNA and initiate transcription
C) to terminate translation of the messenger RNA
D) to translocate polypeptides across the ER membrane
E) to signal the initiation of transcription |
|
|
Term
Answer: B
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
55) When translating secretory or membrane proteins, ribosomes are directed to the ER
membrane by
A) a specific characteristic of the ribosome itself, which distinguishes free ribosomes from bound
ribosomes.
B) a signal-recognition particle that brings ribosomes to a receptor protein in the ER membrane.
C) moving through a specialized channel of the nucleus.
D) a chemical signal given off by the ER.
E) a signal sequence of RNA that precedes the start codon of the message. |
|
|
Term
Answer: B
17
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
56) When does translation begin in prokaryotic cells?
A) after a transcription initiation complex has been formed
B) as soon as transcription has begun
C) after the 5' caps are converted to mRNA
D) once the pre-mRNA has been converted to mRNA
E) as soon as the DNA introns are removed from the template |
|
|
Term
Answer: C
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
57) When a tRNA molecule is shown twisted into an L shape, the form represented is
A) its linear sequence.
B) its 2-dimensional shape.
C) its 3-dimensional shape.
D) its microscopic image. |
|
|
Term
Answer: C
Topic: Concept 17.4
Skill: Synthesis/Evaluation |
|
Definition
58) An experimenter has altered the 3' end of the tRNA corresponding to the amino acid
methionine in such a way as to remove the 3' AC. Which of the following hypotheses describes
the most likely result?
A) tRNA will not form a cloverleaf.
B) The nearby stem end will pair improperly.
C) The amino acid methionine will not bind.
D) The anticodon will not bind with the mRNA codon.
E) The aminoacylsynthetase will not be formed. |
|
|
Term
Answer: E
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to
the growing polypeptide on the other tRNA (#2) in the ribosome already.
59) Which enzyme causes a covalent bond to attach lysine to the polypeptide?
A) ATPase
B) lysine synthetase
C) RNA polymerase
D) ligase
E) peptidyl transferase |
|
|
Term
Answer: D
Topic: Concept 17.4
Skill: Application/Analysis |
|
Definition
A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to
the growing polypeptide on the other tRNA (#2) in the ribosome already.
60) Where does tRNA #2 move to after this bonding of lysine to the polypeptide?
A) A site
B) P site
C) E site
D) Exit tunnel
E) Directly to the cytosol |
|
|
Term
Answer: D
Topic: Concept 17.4
Skill: Application/Analysis |
|
Definition
A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to
the growing polypeptide on the other tRNA (#2) in the ribosome already.
61) Which component of the complex described enters the exit tunnel through the large subunit
of the ribosome?
A) tRNA with attached lysine (#1)
B) tRNA with polypeptide (#2)
C) tRNA that no longer has attached amino acid
D) newly formed polypeptide
E) initiation and elongation factors |
|
|
Term
Answer: B
Topic: Concept 17.4
Skill: Knowledge/Comprehension |
|
Definition
62) The process of translation, whether in prokaryotes or eukaryotes, requires tRNAs, amino
acids, ribosomal subunits, and which of the following?
A) polypeptide factors plus ATP
B) polypeptide factors plus GTP
C) polymerases plus GTP
D) SRP plus chaperones
E) signal peptides plus release factor |
|
|
Term
Answer: A
Topic: Concept 17.4
Skill: Synthesis/Evaluation |
|
Definition
63) When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the
A site. If the translation reaction were to be experimentally stopped at this point, which of the
following would you be able to isolate?
A) an assembled ribosome with a polypeptide attached to the tRNA in the P site
B) separated ribosomal subunits, a polypeptide, and free tRNA
C) an assembled ribosome with a separated polypeptide
D) separated ribosomal subunits with a polypeptide attached to the tRNA
E) a cell with fewer ribosomes |
|
|
Term
Answer: D
Topic: Concept 17.5
Skill: Synthesis/Evaluation |
|
Definition
64) Why might a point mutation in DNA make a difference in the level of protein's activity?
A) It might result in a chromosomal translocation.
B) It might exchange one stop codon for another stop codon.
C) It might exchange one serine codon for a different serine codon.
D) It might substitute an amino acid in the active site.
E) It might substitute the N terminus of the polypeptide for the C terminus. |
|
|
Term
Answer: D
Topic: Concept 17.5
Skill: Synthesis/Evaluation |
|
Definition
65) In the 1920s Muller discovered that X-rays caused mutation in Drosophila. In a related series
of experiments, in the 1940s, Charlotte Auerbach discovered that chemicals she used nitrogen
mustards have a similar effect. A new chemical food additive is developed by a cereal
manufacturer. Why do we test for its ability to induce mutation?
A) We worry that it might cause mutation in cereal grain plants.
B) We want to make sure that it does not emit radiation.
C) We want to be sure that it increases the rate of mutation sufficiently.
D) We want to prevent any increase in mutation frequency.
E) We worry about its ability to cause infection. |
|
|
Term
Answer: B
Topic: Concept 17.5
Skill: Application/Analysis |
|
Definition
66) Which of the following types of mutation, resulting in an error in the mRNA just after the
AUG start of translation, is likely to have the most serious effect on the polypeptide product?
A) a deletion of a codon
B) a deletion of 2 nucleotides
C) a substitution of the third nucleotide in an ACC codon
D) a substitution of the first nucleotide of a GGG codon
E) an insertion of a codon |
|
|
Term
Answer: C
Topic: Concept 17.5
Skill: Knowledge/Comprehension |
|
Definition
67) What is the effect of a nonsense mutation in a gene?
A) It changes an amino acid in the encoded protein.
B) It has no effect on the amino acid sequence of the encoded protein.
C) It introduces a premature stop codon into the mRNA.
D) It alters the reading frame of the mRNA.
E) It prevents introns from being excised. |
|
|
Term
Answer: D
Topic: Concept 17.5
Skill: Application/Analysis |
|
Definition
68) Each of the following options is a modification of the sentence THECATATETHERAT.
Which of the following is analogous to a frameshift mutation?
A) THERATATETHECAT
B) THETACATETHERAT
C) THECATARETHERAT
D) THECATATTHERAT
20
E) CATATETHERAT |
|
|
Term
Answer: C
Topic: Concept 17.5
Skill: Application/Analysis |
|
Definition
69) Each of the following options is a modification of the sentence THECATATETHERAT.
Which of the following is analogous to a single substitution mutation?
A) THERATATETHECAT
B) THETACATETHERAT
C) THECATARETHERAT
D) THECATATTHERAT
E) CATATETHERAT |
|
|
Term
Answer: A
Topic: Concept 17.5
Skill: Application/Analysis |
|
Definition
70) Sickle-cell disease is probably the result of which kind of mutation?
A) point
B) frameshift
C) nonsense
D) nondisjunction
E) both B and D |
|
|
Term
Answer: E
Topic: Concept 17.5
Skill: Knowledge/Comprehension |
|
Definition
71) A frameshift mutation could result from
A) a base insertion only.
B) a base deletion only.
C) a base substitution only.
D) deletion of three consecutive bases.
E) either an insertion or a deletion of a base. |
|
|
Term
Answer: A
Topic: Concept 17.5
Skill: Knowledge/Comprehension |
|
Definition
72) Which of the following DNA mutations is the most likely to be damaging to the protein it
specifies?
A) a base-pair deletion
B) a codon substitution
C) a substitution in the last base of a codon
D) a codon deletion
E) a point mutation |
|
|
Term
Answer: B
Topic: Concept 17.5
Skill: Knowledge/Comprehension |
|
Definition
73) Which point mutation would be most likely to have a catastrophic effect on the functioning
of a protein?
A) a base substitution
B) a base deletion near the start of a gene
C) a base deletion near the end of the coding sequence, but not in the terminator codon
D) deletion of three bases near the start of the coding sequence, but not in the initiator codon
E) a base insertion near the end of the coding sequence, but not in the terminator codon |
|
|
Term
Answer: B
Topic: Concept 17.6
Skill: Knowledge/Comprehension |
|
Definition
74) Which of the following statements are true about protein synthesis in prokaryotes?
A) Extensive RNA processing is required before prokaryotic transcripts can be translated.
B) Translation can begin while transcription is still in progress.
C) Prokaryotic cells have complicated mechanisms for targeting proteins to the appropriate
cellular organelles.
D) Translation requires antibiotic activity.
E) Unlike eukaryotes, prokaryotes require no initiation or elongation factors. |
|
|
Term
Answer: E
Topic: Concept 17.6
Skill: Knowledge/Comprehension |
|
Definition
75) Gene expression in Archaea differs from that in other prokaryotes. It shares features with
which of the following?
A) eubacteria only
B) eukaryotes only
C) protists only
D) fungi only
E) bacteria and eukaryotes |
|
|
Term
Answer: C
22
Topic: Concept 17.6
Skill: Knowledge/Comprehension |
|
Definition
76) Of the following, which is the most current description of a gene?
A) a unit of heredity that causes formation of a phenotypic characteristic
B) a DNA subunit that codes for a single complete protein
C) a DNA sequence that is expressed to form a functional product: either RNA or polypeptide
D) a DNA—RNA sequence combination that results in an enzymatic product
E) a discrete unit of hereditary information that consists of a sequence of amino acids |
|
|
Term
|
Definition
1) In eukaryotic cells, transcription cannot begin until
A) the two DNA strands have completely separated and exposed the promoter.
B) several transcription factors have bound to the promoter.
C) the 5' caps are removed from the mRNA.
D) the DNA introns are removed from the template.
E) DNA nucleases have isolated the transcription unit. |
|
|
Term
|
Definition
2) Which of the following is not true of a codon?
A) It consists of three nucleotides.
B) It may code for the same amino acid as another codon.
C) It never codes for more than one amino acid.
D) It extends from one end of a tRNA molecule.
E) It is the basic unit of the genetic code. |
|
|
Term
|
Definition
3) The anticodon of a particular tRNA molecule is
A) complementary to the corresponding mRNA codon.
B) complementary to the corresponding triplet in rRNA.
C) the part of tRNA that bonds to a specific amino acid.
D) changeable, depending on the amino acid that attaches to the tRNA.
E) catalytic, making the tRNA a ribozyme. |
|
|
Term
|
Definition
4) Which of the following is not true of RNA processing?
A) Exons are cut out before mRNA leaves the nucleus.
B) Nucleotides may be added at both ends of the RNA.
C) Ribozymes may function in RNA splicing.
D) RNA splicing can be catalyzed by spliceosomes.
E) A primary transcript is often much longer than the final RNA molecule that leaves the
nucleus. |
|
|
Term
|
Definition
5) Using Figure 17.5, identify a 5' 3' sequence of nucleotides in the DNA template strand for
an mRNA coding for the polypeptide sequence Phe-Pro-Lys.
A) 5'-UUUGGGAAA-3'
B) 5'-GAACCCCTT-3'
C) 5'-AAAACCTTT-3'
D) 5'-CTTCGGGAA-3'
E) 5'-AAACCCUUU-3' |
|
|
Term
|
Definition
6) Which of the following mutations would be most likely to have a harmful effect on an
organism?
A) a base-pair substitution
B) a deletion of three nucleotides near the middle of a gene
C) a single nucleotide deletion in the middle of an intron
D) a single nucleotide deletion near the end of the coding sequence
E) a single nucleotide insertion downstream of, and close to, the start of the coding sequence |
|
|
Term
|
Definition
7) Which component is not directly involved in translation?
A) mRNA
B) DNA
C) tRNA
D) ribosomes
E) GTP |
|
|
Term
Answer: A
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
1) What does the operon model attempt to explain?
A) the coordinated control of gene expression in bacteria
B) bacterial resistance to antibiotics
C) how genes move between homologous regions of DNA
D) the mechanism of viral attachment to a host cell
E) horizontal transmission of plant viruses |
|
|
Term
Answer: E
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
2) The role of a metabolite that controls a repressible operon is to
A) bind to the promoter region and decrease the affinity of RNA polymerase for the promoter.
B) bind to the operator region and block the attachment of RNA polymerase to the promoter.
C) increase the production of inactive repressor proteins.
D) bind to the repressor protein and inactivate it.
E) bind to the repressor protein and activate it. |
|
|
Term
Answer: E
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
3) The tryptophan operon is a repressible operon that is
A) permanently turned on.
B) turned on only when tryptophan is present in the growth medium.
C) turned off only when glucose is present in the growth medium.
D) turned on only when glucose is present in the growth medium.
E) turned off whenever tryptophan is added to the growth medium. |
|
|
Term
Answer: D
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
4) This protein is produced by a regulatory gene:
A) operon
B) inducer
C) promoter
D) repressor
E) corepressor |
|
|
Term
Answer: C
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
5) A mutation in this section of DNA could influence the binding of RNA polymerase to the
DNA:
A) operon
B) inducer
C) promoter
D) repressor
E) corepressor |
|
|
Term
Answer: E
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
6) A lack of this nonprotein molecule would result in the inability of the cell to "turn off" genes:
A) operon
B) inducer
C) promoter
D) repressor
E) corepressor |
|
|
Term
Answer: B
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
7) When this is taken up by the cell, it binds to the repressor so that the repressor no longer binds
to the operator:
A) operon
B) inducer
C) promoter
D) repressor
E) corepressor |
|
|
Term
Answer: A
Topic: Concept 18.1
Skill: Application/Analysis |
|
Definition
8) A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell would
result in
A) continuous transcription of the structural gene controlled by that regulator.
B) complete inhibition of transcription of the structural gene controlled by that regulator.
C) irreversible binding of the repressor to the operator.
D) inactivation of RNA polymerase by alteration of its active site.
E) continuous translation of the mRNA because of alteration of its structure. |
|
|
Term
Answer: D
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
9) The lactose operon is likely to be transcribed when
A) there is more glucose in the cell than lactose.
B) the cyclic AMP levels are low.
C) there is glucose but no lactose in the cell.
D) the cyclic AMP and lactose levels are both high within the cell.
E) the cAMP level is high and the lactose level is low. |
|
|
Term
Answer: B
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
10) Transcription of the structural genes in an inducible operon
A) occurs continuously in the cell.
B) starts when the pathway's substrate is present.
C) starts when the pathway's product is present.
D) stops when the pathway's product is present.
E) does not result in the production of enzymes. |
|
|
Term
Answer: D
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
11) How does active CAP induce expression of the genes of the lactose operon?
A) It terminates production of repressor molecules.
B) It degrades the substrate allolactose.
C) It stimulates splicing of the encoded genes.
D) It stimulates the binding of RNA polymerase to the promoter.
E) It binds steroid hormones and controls translation. |
|
|
Term
Answer: C
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
12) For a repressible operon to be transcribed, which of the following must occur?
A) A corepressor must be present.
B) RNA polymerase and the active repressor must be present.
C) RNA polymerase must bind to the promoter, and the repressor must be inactive.
D) RNA polymerase cannot be present, and the repressor must be inactive.
E) RNA polymerase must not occupy the promoter, and the repressor must be inactive. |
|
|
Term
Answer: B
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
13) Allolactose induces the synthesis of the enzyme lactase. An E. coli cell is presented for the
first time with the sugar lactose (containing allolactose) as a potential food source. Which of the
following occurs when the lactose enters the cell?
A) The repressor protein attaches to the regulator.
B) Allolactose binds to the repressor protein.
C) Allolactose binds to the regulator gene.
D) The repressor protein and allolactose bind to RNA polymerase.
E) RNA polymerase attaches to the regulator. |
|
|
Term
Answer: C
Topic: Concept 18.1
Skill: Synthesis/Evaluation |
|
Definition
14) Altering patterns of gene expression in prokaryotes would most likely serve the organism's
survival in which of the following ways?
A) organizing gene expression so that genes are expressed in a given order
B) allowing each gene to be expressed an equal number of times
C) allowing the organism to adjust to changes in environmental conditions
D) allowing young organisms to respond differently from more mature organisms
E) allowing environmental changes to alter the prokaryote's genome |
|
|
Term
Answer: B
Topic: Concept 18.1
Skill: Knowledge/Comprehension |
|
Definition
15) In response to chemical signals, prokaryotes can do which of the following?
A) turn off translation of their mRNA
B) alter the level of production of various enzymes
C) increase the number and responsiveness of their ribosomes
D) inactivate their mRNA molecules
E) alter the sequence of amino acids in certain proteins |
|
|
Term
Answer: D
Topic: Concept 18.1
Skill: Application/Analysis |
|
Definition
16) If she moves the promoter for the lac operon to the region between the beta galactosidase
gene and the permease gene, which of the following would be likely?
A) Three structural genes will no longer be expressed.
B) RNA polymerase will no longer transcribe permease.
C) The operon will no longer be inducible.
D) Beta galactosidase will be produced.
E) The cell will continue to metabolize but more slowly. |
|
|
Term
Answer: D
Topic: Concept 18.1
Skill: Application/Analysis |
|
Definition
17) If she moves the operator to the far end of the operon (past the transacetylase gene), which of
the following would likely occur when the cell is exposed to lactose?
A) The inducer will no longer bind to the repressor.
B) The repressor will no longer bind to the operator.
C) The operon will never be transcribed.
D) The structural genes will be transcribed continuously.
E) The repressor protein will no longer be produced |
|
|
Term
Answer: E
Topic: Concept 18.1
Skill: Application/Analysis |
|
Definition
18) If she moves the repressor gene (lac I), along with its promoter, to a position at some several
thousand base pairs away from its normal position, which will you expect to occur?
A) The repressor will no longer be made.
B) The repressor will no longer bind to the operator.
C) The repressor will no longer bind to the inducer.
D) The lac operon will be expressed continuously.
E) The lac operon will function normally. |
|
|
Term
Answer: E
Topic: Concept 18.1
Skill: Synthesis/Evaluation |
|
Definition
19) If glucose is available in the environment of E. coli, the cell responds with very low
concentration of cAMP. When the cAMP increases in concentration, it binds to CAP. Which of
the following would you expect would then be a measurable effect?
A) decreased concentration of the lac enzymes
B) increased concentration of the trp enzymes
C) decreased binding of the RNA polymerase to sugar metabolism-related promoters
D) decreased concentration of alternative sugars in the cell
E) increased concentrations of sugars such as arabinose in the cell |
|
|
Term
Answer: D
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
|
Definition
20) Muscle cells and nerve cells in one species of animal owe their differences in structure to
A) having different genes.
B) having different chromosomes.
C) using different genetic codes.
D) having different genes expressed.
E) having unique ribosomes. |
|
|
Term
Answer: A
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
|
Definition
21) Which of the following mechanisms is (are) used to coordinately control the expression of
multiple, related genes in eukaryotic cells?
A) organization of the genes into clusters, with local chromatin structures influencing the
expression of all the genes at once
B) each of the genes sharing a common control element, allowing several activators to turn on
their transcription, regardless of their location in the genome
C) organizing the genes into large operons, allowing them to be transcribed as a single unit
D) a single repressor able to turn off several related genes
E) environmental signals that enter the cell and bind directly to their promoters |
|
|
Term
Answer: C
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
|
Definition
22) If you were to observe the activity of methylated DNA, you would expect it to
A) be replicating nearly continuously.
B) be unwinding in preparation for protein synthesis.
C) have turned off or slowed down the process of transcription.
D) be very actively transcribed and translated.
E) induce protein synthesis by not allowing repressors to bind to it. |
|
|
Term
Answer: D
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
|
Definition
23) Genomic imprinting, DNA methylation, and histone acetylation are all examples of
A) genetic mutation.
B) chromosomal rearrangements.
C) karyotypes.
D) epigenetic phenomena.
E) translocation. |
|
|
Term
Answer: E
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
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Definition
24) Approximately what proportion of the DNA in the human genome codes for proteins or
functional RNA?
A) 83%
B) 46%
C) 32%
D) 13%
E) 1.5% |
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Term
Answer: D
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
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Definition
25) Two potential devices that eukaryotic cells use to regulate transcription are
A) DNA methylation and histone amplification.
B) DNA amplification and histone methylation.
C) DNA acetylation and methylation.
D) DNA methylation and histone acetylation.
E) histone amplification and DNA acetylation. |
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Term
Answer: A
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
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Definition
26) In both eukaryotes and prokaryotes, gene expression is primarily regulated at the level of
A) transcription.
B) translation.
C) mRNA stability.
D) mRNA splicing.
E) protein stability. |
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Term
Answer: E
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
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Definition
27) In eukaryotes, transcription is generally associated with
A) euchromatin only.
B) heterochromatin only.
C) very tightly packed DNA only.
D) highly methylated DNA only.
E) both euchromatin and histone acetylation. |
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Term
Answer: A
Topic: Concept 18.2
Skill: Application/Analysis |
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Definition
28) A geneticist introduces a transgene into yeast cells and isolates five independent cell lines in
which the transgene has integrated into the yeast genome. In four of the lines, the transgene is
expressed strongly, but in the fifth there is no expression at all. Which is a likely explanation for
the lack of transgene expression in the fifth cell line?
A) A transgene integrated into a heterochromatic region of the genome.
B) A transgene integrated into a euchromatic region of the genome.
C) The transgene was mutated during the process of integration into the host cell genome.
D) The host cell lacks the enzymes necessary to express the transgene.
E) A transgene integrated into a region of the genome characterized by high histone acetylation. |
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Term
Answer: C
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
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Definition
29) During DNA replication,
A) all methylation of the DNA is lost at the first round of replication.
B) DNA polymerase is blocked by methyl groups, and methylated regions of the genome are
therefore left uncopied.
C) methylation of the DNA is maintained because methylation enzymes act at DNA sites where
one strand is already methylated and thus correctly methylates daughter strands after replication.
D) methylation of the DNA is maintained because DNA polymerase directly incorporates
methylated nucleotides into the new strand opposite any methylated nucleotides in the template.
E) methylated DNA is copied in the cytoplasm, and unmethylated DNA in the nucleus. |
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Term
Answer: A
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
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Definition
30) Eukaryotic cells can control gene expression by which of the following mechanisms?
A) histone acetylation of nucleosomes
B) DNA acetylation
C) RNA induced modification of chromatin structure
D) repression of operons
E) induction of operators in the promoter |
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Term
Answer: B
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
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Definition
31) In eukaryotes, general transcription factors
A) are required for the expression of specific protein-encoding genes.
B) bind to other proteins or to a sequence element within the promoter called the TATA box.
C) inhibit RNA polymerase binding to the promoter and begin transcribing.
D) usually lead to a high level of transcription even without additional specific transcription
factors.
E) bind to sequences just after the start site of transcription. |
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Term
Answer: C
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
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Definition
32) This binds to a site in the DNA far from the promoter to stimulate transcription:
A) enhancer
B) promoter
C) activator
D) repressor
E) terminator |
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Term
Answer: D
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
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Definition
33) This can inhibit transcription by blocking the binding of positively acting transcription
factors to the DNA:
A) enhancer
B) promoter
C) activator
D) repressor
E) terminator |
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Term
Answer: E
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
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Definition
34) This is the site in the DNA located near the end of the final exon, encoding an RNA
sequence that determines the 3' end of the transcript:
A) enhancer
B) promoter
C) activator
D) repressor
E) terminator |
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Term
Answer: D
Topic: Concept 18.2
Skill: Knowledge/Comprehension |
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Definition
35) Steroid hormones produce their effects in cells by
A) activating key enzymes in metabolic pathways.
B) activating translation of certain mRNAs.
C) promoting the degradation of specific mRNAs.
D) binding to intracellular receptors and promoting transcription of specific genes.
E) promoting the formation of looped domains in certain regions of DNA. |
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Term
Answer: B
Topic: Concept 18.2
Skill: Application/Analysis |
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Definition
36) A researcher found a method she could use to manipulate and quantify phosphorylation and
methylation in embryonic cells in culture. In one set of experiments using this procedure in
Drosophila, she was readily successful in increasing phosphorylation of amino acids adjacent to
methylated amino acids in histone tails. Which of the following results would she most likely
see?
A) increased chromatin condensation
B) decreased chromatin concentration
C) abnormalities of mouse embryos
D) decreased binding of transcription factors
E) inactivation of the selected genes |
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Term
Answer: A
Topic: Concept 18.2
Skill: Application/Analysis |
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Definition
37) A researcher found a method she could use to manipulate and quantify phosphorylation and
methylation in embryonic cells in culture. In one set of experiments she succeeded in decreasing
methylation of histone tails. Which of the following results would she most likely see?
A) increased chromatin condensation
B) decreased chromatin concentration
C) abnormalities of mouse embryos
D) decreased binding of transcription factors
E) inactivation of the selected genes |
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Term
Answer: E
Topic: Concept 18.2
Skill: Application/Analysis |
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Definition
38) A researcher found a method she could use to manipulate and quantify phosphorylation and
methylation in embryonic cells in culture. One of her colleagues suggested she try increased
methylation of C nucleotides in a mammalian system. Which of the following results would she
most likely see?
A) increased chromatin condensation
B) decreased chromatin concentration
C) abnormalities of mouse embryos
D) decreased binding of transcription factors
E) inactivation of the selected genes |
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Term
Answer: C
Topic: Concept 18.2
Skill: Application/Analysis |
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Definition
39) A researcher found a method she could use to manipulate and quantify phosphorylation and
methylation in embryonic cells in culture. She tried decreasing the amount of methylation
enzymes in the embryonic stem cells and then allowed the cells to further differentiate. Which of
the following results would she most likely see?
A) increased chromatin condensation
B) decreased chromatin concentration
C) abnormalities of mouse embryos
D) decreased binding of transcription factors
E) inactivation of the selected genes |
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Term
Answer: D
Topic: Concept 18.2
Skill: Synthesis/Evaluation |
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Definition
40) Transcription factors in eukaryotes usually have DNA binding domains as well as other
domains also specific for binding. In general, which of the following would you expect many of
them to be able to bind?
A) repressors
B) ATP
C) protein-based hormones
D) other transcription factors
E) tRNA |
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Term
Answer: C
Topic: Concept 18.2
Skill: Synthesis/Evaluation |
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Definition
41) Gene expression might be altered at the level of post-transcriptional processing in eukaryotes
rather than prokaryotes because of which of the following?
A) Eukaryotic mRNAs get 5' caps and 3' tails.
B) Prokaryotic genes are expressed as mRNA, which is more stable in the cell.
C) Eukaryotic exons may be spliced in alternative patterns.
D) Prokaryotes use ribosomes of different structure and size.
E) Eukaryotic coded polypeptides often require cleaving of signal sequences before localization. |
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Term
Answer: B
Topic: Concept 18.2
Skill: Synthesis/Evaluation |
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Definition
42) Which of the following experimental procedures is most likely to hasten mRNA degradation
in a eukaryotic cell?
A) enzymatic shortening of the poly(A) tail
B) removal of the 5' cap
C) methylation of C nucleotides
D) memethylation of histones
E) removal of one or more exons |
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Term
Answer: A
Topic: Concept 18.2
Skill: Synthesis/Evaluation |
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Definition
43) Which of the following is most likely to have a small protein called ubiquitin attached to it?
A) a cyclin that usually acts in G1, now that the cell is in G2
B) a cell surface protein that requires transport from the ER
C) an mRNA that is leaving the nucleus to be translated
D) a regulatory protein that requires sugar residues to be attached
E) an mRNA produced by an egg cell that will be retained until after fertilization |
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Term
Answer: A
Topic: Concept 18.3
Skill: Knowledge/Comprehension |
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Definition
44) The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence
complementary to an introduced double-stranded RNA is called
A) RNA interference.
B) RNA obstruction.
C) RNA blocking.
D) RNA targeting.
E) RNA disposal. |
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Term
Answer: D
Topic: Concept 18.3
Skill: Knowledge/Comprehension |
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Definition
45) At the beginning of this century there was a general announcement regarding the sequencing
of the human genome and the genomes of many other multicellular eukaryotes. There was
surprise expressed by many that the number of protein-coding sequences is much smaller than
they had expected. Which of the following accounts for most of the rest?
A) "junk" DNA that serves no possible purpose
B) rRNA and tRNA coding sequences
C) DNA that is translated directly without being transcribed
D) non-protein coding DNA that is transcribed into several kinds of small RNAs with biological
function
E) non-protein coding DNA that is transcribed into several kinds of small RNAs without
biological function |
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Term
Answer: A
Topic: Concept 18.3
Skill: Knowledge/Comprehension |
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Definition
46) Which of the following best describes siRNA?
A) a short double-stranded RNA, one of whose strands can complement and inactivate a
sequence of mRNA
B) a single-stranded RNA that can, where it has internal complementary base pairs, fold into
cloverleaf patterns
C) a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor
D) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or
small subunits
E) a molecule, known as Dicer, that can degrade other mRNA sequences |
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Term
Answer: C
Topic: Concept 18.3
Skill: Synthesis/Evaluation |
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Definition
47) One of the hopes for use of recent knowledge gained about non-coding RNAs lies with the
possibilities for their use in medicine. Of the following scenarios for future research, which
would you expect to gain most from RNAs?
A) exploring a way to turn on the expression of pseudogenes
B) targeting siRNAs to disable the expression of an allele associated with autosomal recessive
disease
C) targeting siRNAs to disable the expression of an allele associated with autosomal dominant
disease
D) creating knock-out organisms that can be useful for pharmaceutical drug design
E) looking for a way to prevent viral DNA from causing infection in humans |
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Term
Answer: D
Topic: Concept 18.3
Skill: Knowledge/Comprehension |
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Definition
48) Which of the following describes the function of an enzyme known as Dicer?
A) It degrades single-stranded DNA.
B) It degrades single-stranded mRNA.
C) It degrades mRNA with no poly(A) tail.
D) It trims small double-stranded RNAs into molecules that can block translation.
E) It chops up single-stranded DNAs from infecting viruses. |
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Term
Answer: C
Topic: Concept 18.3
Skill: Synthesis/Evaluation |
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Definition
49) In a series of experiments, the enzyme Dicer has been inactivated in cells from various
vertebrates, and the centromere is abnormally formed from chromatin. Which of the following is
most likely to occur?
A) The usual mRNAs transcribed from centromeric DNA will be missing from the cells.
B) Tetrads will no longer be able to form during meiosis I.
C) Centromeres will be euchromatic rather than heterochromatic and the cells will soon die in
culture.
D) The cells will no longer be able to resist bacterial contamination.
E) The DNA of the centromeres will no longer be able to replicate. |
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Term
Answer: E
Topic: Concept 18.3
Skill: Synthesis/Evaluation |
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Definition
50) Since Watson and Crick described DNA in 1953, which of the following might best explain
why the function of small RNAs is still being explained?
A) As RNAs have evolved since that time, they have taken on new functions.
B) Watson and Crick described DNA but did not predict any function for RNA.
C) The functions of small RNAs could not be approached until the entire human genome was
sequenced.
D) Ethical considerations prevented scientists from exploring this material until recently.
E) Changes in technology as well as our ability to determine how much of the DNA is expressed
have now made this possible. |
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Term
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Definition
1) If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then the
A) amino acid inactivates the repressor.
B) enzymes produced are called inducible enzymes.
C) repressor is active in the absence of the amino acid.
D) amino acid acts as a corepressor.
E) amino acid turns on transcription of the operon. |
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Term
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Definition
2) Muscle cells differ from nerve cells mainly because they
A) express different genes.
B) contain different genes.
C) use different genetic codes.
D) have unique ribosomes.
E) have different chromosomes. |
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Term
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Definition
3) What would occur if the repressor of an inducible operon were mutated so it could not bind
the operator?
A) irreversible binding of the repressor to the promoter
B) reduced transcription of the operon's genes
C) buildup of a substrate for the pathway controlled by the operon
D) continuous transcription of the operon's genes
E) overproduction of catabolite activator protein (CAP) |
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Term
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Definition
4) The functioning of enhancers is an example of
A) transcriptional control of gene expression.
B) a post-transcriptional mechanism for editing mRNA.
C) the stimulation of translation by initiation factors.
D) post-translational control that activates certain proteins.
E) a eukaryotic equivalent of prokaryotic promoter functioning. |
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Term
|
Definition
5) Absence of bicoid mRNA from a Drosophila egg leads to the absence of anterior larval body
parts and mirror-image duplication of posterior parts. This is evidence that the product of the
bicoid gene
A) is transcribed in the early embryo.
B) normally leads to formation of tail structures.
C) normally leads to formation of head structures.
D) is a protein present in all head structures.
E) leads to programmed cell death. |
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Term
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Definition
6) Which of the following statements about the DNA in one of your brain cells is true?
A) Most of the DNA codes for protein.
B) The majority of genes are likely to be transcribed.
C) Each gene lies immediately adjacent to an enhancer.
D) Many genes are grouped into operon-like clusters.
E) It is the same as the DNA in one of your heart cells. |
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Term
|
Definition
7) Cell differentiation always involves the
A) production of tissue-specific proteins, such as muscle actin.
B) movement of cells.
C) transcription of the myoD gene.
D) selective loss of certain genes from the genome.
E) cell's sensitivity to environmental cues such as light or heat. |
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Term
|
Definition
8) Which of the following is an example of post-transcriptional control of gene expression?
A) the addition of methyl groups to cytosine bases of DNA
B) the binding of transcription factors to a promoter
C) the removal of introns and splicing together of exons
D) gene amplification during a stage in development
E) the folding of DNA to form heterochromatin |
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Term
|
Definition
9) Within a cell, the amount of protein made using a given mRNA molecule depends partly on
A) the degree of DNA methylation.
B) the rate at which the mRNA is degraded.
C) the presence of certain transcription factors.
D) the number of introns present in the mRNA.
E) the types of ribosomes present in the cytoplasm. |
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Term
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Definition
10) Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best
explains the presence of these potential time bombs in eukaryotic cells?
A) Proto-oncogenes first arose from viral infections.
B) Proto-oncogenes normally help regulate cell division.
C) Proto-oncogenes are genetic "junk."
D) Proto-oncogenes are mutant versions of normal genes.
E) Cells produce proto-oncogenes as they age. |
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