Download 3.4 A: Structure of DNA and RNA Quiz PROCTOR VERSION

PROCTOR VERSION
3.4 A: Structure of DNA and RNA Quiz
1.
The diagram below shows the synthesis of a polynucleotide by the formation of a phosphodiester
bond.
Which statement best describes how the nucleotides are joined to form the polynucleotide?
(A) The phosphate group gives up an H+ ion and forms an ionic bond with the deoxyribose
sugar.
Distractor Rationale:
This answer suggests the student may understand that phosphate groups can lose an H+
ion and form ionic bonds with other substances, but does not understand that this would
not occur with a deoxyribose molecule because these groups are covalently bonded by
dehydration reactions.
(B) A hydrogen atom and a hydroxide group are removed from the phosphate and deoxyribose
molecules, and a covalent bond is formed via dehydration synthesis.
Rationale:
This answer suggests the student understands that DNA nucleotides are attached to form a
DNA polymer (sequence of nucleotides) by means of dehydration reactions between
phosphate and deoxyribose groups.
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PROCTOR VERSION
3.4 A: Structure of DNA and RNA Quiz
(C) The phosphate group is strongly electronegative and forms a hydrogen bond with a
positively charged region on the deoxyribose sugar.
Distractor Rationale:
This answer suggests the student may understand that phosphate groups are
electronegative and can form hydrogen bonds with polar molecules, but does not
understand that this would not form a strong helix because the hydrogen bond is weak and
easily separated.
(D) A water molecule is split via hydrolysis, and the phosphate group and the deoxyribose sugar
are covalently linked.
Distractor Rationale:
This answer suggests the student may understand that a water molecule is involved in the
synthesis of a polymer, but does not understand that water is a product of the dehydration
synthesis of a polynucleotide because a molecule of water is formed when the hydroxyl
group (–OH) from both the phosphate group and the deoxyribose combine to form a
covalent bond, while the separation of polymers into monomers is achieved through
hydrolysis (the addition of water).
Aligned to: LO 3.4 CA 3.4: Represent Genetic Information
2.
The diagram below represents the replication of a DNA strand.
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PROCTOR VERSION
3.4 A: Structure of DNA and RNA Quiz
Which statement best explains how the DNA polymerases will interact with the DNA strands?
(A) As the replication fork opens, both DNA polymerases will continue to move toward the
replication fork and attach complementary DNA nucleotides to each template strand,
because DNA can only be replicated by enzymes moving toward the replication fork, in
either the 3'
5' or 5'
3' direction.
Distractor Rationale:
This answer suggests the student may understand that replication in the direction of the
replication fork is most efficient, but does not understand that this cannot occur on the right
strand because DNA polymerase can only move in the 3'
5' direction on the DNA
template strand.
(B) As the replication fork opens, only the DNA polymerase on the left strand of the molecule
will be able to place complementary bases on the DNA template, because DNA can only be
replicated by enzymes moving in the 3'
5' direction on the template strand.
Distractor Rationale:
This answer suggests the student may understand that, during replication, DNA polymerase
can only move in the 3'
5' direction on the DNA template strand, but does not
understand that this would mean that the DNA polymerase on the right template would
move away from the replication fork because it also has to move in the 3'
5' direction.
(C) As the replication fork opens, the DNA polymerase on the left strand of the molecule will
place complementary bases on the DNA template moving toward the replication fork, and
the DNA polymerase on the right strand of the molecule will replicate moving away from the
replication fork, because DNA can only be replicated by enzymes moving in the 3'
5'
direction on the template strand.
Rationale:
This answer suggests the student understands that DNA polymerase can only move in the
3'
5' direction on the DNA template strand and that the enzyme on the left strand moves
toward the replication fork and the enzyme on the right strand moves away from the
replication fork.
(D) As the replication fork opens, the DNA polymerase on the left strand of the molecule will
place complementary bases on the DNA template strand moving away from the replication
fork, and the DNA polymerase on the right strand of the molecule will replicate moving
toward the replication fork, because DNA can only be replicated by enzymes moving in the
5'
3' direction.
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PROCTOR VERSION
3.4 A: Structure of DNA and RNA Quiz
Distractor Rationale:
This answer suggests the student may understand that DNA is replicated in antiparallel
directions, but may not understand that DNA polymerase can only move in the 3'
5'
direction.
Aligned to: LO 3.4 CA 3.4: Represent Genetic Information
3.
The diagram below shows parts of a structural gene.
Which statement most accurately describes how the gene will be transcribed by RNA
polymerase?
(A) The RNA polymerase will only transcribe the nucleotides on strand B from the transcription
start site to the termination site and will produce an mRNA transcript in the 5'
3' direction.
Rationale:
This answer suggests the student understands that RNA polymerase can only move in the
3'
5' direction from the transcription start site to the termination site on the DNA, so
strand B must be the coding strand of the gene and the mRNA transcript produced will be in
the 5'
3' direction.
(B) The RNA polymerase will only transcribe the nucleotides on strand A from the promoter
region to the termination site and will produce an mRNA transcript in the 3'
5' direction.
Distractor Rationale:
This answer suggests the student may understand that transcription occurs along one DNA
strand and that the mRNA molecule is synthesized in an antiparallel fashion, but does not
understand that this cannot occur on strand A because DNA polymerase can only move in
the 3'
5' direction on the DNA template strand.
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PROCTOR VERSION
3.4 A: Structure of DNA and RNA Quiz
(C) The RNA polymerase will transcribe the nucleotides on strand B from the promoter to the
termination site and then will transcribe strand A back to the promoter region to produce a
complete mRNA transcript.
Distractor Rationale:
This answer suggests the student may understand that, during transcription, RNA
polymerase can only move in the 3'
5' direction on the DNA template strand, but does
not understand that the non-template strand (strand A) would not be transcribed because
strand A is non-coding in protein synthesis.
(D) The RNA polymerase will transcribe the nucleotides in the exon regions of strand A and
strand B, beginning at the transcription start site and ending at the termination site, to
produce the correct mRNA transcript.
Distractor Rationale:
This answer suggests the student may understand that only some regions of the gene
sequence are translated into a polypeptide and that genes contain many non-coding
regions, but does not understand that the non-coding strand (strand A) would not be
transcribed because transcription only occurs in the 3'
5' direction on the DNA template
strand.
Aligned to: LO 3.4 CA 3.4: Represent Genetic Information
4.
The diagram below represents a nucleic acid found in a cell.
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PROCTOR VERSION
3.4 A: Structure of DNA and RNA Quiz
Which statement best describes what the role of this molecule will be in protein synthesis?
(A) The anticodon on the mRNA in the diagram will bind to the tRNA triplet 5'-UUC-3' in a
ribosome and place a specific amino acid onto the polypeptide being assembled.
Distractor Rationale:
This answer suggests the student may understand that the anticodon 3'-AAG-5' pairs with
the codon 5'-UUC-3', but does not understand that the nucleic acid pictured in the diagram
is tRNA, because the student does not recognize the unique structure of tRNA, including the
anticodon that is located opposite the attachment site and that enables tRNA to read mRNA
and place the correct amino acid in the polypeptide chain.
(B) The anticodon on the mRNA in the diagram will bind to the tRNA codon 5'-UUC-3' in a
ribosome and signal to the tRNA to place the appropriate amino acid onto the polypeptide
chain.
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PROCTOR VERSION
3.4 A: Structure of DNA and RNA Quiz
Distractor Rationale:
This answer suggests the student may understand that the anticodon 3'-AAG-5' pairs with
the codon 5'-UUC-3', but does not understand that the nucleic acid pictured in the diagram
is tRNA, because the student does not recognize the unique structure of tRNA, including the
anticodon that is located opposite the attachment site and that enables the tRNA to read
mRNA and place the correct amino acid in the polypeptide chain.
(C) The anticodon on the tRNA in the diagram will bind to the mRNA codon 5'-UUC-3' in a
ribosome and signal to the mRNA to place the appropriate amino acid onto the polypeptide
chain.
Distractor Rationale:
This answer suggests the student may understand that the anticodon 3'-AAG-5' on the tRNA
pictured in the diagram pairs with the mRNA codon 5'-UUC-3', but does not understand
that mRNA is not involved in forming peptide bonds because that is the role of the tRNA
molecule.
(D) The anticodon on the tRNA in the diagram will bind to the mRNA codon 5'-UUC-3' in a
ribosome and place a specific amino acid onto the polypeptide being assembled.
Rationale:
This answer suggests the student understands that the anticodon 3'-AAG-5' on the tRNA
pictured in the diagram pairs with the codon 5'-UUC-3' on mRNA because it is the
complementary sequence, and when this occurs, a specific amino acid will be placed on the
polypeptide chain.
Aligned to: LO 3.4 CA 3.4: Represent Genetic Information
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