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Science
10th -
12thgrade
AP Biology Unit 6: Gene Expression & Regulation
60 questions
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- 1. Multiple Choice
What does transformation involve in bacteria?
the infection of cells by a phage DNA molecule
assimilation of external DNA into a cell
- 2. Multiple Choice
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?
12%
24%
31%
38%
- 3. Multiple Choice
Why does the DNA double helix have a uniform diameter?
Purines pair with pyrimidines.
Deoxyribose sugars bind with ribose sugars.
- 4. Multiple Choice
What kind of chemical bond is found between paired bases of the DNA double helix?
hydrogen
ionic
covalent
- 5. Multiple Choice
In an analysis of the nucleotide composition of DNA, which of the following will be found?
A = G and C = T
A + C = G + T
- 6. Multiple Choice
Replication in prokaryotes differs from replication in eukaryotes for which of these reasons?
Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.
Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not.
- 7. Multiple Choice
What is meant by the description ʺantiparallelʺ regarding the strands that make up DNA?
The 5ʹ to 3ʹ direction of one strand runs counter to the 5ʹ to 3ʹ direction of the other strand.
One strand is positively charged and the other is negatively charged.
- 8. Multiple Choice
Which enzyme catalyzes the elongation of a DNA strand in the 5ʹ → 3ʹ direction?
primase
DNA ligase
DNA Polymerase
helicase
- 9. Multiple Choice
What determines the nucleotide sequence of the newly synthesized strand during DNA replication?
the nucleotide sequence of the template strand
the primase used in the reaction
- 10. Multiple Choice
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
leading strands and Okazaki fragments
lagging strands and Okazaki fragments.
- 11. Multiple Choice
Which of the following separates the DNA strands during replication?
helicase
DNA polymerase
primase
- 12. Multiple Choice
Which of the following covalently connects segments of DNA?
helicase
DNA polymerase
ligase
- 13. Multiple Choice
Which of the following synthesizes short segments of RNA?
helicase
DNA polymerase
primase
- 14. Multiple Choice
The leading and the lagging strands differ in that
the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.
the leading strand is synthesized by adding nucleotides to the 3ʹ end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5ʹ end.
- 15. Multiple Choice
A new DNA strand elongates only in the 5ʹ to 3ʹ direction because
DNA polymerase can only add nucleotides to the free 3ʹ end
Okazaki fragments prevent elongation in the 3ʹ to 5ʹ direction.
- 16. Multiple Choice
Which would you expect of a eukaryotic cell lacking telomerase?
a reduction in chromosome length
production of Okazaki fragments
- 17. Multiple Choice
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?
methylation and phosphorylation of histone tails
nucleotide excision and reconstruction
- 18. Multiple Choice
Based your answer on the figure: A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation?
an accumulation of A and no production of B and C
an accumulation of A and B and no production of C
- 19. Multiple Choice
The genetic code is essentially the same for all organisms. From this, one can logically assume all of the following except
a gene from an organism could theoretically be expressed by any other organism.
all organisms have a common ancestor.
DNA was the first genetic material.
the same codons in different organisms usually translate into the same amino acids.
- 20. Multiple Choice
In which of the following actions does RNA polymerase differ from DNA polymerase?
RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis.
RNA polymerase binds to single-stranded DNA, and DNA polymerase binds to double-stranded DNA.
- 21. Multiple Choice
RNA polymerase moves in which direction along the DNA?
3ʹ → 5ʹ along the template strand
3ʹ → 5ʹ along the coding (sense) strand
- 22. Multiple Choice
What are the coding segments of a stretch of eukaryotic DNA called?
introns
exons
- 23. Multiple Choice
Introns are significant to biological evolution because
their presence allows exons to be shuffled.
they protect the mRNA from degeneration.
- 24. Multiple Choice
A mutation in which of the following parts of a gene is likely to be most damaging to a cell?
intron
exon
- 25. Multiple Choice
Alternative RNA splicing
is a mechanism for increasing the rate of transcription.
can allow the production of proteins of different sizes from a single mRNA
- 26. Multiple Choice
A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is
TTT
UUU
- 27. Multiple Choice
When does translation begin in prokaryotic cells?
as soon as transcription has begun
once the pre-mRNA has been converted to mRNA
- 28. Multiple Choice
Why might a point mutation in DNA make a difference in the level of proteinʹs activity?
It might substitute an amino acid in the active site.
It might exchange one stop codon for another stop codon.
- 29. Multiple Choice
A frameshift mutation could result from
a base insertion only.
either an insertion or a deletion of a base.
a base deletion only.
- 30. Multiple Choice
What does the operon model attempt to explain?
the coordinated control of gene expression in bacteria
the mechanism of viral attachment to a host cell
- 31. Multiple Choice
The tryptophan operon is a repressible operon that is
turned off whenever tryptophan is added to the growth medium
turned on only when glucose is present in the growth medium.
- 32. Multiple Choice
When this is taken up by the cell, it binds to the repressor so that the repressor no longer binds to the operator:
inducer
repressor
- 33. Multiple Choice
Transcription of the structural genes in an inducible operon
occurs continuously in the cell.
starts when the pathwayʹs substrate is present.
- 34. Multiple Choice
Altering patterns of gene expression in prokaryotes would most likely serve the organismʹs survival in which of the following ways?
allowing the organism to adjust to changes in environmental conditions
organizing gene expression so that genes are expressed in a given order
allowing environmental changes to alter the prokaryoteʹs genome
- 35. Multiple Choice
Muscle cells and nerve cells in one species of animal owe their differences in structure to
having different genes.
having different genes expressed.
- 36. Multiple Choice
If you were to observe the activity of methylated DNA, you would expect it to
be unwinding in preparation for protein synthesis.
have turned off or slowed down the process of transcription.
- 37. Multiple Choice
This can inhibit transcription by blocking the binding of positively acting transcription factors to the DNA:
enhancer
promoter
repressor
- 38. Multiple Choice
Which of the following statements is true about stem cells?
Stem cells can differentiate into specialized cells
Stem cells are found only in bone marrow.
- 39. Multiple Choice
The incidence of cancer increases dramatically in older humans because
as we age, normal cell division inhibitors cease to function
the longer we live, the more mutations we accumulate.
- 40. Multiple Choice
Which enzyme was used to produce the molecule in the Figure?
ligase
a restriction enzyme
- 41. Multiple Choice
What is the enzymatic function of restriction enzymes?
to cleave nucleic acids at specific sites
to add new nucleotides to the growing strand of DNA
- 42. Multiple Choice
Bacteria containing recombinant plasmids are often identified by which process?
exposing the bacteria to an antibiotic that kills cells lacking the resistant plasmid
producing antibodies specific for each bacterium containing a recombinant plasmid
- 43. Multiple Choice
A principal problem with inserting an unmodified mammalian gene into a bacterial plasmid, and then getting that gene expressed in bacteria, is that
prokaryotes use a different genetic code from that of eukaryotes.
bacteria cannot remove eukaryotic introns.
- 44. Multiple Choice
Which of the following separates molecules by movement due to size and electrical charge?
gel electrophoresis
gene cloning
- 45. Multiple Choice
Restriction fragments of DNA are typically separated from one another by which process?
gel electrophoresis
PCR
- 46. Multiple Choice
The segment of DNA shown in the figure has restriction sites I and II, which create restriction fragments A, B, and C. Which of the gels produced by electrophoresis shown below best represents the separation and identity of these fragments?
- 47. Multiple Choice
The DNA profiles in the figure represent four different individuals. Which of the following statements is consistent with the results?
B is the child of A and C.
C is the child of A and B.
- 48. Multiple Choice
Which of the following are characteristics of Prokaryotic DNA?
Single linear strand
Single circular strand
Multiple linear strands
Plasmids
Contains histones
- 49. Multiple Choice
Which of the following are characteristics of plasmids?
Circular DNA strand
RNA strands
Contain resistance genes
Found in eukaryotes
Found in prokaryotes
- 50. Multiple Choice
Which of the following describes chromatin?
DNA nucleosomes wrapped around histone proteins
Condensed DNA prepared for cell division
Complimentary RNA coding of primary DNA
Unpackaged DNA that is loose and always accessible
- 51. Multiple Choice
Which of the following describe the structure of mature RNA?
Contains Uracil
Contains introns and exons
Has a poly-A tail and 5' cap
Single stranded
Circular strand
- 52. Multiple Choice
Which of the following would be transcribed from the following DNA sequence? 3' ATC GAA TTA CGA 5'
5' UAG CUU AAU GCU 3'
5' AUC GAA UUA CGA 3'
3' UCG UAA UUC UAG 5'
3' TAG CTT AAT GCT 5'
5' TAG CTT AAT GCT 3'
- 53. Multiple ChoiceIn the lac operon model the genes within the operon will be expressed if:lactose is absent in the cellglucose is present in the celllactose is present in the cell
- 54. Multiple Choice
Which of the following is true of DNA Replication?
DNA is semi conservative because it creates two new strands of old nucleotide.
New DNA strands are being synthesized in the 5' to 3' direction
DNA is being synthesized in the 3' to 5' directions from a template strand
RNA is being synthesized by RNA polymerase in the 5' to 3' direction
A sense strand is created from a nonsense strand of DNA using RNA polymerase
- 55. Multiple Choice
The following mutation occurs:
5' TAC GGC CGA AGT CGT 3'
becomes
5' TAC GGC CGA ATT CGT 3'
What type of mutation is this?
sense
nonsense
frameshift
translocation
duplication
- 56. Multiple Choice
Where does RNA polymerase bind to DNA?
at an activator site
on the coding gene sequence
at a promoter region
downstream of the coding sequence
Where the RNA primer is placed
- 57. Multiple Choice
Which of the following occur during RNA processing?
exons can be removed
spliceosomes remove introns
a poly-A tail and GTP cap are added
DNA helicase unzips DNA
activator sequences initiate transcription
- 58. Multiple Choice
Which of the following is a similarity between the process prokaryotic and eukaryotic organisms implement for protein synthesis?
Transcription takes place in the nucleus, translation takes place in the cytoplasm
Introns are removed by spliceosomes
RNA processing adds a cap and tail to the mature RNA strand
Transcription and translation happen simultaneously
Ribosomes for phosphodiester bonds between amino acids
- 59. Multiple Choice
Which of the following is true of regulatory genes?
a promoter site for RNA polymerase to bind
a gene that produces repressor proteins to block RNA polymerase
a coding region responsible for the production of multiple proteins downstream of an activator site
a gene that codes for activator proteins to enhance transcription
an allosteric inhibitor for transcription factors
- 60. Multiple Choice
Bacterial cells that contain pGal will fluoresce blue under ultraviolet light. Which of the following is the most likely outcome of replacing the lacA gene in the E. coli lac operon with the gene encoding pGal?
When lacY and lac Z are breaking down and transporting lactose, the bacteria will fluoresce blue under ultraviolet light
lacZ will only produce the enzyme for breaking down galactose in the presence of ultraviolet light
the repressor enzyme will only be able to bind to the operator under the presence of lactose
When the regulatory gene is stimulated by lactose, it will cause the gene to fluoresce blue
All structural genes downstream from the placement of lacA will be inhibited due to this substitution mutation.
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