Genetics Practice Exam 55 Questions with Verified Answers
Which process is represented by the arrow labeled W?
A. replication
B. translation
C.
... [Show More] transcription
D. RNA splicing - CORRECT ANSWER C
Which of the labeled structures contains RNA with a catalytic
function?
A. 1
B. 2
C. 4
D. 5
E. 2, 3 and 4 - CORRECT ANSWER C
Which of the labeled is made of chromatin?
A. 1
B. 1 and 4
C. 4
D. 5 - CORRECT ANSWER A
Which of the following molecules, NOT represented on this diagram, are critical to process X?
A. RNA polymerase
B. tRNAs
C. snRNAs
D. histones
E. DNA polymerase - CORRECT ANSWER C
5. How many hydrogen bonds form between Cytosine and Guanine in a DNA strand?
A. 1
B. 2
C. 3
D. 4 - CORRECT ANSWER C
Based on Chargaff's Rules, if ADENINE makes up 30% of the bases in a certain DNA sample,
what percentage of the bases must be CYTOSINE?
A. 10%
B. 20%
C. 30%
D. 50%
E. Not enough information to tell. - CORRECT ANSWER B
7. A piece of DNA wound around 8 histone proteins makes a unit of structure known as a.....
A. replisome
B. nucelosome
C. Okazaki fragment
D. Ribosome - CORRECT ANSWER B
8. Genes that are found in regions of genomic DNA associated with histones with highly
ACETYLATED tails are likely to be ................
A. active
B. inactive
C. mutated
D. B and C - CORRECT ANSWER A
What is the C-value paradox?
A. DNA sometimes replicates by a conservative rather than semi-conservative mechanism
B. There is no correlation between genome size and organism complexity
C. Genomes contain more cytosine than the other 3 bases
D. Chemical changes to DNA bases can affect gene transcription without changing the "code" - CORRECT ANSWER B
Which enzyme SYNTHESIZES the DNA component of an
Okazaki fragment?
A. Reverse transcriptase
B. DNA polymerase III
C. Primase
D. DNA ligase
E. DNA polymerase I - CORRECT ANSWER B
How many of the molecules shown in the diagram represent
catalytic subunits of DNA polymerase III?
A. 1
B. 2
C. 3 - CORRECT ANSWER B
12. Which enzyme is responsible for REMOVING
SUPERCOILING in the DNA strand ahead of the replication
fork during replication?
A. Helicase
B. Telomerase
C. DNA ligase
D. DNA topoisomerase (gyrase) - CORRECT ANSWER D
Which of the following statements is true concerning DNA replication?
A. both leading and lagging strands are synthesized in a 5'to 3'direction
B. the leading strand is synthesized in a 5'to 3'direction the lagging strand in a 3' to 5'
C. both leading and lagging strands are synthesized in a 3'to 5'direction
D. DNA polymerase I is responsible for the bulk of the nucleotide polymerization - CORRECT ANSWER A
. After receiving a sample of human cells, you determine that the enzyme telomerase is NOT
expressed in these cells. What possible conclusion(s) can you make about those cells?
A. the cells are most likely cancerous
B. the cells are most likely healthy somatic cells
C. the cells are gamete producing cells
D. these cells probably have bacterial contamination - CORRECT ANSWER B
15. Which of the following classes of RNA provide the specificity component for RISC complexes?
A. mRNA
B. rRNA
C. tRNA
D. siRNA
E. A, B and C - CORRECT ANSWER D
16. Which of the following classes of RNA are involved in mRNA splicing?
A. snRNA
B. rRNA
C. tRNA
D. siRNA - CORRECT ANSWER A
17. Bacterial RNA polymerase II holoenzyme complexes have variable σ subunits. What effect does
this variation lead to?
A. the different complexes synthesize RNA at different speeds
B. the different complexes synthesize have different enzyme activities
C. the different complexes synthesize different classes of RNA
D. the different complexes recognize different promoter sequences - CORRECT ANSWER D
18. Which of the following processes involve GTP-dependent release factors?
A. initiation of transcription
B. termination of transcription
C. RNAi
D. termination of translation
E. B and C - CORRECT ANSWER D
19. What is the function of the Shine-Delgarno sequence in prokaryotes?
A. it contains the DNA sequence to which the σ subunit of RNA polymerase recognizes
B. it is A and T rich and provides a site where it is easy to separate the DNA strands
C. it pairs with a region of rRNA to position the ribosome correctly to start translation
D. it contains the termination signal for translation - CORRECT ANSWER C
20. Which of the following factors are involved in eukaryotic but not prokaryotic transcription?
A. Transcription factors
B. Chromatin remodeling
C. TATA boxes
D. Reverse transcriptase
E. the first codon is always methionine - CORRECT ANSWER B
21. Which enzyme is responsible for processing siRNAs into ~17-22 base fragments?
A. Restriction enzymes
B. Telomerase
C. DNA polymerase I
D. Dicer - CORRECT ANSWER D
22. If you are looking at hemoglobin at the level that includes multiple amino acid chains and
associated metal ions, what level of structure are you looking at?
A. quaternary
B. tertiary
C. secondary
D. primary - CORRECT ANSWER A
23. Which type of bond is created by ribosomes?
A. phosphodiester
B. hydrogen
C. peptide
D. amino-acyl - CORRECT ANSWER C
24. What function do tRNAfmet (in prokaryotes) or tRNAi
met (in eukaryotes) have?
A) they are always used to decode methionine codons
B) they are always used to decode the first amino acid codon in all proteins synthesized
C. they are release factors
D. they are termination factor factors - CORRECT ANSWER B
25. Though the human genome encodes only~ 25,000 genes, our bodies make >100,000 different
proteins. Which of the following factors is the main way that this is achieved?
A) Many human mRNA encode more than one protein on a single mRNA strand
B) Alternative splicing of transcripts to produce different mRNAs
C) Because of degeneracy in the triplet code different proteins can be made from a single mRNA
D) RNAi
E) Eukaryotes have more than one RNA polymerase and these can transcribe genes differently - CORRECT ANSWER B
26. Which of the following amino acids DO NOT exhibit "degeneracy"?
A. Tryptophan (Trp)
B. Serine (Ser)
C. Leucine (Leu)
D. Glutamine (Glu)
E. Methionine (Met) - CORRECT ANSWER A and E
27. Which of these RNA sequence(s) encode the peptide MetArg-Pro-Val?
A. AUGAGGCCAGUU
B. AUGCGCCCUGUA
C. AUGAGACCCGUC
D. AUGCGACCGGUG
E. All of the above - CORRECT ANSWER E
28. Ribosomes are composed of:
A. Only rRNA
B. rRNA subunits and proteins
C. chromatin
D. proteins - CORRECT ANSWER B
29. The figure on the right shows a tRNA for which amino acid?
A. Ser
B. Arg
C. Ala
D. Cys - CORRECT ANSWER C
30. What class of enzyme is represented in the figure at the right?
A. protease
B. RNA ligase
C. aminoacyl-tRNA synthetase
D. protein kinase
E. peptidyl transferase - CORRECT ANSWER C
31. Termination of TRANSLATION involves cleaving the polypeptide chain from the tRNA to
which it is attached. Which are the following are responsible for this process?
A. cis-acting DNA elements
B. hairpin structures forming in mRNA
C. GTP-dependent release factors
D. proteases
E. hairpin structures forming in the polypeptide - CORRECT ANSWER C
32. What causes RNA polymerase to stop transcribing and fall off the DNA strand at the end of a
gene?
A. A stop codon
B. A GTP-dependent release factor is recruited to cleave and release the RNA chain from the DNA
C. a hair-pin loop forms in the RNA which causes the RNA polymerase complex to drop off
D. a RISC complex - CORRECT ANSWER C
33. What would the addition of a ubiquitin chain to a protein cause?
A. targeting of that protein to the Golgi apparatus
B. degradation of that protein
C. secretion of that protein
D. activation of the catalytic activity of that protein - CORRECT ANSWER B
34. Phosphorylation/dephosphorylation events are one of the most important events in cell
signaling. Which class of enzymes DEPHOSPHORYLATES proteins?
A. proteases
B. protein phosphatases
C. protein kinases
D. peptidyl transferases - CORRECT ANSWER B
Mutations that result from the influence of an EXTERNAL FACTOR are called......
A. neutral mutations
B. induced mutations
C. somatic mutations
D. spontaneous mutations
E. point mutations - CORRECT ANSWER B
36. Which class of mutation is most likely to result in a truncated protein?
A. silent mutations
B. point mutations
C. mis-sense mutations
D. frameshift - CORRECT ANSWER D
37. Which of the following classes of mutation are NEVER heritable?
A. somatic mutations
B. germ-line mutations
C. autosomal mutations
D. X-linked mutations - CORRECT ANSWER A
38. If a codon is mutated from CAA to TAA what type of mutation has occurred? (n.b. there is a
codon usage table above)
A. mis-sense mutation
B. non-sense mutation
C. silent mutation
D. frame shift mutation - CORRECT ANSWER B
39. UV light is a major cause of skin cancer. What does it cause in DNA that can lead to mutations?
A. tautomeric shifts
B. slippage of the replisome
C. formation pyrimidine dimers
D. alkylation of nucleotides - CORRECT ANSWER C
40. Most spontaneous mutations are corrected by the DNA replication machinery in a process
called.....
A. mis-match repair
B. proofreading
C. post-replication repair
D. photoreactivation repair
E. the Ames Test - CORRECT ANSWER B
41. Individuals suffering from the disease xeroderma pigmentosum (XP) have lost the ability to
undergo ......
A. proofreading
B. post-replication repair
C. photoreactivation repair
D. nucleotide excision repair - CORRECT ANSWER D
42. What are "tautomeric shifts"?
A. small insertions or deletions during replication
B. formation of pyrimidine dimers in DNA strands
C. chemical modifications to DNA bases that lead to mutation by incorrect base pairing
D. flexibility in pairing at the 3rd base position of tRNAs with mRNA - CORRECT ANSWER C
43. After synthesizing the 1st DNA strand in cDNA synthesis which enzyme is used to replace the
RNA template (original mRNA) strand with a second DNA strand?
A. helicase
B. DNA polymerase III
C. DNA polymerase I
D. reverse transcriptase - CORRECT ANSWER C
44. Which of the following enzyme(s) would NOT be used in the construction of either a cDNA or a
genomic library?
A. RNA polymerase
B. DNA ligase
C. restriction enzymes
D. reverse transcriptase - CORRECT ANSWER A
45. What feature engineered into plasmid cloning vectors, allows you to select only the host cells
that possess a PLASMID?
A. Antibiotic resistance
B. Lac Z
C. Green fluorescent protein
D. Restriction Sites (polylinker region)
E. a 6X His tag leader peptide - CORRECT ANSWER A
46. Which of the following is true about a cDNA library?
A. all the genes are represented in the same ratio as they are present in the genome
B. intron sequences are present in the library
C. regulatory regions are present in the library
D. only genes expressed in the source tissue extracted will be represented
E. A, B and C - CORRECT ANSWER D
47. For which of the following techniques could you use a labeled ANTIBODY to detect the
molecule you were investigating?
A) Southern blot
B) Western blot
C) Northern blot
D) in situ hybridization
E) A, C and D - CORRECT ANSWER B
48. Which of the pairs of "primer" sequences below could you use to amplify the DNA sequence
below by PCR? (all sequences are written 5' to 3')
ATGCGGACAGCAAAGGTCGAGATAAAGAGGATTGAAAACTCGAATATCAGACAAGTGA
CGTATTCAAACAGGAGAGGAGATCTCGTGATTACTGCAGTCCAAGTTCCTC
A. ATGCGGACAGCAAAGGTC and GCAGTCCAAGTTCCTC
B. ATGCGGACAGCAAAGGTC and CTCCTTGAACCTGACG
C. ATGCGGACAGCAAAGGTC and GAGGAACTTGGACTGC
D. ATGCGGACAGCAAAGGTC and CGTCAGGTTCAAGGAG - CORRECT ANSWER C
49. What does the term "annealing" refer to in a PCR reaction?
A. Separation of the template DNA strands
B. Polymerization of the growing DNA strands
C. Hybridization of the primers with the DNA template - CORRECT ANSWER C
50. Why are fluorescent proteins a revolutionary innovation as molecular tools?
A. they can be imaged in live tissues
B. they can be used to study the localization of other proteins in vivo
C. they can be use to visualize internal organelle structure
D. all of the above - CORRECT ANSWER D
CQ: Which of the following classes of RNA provide the specificity for RISC?
A mRNA
B rRNA
C rRNA
D siRNA
E A, B, C - CORRECT ANSWER D
Which od rhe following classes of RNA are the target of RISC complexes in gene regulation?
A mRNA
B rRNA
C rRNA
D siRNA
E A, B, C - CORRECT ANSWER A
CQ: Bacterial RNA poly 2 holoenzyme complexes have variable subunits? - CORRECT ANSWER D: the different complexes synthesize recognize different promoter sequences
CQ: Which subunit of the bacterial RNA poly 2 holoenzyme complex is variable?
A: alpha
B: beta
C: beta plus
D: sigma - CORRECT ANSWER Sigma???
Nucleosomes are the organizational unit of eukaryotic genes what are the compromised of? - CORRECT ANSWER C: A DNA strand wound around 8 histone proteins [Show Less]