Molecular Biology Exam #3

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Molecular Biology Quizzes & Trivia
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  • 1. 
    Please put the following steps of RNA Cap synthesis in the correct order. (1) N7 of the capping guanine is methylated(2) The terminal phosphate is removed from the pre-mRNA.(3) A capping GMP is added to the pre-mRNA(4) the 2'-O-methyl group of the penultimate nucleotide is methylated 
    • A. 

      1,2,3,4

    • B. 

      2,3,1,4

    • C. 

      1,4,3,2

    • D. 

      2,4,1,3

    • E. 

      4,3,2,1


  • 2. 
    When does capping of the pre-mRNA occur? 
    • A. 

      It occurs before the mRNA reaches a chain length of 30 nt.

    • B. 

      It is the first nucleotide added by the RNA polymerase

    • C. 

      It occurs after poly(A) tail has been added.

    • D. 

      It occurs after splicing has occurred

    • E. 

      It occurs after export of the mRNA into the cytoplasm


  • 3. 
    You have isolated a new species of mRNA using an oligo dT column. You then perform an R-looping experiment to determine if the gene encoding for your mRNA contains introns. Below is a representation of the electron micrograph results. Which of the following can you conclude from your experiment? 
    • A. 

      The gene contains no introns

    • B. 

      The gene contains one intron

    • C. 

      The gene contains two introns.

    • D. 

      The gene contains three intron

    • E. 

      The results are inconclusive


  • 4. 
    Which of the following experiments was useful in determining the existence of introns in the adenovirus genome? 
    • A. 

      DNA/DNA hybridization

    • B. 

      RNA/RNA hybridization

    • C. 

      RT-PCR

    • D. 

      R-looping experiments

    • E. 

      CDNA cloning experiments


  • 5. 
    The first two bases and the last two bases in the splicing signal consensus sequences are 
    • A. 

      GT-AG

    • B. 

      GT-TG

    • C. 

      CU-AG

    • D. 

      GU-AC

    • E. 

      GU-AG


  • 6. 
    Which of the following is the name for the yeast 40S particle where mRNA splicing takes place? 
    • A. 

      Ribosome

    • B. 

      Nucleolus

    • C. 

      HnRNA

    • D. 

      Spliceosome

    • E. 

      R-loop


  • 7. 
    "Snurps" or snRNPs are composed of 
    • A. 

      RNA

    • B. 

      RNA and protein

    • C. 

      DNA

    • D. 

      Protein

    • E. 

      DNA and RNA


  • 8. 
    Bioinformatics databases include all EXCEPT 
    • A. 

      Swiss data bank

    • B. 

      GenBank

    • C. 

      EMBL

    • D. 

      Swissprot

    • E. 

      TIGR


  • 9. 
    DNA microarrays can be used to study
    • A. 

      The DNA sequence of multiple chromosomes

    • B. 

      The clustering of expression of genes in time and space

    • C. 

      The DNA sequence of multiple genomes

    • D. 

      Chromosomal rearrangements

    • E. 

      Chromosomal abnormalities


  • 10. 
    Genomic sequence information can be applied to study which of the following? 
    • A. 

      Evolution of genomes

    • B. 

      Function of genomes

    • C. 

      Structure of genomes

    • D. 

      Proteomics

    • E. 

      All of the choices are correct


  • 11. 
    The catalytic center of the spliceosome appears to include 
    • A. 

      Mg2+ U2, and U6 snRNP together with the branch point region of the intron

    • B. 

      U2 and U6 snRNP

    • C. 

      The branch point region of the intron

    • D. 

      Mg2+ and the branch point region of the intron.

    • E. 

      Mg2+


  • 12. 
    Which of the following snRNP is mismatched with its function? 
    • A. 

      U1: base pairs with 5' splice site of mRNA

    • B. 

      U2: base pairs with the conserved sequence at splicing branch point

    • C. 

      U4: base pairs with 3' splice site of mRNA

    • D. 

      U5: associates with last nucleotide in one exon and the first nucleotide in the next exon

    • E. 

      U6: base pairs with 5' end of the intron.


  • 13. 
    Spliceosomal lariat is 
    • A. 

      Cowboy's lasso

    • B. 

      Texan lariat

    • C. 

      Hairpin RNA

    • D. 

      Splicing intermediate

    • E. 

      Stem and loop DNA


  • 14. 
    Which of the followign is NOT a function of the mRNA Cap? 
    • A. 

      It protects the mRNA from degradation

    • B. 

      It enhances translatability of the mRNA

    • C. 

      It helps regulate expression of the mRNA from the promoter

    • D. 

      It enhances splicing of the mRNA

    • E. 

      It enhances transport of the mRNA to the cytoplasm


  • 15. 
    Although snRNA U1 functions in the nucleus, it receives a 5' Cap to enhance its 
    • A. 

      Export to the cytoplasm

    • B. 

      Binding to snRNPs

    • C. 

      Export too the ER lumen

    • D. 

      Export out of the cell

    • E. 

      Binding to the mature mRNA


  • 16. 
    Which of the following is the mRNA polyadenylation signal motif found in mammalian cells? 
    • A. 

      AAGAAA

    • B. 

      AAUGGG

    • C. 

      AAUAAA

    • D. 

      UUAUUU

    • E. 

      GGAUUU


  • 17. 
    Which of the following was the first free living organism to have its genome sequenced? 
    • A. 

      Herpes simplex virus

    • B. 

      Haemophilus influenzae Rd

    • C. 

      Beta X174

    • D. 

      Methanococcus jannaschii

    • E. 

      Saccharomyces cerevisiae


  • 18. 
    Which of the following free living organisms have the smallest genome, containing about only 470 genes? 
    • A. 

      Mycoplasma genitalium

    • B. 

      Haemophilus influenzae Rd

    • C. 

      Methanococcus jannaschii

    • D. 

      Saccharomyces cerevisiae

    • E. 

      Caenorhabditis elegans


  • 19. 
    Which is not correct about annotated genes? 
    • A. 

      Known genes: their sequences are identical to known human genes

    • B. 

      Related genes: their sequences are homologous to known human genes

    • C. 

      Predicted genes that contain sequences are homologous to EST (expressed sequence tags)

    • D. 

      Pseudogenes are exons that direct translation

    • E. 

      Pseudogenes have trouble to express


  • 20. 
    Which of the following is not required for mammalian cell polyadenylation of pre-mRNA? 
    • A. 

      PAP

    • B. 

      CPSF

    • C. 

      DNA polymerase I

    • D. 

      PABII

    • E. 

      RNA polymerase II


  • 21. 
    The Shine-Dalgarno sequence can be found in 
    • A. 

      TRNAa

    • B. 

      MRNA

    • C. 

      5S rRNA

    • D. 

      16S rRNA

    • E. 

      30S ribosome


  • 22. 
    Which of the following is not a finding from analysis of the complete DNA sequence of human chromosome 22? 
    • A. 

      It contains very little noncoding DNA

    • B. 

      It contains local and long range duplications

    • C. 

      It contains orthologs to the mouse chromosome

    • D. 

      It contains 679 annotated genes

    • E. 

      It contains "poison regions" or gaps that may never get sequenced


  • 23. 
    The estimated total number of genes in the human genome is 
    • A. 

      10,000- 15,000

    • B. 

      20,000- 25,000

    • C. 

      40,000 -50,000

    • D. 

      50,000 - 75,000

    • E. 

      100,000 - 130,000


  • 24. 
    The shine-Dalgarno sequence is 
    • A. 

      UCCUCCA

    • B. 

      AGGAGGU

    • C. 

      AUGAUGU

    • D. 

      AGGAGGT

    • E. 

      AGGUGGU


  • 25. 
    Put the followign steps of prokaryotic translation initiation in the correct order (1) Binding of IF1, IF2, and GTP to the 30s subunit (2) Binding of IF3 to the 30S subunit (3) Binding of the 50S subunit and loss of IF1 and IF3(4) Dissociation of the 70S ribosome (5) Formation of the 70S initiation complex by dissociation of IF2 and GTP hydrolysis (6) formation of the 30S initiation complex 
    • A. 

      2,4,1,6,3,5

    • B. 

      2,1,6,3,5,4

    • C. 

      5,6,3,2,1,4

    • D. 

      1,2,3,4,5,6

    • E. 

      4,2,1,6,3,5


  • 26. 
    Which of the following statements is not true concerning the genetic code? 
    • A. 

      It is an almost universal code

    • B. 

      It is a "comma-less" code

    • C. 

      It is an overlapping code.

    • D. 

      It is capable of wobble base pairing

    • E. 

      It is a triplet code


  • 27. 
    Genetic code has all EXCEPT 
    • A. 

      Non-overlapping codons

    • B. 

      Absolutely universal code

    • C. 

      No gaps

    • D. 

      Triplets

    • E. 

      Wobbles


  • 28. 
    About direction of translation, which is likely? 
    • A. 

      Start from C-terminal

    • B. 

      MRNA is read int he 3' to -5' direction

    • C. 

      Protein is made in C-to-N direction

    • D. 

      Protein is made in the N-to-C direction, starting from N terminal

    • E. 

      Start fromn both C- and N-terminal


  • 29. 
    Which of the following initiation factors prevents re-association of the 70s ribosome by binding to the free 30s subunit? 
    • A. 

      IF1

    • B. 

      IF2

    • C. 

      IF3

    • D. 

      IF4

    • E. 

      IF5


  • 30. 
    Which of the following is not part of the 30S initiation complex? 
    • A. 

      IF1, IF2, and IF3

    • B. 

      Amino-acyl tRNA

    • C. 

      16s rRNA

    • D. 

      5S rRNA

    • E. 

      MRNA


  • 31. 
    Which of the following is the best definition of translation? 
    • A. 

      A process by which pre-mRNA is transformed into mature mRNA

    • B. 

      The process by which pre-mRNA is translated by ribozymes to produce proteins

    • C. 

      A process by which a gene is converted into a protein

    • D. 

      The process by which tRNA read the genetic message to produce a protein

    • E. 

      A process by which a gene is converted into mRNA


  • 32. 
    Which if false? 
    • A. 

      Similar to prokaryotes, eukaryotic translation incorporates a N-formyl-methionine as the first amino acid

    • B. 

      In prokaryotes the first amino acid in all mature proteins is an N-formyl-methionine

    • C. 

      Most eukaryotic mRNAs have 5' caps that function in translation initiation instead of Shine-Dalgarno sequences.

    • D. 

      Translation initiation in eukaryotes involves scanning of the mRNA to locate a favorable AUG

    • E. 

      Phosphorylation of eukaryotic initiation factors can play both an inhibitory and stimulatory role in translational control of gene expression


  • 33. 
    Function of EF-Tu is to 
    • A. 

      Properly fold proteins

    • B. 

      Ensure proper ribosome assembly

    • C. 

      Protect rRNA from degradation of RNase

    • D. 

      Escrot aminoacyl-tRNA to the ribosome

    • E. 

      Stabilize mRNA within the ribosome


  • 34. 
    Please place the steps of translation elongation in the correct order (1) Peptidyl transferase forms a peptide bond betwen the peptide in the P site and the newly arrived aminoacyl-tRNA in the A site (2) EF-G with GTP, translocates peptidyl-tRNA to the P site(3) EF-Tu, with GTP, binds an aminoacyl-tRNA to the ribosomal A site 
    • A. 

      1,3,2

    • B. 

      3,2,1

    • C. 

      1,2,3,

    • D. 

      3,1,2

    • E. 

      2,3,1


  • 35. 
    Which is correct? 
    • A. 

      Uncapped mRNA is much more stable than capped mRNA

    • B. 

      The 5' cap of mRNA has no effect on the translatability

    • C. 

      Poly (A) tails are added to the 5' end of the mRNA molecule

    • D. 

      The addition of poly(A) to mRNA seems to be important for its translatability

    • E. 

      Pre-mRNA must be cleaved before it is polyadenylated.


  • 36. 
    Which of the following are the three naturally 
    • A. 

      UAG, UAA, UGG

    • B. 

      UGA, UGG, UAG

    • C. 

      UAG, UAA, UGA

    • D. 

      UAA, AUU, GUU

    • E. 

      UAA, UUA, GGA


  • 37. 
    Which is false? 
    • A. 

      There are only 64 codons in the genetic code

    • B. 

      Peptidyl transferase activity can be inhibited in prokaryotic cells by penicillin

    • C. 

      A transversion is a mutation in the genetic code that changes a purine to a pyrimidine

    • D. 

      Wobble base pairing can occur between tRNA and the third base in the mRNA codon

    • E. 

      Mitochondrial mRNAs carry codons that don't conform to the universal genetic code


  • 38. 
    Which of the following enzymes is used to search for CpG island? 
    • A. 

      Uracil-N-glycosylase

    • B. 

      Lysozyme

    • C. 

      The restriction enzymes that cut both methylated and unemthylated CCGG

    • D. 

      The restriction enzymes that cut methylated CCGG

    • E. 

      The restriction enzymes that cut only unmethylated CCGG


  • 39. 
    How were the genetic markers that are linked to Huntington disease genes screened originally? 
    • A. 

      By RFLPs

    • B. 

      By exon trapping

    • C. 

      By genome sequencing

    • D. 

      By S1 mapping

    • E. 

      By DNase mapping


  • 40. 
    The binding of which of the following snRNPs to spliceosome requires ATP? 
    • A. 

      U1

    • B. 

      U2

    • C. 

      U4

    • D. 

      U5

    • E. 

      U6


  • 41. 
    How were Huntington disease genes identified? 
    • A. 

      By exon trapping

    • B. 

      By RFLPs

    • C. 

      By genome sequencing

    • D. 

      By S1 mapping

    • E. 

      By DNase mapping


  • 42. 
    Regarding to identifying the gene for Huntington disease (HD), which is not correct? 
    • A. 

      The HD gene is located in chromosome 4

    • B. 

      It is identified with Exon trap

    • C. 

      The mutation: a CAG repeat increases its copies leading to extra glutamines inserted into huntingtin

    • D. 

      The HD gene is actually prokaryotic gene

    • E. 

      The HD gene is mapped with positional cloning


  • 43. 
    Which of the following processes was used to locate the gene responsible for Huntington disease? 
    • A. 

      Positional cloning

    • B. 

      Shot-gun cloning

    • C. 

      Genome sequencing

    • D. 

      2D gel

    • E. 

      Proteomics


  • 44. 
    With respect to human genome project, which approach is wrong to take? 
    • A. 

      Vector for large-scale genome projects

    • B. 

      The clone-by clone strategy

    • C. 

      Linker insertion to map replication origins

    • D. 

      Sequencing standards

    • E. 

      Shotgun cloning


  • 45. 
    Which of the following are techniques used for genomic functional profiling? 
    • A. 

      DNA microchips

    • B. 

      RNAi analysis

    • C. 

      Deletion analysis

    • D. 

      RFLP

    • E. 

      RNAi analysis and deletion analysis


  • 46. 
    Why proteomics is useful? Because of 
    • A. 

      About 50% or more of polyadenylated RNAs that do not encode proteins, and noncoding RNAs (ncRNA), or transcripts of unknown functions (TUFs).

    • B. 

      Splicing of a transcript that may encode several proteins

    • C. 

      Degradation of mRNAs

    • D. 

      Post-translational modifications

    • E. 

      All likely


  • 47. 
    This initiation factor is involved in binding tRNA to the ribosome 
    • A. 

      EIF2

    • B. 

      EIF1

    • C. 

      EIF3

    • D. 

      EIF4F

    • E. 

      EIF6


  • 48. 
    This initiation factor binds to the 40s subunit and inhibits re-association of the 40S and 60s subunits 
    • A. 

      EIF2

    • B. 

      EIF1

    • C. 

      EIF3

    • D. 

      EIF4F

    • E. 

      EIF6


  • 49. 
    This initation factor is a Cap binding protein 
    • A. 

      EIF2

    • B. 

      EIF1

    • C. 

      EIF3

    • D. 

      EIF4F

    • E. 

      EIF6


  • 50. 
    This initiation factor binds to the 60s subunit and inhibits reassociation of the 40S and 60s subunits. 
    • A. 

      EIF2

    • B. 

      EIF1

    • C. 

      EIF3

    • D. 

      EIF4F

    • E. 

      EIF6


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