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BSC 2010- Exam4 (80 points total); 11/07/03
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INSTRUCTIONS: There are 40 x 2 pts questions. Best of luck!
1. If you were to determine the base content of DNA, you would discover that in terms of relative amounts
___________.
(A) A=C,
(B) A=T,
(C) A=G,
(D) G=A
(E) G=U.
2. The backbone of each DNA strand ( not the double helix) is formed by ______
(A) the covalent bonding of base to base,
(B) hydrogen bonding of base to base,
(C) hydrogen bonding of amino group to the sugar,
(D) hydrogen bonding of sugar to base,
(E) covalent bonding of sugar to sugar
3. DNA consists of two strands wrapped around each other. If you are looking at one end of the DNA double
helix, one strand begins with a(an) ______ and the other strand begins with a(an) ________.
(A) phosphate, phosphate,
(B) amino group, phosphate,
(C) phosphate, hydroxyl,
(D) hydroxyl, hydroxyl
(E) none of the above.
4. After the first round of DNA replication, the original parent strands will _____
(A) be found as one of the strands in both daughter DNA double helices,
(B) be found in none of the daughter DNA helices,
(C) be found in only one of the daughter DNA helices,
(D) be found as fragments in all the strands of the daughter double helices
(E) not appear until the third round of replication
5. During transcription, the direction of synthesis of the RNA is ____ (refers to the RNA)
(A) from 3’ to 3’,
(B) from 5’ to 3’,
(C) from 5’ to 5’,
(D) from 3’ to 5’
(E) in the same direction as reading from the DNA template.
6. RNA plays a special role in DNA replication in that ___
(A) RNA forms the major structure of ribosomes,
(B) RNA forms small primers for initiation of synthesis of the new strand,
(C) RNA is involved in opening of the DNA double helix,
(D) RNA carries the message out of the nucleus
(E) RNA provides energy.
7. Which of the following proteins is (are) involved in DNA replication _____
(A) helicase,
(B) primase,
(C) single strand binding proteins,
(D) DNA polymerase
(E) all of the above.
8. An Okazaki fragment ________
(A) is found in the lagging strand,
(B) is made during DNA replication,
(C) is started by the presence of an RNA-DNA complex
(D) all of the above
(E) none of the above.
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9. The promoter on the DNA molecule consists of the following _____
(A) TATA box and initiation site,
(B) introns plus exons,
(C) TATA box plus termination site site,
(D) initiation and termination sites
(E) TATA box plus poly A tail.
10. Which of the following is(are) a function of RNA polymerase II _____ .
(A) binds to promoter site
(B) unwinds DNA duplex
(C) catalyzes the attachment of nucleotides to a growing RNA chain,
(D) all of the above
(E) none of the above.
11. One strand of a DNA double helix has the sequence 5’-ATTCGC-3’. What would be the sequence of the
other strand of DNA?(A) 5’-ATTCGC-3’,
(B) 3’-ATTCGC-5’,
(C) 3’-UAAGCG-5’,
(D) 5’-TAAGCG-3’
(E) 3’-TAAGCG-5’
For questions 12-14 refer to the table below.
UUU
UUC
UUA
UUG
CUU
CUC
CUA
CUG
AUU
AUC
AUA
AUG
GUU
GUC
GUA
GUG
Phe
Phe
Leu
Leu
Leu
Leu
Leu
Leu
Ile
Ile
Ile
Met
Val
Val
Val
Val
UCU
UCC
UCA
UCG
CCU
CCC
CCA
CCG
ACU
ACC
ACA
ACG
GCU
GCC
GCA
GCG
Ser
Ser
Ser
Ser
Pro
Pro
Pro
Pro
Thr
Thr
Thr
Thr
Ala
Ala
Ala
Ala
UAU
UAC
UAA
UAG
CAU
CAC
CAA
CAG
AAU
AAC
AAA
AAG
GAU
GAC
GAA
GAG
Tyr
Tyr
Stop
Stop
His
His
Gln
Gln
Asn
Asn
Lys
Lys
Asp
Asp
Glu
Glu
UGU
UGC
UGA
UGG
CGU
CGC
CGA
CGG
AGU
AGC
AGA
AGG
GGU
GGC
GGA
GGG
Cys
Cys
Stop
Trp
Arg
Arg
Arg
Arg
Ser
Ser
Arg
Arg
Gly
Gly
Gly
Gly
12. Which of the amino acids listed below is the most redundant in terms of codons ?
(A) Phe, (B) Tyr, (C) Asn, (D) Leu or (E) Trp.
13. Suppose you isolated a small piece of mRNA consisting of the following sequence- 5’AUCGGGGACUAU-3’. What would be the sequence of this small peptide coded for by the RNA?
(A)
(B)
(C)
(D)
(E)
IleLysMetGly,
GlyTyrLeuVal,
IleGlyAspTyr,
TyrAspGlyPhe
GlyGlyGlyGly.
14. For the mRNA sequence in question # 13, suppose there was a mutation in which the first A was deleted
leaving only 11 nucleotides. What would be the sequence of this small peptide?
(A) GlyThrPhe,
(B) SerGlyThr,
(C) GlySerTyr,
(D) AlaSerTyr
(E) LysGlyAsp.
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15. Bacteriophage genetic material that has become incorporated into the host cell’s DNA is known as
_______
(A) a retrophage,
(B) a plasmid,
(C) a prophage,
(D) lysis
(E) none of the above.
16. A mature mRNA molecule (one ready for translation) in eukaryotes has the following components
EXCEPT ____
(A) INTRONS,
(B) EXONS,
(C) polyA tail,
(D) GTP cap
(E) none of the above.
17. Reverse transcriptase (RT) catalyzes which of the following reactions:
(A) RNA  DNA,
(B) RNA  protein,
(C) mRNA  tRNA,
(D) DNA mRNA
(E) protein RNA.
18. The P and the A sites are located in the ____
(A) mRNA,
(B) spliceosome,
(C) ribosome,
(D) tRNA
(E) none of the above.
19. The number of different tRNA molecules is _____
(A) equal to the number of different amino acids,
(B) equal to the number of different codons,
(C) somewhat less than the number of different codons,
(D) greater than the number of different codons
(E) equal to twelve.
20. During translation, when the termination codon reaches the _____ site, a _________ binds to the codon
causing the cleavage (=cutting) of the peptidyl-tRNA thereby releasing the polypeptide.
(A) A, termination factor,
(B) P, waterase,
(C) A, waterase,
(D) P, cap protein,
(E) A, P protein.
21. Which of the following is a kind of post-translational modification(A) cleavage of protein by a protease (enzyme that cuts proteins),
(B) attachment of phosphate molecules,
(C) attachment of sugar molecules,
(D) attachment of lipid molecules
(E) all of the above.
22. Aminoacylsynthetases are enzymes that ____
(A) catalyze peptide bond synthesis,
(B) attach amino acids onto mRNAs,
(C) attach amino acids onto tRNAs,
(D) are involved in post-translational modification of proteins
(E) terminate RNA translation.
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23. Polyribosomes consist of _____
(A) many ribosomes cooperating together to translate two or more messages at the same time,
(B) many ribosomes cooperating together to translate a single mRNA message into many copies of the
protein,
(C) many ribosomes cooperating together to make a single protein molecule,
(D) structures which are found in the nucleus
(E) none of the above.
24. Consider the following DNA sequence- AATGACAT. Which of the following is a point mutation.
(A) substitution of an A for the G in the sequence,
(B) substitution of a T for the C in the sequence,
(C) deletion of the G in the sequence,
(D) all of the above
(A) none of the above.
25. Viruses containing DNA cause the cells that they infect to _____
(A) make virus protein,
(B) make virus mRNA,
(C) replicate virus DNA,
(D) all of the above
(E) none of the above.
26. In the lytic phase of the phage life cycle which of the following does not occur?
(A) new phages are assembled,
(B) the bacterial cell dies,
(C) phage proteins are synthesized,
(D) the phage DNA becomes incorporated into the bacterial DNA
(E) phage DNA is replicated.
27. The role of the polyA tail in mRNA is to _____
(A) facilitate binding of the mRNA to the nucleus,
(B) enhance the stability of the mRNA,
(C) prevent the mRNA from leaving the nucleus,
(D) stop transcription
(E) stop translation.
28. HIV, the causative agent of AIDS, _______
(A) is a retrovirus,
(B) contains RNA,
(C) triggers synthesis of viral proteins by the infected cell,
(D) all of the above
(E) none of the above.
29. After the tRNA molecule advances to the E site on the ribosome it _____________ .
(A) is attached to the growing polypeptide chain
(B) has water attached to the amino acyl end
(C) becomes complexed with an initiation factor
(D) is released from the ribosome/mRNA complex
(E) is polyadenylated
30. The mutation that produced the sickle cell hemoglobin defect is a ____________mutation.
(A) chromosomal
(B) nonsense
(C) silent
(D) missense
(E) frame shift
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31. Transformation in bacteria is the process by which _______________. (A) plasmids are exchanged
between bacteria, (B) genes are expressed, (C) genes are transferred to bacteria by phages, (D) foreign
DNA is taken up and incorporated, OR (E) RNA is made from DNA.
32. Consider the TRYP OPERON. When tryptophan levels are high in bacterial cells___________. (A) the
repressor protein becomes capable of binding to the TATA box, (B) the repressor protein becomes incapable
of binding to the TATA box, (C) the repressor protein becomes capable of binding to the regulatory gene, (D)
the repressor protein becomes incapable of binding to the operator OR (E) the repressor protein becomes
capable of binding to the operator.
33. Consider the LAC OPERON. When lactose is removed from the medium, lactose levels in the bacterial
cell fall. This will _______________. (A) cause the repressor protein to be incapable of binding to the
operator, (B) result in a decrease in the transcription of structural genes controlled by the LAC operon, (C)
make the repressor protein capable of binding to the operator, (D) A and B but not C OR (E) B and C but not
A.
34. When the ___________ binds to the enhancer sites in a eukaryotic gene, the DNA folds in such a way
that it comes in close proximity to the ____________. (A) RNA polymerase II, promoter region, (B) mRNA,
activator region, (C) activator proteins, termination site, (D) start codon, stop codon OR (E) activator proteins,
promoter region.
35. A prion _____________. (A) consists of protein, (B) lacks DNA, (C) is infectious, (D) all of the above OR
(E) none of the above.
36. Retroviruses differ from bacteriophages in that they ______________. (A) Infect bacterial cells only, (B)
contain both DNA and RNA as their genetic information, (C) do not produce diseases in humans, (D) contain
RNA as their genetic information OR (E) lack protein in their capsids.
37. Consider the DNA sequence: 3’- ATGAGGTCTTTTACGT-5’. The mRNA transcript from this DNA
sequence would be _______________________. (A) 5’- TACTCCAGAAAATGCA-3’,
(B) 3’- TACTCCAGAAAATGCA-5’, (C) 3’- UACUCCAGAAAAUGCA-5’, (D) 5’- UACUCCAGAAAAUGCA-3’
or (E) 5’- TACTCCAGAAAATGCA-5’.
38. ______________ a small circular piece of DNA found in bacteria which usually carries a few genes that
code for traits used in special environments. (A) nucleoid, (B) chromosome, (C) plasmid, (D) provirus or (E)
prophage.
39. Newly synthesized mRNA in prokaryotes can be used immediately for translation
because____________. (A) it does not need to be transported out of the nucleus, (B) it lacks INTRONS, (C)
it does not require a polyA tail, (D) it does not require a GTP cap or (E) all of the above.
40. Signal or targeting sequences in proteins _______________. (A) tell the cell to transport the protein to
particular places such as mitochondria or the Golgi apparatus, (B) are located at the N-terminal end of the
protein, (C) are cleaved (cut by protease) to form the mature protein, (D) all of the above or (E) none of the
above.
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