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BSC 2010 (Ellington) Practice Exam4
1. In terms of the nucleotide composition of DNA ______, (A) A is always > T, (B)
T is always > A, (C) G is always > C, (D) C is always > G or (E) none of the
above.
2. Which of the following interactions between the two strands of a DNA molecule
is the strongest? (A) TT, (B) AT, (C) GC, (D) GG or (E) AA.
3. After two rounds of DNA replication, the original parent strands will _______.
(A) be present in all daughter strands, (B) be present in 1 of the 4 daughter
strands, (C) be present in 3 of the 4 daughter strands, (D) be present in none of the
daughter strands or (E) be present in 2 of the 4 daughter strands.
4. Single strand binding proteins _____________. (A) prevent strands from
hydrogen bonding back together, (B) are involved in DNA replication, (C) are
present in the replication fork, (D) all of the above or (E) none of the above.
5. In DNA replication the primer ________. (A) consists of RNA, (B) is made by an
enzyme known as ligase, (C) ultimately becomes incorporated into the daughter
strand, (D) is only needed in the leading strand or (E) none of the above.
6. Consider the following mRNA molecule:
3’-AACAAACUGCUAAUUCCA-5’
use the following “dictionary” to answer questions 19 and 20.
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
The translation of this sequence is _______________. (A) LeuThrLysIleValGln, (B)
GlnLysValIleLeuThr, (C) ThrLeuIleValLysGln, (D) IleThrLeuGlnLysVal or (E)
none of the above.
7. Of the amino acids coded for in this protein which is the most redundant in terms
of codons? (A) Lys, (B) Leu, (C) Gln, (D) Val or (E) Thr.
8. mRNA produced by prokaryotes is processed by ______. (A) addition of polyA
tails, (B) addition of introns, (C) removal of introns, (D) GTP caping or (E) none
of the above.
9. During transcription _______________. (A) mRNA is formed from 5’ to 3’, (B)
mRNA is formed from 3’ to 5’, (C) DNA is read from 3’ to 5’, (D) both A and C
or (E) both B and C.
10. The purpose of modification of eukaryotic mRNA immediately AFTER
transcription is to _______. (A) enhance its stability, (B) remove non proteincoding information, (C) facilitate its transport out of the nucleus, (D) all of the
above or (E) none of the above.
11. The TATA box is found ________________. (A) just before the START codon,
(B) in the first intron after the START codon, (C) in the middle of the coding
region of the gene, (D) after the STOP codon or (E) in the promoter site.
12. In terms of relative concentrations we would find that in RNA ______. (A) A=T,
(B) G=T, (C) U=T, (D) C=T or (E) A=U.
13. tRNA molecules perform a vital function by acting as intermediaries between
proteins and mRNAs because they ________. (A) can form covalent bonds to the
amino acid for the which their respective anti-codon site codes for, (B) bind
specifically to codons on the mRNA, (C) are the substrates of amino acyl
synthetases , (D) all of the above or (E) A and C only.
14. The first step in the initiation process of translation involves __________ . (A) the
binding of Met-tRNA to the START codon on the mRNA, (B) the binding of the
small ribosomal subunit to the mRNA, (C) peptide bond formation, (D) the
binding of the mRNA to the large ribosomal subunit first or (E) none of the
above.
15. The translocation step in translation involves ______ (A) movement of the amino
acyl tRNA into the P site, (B) movement of the peptidyl tRNA to the A site, (C)
movement of the peptidyl tRNA to the E site, (D) binding of a tRNA to the E site
or (E) movement of the peptidyl tRNA to the P site.
16. Binding of the release factor to the A site results in _____. (A) breakage of the
polypeptide-tRNA bond, (B) release of the polypeptide, (C) release of the mRNA,
(D) break-up of the large and small ribosomal subunits complex or (E) all of the
above.
17. Consider the following mRNA sequence for questions 6-8 (USE THE
DICTIONARY FOUND IN PRACTICE EXAM3):
3’-AUUAUUGGGGGGAAAGGC-5’
18. Suppose you inserted a U between the G and the C. What would be the sequence
of the new peptide? (remember to read the message in the correct direction!) (A)
ArgArgGlyGlyIleLeu, (B) GlyGlyValGluTyrLys, (C) LeuGluArgGlyValIle, (D)
GlyLysArgGlyGlyTyrAla, or (E) none of the above.
19. Suppose you deleted the C from the message. What would be the sequence of the
new peptide? (A) GlyLysGlyGlyTyr, (B) AlaAlaTyrGlyGln, (C)
LeuGlyTyrArgHis, (D) GluGluGlyArgIle or (E) none of the above.
20. Suppose we changed the C to an A; this would produce ______ in the first codon.
(A) a frameshift mutation, (B) a silent mutation, (C) a misense mutation, (D) a
nonsense mutation or (E) no mutation.
21. In the lytic cycle of a bacteriophage _______. (A) the virus DNA becomes
incorporated into thye host’s DNA, (B) the virus DNA is passd onto daughter
cells as a prophage, (C) the host cells makes many virus particles, (D) all of the
above or (E) none of the above.
22. Reverse transcriptase is _________. (A) is found in DNA containing viruses, (B)
is made up of RNA, (C) catalyzes the formation of RNA, (D) catalyzes the
formation of DNA or (E) none of the above.
23. Which of the following is NOT a form of genetic recombination in bacteria? (A)
lysis, (B) transformation, (C) transduction, (D) conjugation or (E) none of the
above.
24. In the lac operon the promoter site binds_______. (A) lactose only, (B) the
inactive repressor protein-lactose complex only, (C) the active repressor protein
only, (D) permease only or (E) RNA polymerase only.
25. An enhancer site in a eukaryotic gene _________. (A) binds activator protein, (B)
is typically located far upstream of the TATA box, (C) typically controls gene
expression, (D) all of the above or (C) none of the above.