Bio102 Problems
Translation
1. If a eukaryotic protein needs to be secreted from the cell into the bloodstream, it must be
synthesized
A. in the nucleus.
B. in the Golgi apparatus.
C. by a soluble ribosome.
D. on the rough ER.
E. on the spliceosome.
2. For each event listed below, indicate if it happens in prokaryotes, eukaryotes, both or neither by
circling your answer.
tRNA molecules are transcribed by RNA polymerase III.
A terminator sequence causes replication to end.
The large subunit of the ribosome binds to the 5′ cap on the mRNA.
tRNA molecules become ‘charged’ when an amino acid is covalently
attached.
Some mRNA molecules contain more than one functional start
codon.
RNA molecules are made more stable by making them longer.
Prokaryotes
Eukaryotes
Both
Neither
Prokaryotes
Eukaryotes
Both
Neither
Prokaryotes
Eukaryotes
Both
Neither
Prokaryotes
Eukaryotes
Both
Neither
Prokaryotes
Eukaryotes
Both
Neither
Prokaryotes
Eukaryotes
Both
Neither
3. If a protein is synthesized on a free ribosome (in other words, not part of the rough ER), which
cellular compartment could that protein end up in?
A. Cytosol
B. Golgi
C. Rough ER
D. Lysosome
E. Secreted outside the cell
4. Used tRNAs exit the ribosome from what site?
A. P
B. M
C. E
D. A
E. T
5. The aminoacyl-tRNA synthetases are a set of enzymes that catalyze which chemical reaction?
A. Termination of transcription
B. Capping
C. Translation
D. Polyadenylation
E. Charging
6. Which one regulatory sequence is found in RNA (not DNA)?
A. Enhancer
B. Terminator
C. Origin
D. Promoter
E. Shine-Dalgarno sequence
7. Matching. Each statement below describes one of the terms listed on the right. Write the number
of the correct term in the corresponding blank.
11
18
19
5
3
7
4
9
1. -10/-35 boxes
11. RNA polymerase I
2. Cap
12. RNA polymerase II
3. Enhancer
13. RNA polymerase III
4. Exon
14. Shine-Dalgarno Sequence
5. Intron
15. Sigma Factor
6. mRNA
16. Start Codon
A modification to the 3’ end of mRNAs
7. PolyA tail
17. Stop Codon
Contains the codons
8. Promoter
18. tRNA
Protein that causes protein synthesis to stop
after the last amino acid has been polymerized
9. Release Factor
19. TATA box
10. rRNA
20. None of these
The protein that polymerizes nucleotides to
form a structural part of the ribosome in
human cells
A polymer of nucleotides that can be
covalently attached to a specific amino acid
The nucleotide sequence that is responsible
for determining where transcription begins in
eukaryotes
The sequence of mRNA that is discarded after
splicing
A DNA sequence that binds a specific
activator to increase the rate of transcription
8. Which one event happens in prokaryotes?
A. tRNA charging
B. 5’ capping
C. nuclear export
D. polyadenylation
E. splicing
9. Which one statement does NOT correctly describe tRNAs?
A. Many tRNA molecules exist within every cell.
B. tRNA molecules have intramolecular basepairing, which is antiparallel.
C. In eukaryotes, tRNA molecules are made by RNA polymerase II.
D. tRNA molecules contain the anticodon.
E. tRNA molecules are substrates for aminoacyl tRNA synthetase enzymes.
10. Which one statement does NOT correctly describe prokaryotic ribosomes?
A. Ribosomes can associate with a specific sequence of RNA.
B. Ribosomes are able to act as enzymes by catalyzing a chemical reaction.
C. Ribosomes contain many proteins.
D. Some ribosomes are associated with the endoplasmic reticulum.
E. Ribosomes contain large amounts of RNA.
11. If an intron isn’t correctly removed, the most probable result is
A. the polyA tail won’t be added properly.
B. a frameshift mutation.
C. replication of the lagging strand will cease.
D. a substitution mutation.
E. that there will be no effect on gene expression.
12. A tRNA has an anticodon sequence of 5’ GAU 3’. What amino acid should be attached to this
tRNA?
Ile
13.
A tRNA from a prokaryotic cell has the anticodon 5’-GAA-3’. What amino acid should be
covalently linked to this tRNA molecule?
Phe
14. Name one anticodon sequence that is not found on any prokaryotic tRNA.
5’-UCA-3’ (orUUA or CUA)
15. Many regulatory processes are controlled by proteins that bind to specific sequences. Name the regulatory
sequence bound by each of the following proteins, circle which process is being regulated and what type(s) of
organism it is found in.
Protein
TFIID
Initiator Protein
Lac Repressor
Estrogen Receptor
Name of Sequence
TATA box
Origin of Replication
lac operator
estrogen response element
Process
Organism(s)
Replication
Transcription
Splicing
Translation
Replication
Transcription
Splicing
Translation
Replication
Transcription
Splicing
Translation
Replication
Transcription
Splicing
Translation
Prokaryotes
Eukaryotes
Both
Neither
Prokaryotes
Eukaryotes
Both
Neither
Prokaryotes
Eukaryotes
Both
Neither
Prokaryotes
Eukaryotes
Both
Neither
16. Amino acids and nucleic acids are connected together by a covalent bond in which molecule?
A. 5’ cap
B. mRNA
C. Okazaki fragment
D. tRNA
E. Amino acids and nucleic acids are never covalently connected.
17. Release Factor is needed to stop
A. transcription.
B. polyadenylation.
C. replication.
D. splicing.
E. translation.
18. VEGF is a molecule that is secreted into the blood by many human cancer cells and is a polymer of
154 amino acids. The peptide bonds of this molecule must have been made
A. in the Golgi apparatus.
B. on free ribosomes.
C. outside of the cell.
D. in or near the nucleolus.
E. on the rough endoplasmic reticulum.
19. Prokaryotic cells can have more than one functional start codon per mRNA because:
A. They have no introns.
B. Both transcription and translation happen in the same cellular compartment.
C. The activity of the lac repressor is regulated based on the physiological conditions.
D. Prokaryotic promoters consist of two separated sequences: the -10 box and the -35 box.
E. Prokaryotic ribosomes bind to Shine-Dalgarno sequences
20. Which enzyme charges tRNAs?
A. Aminoacyl-tRNA synthetase
B. Hexosaminidase A
C. RNA ligase
D. RNA polymerase
E. Topoisomerase
21. An mRNA molecule which contains the following sequence was purified from the cytosol of a
wild-type plant cell:
3’…UGAUGCUACGAUAAUAAAUCGGAGUACCUAGCUAU…5’
21A. Write out the sequence of the template strand of DNA for this gene. Be sure to label your
ends.
Terminator
5’ACTACGATGCTATTATTTAGCCTCATGGATCGATA 3’
Promoter
21B. On your DNA sequence in 26A, show which side the promoter would be found on. Also
indicate what important sequence is found on the other side.
21C. There is more than one potential start codon in this mRNA. How does the cell select which
start codon to use?
The small subunit of the ribosome binds to the 5’ cap structure then slides towards the 3’ end of the
mRNA. Translation initiates at the first AUG codon that is found.
21D. Give the correct amino-acid sequence of the protein encoded by this gene. Be sure to label
the ends.
N-Met-Arg-Leu-Asn-Asn-Ser-Ile-Val-… -C
21E. What is sequence of the anticodon found on the tRNA needed to translate the second amino
acid of this protein?
5’ CCU 3’
21F. Make a single nucleotide change in the mRNA above that you are confident will not affect
the phenotype of this plant. Draw a circle around this change.
Change the circled U to any other nucleotide
21G. Make a single nucleotide change in the mRNA above that you are confident will affect the
phenotype of this plant. Draw a square around this change.
Changing the circled A to any other nucleotide disrupts the start codon
22. Consider the double-stranded DNA sequence of a prokaryotic gene shown below.
template 5’ CCCTGCAAGATGCCTAACGTCTCATTGCCATACCTCCTAGCATGC 3’ -10 &35
3’ GGGACGTTCTACGGATTGCAGAGTAACGGTATGGAGGATCGTACG 5’
to C
After transcription, the following mRNA is produced. The Shine-Dalgarno sequence is
underlined.
5’-GCAUGCUAAGGAGGUAUGGCAAUGAGACGUUAGGCAUCUUGCAGGG-3’
5’ UTR
3’UTR
22A. Label the 5′ and 3′ ends on the DNA sequence and indicate which one is the template strand.
22B. Label and name both UTRs.
22C. The promoter consists of two key sequences. Name both of them and show where on the DNA
or RNA sequence they would be expected. (You do not have to know or find their actual DNA
sequences.) In the space below, explain how you chose where to place these two key
sequences.
The -10 and -35 boxes need to be located to the right of the gene above. This allows
transcription from right-to-left, to make the indicated mRNA from it’s 5’ to it’s 3’ end.
22D. What is the sequence of the protein made from this gene? Be sure to label both ends.
N-Met-Ala-Met-Arg-Arg-C
22E. The amino acids are connected with ___peptide__ bonds.
22F. As we learned in lab, sodium azide introduces base substitution mutations. Show one base
substitution in the DNA sequence above that would be a missense mutation and show the new
protein sequence below.
N-Met-Arg-Met-Arg-Arg-C
22G. What is the sequence of the anticodon on the last tRNA that is needed to translate this protein?
5’ACG3’