Microbiology 201—Spring 2024 Exam 2 Version A
Read each question carefully and determine exactly what is being asked. Occasionally more than one answer might be
technically correct. Choose the BEST answer.
1. Where does bacterial chromosome replication start?
a. The origin of replication
b. The replication initiation sequence
c. The Shine-Dalgarno sequence
d. The DnaA sequence
e. The promoter region
2. The enzyme that catalyzes the synthesis of DNA is called ____________.
a. DNA helicase
b. DNA gyrase
c. DNA polymerase
d. DNA primase
e. DNA ligase
3. Which enzyme is responsible for forming a phosphodiester bond between 3’-hydroxyl of a growing DNA strand and
the 5’-phosphate of an Okazaki fragment?
a. DNA ligase
b. DNA primase
c. DNA gyrase
d. DNA topoisomerase
e. DNAse
4. In the figure to the right, what labels should
occupy locations A and B?
a. Shine-Dalgarno Region, Promoter
b. Promoter, Operator
c. Promoter, Transcription Start Site
d. Enhancer, Promoter
e. TATA Box, Enhancer
5. If the following mRNA molecule was translated, how many amino acids would the resulting peptide contain?
5’UCAGGACCUUAUG/GAC/CAU/UGC/UGG/GAC/CUU/UGAGUGCUGUACCAUAGUUAAAGAUA 3’
a. 6
b. 14
c. 10
d. 13
e. 7
f.
6. A tRNA molecule with the anticodon sequence 5’CAU 3’ will pair with which mRNA codon?
a. 5’ ATG 3’
b. 5’ AGC 3’
c. 5’ TUG 3’
d. 5’ AUG 3’
e. 5’ UAC 3’
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, 7. What mRNA sequence can be transcribed off the DNA sequence given below?
5’ CATGCCGATC 3’
3’ GTACGGCTAG 5’
a. 5’ CAUGCCGAUC 3’
b. 5’ GUACGGCUAG 3’
c. 3’ CAUGCCGAUC 5’
d. 5’ CUAGCCGUAC 3’
e. 5’ GAUCGGCAUG 3’
8. What enzyme is responsible for creating peptide bonds between adjacent amino acids in the A and P sites of the
ribosome?
a. peptidase
b. aminocyclase
c. peptidyl transfersase
d. ribyl proteinase
e. catalase
9. Which of the following statements is TRUE?
a. Carboxyl group of the A site amino acid reacts with the amino group of the C-terminal amino acid on the P
site tRNA
b. Amino group of the A site amino acid reacts with the carboxyl group of the C-terminal amino acid on the P
site tRNA
c. Amino group of the tRNA-bound amino acid reacts with the carboxyl group of the C-terminal amino acid on
the P site
d. Carboxyl group of the tRNA-bound amino acid reacts with the amino group of the C-terminal amino acid on
the P site
e. None of the above
10. DNA replication is discontinuous due to __________.
a. polymerase slippage.
b. trinucleotide repeats.
c. being restricted to synthesis in the 5' to 3' direction.
d. topoisomerases cutting the DNA in a random fashion.
e. bidirectional replication.
11. DNA polymerases generally have a 3’ exonuclease activity that serves what function?
a. To cut DNA at restriction sites
b. For DNA proofreading
c. To remove RNA primers
d. To relieve DNA supercoiling
e. For DNA replication
12. The enzymes that unwind and separate short stretches of the DNA helix immediately ahead of a replication fork are
a. Single-stranded binding proteins
b. Unwindases
c. Primases
d. Ligases
e. Helicases
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Read each question carefully and determine exactly what is being asked. Occasionally more than one answer might be
technically correct. Choose the BEST answer.
1. Where does bacterial chromosome replication start?
a. The origin of replication
b. The replication initiation sequence
c. The Shine-Dalgarno sequence
d. The DnaA sequence
e. The promoter region
2. The enzyme that catalyzes the synthesis of DNA is called ____________.
a. DNA helicase
b. DNA gyrase
c. DNA polymerase
d. DNA primase
e. DNA ligase
3. Which enzyme is responsible for forming a phosphodiester bond between 3’-hydroxyl of a growing DNA strand and
the 5’-phosphate of an Okazaki fragment?
a. DNA ligase
b. DNA primase
c. DNA gyrase
d. DNA topoisomerase
e. DNAse
4. In the figure to the right, what labels should
occupy locations A and B?
a. Shine-Dalgarno Region, Promoter
b. Promoter, Operator
c. Promoter, Transcription Start Site
d. Enhancer, Promoter
e. TATA Box, Enhancer
5. If the following mRNA molecule was translated, how many amino acids would the resulting peptide contain?
5’UCAGGACCUUAUG/GAC/CAU/UGC/UGG/GAC/CUU/UGAGUGCUGUACCAUAGUUAAAGAUA 3’
a. 6
b. 14
c. 10
d. 13
e. 7
f.
6. A tRNA molecule with the anticodon sequence 5’CAU 3’ will pair with which mRNA codon?
a. 5’ ATG 3’
b. 5’ AGC 3’
c. 5’ TUG 3’
d. 5’ AUG 3’
e. 5’ UAC 3’
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, 7. What mRNA sequence can be transcribed off the DNA sequence given below?
5’ CATGCCGATC 3’
3’ GTACGGCTAG 5’
a. 5’ CAUGCCGAUC 3’
b. 5’ GUACGGCUAG 3’
c. 3’ CAUGCCGAUC 5’
d. 5’ CUAGCCGUAC 3’
e. 5’ GAUCGGCAUG 3’
8. What enzyme is responsible for creating peptide bonds between adjacent amino acids in the A and P sites of the
ribosome?
a. peptidase
b. aminocyclase
c. peptidyl transfersase
d. ribyl proteinase
e. catalase
9. Which of the following statements is TRUE?
a. Carboxyl group of the A site amino acid reacts with the amino group of the C-terminal amino acid on the P
site tRNA
b. Amino group of the A site amino acid reacts with the carboxyl group of the C-terminal amino acid on the P
site tRNA
c. Amino group of the tRNA-bound amino acid reacts with the carboxyl group of the C-terminal amino acid on
the P site
d. Carboxyl group of the tRNA-bound amino acid reacts with the amino group of the C-terminal amino acid on
the P site
e. None of the above
10. DNA replication is discontinuous due to __________.
a. polymerase slippage.
b. trinucleotide repeats.
c. being restricted to synthesis in the 5' to 3' direction.
d. topoisomerases cutting the DNA in a random fashion.
e. bidirectional replication.
11. DNA polymerases generally have a 3’ exonuclease activity that serves what function?
a. To cut DNA at restriction sites
b. For DNA proofreading
c. To remove RNA primers
d. To relieve DNA supercoiling
e. For DNA replication
12. The enzymes that unwind and separate short stretches of the DNA helix immediately ahead of a replication fork are
a. Single-stranded binding proteins
b. Unwindases
c. Primases
d. Ligases
e. Helicases
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