BIO 340 Final Exam/ 491 Qs & Ans/ A+ Score
Solution/ 2024-2025.
What type of bonds are formed between complementary DNA bases? - Answer: Hydrogen
Bonds
Which of the following forms the backbone of a polynucleotide chain? - Answer: alternating
sugar and phosphate groups
Guanine and adenine are purines found in DNA - Answer: true
Page 1 of 60
,What fraction of the nucleotides in a doubles-stranded DNA molecule are cytosine and
thymine? - Answer: 50%
What is one difference between DNA replication in bacteria versus eukaryotes? - Answer:
Eukaryotic chromosomes have many origins of replication, while bacteria have only one origin
of replication
What is the maximum rate between DNA replication in E. coli - Answer: 1000 nucleotides
During DNA replication in E. coli, what is the role of DNA? - Answer: DnaA bends DNA,
hydrolyzing the hydrogen bonds in the 13-mer region of otic and creating an open complex
Which of the following statements about DNA replication is true? - Answer: Single-strand
binding proteins stabilize the open conformation of the unwound DNA
Which of the following reagents is not required for the polymerase chain reaction? - Answer:
Dideoxynucleotide triphosphate
Which of the following would you find in a Sanger sequencing reaction but not in a polymerase
chain reaction? - Answer: ddNTPs
Which of the following statements about ddNTPs is true? - Answer: they have a hydrogen at the
3' carbon of the sugar
The principles of complementary base pairing and antiparallel polarity of nucleic acid strands is
a duplex are universal for the formation of nucleic acid duplexes. What is the chemical basis for
this university? - Answer:
Page 2 of 60
,You wish to create a mutation in which you prevent access of RNA polymerase to the gene.
Which region of a gene would you target? - Answer: promoter sequence
Which region(s) of a gene are not found within the mRNA transcript? - Answer: promoter region
Which of the following statements regarding Nucleotide Excision repair (NER) and Base Excision
Repair (BER) is true? - Answer: both NER and BER involve the removal of one or more damaged
bases by a nuclease
How large is an origin of replication of E. coli? - Answer: 245 base pairs
Which of the following enzymatic activities is NOT involved in DNA replication - Answer: RNA-
dependent DNA polymerase
Which activity of DNA polymerase is responsible for its ability to proofread newly synthesized
DNA - Answer: 3'>5' exonuclease which cleaves mismatched nucleotides
How many mutations would you expect to see in the human genome (6x10^9) if mismatches
could not be repaired? - Answer: 6x10^9/10^4= 600,000 mutations
What would the consequences be of having DNA polymerase with out 5' -> 3' exonuclease
activity? - Answer: the RNA primer will stay
What is the correct order of enzyme action during DNA replication? - Answer:
helices/topoisomerase activity, priming, DNA polymerization/proofreading, 5'-3' exonuclease
activity/DNA polymerization, ligation
Why is telomerase important? - Answer: It is important for extension
Page 3 of 60
, You isolate a mutant of this gene that encodes the following protein:
N-Met-Gln-Cys-Lys-Ser-C
What mutation can give you this mutant protein - Answer: Deletion of a C
Which of the following statements are FALSE? - Answer: the Trp Operon is under positive
control
*LAC has both positive and negative regulation* - Answer:
Trp is negative controlled - Answer:
Under which of the following conditions will E. coli make large amounts of B- galactosidase? -
Answer: I+O+Z+, glucose absent, lactose present
I-OcZ+, glucose absent, lactose absent
Under what condition will E. coli make the least amount of B-galactosidase? - Answer: IsO+Z+,
glucose absent, lactose present
For the lac operon gene regulation system, which of the following is false? - Answer: in the
presence of low levels of glucose and lactose, even with mutation happening on the operator
(operator cannot bind to repressor), there are still no transcription of lac genes
The expression of a gene can be increase by? - Answer: knocking out its repressor
In the Trp operon of E. coli, the Trytophan repressor protein, Trp R, will bind to the operator to
prevent transcription only in the presence of tryptophan. What is tryptophan an example of? -
Answer: Co-repressor
Which of the following is required for transcription - Answer: RNA polymerase
Page 4 of 60
Solution/ 2024-2025.
What type of bonds are formed between complementary DNA bases? - Answer: Hydrogen
Bonds
Which of the following forms the backbone of a polynucleotide chain? - Answer: alternating
sugar and phosphate groups
Guanine and adenine are purines found in DNA - Answer: true
Page 1 of 60
,What fraction of the nucleotides in a doubles-stranded DNA molecule are cytosine and
thymine? - Answer: 50%
What is one difference between DNA replication in bacteria versus eukaryotes? - Answer:
Eukaryotic chromosomes have many origins of replication, while bacteria have only one origin
of replication
What is the maximum rate between DNA replication in E. coli - Answer: 1000 nucleotides
During DNA replication in E. coli, what is the role of DNA? - Answer: DnaA bends DNA,
hydrolyzing the hydrogen bonds in the 13-mer region of otic and creating an open complex
Which of the following statements about DNA replication is true? - Answer: Single-strand
binding proteins stabilize the open conformation of the unwound DNA
Which of the following reagents is not required for the polymerase chain reaction? - Answer:
Dideoxynucleotide triphosphate
Which of the following would you find in a Sanger sequencing reaction but not in a polymerase
chain reaction? - Answer: ddNTPs
Which of the following statements about ddNTPs is true? - Answer: they have a hydrogen at the
3' carbon of the sugar
The principles of complementary base pairing and antiparallel polarity of nucleic acid strands is
a duplex are universal for the formation of nucleic acid duplexes. What is the chemical basis for
this university? - Answer:
Page 2 of 60
,You wish to create a mutation in which you prevent access of RNA polymerase to the gene.
Which region of a gene would you target? - Answer: promoter sequence
Which region(s) of a gene are not found within the mRNA transcript? - Answer: promoter region
Which of the following statements regarding Nucleotide Excision repair (NER) and Base Excision
Repair (BER) is true? - Answer: both NER and BER involve the removal of one or more damaged
bases by a nuclease
How large is an origin of replication of E. coli? - Answer: 245 base pairs
Which of the following enzymatic activities is NOT involved in DNA replication - Answer: RNA-
dependent DNA polymerase
Which activity of DNA polymerase is responsible for its ability to proofread newly synthesized
DNA - Answer: 3'>5' exonuclease which cleaves mismatched nucleotides
How many mutations would you expect to see in the human genome (6x10^9) if mismatches
could not be repaired? - Answer: 6x10^9/10^4= 600,000 mutations
What would the consequences be of having DNA polymerase with out 5' -> 3' exonuclease
activity? - Answer: the RNA primer will stay
What is the correct order of enzyme action during DNA replication? - Answer:
helices/topoisomerase activity, priming, DNA polymerization/proofreading, 5'-3' exonuclease
activity/DNA polymerization, ligation
Why is telomerase important? - Answer: It is important for extension
Page 3 of 60
, You isolate a mutant of this gene that encodes the following protein:
N-Met-Gln-Cys-Lys-Ser-C
What mutation can give you this mutant protein - Answer: Deletion of a C
Which of the following statements are FALSE? - Answer: the Trp Operon is under positive
control
*LAC has both positive and negative regulation* - Answer:
Trp is negative controlled - Answer:
Under which of the following conditions will E. coli make large amounts of B- galactosidase? -
Answer: I+O+Z+, glucose absent, lactose present
I-OcZ+, glucose absent, lactose absent
Under what condition will E. coli make the least amount of B-galactosidase? - Answer: IsO+Z+,
glucose absent, lactose present
For the lac operon gene regulation system, which of the following is false? - Answer: in the
presence of low levels of glucose and lactose, even with mutation happening on the operator
(operator cannot bind to repressor), there are still no transcription of lac genes
The expression of a gene can be increase by? - Answer: knocking out its repressor
In the Trp operon of E. coli, the Trytophan repressor protein, Trp R, will bind to the operator to
prevent transcription only in the presence of tryptophan. What is tryptophan an example of? -
Answer: Co-repressor
Which of the following is required for transcription - Answer: RNA polymerase
Page 4 of 60
