Biochemistry ACS Exam | Actual Questions and Answers Latest
Updated 2026/2027 (Graded A+)
• Question
Helicase
Correct Answer: Catalyzes ATP-dependent unwinding of DNA double helices
• Question
What is the helicase in E. Coli?
Correct Answer: DNAB
• Question
Single-Stranded Binding Protein
Correct Answer: Binds to unwound strands of DNA to prevent reannealing
• Question
DNA Polymerase
Correct Answer: Enzyme responsible for DNA replication
Uses ssDNA as a template and makes a complimentary strand by polymerizing
deoxynucleotides
Synthesis in 5' to 3' direction
• Question
List the DNA polymerases in E. Coli
Correct Answer: Pol I, II, III
• Question
DNA pol I
Correct Answer: Removes RNA primers and fills the gaps, proofreads
• Question
DNA pol II
Correct Answer: DNA repair enzyme expressed in response to DNA damage
,• Question
DNA pol III
Correct Answer: Using parental DNA as a template, synthesizes new DNA strand by
adding nucleotides to an RNA primer or a pre-existing DNA strand
• Question
List the DNA polymerases in eukaryotes
Correct Answer: α, β, δ, ε, γ
• Question
α polymerase
Correct Answer: Initiation of nuclear DNA replication
• Question
β polymerase
Correct Answer: DNA repair
• Question
δ polymerase
Correct Answer: Principal polymerase in leading and lagging strand sythesis, highly
processive
• Question
ε polymerase
Correct Answer: Leading and lagging strand synthesis, sensor of DNA damage,
checkpoint control
• Question
γ polymerase
Correct Answer: Mitochondrial DNA replication
• Question
RNAse H
Correct Answer: A nuclease that specifically degrades RNA chains in DNA in eukaryotes
(DNA Poly I in prokaryotes)
• Question
DNA Ligase
Correct Answer: Seals nicks in dsDNA
, • Question
Telomerase
Correct Answer: Adds telomeres to the ends of chromosomal DNA, RNA-dependent DNA
polymerase (has its own RNA primer)
• Question
Semi-conservative model
Correct Answer: One parent strand and one newly synthesized strand
• Question
Discontinuous model
Correct Answer: In DNA replication, lagging strand makes okazaki fragments that need
to be glued together by ligase
• Question
Central Dogma
Correct Answer: DNA -> RNA -> Protein
DNA replicates, DNA is transcribed into RNA, RNA is translated to protein
• Question
What direction is RNA synthesized?
Correct Answer: 5' to 3'
• Question
In what direction is DNA template read?
Correct Answer: 3' to 5'
• Question
Hydrogen bond
Correct Answer: Hydrogen covalently bonded to an electronegative atom in one
molecule
Forms a non-covalent bond with electronegative atoms of another molecule (N, O, F)
Adds to solubility of a molecule of water
Updated 2026/2027 (Graded A+)
• Question
Helicase
Correct Answer: Catalyzes ATP-dependent unwinding of DNA double helices
• Question
What is the helicase in E. Coli?
Correct Answer: DNAB
• Question
Single-Stranded Binding Protein
Correct Answer: Binds to unwound strands of DNA to prevent reannealing
• Question
DNA Polymerase
Correct Answer: Enzyme responsible for DNA replication
Uses ssDNA as a template and makes a complimentary strand by polymerizing
deoxynucleotides
Synthesis in 5' to 3' direction
• Question
List the DNA polymerases in E. Coli
Correct Answer: Pol I, II, III
• Question
DNA pol I
Correct Answer: Removes RNA primers and fills the gaps, proofreads
• Question
DNA pol II
Correct Answer: DNA repair enzyme expressed in response to DNA damage
,• Question
DNA pol III
Correct Answer: Using parental DNA as a template, synthesizes new DNA strand by
adding nucleotides to an RNA primer or a pre-existing DNA strand
• Question
List the DNA polymerases in eukaryotes
Correct Answer: α, β, δ, ε, γ
• Question
α polymerase
Correct Answer: Initiation of nuclear DNA replication
• Question
β polymerase
Correct Answer: DNA repair
• Question
δ polymerase
Correct Answer: Principal polymerase in leading and lagging strand sythesis, highly
processive
• Question
ε polymerase
Correct Answer: Leading and lagging strand synthesis, sensor of DNA damage,
checkpoint control
• Question
γ polymerase
Correct Answer: Mitochondrial DNA replication
• Question
RNAse H
Correct Answer: A nuclease that specifically degrades RNA chains in DNA in eukaryotes
(DNA Poly I in prokaryotes)
• Question
DNA Ligase
Correct Answer: Seals nicks in dsDNA
, • Question
Telomerase
Correct Answer: Adds telomeres to the ends of chromosomal DNA, RNA-dependent DNA
polymerase (has its own RNA primer)
• Question
Semi-conservative model
Correct Answer: One parent strand and one newly synthesized strand
• Question
Discontinuous model
Correct Answer: In DNA replication, lagging strand makes okazaki fragments that need
to be glued together by ligase
• Question
Central Dogma
Correct Answer: DNA -> RNA -> Protein
DNA replicates, DNA is transcribed into RNA, RNA is translated to protein
• Question
What direction is RNA synthesized?
Correct Answer: 5' to 3'
• Question
In what direction is DNA template read?
Correct Answer: 3' to 5'
• Question
Hydrogen bond
Correct Answer: Hydrogen covalently bonded to an electronegative atom in one
molecule
Forms a non-covalent bond with electronegative atoms of another molecule (N, O, F)
Adds to solubility of a molecule of water
