Exam 5 Flashcards
(Exam 5) A piece of DNA has 15 base pairs per twists (bp/twist). This DNA will exhibit:
-Positive supercoiling
-Negative supercoiling
-Negative supercoiling
(Exam 5) DNA polymerases:
-catalyze phosphodiester bonds between two strands of DNA
-synthesizes the new DNA strand in 3’ to 5’ direction
-are always very processive
-always contain proofreading ability
-can catalyze the same reaction without releasing its substrate
-can catalyze the same reaction without releasing its substrate
(Exam 5) DNA helicase:
-utilizes ATP to help separate double stranded DNA (dsDNA).
-helps relieve supercoiling that results from unwinding DNA.
-induces negative supercoiling.
-proofread DNA bases.
-helps protects single stranded DNA after double stranded DNA has been separated.
-utilizes ATP to help separate double stranded DNA (dsDNA).
(Exam 5) Sliding clamp is loaded onto a double-stranded nucleic acid template via:
-Clamp loading complex
-DNA polymerase
-Clamp loading complex
(Exam 5) Which one of the following is not a part of the replisome?
-DNA primase
-Topoisomerase
-DNA polymerase
-Clamp loader
-Sliding clamp
-Topoisomerase
(Exam 5) Initiation of DNA replication in E. coli requires:
-High concentrations of DnaA complexed with ATP
-DnaB to unwind the DNA unwinding element
-Hemimethylated DNA unwinding element
-High concentrations of DnaA complexed with ADP
-DnaA to load DnaB onto the DNA unwinding element
-High concentrations of DnaA complexed with ATP
(Exam 5) The main replicative DNA polymerase in E. coli is:
-DNA polymerase I
-DNA polymerase II
-DNA polymerase III
-DNA polymerase IV
-DNA polymerase V
-DNA polymerase III
(Exam 5) In E. coli, RNA primers are removed from newly synthesized DNA using:
-Flap endonuclease 1 (FEN1)
-DNA polymerase III
-DNA polymerase I
-Primase
-DNA polymerase delta (δ)
-DNA polymerase I
(Exam 5) The termination of DNA replication in E. coli occurs at:
-random sites of DNA
-Tus/Ter complexes
-Tus/Ter complexes
(Exam 5) In eukaryotes, initiation of DNA replication starts when __________binds to the origin of replication.
-Origin recognition complex
-DnaA-ATP
-Origin recognition complex
(Exam 5) The DNA polymerase in eukaryotes that synthesizes the majority of the lagging strand is:
-DNA polymerase III
-DNA polymerase alpha (α)
-DNA polymerase delta (δ)
-DNA polymerase epsilon (ε)
-DNA polymerase I
-DNA polymerase delta (δ)
(Exam 5) What is the correct order of DNA polymerase function for leading strand synthesis in eukaryotes?
-DNA polymerase alpha (α) → DNA polymerase delta (δ)
-DNA polymerase alpha (α) → DNA polymerase epsilon (ε) → DNA polymerase delta (δ)
-DNA polymerase delta (δ) → DNA polymerase epsilon (ε) → DNA polymerase alpha (α)
-DNA polymerase alpha (α) → DNA polymerase epsilon (ε)
-DNA polymerase alpha (α) → DNA polymerase delta (δ) → DNA polymerase epsilon (ε)
-DNA polymerase alpha (α) → DNA polymerase delta (δ) → DNA polymerase epsilon (ε)
(Exam 5) Telomeres:
-protect tips of prokaryotic chromosomes
-protects 3’ ends of prokaryotic mRNA
-protects tips of eukaryotic chromosomes
-protects 5’ ends of eukaryotic mRNA
-protects 5’ ends of prokaryotic mRNA
-protects tips of eukaryotic chromosomes
(Exam 5) __________ only occurs during DNA replication (i.e., S and G2 phase).
-Base excision repair
-Nucleotide excision repair
-Mismatch repair
-Direct reversal
-Non-homologous end joining
-Mismatch repair
(Exam 5) The use of a specialized polymerase to read through DNA lesions is called:
-damage avoidance
-homologous recombination
-translesion synthesis
-mismatch repair
-polymerase switch
-translesion synthesis
(Exam 5) When repairing DNA, __________ removes and replaces only the damaged nucleotide from DNA.
-Base excision repair
-Nucleotide excision repair
-Mismatch repair
-Direct reversal
-Non-homologous end joining
-Base excision repair
(Exam 5) Holliday junction resolution occurs when:
-two Holliday junctions collide, resulting in the unravelling of both Holliday junctions.
-two strands of DNA are cut resulting in one Holliday junction being unraveled.
-two strands of DNA are cut resulting in one Holliday junction being unraveled.
(Exam 5) The sugar ring in RNA is:
-ribose
-deoxyribose
-ribose
(Exam 5) Tertiary structure of RNA:
-Occurs between two different strands of RNA
-Occurs between one strand of RNA and a protein
-Occurs between complimentary base pairs between 2 (or more) secondary structure elements
-Is the linear sequence of nitrogenous bases written in 5’ to 3’ direction
-Occurs between one strand of RNA and one strand of DNA
-Occurs between complimentary base pairs between 2 (or more) secondary structure elements
(Exam 5) RNA synthesis in humans:
-does not require DNA.
-Involves RNA polymerase reading DNA via Watson-Crick base pairs.
-Results from polymerization of deoxyribonucleotides.
-Requires a primer to load the RNA polymerase.
-Does not occur as part of DNA replication
-Involves RNA polymerase reading DNA via Watson-Crick base pairs.
(Exam 5) __________ recognizes the promoter during initiation of prokaryotic transcription.
-The sigma (σ)-subunit
-TFIID
-TFIIH
-RNA polymerase II
-TFIIF
-The sigma (σ)-subunit
(Exam 5) During transcriptional initiation in eukaryotes, the mediator:
-prevents DNA bending
-promotes DNA bending
-allows interactions between proteins bound to the enhancer and promoter
-allows interactions between proteins bound to the proximal regulatory region and the promoter
-directly binds DNA at the site of promoter to help recruit RNA polymerase II
-allows interactions between proteins bound to the enhancer and promoter
(Exam 5) In prokaryotes, factor-independent termination involves:
-RNA polymerase decoding the Rho-recognition site.
-The recruitment of a protein complex to dislodge the RNA polymerase from the DNA template.
-The recruitment of a protein complex to cut the RNA off the RNA polymerase.
-formation of a secondary structure in the transcribed RNA which destabilizes the DNA-RNA interaction.
-a helicase inducing positive supercoiling of DNA that stalls the RNA polymerase.
-formation of a secondary structure in the transcribed RNA which destabilizes the DNA-RNA interaction.
(Exam 5) In prokaryotes, the AT-rich region of DNA that is separated during the initiation of transcription is called:
-Pribnow box
-DNA unwinding element
-Pribnow box
(Exam 5) When a CpG island is heavily methylated (i.e., 5-methlycytosine), it likely means that transcriptional activators:
-will be bound by DNA.
-will not be bound by DNA
-will not be bound by DNA
(Exam 5) 5-methylcytosine:
-Is often reversible
-Found at all instances of CpG residues in humans
-Is immune to all forms of DNA damage
-Forms complimentary base pairs with adenine
-Often results in decreased gene expression
-Often results in decreased gene expression
(Exam 5) What effect does hyperacetylation of histones have on histone-DNA interaction?
-Promotes degradation of histones, thus destabilizing histone-DNA interactions
-Promotes binding of RNA to DNA, resulting in destabilization of histone-DNA
interactions
-Histones become less positively charged, destabilizing histone-DNA interactions
-Histones become more positively charged, stabilizing histone-DNA interactions
-Acetylation does not affect histone-DNA interactions
-Histones become less positively charged, destabilizing histone-DNA interactions
(Exam 5) The spread of histone modifications is stopped by:
-Barrier (or insulator) proteins
-Histone terminating (or conclusion) proteins
-Barrier (or insulator) proteins
