MCB Final Exam Document Flashcards
What is the primary replicating enzyme?
DNA polymerase delta
What is the prokaryotic ortholog for DNA polymerase delta?
DNA polymerase III
What is responsible for RNA primer synthesis?
Primase
What is PCNA?
Sliding clamp
What is the prokaryotic ortholog for PCNA?
Beta subunit
What is the RFC?
The clamp loader (RFC - reload the fucking clamp)
Prokaryotic ortholog for RFC
Gamma complex
What is the role of RPA?
Maintain and protect ssDNA
What is the prokaryotic ortholog for RPA?
SSB
What are MCM and CDC6?
Helicase and helicase loader respectively
What is the prokaryotic ortholog for MCM and CDC6?
DnaB and DnaC respectively
What is the function of ligase?
Links adjacent Okazaki fragments
FEN1/RNaseH does what?
Removes RNA primer
What is the prokaryotic ortholog for FEN1/RNaseH?
DNA polymerase I
What is the role of DNA polymerase epsilon?
Fills in gap left by primer
What is the prokaryotic ortholog for DNA polymerase epsilon?
DNA polymerase I
Which topoisomerase nicks DNA, does not require ATP, and removes supercoils one at a time?
Topoisomerase type I
Which topoisomerase cuts double stranded DNA, requires ATP, can induce or remove supercoils (2 at a time)
Topoisomerase type II
What enzyme plays a role in chromatin remodeling by cartelizing the removal of acetyl groups from lysine and arginine residues?
HDACs
Which enzymes play a role in chromatin remodeling by catalyzing transfer of acetyl groups from acetyl CoA to various lysine and arginine residues in amino terminal regions of histone proteins?
HATs
____________ prevents chromatin from folding in compact structures, maintaining euchromatic state
Acetylation
Enzymes that covalently modify the core histone son nucleosomes are?
HATs and HDACs
Which enzymes remodel nucleosomes on DNA by actively moving or displacing nucleosomes?
SWI/SNF complexes
Which enzymes use ATP to remodel nucleosomes on the DNA?
SWI/SNF complexes
How do SWI/SNF complexes actively move or displace nucleosomes?
By creating hypersensitive sites in DNA which stimulate binding of TFs
Mismatch repair occurs in which phase of the cell cycle?
G2 cycle
What is occurring in the G2 phase of the cell cycle?
Cell is preparing to divide
Nucleotide excision repair occurs in which phase of the cell cycle?
G1 phase
What is occurring in the G1 phase of the cell cycle?
The cell grows
When in the cell cycle does proofreading occur?
S phase
What is occurring in the S phase of the cell cycle?
DNA is being replicated
What proteins recognize mismatches by DNA polymerase?
MutS and MutL, these require ATP
DNA is threaded through MutS/MutL complex until it reaches MutH protein bound to a ______________________, then what happens?
Hemimethylated GATC site, MutH nicks the newly synthesized strand
After nick from MutH, and cleavage from helicase and exonuclease activity, _________________ will resynthesize the strand and ______________ will fix the nick
DNA polymerase III, DNA ligase
Nucleotide excision repair removes bulky lesions such as?
Pyrimidine dimers and nucleotides with chemicals attached
What is the preferential repair of template strand where RNA polymerase has stalled? It has CSB protein involvement which is a component of TFIIH complex
Transcription coupled pathway (part of NER)
_____ and _____ are DNA ____________ in NER that act to unwind the region of DNA
XPB and XPD, helicases
Which type of eukaryotic RNA polymerase is found in nucleolus and has cellular transcripts 18S, 5.8S, 28S rRNA?
Polymerase type I
Which type of eukaryotic polymerase is found in the nucleoplasm and has the cellular transcripts: mRNA precursors and snRNA?
RNA polymerase type II
Which type of eukaryotic polymerase is found in the nucleoplasm and has tRNA and 5S rRNA cellular transcripts?
RNA polymerase type III
Effects of amanitin on eukaryotic RNA polymerase type I, II, and III?
Type I: insensitive,
Type 2: strongly inhibited
Type 3: inhibited by high concentrations
What acts indirectly as a bridge between DNA -binding transactivators and complex composed of polymerase II and General TFs?
Co-activators
May be thousands of base pairs away from transcription initiation site and make contact with initiator sites through transactivators
Enhancers
What limits the action range of enhancers and might bind to nuclear matrix giving looped domains?
Insulators
Regulatory elements like promoters and enhancers that are on same chromosome as transcribed gene are acting in _____?
Cis
Activator or repressor proteins reach point of action by diffusion and act in ____?
Trans
Epinephrine activates what type of receptors?
G-protein coupled receptors
Activated G-protein coupled receptors bind to and activate what?
Adenylyl cyclase giving increased cAMP levels
cAMP binds to what?
Regulatory subunit of protein kinase A (PKA) which moves into the nucleus
After PKA moves into the nucleus, it’s catalytic subunit phosphorylates what?
cAMP response element binding proteins (CREB)
P-CREB binds to cAMP response elements in promoter of target genes and binds to coactivator CREB binding protein (CRB) yielding what?
Facilitation of transcription via histone acetylation and chromatin remodeling
Wobble position in anticodon is there for what?
Steric freedom so other bases may pair