CMB 311 EXAM 2 WITH COMPLETE
SOLUTION
Which of the following enzymes uses a nucleic acid as a template for
synthesis? - ANSWER DNA polymerase
RNA polymerase
The Ribosome
what are the correct substrates for DNA polymerase? - ANSWER dATP
dCTP
dGTP
dTTP
what is the primary role of DNA Pol 1 in replication - ANSWER removal RNA
primers from Okazaki fragments and replacements with DNA
what is the function of 3' -> 5' exonuclease activity of DNA polymerase? -
ANSWER removal of erroneously incorporated nucleotides
what is the role of DnaG Primase in replication? - ANSWER synthesis of RNA
primers
what is meant by the statement that DNA replication is semiconservative? -
ANSWER each daughter DNA molecule DNA molecule contains one original
strand and newly synthesized strand
what is the role of DnaB helices replication? - ANSWER unwind the DNA
double helix strands
,what is one thing that RNA Polymerase can do that DNA polymerase cannot?
- ANSWER initiate synthesis de novo without a primer
what is meant by the statement that DNA replication is semidiscontinuous -
ANSWER DNA synthesis is continuous on the leading strand and
discontinuous on the lagging strand
what is the function of DNA Pol 3 clamp loader complex - ANSWER add a
new B-sliding clamp to the DNA Pol 3 at the start of each Okazaki fragment
add the B-sliding clamp on the leading strand at the stat of synthesis
recruit free B-sliding clamp molecules to the replisome during replication
fork movement
what are the correct substrates for RNA POLYMERASES ( RNAP ) - ANSWER
ATP
CTP
GTP
UTP
Place the three main types of RNA in their order of abundance, from most to
least - ANSWER rRNA > tRNA > mRNA
which species of RNA is produced by each of the three eukaryotic RNA
Polymerase - ANSWER Pol 1 = rRNA
Pol 2 = mRNA
Pol 3 = tRNA
5s = rRNA
,what is the role of sigma factor in transcription - ANSWER recognize
promoter sequences
what is the role of rho factor in transcription - ANSWER trigger transcription
termination
what feature defines rho - independent transcription termination - ANSWER
a stem- loop structure followed by a run of U residues in the RNA
which subunit if RNA polymerase dissociates from the core enzyme after
initiation - ANSWER sigma
Formation of the open complex (OC) during transcription occurs upon what
event - ANSWER unwinding of the promoter DNA by RNAP
which feature of transcription is found in bacteria and not eukaryotes -
ANSWER coupling of transcription and translation
at what stages of transcription does the C-terminal domain of RNA Pol 2
participate? - ANSWER imitation, elongation, termination
DNA replication errors are repaired by which system - ANSWER mismatch
repair (MMR)
thymine dimers are repaired by which DNA repair system - ANSWER
Nucleotide Excision Repair (NER)
what does MMR, BER, and NER systems have in common - ANSWER they
remove a stretch of nucleotides of one strand and replace it by new synthesis
which of the following changes results from deamination and is mutagenic if
not repaired - ANSWER C -> U
which type of introns are removed by RNA catalysis - ANSWER Group 1 and 2
, Which of the following RNA alterations occurring both bacteria and
eukaryotes - ANSWER processing of rRNA and tRNA precursors
Which introns form a lariat structure as a splicing intermediate? - ANSWER
group II and spliceosomal
what roles can post transcriptional modification or editing of RNA serve -
ANSWER influence stability or ocal structure in tRNAs
influence decoding properties of tRNAs
alter identity of specific codons in mRNAs
alter splice-site selection in mRNAs
what do cells control gene expression - ANSWER to synthesize proteins in the
amount needed
to respond to changes in environment or stress
to produce proteins at the appropriate time during development
to produce proteins in the tissue where they are needed
how is expression of the lac operon negatively controlled - ANSWER lac
repressor bind to the lac operator in the absence of lactose
how is expression of the lac operon positively controlled - ANSWER CAP
binds cAMP, binds near the lac promoter, stimulates RNAP binding
which statement about the top operons is not true - ANSWER the trp operon
attention mechanism depends on termination factor rho
which statement about the top operons is true - ANSWER the trp operon is
controlled by alternative mRNA secondary structures
SOLUTION
Which of the following enzymes uses a nucleic acid as a template for
synthesis? - ANSWER DNA polymerase
RNA polymerase
The Ribosome
what are the correct substrates for DNA polymerase? - ANSWER dATP
dCTP
dGTP
dTTP
what is the primary role of DNA Pol 1 in replication - ANSWER removal RNA
primers from Okazaki fragments and replacements with DNA
what is the function of 3' -> 5' exonuclease activity of DNA polymerase? -
ANSWER removal of erroneously incorporated nucleotides
what is the role of DnaG Primase in replication? - ANSWER synthesis of RNA
primers
what is meant by the statement that DNA replication is semiconservative? -
ANSWER each daughter DNA molecule DNA molecule contains one original
strand and newly synthesized strand
what is the role of DnaB helices replication? - ANSWER unwind the DNA
double helix strands
,what is one thing that RNA Polymerase can do that DNA polymerase cannot?
- ANSWER initiate synthesis de novo without a primer
what is meant by the statement that DNA replication is semidiscontinuous -
ANSWER DNA synthesis is continuous on the leading strand and
discontinuous on the lagging strand
what is the function of DNA Pol 3 clamp loader complex - ANSWER add a
new B-sliding clamp to the DNA Pol 3 at the start of each Okazaki fragment
add the B-sliding clamp on the leading strand at the stat of synthesis
recruit free B-sliding clamp molecules to the replisome during replication
fork movement
what are the correct substrates for RNA POLYMERASES ( RNAP ) - ANSWER
ATP
CTP
GTP
UTP
Place the three main types of RNA in their order of abundance, from most to
least - ANSWER rRNA > tRNA > mRNA
which species of RNA is produced by each of the three eukaryotic RNA
Polymerase - ANSWER Pol 1 = rRNA
Pol 2 = mRNA
Pol 3 = tRNA
5s = rRNA
,what is the role of sigma factor in transcription - ANSWER recognize
promoter sequences
what is the role of rho factor in transcription - ANSWER trigger transcription
termination
what feature defines rho - independent transcription termination - ANSWER
a stem- loop structure followed by a run of U residues in the RNA
which subunit if RNA polymerase dissociates from the core enzyme after
initiation - ANSWER sigma
Formation of the open complex (OC) during transcription occurs upon what
event - ANSWER unwinding of the promoter DNA by RNAP
which feature of transcription is found in bacteria and not eukaryotes -
ANSWER coupling of transcription and translation
at what stages of transcription does the C-terminal domain of RNA Pol 2
participate? - ANSWER imitation, elongation, termination
DNA replication errors are repaired by which system - ANSWER mismatch
repair (MMR)
thymine dimers are repaired by which DNA repair system - ANSWER
Nucleotide Excision Repair (NER)
what does MMR, BER, and NER systems have in common - ANSWER they
remove a stretch of nucleotides of one strand and replace it by new synthesis
which of the following changes results from deamination and is mutagenic if
not repaired - ANSWER C -> U
which type of introns are removed by RNA catalysis - ANSWER Group 1 and 2
, Which of the following RNA alterations occurring both bacteria and
eukaryotes - ANSWER processing of rRNA and tRNA precursors
Which introns form a lariat structure as a splicing intermediate? - ANSWER
group II and spliceosomal
what roles can post transcriptional modification or editing of RNA serve -
ANSWER influence stability or ocal structure in tRNAs
influence decoding properties of tRNAs
alter identity of specific codons in mRNAs
alter splice-site selection in mRNAs
what do cells control gene expression - ANSWER to synthesize proteins in the
amount needed
to respond to changes in environment or stress
to produce proteins at the appropriate time during development
to produce proteins in the tissue where they are needed
how is expression of the lac operon negatively controlled - ANSWER lac
repressor bind to the lac operator in the absence of lactose
how is expression of the lac operon positively controlled - ANSWER CAP
binds cAMP, binds near the lac promoter, stimulates RNAP binding
which statement about the top operons is not true - ANSWER the trp operon
attention mechanism depends on termination factor rho
which statement about the top operons is true - ANSWER the trp operon is
controlled by alternative mRNA secondary structures
