BICH 431 Exam 1 Questions and
Answers
Northern Blot - ANSWER-detects abundance and size of RNA, similar to a southern
but the RNA must be denatured out of secondary structure
Which strand is extended? - ANSWER->
At what stage is DNA replication regulated? - ANSWER-Initiation for both bacteria
and eukaryotes. After Initiation, replication will proceed at a steady rate until the
chromosome is replicaed
Where are DNA Strands separated to create a replication fork? - ANSWER-The
origin of replication oriC, which is AT rich and 245bp
ARS - ANSWER-Autonomously replicating sequences- origins of replication in yeast
How do bacteria perform replication in 10 hours rather than the time calculated using
genome size and speed of polymerase? - ANSWER-Using multiple origins across
the chromosome to accelerate replication
What is the initiator protein and what is its function? - ANSWER-DnaA is the initiator
protein which binds to oriC and undwinds the DNA and recruits helicase onto the
lagging strand
What is a replicon? - ANSWER-The length of DNA replicated by one origin
What are SSB proteins and what are their function? - ANSWER-Single strand
binding proteins bind to DNA that is single stranded where it has been separated,
coating the DNA
What does primase do - ANSWER-After being recruited by its associated enzyme
helicase, primase creates an RNA primer of about 11-13nt
Clamp Loader - ANSWER-Primed DNA is recognized by a clamp loader, which loads
on a sliding clamp, which leads to DNAPIII associating and polymerizing.
How is initiation regulated in E. Coli? - ANSWER-the origins are hemi-methylated at
a GATC site, and the protein SeqA binds it, preventing DnaA from binding it. Dam
methylase will re-activate it when necessary by methylating the DNA again
SeqA - ANSWER-The protein that binds hemimethylated origin sites and keeps them
from binding DnaA and initiating replication
Answers
Northern Blot - ANSWER-detects abundance and size of RNA, similar to a southern
but the RNA must be denatured out of secondary structure
Which strand is extended? - ANSWER->
At what stage is DNA replication regulated? - ANSWER-Initiation for both bacteria
and eukaryotes. After Initiation, replication will proceed at a steady rate until the
chromosome is replicaed
Where are DNA Strands separated to create a replication fork? - ANSWER-The
origin of replication oriC, which is AT rich and 245bp
ARS - ANSWER-Autonomously replicating sequences- origins of replication in yeast
How do bacteria perform replication in 10 hours rather than the time calculated using
genome size and speed of polymerase? - ANSWER-Using multiple origins across
the chromosome to accelerate replication
What is the initiator protein and what is its function? - ANSWER-DnaA is the initiator
protein which binds to oriC and undwinds the DNA and recruits helicase onto the
lagging strand
What is a replicon? - ANSWER-The length of DNA replicated by one origin
What are SSB proteins and what are their function? - ANSWER-Single strand
binding proteins bind to DNA that is single stranded where it has been separated,
coating the DNA
What does primase do - ANSWER-After being recruited by its associated enzyme
helicase, primase creates an RNA primer of about 11-13nt
Clamp Loader - ANSWER-Primed DNA is recognized by a clamp loader, which loads
on a sliding clamp, which leads to DNAPIII associating and polymerizing.
How is initiation regulated in E. Coli? - ANSWER-the origins are hemi-methylated at
a GATC site, and the protein SeqA binds it, preventing DnaA from binding it. Dam
methylase will re-activate it when necessary by methylating the DNA again
SeqA - ANSWER-The protein that binds hemimethylated origin sites and keeps them
from binding DnaA and initiating replication
