JMU BIO 140 LATEST EXAMS SCRIPT ALL
QUESTIONS AND ANSWERS SURE A+
✔✔The lagging strand is away or towards the fork? - ✔✔away
✔✔The leading strand is away or towards the fork? - ✔✔towards
✔✔How many DNA polymerase are used in a replication bubble? - ✔✔4
✔✔Replication forks are ________. - ✔✔asymmetrical
✔✔Define okazaki fragments - ✔✔The noncontinuous segments of newly synthesized
DNA along the lagging strand
✔✔What are the steps of replication? - ✔✔-unwinding of the DNA duplex
-elongation occurs from 5' to 3' on the template strand
-DNA polymerase extends the RNA primer
-A different DNA polymerase removes the primer and replaced with DNA
-fragments of the discontinuous strand are ligated with DNA ligase
✔✔What does RNA primase do? - ✔✔lays down an RNA primer
✔✔How many RNA primers are on the leading strand? - ✔✔one
,✔✔How many RNA primers are on the lagging strand? - ✔✔multiple
✔✔What does DNA polumerase do? - ✔✔extends the RNA primer
✔✔What does helicase do? - ✔✔unwinds the DNA duplex
✔✔What does topoisomerase II do? - ✔✔relieves the stress of the unwinding DNA
✔✔What does single-stranded binding proteins do? - ✔✔stabilize single strands of DNA
✔✔What occurs when the okazaki fragments are being synthesized? - ✔✔the lagging
strand forms a loop that persists until the new lagging strand encounters the previous
fragment
✔✔What helps the DNA when an nucleotide is added incorrectly? - ✔✔the proofreading
function of DNA polymerase removes the incorrect nucleotide
✔✔What is the main difference in replication between eukaryotic chromosomes and
prokaryotic chromosomes? - ✔✔eukaryotic chromosomes have multiple origins of
replication and prokaryotic chromosomes have one
✔✔How does replication start in circular chromosomes? - ✔✔starts at the origin and
moves around the circular chromosome in both directions
✔✔What type of organism has circular chromosome? - ✔✔bacteria
✔✔What occurs every time DNA is replicated? - ✔✔the strand gets slightly shorter
✔✔What helps keep DNA from shortening in every replication? - ✔✔telomeres and
teomerase
✔✔What are the steps of telomeres and telomerase that help with replicating
chromosomal ends? - ✔✔-terminal part of the telomere in the template DNA strand
remains unreplicated
-telomerase enzyme contains an RNA template that allows the shortened 3' end of the
template strand to be restored by the addition of more telomere repeats
-a new segment of lagging strand can be formed so that the original telomere in the
template strand is comepletely restored
✔✔What is PCR? - ✔✔repeated rounds of DNA replication in a test tube
✔✔What are the three steps in PCR? - ✔✔-denaturation
-annealing
, -extension
✔✔What is denaturation? - ✔✔heating to separate the DNA into two individual strands
✔✔What is annealing? - ✔✔when the solution is cooled, the two primers anneal to their
complementary sequence on the strands of the template duplex
✔✔What is extension? - ✔✔DNA polymerase synthesizes new DNA strand by
extending primers in a 5' to 3' direction
✔✔What is the equation for PCR copies? - ✔✔2^n
✔✔What does gel electrophoresis do? - ✔✔separates DNA fragments according to size
✔✔How do DNA fragments move in gel electrophoresis? - ✔✔towards the positive pole
according to their size
✔✔How do smaller or larger DNA fragments move in gel electrophoresis? - ✔✔smaller
fragments move faster and larger ones move slower
✔✔What is the difference between deoxynuxleotide and dideoxynucleotide? -
✔✔dideoxynucleotide lacks 3' hydroxyl group
✔✔What occurs when a dideoxynucleotide is added? - ✔✔the DNA strand can't be
elongated
✔✔Define DNA replication - ✔✔process of duplicating a DNA molecule, during which
the parental strands separate and new partner strands are made
✔✔Define template strand - ✔✔the parental strand whose sequence is used to
synthesize a complementary daughter strand
✔✔Define daughter strand - ✔✔the strand synthesized from parental template strand
✔✔What is usually the sequence for telomere? - ✔✔3′-GGGATT-5'
✔✔Define polymerase chain reaction - ✔✔selective and highly sensitive method for
making copies of a piece of DNA, which allows a targeted region of a DNA molecule to
be replicated into as many copies as desired
✔✔Define Oligonucleotiedes - ✔✔a short, single-stranded molecule of known sequence
produced by chemical synthesis
QUESTIONS AND ANSWERS SURE A+
✔✔The lagging strand is away or towards the fork? - ✔✔away
✔✔The leading strand is away or towards the fork? - ✔✔towards
✔✔How many DNA polymerase are used in a replication bubble? - ✔✔4
✔✔Replication forks are ________. - ✔✔asymmetrical
✔✔Define okazaki fragments - ✔✔The noncontinuous segments of newly synthesized
DNA along the lagging strand
✔✔What are the steps of replication? - ✔✔-unwinding of the DNA duplex
-elongation occurs from 5' to 3' on the template strand
-DNA polymerase extends the RNA primer
-A different DNA polymerase removes the primer and replaced with DNA
-fragments of the discontinuous strand are ligated with DNA ligase
✔✔What does RNA primase do? - ✔✔lays down an RNA primer
✔✔How many RNA primers are on the leading strand? - ✔✔one
,✔✔How many RNA primers are on the lagging strand? - ✔✔multiple
✔✔What does DNA polumerase do? - ✔✔extends the RNA primer
✔✔What does helicase do? - ✔✔unwinds the DNA duplex
✔✔What does topoisomerase II do? - ✔✔relieves the stress of the unwinding DNA
✔✔What does single-stranded binding proteins do? - ✔✔stabilize single strands of DNA
✔✔What occurs when the okazaki fragments are being synthesized? - ✔✔the lagging
strand forms a loop that persists until the new lagging strand encounters the previous
fragment
✔✔What helps the DNA when an nucleotide is added incorrectly? - ✔✔the proofreading
function of DNA polymerase removes the incorrect nucleotide
✔✔What is the main difference in replication between eukaryotic chromosomes and
prokaryotic chromosomes? - ✔✔eukaryotic chromosomes have multiple origins of
replication and prokaryotic chromosomes have one
✔✔How does replication start in circular chromosomes? - ✔✔starts at the origin and
moves around the circular chromosome in both directions
✔✔What type of organism has circular chromosome? - ✔✔bacteria
✔✔What occurs every time DNA is replicated? - ✔✔the strand gets slightly shorter
✔✔What helps keep DNA from shortening in every replication? - ✔✔telomeres and
teomerase
✔✔What are the steps of telomeres and telomerase that help with replicating
chromosomal ends? - ✔✔-terminal part of the telomere in the template DNA strand
remains unreplicated
-telomerase enzyme contains an RNA template that allows the shortened 3' end of the
template strand to be restored by the addition of more telomere repeats
-a new segment of lagging strand can be formed so that the original telomere in the
template strand is comepletely restored
✔✔What is PCR? - ✔✔repeated rounds of DNA replication in a test tube
✔✔What are the three steps in PCR? - ✔✔-denaturation
-annealing
, -extension
✔✔What is denaturation? - ✔✔heating to separate the DNA into two individual strands
✔✔What is annealing? - ✔✔when the solution is cooled, the two primers anneal to their
complementary sequence on the strands of the template duplex
✔✔What is extension? - ✔✔DNA polymerase synthesizes new DNA strand by
extending primers in a 5' to 3' direction
✔✔What is the equation for PCR copies? - ✔✔2^n
✔✔What does gel electrophoresis do? - ✔✔separates DNA fragments according to size
✔✔How do DNA fragments move in gel electrophoresis? - ✔✔towards the positive pole
according to their size
✔✔How do smaller or larger DNA fragments move in gel electrophoresis? - ✔✔smaller
fragments move faster and larger ones move slower
✔✔What is the difference between deoxynuxleotide and dideoxynucleotide? -
✔✔dideoxynucleotide lacks 3' hydroxyl group
✔✔What occurs when a dideoxynucleotide is added? - ✔✔the DNA strand can't be
elongated
✔✔Define DNA replication - ✔✔process of duplicating a DNA molecule, during which
the parental strands separate and new partner strands are made
✔✔Define template strand - ✔✔the parental strand whose sequence is used to
synthesize a complementary daughter strand
✔✔Define daughter strand - ✔✔the strand synthesized from parental template strand
✔✔What is usually the sequence for telomere? - ✔✔3′-GGGATT-5'
✔✔Define polymerase chain reaction - ✔✔selective and highly sensitive method for
making copies of a piece of DNA, which allows a targeted region of a DNA molecule to
be replicated into as many copies as desired
✔✔Define Oligonucleotiedes - ✔✔a short, single-stranded molecule of known sequence
produced by chemical synthesis
