JMU BIO 140 EXAM 1 FINAL PAPER 2026
QUESTIONS WITH FULL SOLUTION GRADED
A+
◉ Is replication conservative, semi-conservative, or dispersive?
Answer: semi-conservative
◉ What does it mean to be conservative? Answer: the original DNA
is kept and an exact replica is made
◉ What does it mean for DNA is be dispersive? Answer: parts of the
old and new DNA are chopped together
◉ What does it mean for DNA to be semi-conservative? Answer:
each new daughter DNA is one old strand and one new strand
◉ What was the experiment that proved semi-conservative?
Answer: Meselsohn and Stahl experiment
◉ What was the Meselsohn and Stahl experiment? Answer: -DNA
was labeled with N15 to create heavy DNA
-After one round of replication the parent strand still contained
heavy DNA but the daughter strand contains light nitrogen
,- After two rounds, half of the DNA had heavy strand and a lighter
strand and the other half had both lighter strands
◉ What new technology confirmed the Meselsohn and Stahl
experiment? Answer: fluorescent nucleotides
◉ What energy is used to add nucleotides to a daughter strand?
Answer: the breaking of the phosphate bonds from the nucleotide
◉ Nucleotides are added to what end of the daughter strand?
Answer: 3' end
◉ The template strand goes from what end to what end? Answer: 3'
to 5'
◉ The daughter strand goes from what end to what end? Answer: 5'
to 3'
◉ Where does new DNA synthesis occur? Answer: replication forks
◉ How many replication forks are there in a replication bubble?
Answer: two
◉ The lagging strand is away or towards the fork? Answer: away
,◉ The leading strand is away or towards the fork? Answer: towards
◉ How many DNA polymerase are used in a replication bubble?
Answer: 4
◉ Replication forks are ________. Answer: asymmetrical
◉ Define okazaki fragments Answer: The noncontinuous segments
of newly synthesized DNA along the lagging strand
◉ What are the steps of replication? Answer: -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? Answer: lays down an RNA primer
◉ How many RNA primers are on the leading strand? Answer: one
, ◉ How many RNA primers are on the lagging strand? Answer:
multiple
◉ What does DNA polumerase do? Answer: extends the RNA primer
◉ What does helicase do? Answer: unwinds the DNA duplex
◉ What does topoisomerase II do? Answer: relieves the stress of the
unwinding DNA
◉ What does single-stranded binding proteins do? Answer: stabilize
single strands of DNA
◉ What occurs when the okazaki fragments are being synthesized?
Answer: 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?
Answer: the proofreading function of DNA polymerase removes the
incorrect nucleotide
◉ What is the main difference in replication between eukaryotic
chromosomes and prokaryotic chromosomes? Answer: eukaryotic
QUESTIONS WITH FULL SOLUTION GRADED
A+
◉ Is replication conservative, semi-conservative, or dispersive?
Answer: semi-conservative
◉ What does it mean to be conservative? Answer: the original DNA
is kept and an exact replica is made
◉ What does it mean for DNA is be dispersive? Answer: parts of the
old and new DNA are chopped together
◉ What does it mean for DNA to be semi-conservative? Answer:
each new daughter DNA is one old strand and one new strand
◉ What was the experiment that proved semi-conservative?
Answer: Meselsohn and Stahl experiment
◉ What was the Meselsohn and Stahl experiment? Answer: -DNA
was labeled with N15 to create heavy DNA
-After one round of replication the parent strand still contained
heavy DNA but the daughter strand contains light nitrogen
,- After two rounds, half of the DNA had heavy strand and a lighter
strand and the other half had both lighter strands
◉ What new technology confirmed the Meselsohn and Stahl
experiment? Answer: fluorescent nucleotides
◉ What energy is used to add nucleotides to a daughter strand?
Answer: the breaking of the phosphate bonds from the nucleotide
◉ Nucleotides are added to what end of the daughter strand?
Answer: 3' end
◉ The template strand goes from what end to what end? Answer: 3'
to 5'
◉ The daughter strand goes from what end to what end? Answer: 5'
to 3'
◉ Where does new DNA synthesis occur? Answer: replication forks
◉ How many replication forks are there in a replication bubble?
Answer: two
◉ The lagging strand is away or towards the fork? Answer: away
,◉ The leading strand is away or towards the fork? Answer: towards
◉ How many DNA polymerase are used in a replication bubble?
Answer: 4
◉ Replication forks are ________. Answer: asymmetrical
◉ Define okazaki fragments Answer: The noncontinuous segments
of newly synthesized DNA along the lagging strand
◉ What are the steps of replication? Answer: -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? Answer: lays down an RNA primer
◉ How many RNA primers are on the leading strand? Answer: one
, ◉ How many RNA primers are on the lagging strand? Answer:
multiple
◉ What does DNA polumerase do? Answer: extends the RNA primer
◉ What does helicase do? Answer: unwinds the DNA duplex
◉ What does topoisomerase II do? Answer: relieves the stress of the
unwinding DNA
◉ What does single-stranded binding proteins do? Answer: stabilize
single strands of DNA
◉ What occurs when the okazaki fragments are being synthesized?
Answer: 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?
Answer: the proofreading function of DNA polymerase removes the
incorrect nucleotide
◉ What is the main difference in replication between eukaryotic
chromosomes and prokaryotic chromosomes? Answer: eukaryotic
