JMU BIO 140 ACTUAL TEST SCRIPT WITH SOLVED QUESTIONS AND VERIFIED ANSWERS

JMU BIO 140 ACTUAL TEST SCRIPT WITH
SOLVED QUESTIONS AND VERIFIED
ANSWERS

●● 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?