What is a replication error?
A Replication Error results from the covalent addition of an incorrect nucleotide subunit, or the lack of addition of a nucleotide subunit, during polymerization of the growing newly synthesized DNA strand during replication. (
What causes DNA replication errors?
Today, scientists suspect that most DNA replication errors are caused by mispairings of a different nature: either between different but nontautomeric chemical forms of bases (e.g., bases with an extra proton, which can still bind but often with a mismatched nucleotide, such as an A with a G instead of a T) or between …
Which of the following would cause an error in DNA replication answers?
Answer Expert Verified The enzyme DNA ligase repairs the breaks or irregularities in the DNA molecules, such as joining of Okajaki fragments. Therefore, defects in DNA ligase that take apart chunks of DNA would cause an error during DNA replication. Thus, the correct answer is ‘option B). ‘
Which mechanism helps prevent errors in DNA replication?
Base excision repair (BER) is a mechanism that helps protect cells from erroneous DNA by repairing damage throughout the cell cycle.
Why does DNA replication only occur in the 5 to 3 direction?
DNA is always synthesized in the 5′-to-3′ direction, meaning that nucleotides are added only to the 3′ end of the growing strand. As shown in Figure 2, the 5′-phosphate group of the new nucleotide binds to the 3′-OH group of the last nucleotide of the growing strand.
Why can nucleotides only be added to the 3 end?
DNA Polymerase can only add nucleotides at the -OH group which is on the 3′ end. This free -OH group is necessary because it can carry out a nucleophilic attack on phosphate group of the incoming deoxyribonucleoside triphosphate which would contain the base that is complementary to the template strand.
Why can’t nucleotides be added to the 5 end?
DNA pol uses the energy provided by hydrolysis of the high-energy phosphate bond at the 5′ end of the incoming nucleotide to add it to the 3′ end of the growing DNA. Without the high-energy phosphate bond, the correct nucleotide can not be added.
What is the role of DNA polymerase III in DNA replication?
Abstract. DNA polymerase III holoenzyme (Pol III HE) is an enzyme that catalyzes elongation of DNA chains during bacterial chromosomal DNA replication. Bacterial cells contain several distinct DNA polymerases.
What is the purpose of DNA replication?
DNA replication is a crucial process; therefore, to ensure that mistakes, or mutations, are not introduced, the cell proofreads the newly synthesized DNA. Once the DNA in a cell is replicated, the cell can divide into two cells, each of which has an identical copy of the original DNA.
What enzyme unzips DNA during replication?
helicases
What is the end result of DNA replication quizlet?
The outcome of DNA replication is two DNA nearly identical DNA double helix molecules. Each DNA is made up of one DNA strand from the original DNA and a newly created strand.
What is the second step in DNA replication?
Step 2: Primer Binding The leading strand is the simplest to replicate. Once the DNA strands have been separated, a short piece of RNA called a primer binds to the 3′ end of the strand. The primer always binds as the starting point for replication. Primers are generated by the enzyme DNA primase.
Why is replication called Semiconservative?
Semiconservative replication derives its name from the fact that this mechanism of transcription was one of three models originally proposed for DNA replication: Semiconservative replication would produce two copies that each contained one of the original strands of DNA and one new strand.
How do you prove DNA replication is Semiconservative?
Meselson and Stahl Experiment was an experimental proof for semiconservative DNA replication. In 1958, Matthew Meselson and Franklin Stahl conducted an experiment on E. coli which divides in 20 minutes, to study the replication of DNA.
Why is it important that DNA replication is Semiconservative?
Semi-conservative DNA replication involves splitting open the parent cells DNA duplex and exposing both strands. This is very important because cells want to minimise errors in replication when dividing, so that mutations (such as incorrect bases, deletions, insertions) are not brought into the genome.