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HS 4212 Discussion forum, genetics from unit 1 to unit 8 very essential for for your academic career. Please check this vital assignments for you doing genetics especially the student of university of the people.$8.13
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HS 4212 Discussion forum, genetics from unit 1 to unit 8 very essential for for your academic career. Please check this vital assignments for you doing genetics especially the student of university of the people.
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Course
HS 4212 GENECTICS
Institution
University Of The People - California
HS 4212 Discussion forum, genetics from unit 1 to unit 8 very essential for for your academic career. Please check this vital assignments for you doing genetics especially the student of university of the people.
As the cell multiplies innumerable times during development and even now as an adult, DNA replication
is a remarkable biological event that happens swiftly. One new strand of DNA is generated in one piece,
while the other is first formed in fragments and is then put together.
How do you think this could affect the rate of mistakes being made during replication?
Human DNA cells contain around 6 billion base pairs, and since errors in DNA replication happen at a
rate of roughly 1 error for every 100,000 nucleotides, there are approximately 120,000 errors made
every time a cell divides (Pray, 2014). Errors that go uncorrected occasionally have catastrophic
repercussions, like cancer (OpenStax, 2016).
What are the mechanisms by which the cell has to fix these mistakes?
When a DNA polymerase inserts the incorrect nucleotide during DNA replication, errors are frequently
made. And if this error is not addressed, catastrophic repercussions like cancer could result. The
mechanism that gives the cell the chance to correct these errors happens either during replication or
after replication. DNA Proof Reading, which is the correction carried out during replication, is
distinguished from Mismatch Repair, in which the repair is carried out after replication.
According to DNA Proofreading, DNA polymerase quickly corrects the majority of errors made during
DNA replication by checking the newly inserted base for errors. Before adding the subsequent base, the
DNA pol reads the recently added base during proofreading so that a correction can be made (OpenStax,
2016).
This is accomplished by using the polymerase to confirm that the newly added base has successfully
mated with the base in the template strand. The following nucleotide is added if the base is the proper
one. In the event that the wrong base has been added, the enzyme splits the phosphodiester link and
releases the wrong nucleotide. This is accomplished by DNA pol III acting as an exonuclease. Following
the removal of the erroneous nucleotide, another one will be added. Additionally, this entire procedure
is known as DNA polymerase proofreading: Mismatch repair, on the other hand, is "a mechanism for
identifying and repairing some forms of DNA damage and error-prone insertion, deletion, or mis-
incorporation of bases that can happen during DNA replication and recombination. The wrong base is
subsequently inserted in its place once the faulty nucleotide has been excised by the repair mechanism
(OpenStax, 2016).
To sum up, I should remark that among the ways by which the cell corrects errors in DNA replication,
proofreading resolves around 99% of them. If, however, any are missed during replication, mismatch
repair performed after replication further lowers the ultimate error rate. "The secondary structure of
the completed DNA molecule exhibits abnormalities due to improperly linked nucleotides. By
eliminating the improperly matched nucleotide and replacing it with the proper nucleotide, enzymes
recognize and rectify these abnormalities during mismatch repair. (Pray, 2008)
References:
Pray, L. (2008) DNA Replication and Causes of Mutation. Nature Education 1(1):214.
https://www.nature.com/scitable/topicpage/dna-replication-and-causes-of-mutation-409/
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