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DNA Replication and the changes that may cause it to speed up and be more efficient I've listed a few factors in this prezi of what things might affect the speeding up or change in efficiency of DNA

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Jessica Jolly

on 14 December 2012

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Transcript of DNA Replication and the changes that may cause it to speed up and be more efficient I've listed a few factors in this prezi of what things might affect the speeding up or change in efficiency of DNA

DNA Stands for Deoxyribonucleic acid. DNA is the genetic material of an organism, stored in chromosones in the nucleus. DNA is Made up of units called nucleotides Phosphate
sugar (deoxyribose)
Nitrogen base Contain DNA Nucleotide looks like this: DNA is a molecule that has two strands twisted into a spiral shape. We therefore refer to DNA as "the double-helix" These strands are made out of nucleotides. There are only four nitrogenous bases in DNA Adenine Gunanine Thymine
Cytosine Each nucleotide has only one base, either A, T, G, or C. The bases bond in the center of the DNA molecule. Chargoff's rule states that A always bonds to T with double bonds
and G always bonds to C with triple bonds. A T G C CODE The sequence of these nitrogen bases is the "code" of DNA.
The DNA sequence on one strand of DNA tells you the sequence of the other. for instance: ATGCAAGGCC

TACGTTCCGA This genetic "code" tells the cell
how to build a protein, and proteins are the building blocks of many, many important molecules in the body. The structure of the DNA molecule was discovered in 1953 by James Watson and Francis Crick, though X-Ray crystallographer Rosalind Franklin contributed as well. When cells divide (a process called mitosis) a copy of the DNA must be put into the new cells. The process by which DNA makes a copy of itself is called "DNA replication", which occurs in the nucleus of cells. DNA The first step to copying the DNA is that the enzyme Helicase unwinds the DNA strand and unzips it along the center. Then, the enzyme DNA Polymerase reads the DNA strands and lays down matching nitrogenous bases. Finally, Helicase re-winds the DNA strands after zipping them back up. The result of this process is two DNA strands, both of them are half new, and half old. This model is referred to as Semi-Conservative replication of DNA DNA is a code for making protein.
When the cell requires a specific protein to be made,
the gene for that protein is found and copied into a message than we call RNA, which can leave the nucleus to go to a ribosome where proteins are made M replication
DNA mRNA Transcription During this process, the enzyme Helicase unwinds and unzips
the DNA strand and then the enzyme RNA Polymerse copies
the DNA template into the mRNA message. The message then must recieve a cap and a Poly A Tail for protection from the cytoplasmic enzymes, then it leaves the nucleus and leaves straight from the ribosome. Translation mRNA proteins The ribosome reads the message, grabs amino acids
that match the mRNA three letter codes (called codons)
and begins building a chain of amino acids. When complete, the chain of amino acids will be a functional protein. RNA Thymine



nucleus Sidenote on transcription-
when the DNA transcribes to mRNA,
you change all of the Thymine bases
to Uracil bases. Uracil



cytoplasm Cytosine
carry "code" Some errors in Dna replication Biologists initially speculated that most replication errors were caused by what are called tautomeric (Chemical format) shifts. Both the purine and pyrimidine bases in DNA exist in different chemical forms, , in which the protons occupy different positions in the molecule . 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 "normal" bases that nonetheless bond inappropriately (e.g., again, an A with a G instead of a T) because of a slight shift in position of the nucleotides in space This type of mispairing is known as wobble. It occurs because the DNA double helix is flexible and able to accommodate slightly misshaped pairings Replication errors can also involve insertions or deletions of nucleotide bases that occur during a process called strand slippage. Sometimes, a newly synthesized strand loops out a bit, resulting in the addition of an extra nucleotide base . Other times, the template strand loops out a bit, resulting in the omission, or deletion, of a nucleotide base in the newly synthesized, or primer, strand. Regions of DNA containing many copies of small repeated sequences are particularly prone to this type of error. One way of Fixing these Errors and Speeding up the process of Dna Replication I think would be by --------------------------------------------|> * Adding More Complex Eukaryotes to DNA Replication

*The Genome of complex eukaryotes is huge and the process of DNA Replication should be incredibly fast. It is amazing that a Chromosome of 250 million pair of bases can be replicated in several hours. The speed of DNA replication for the humans is about 50 nucleotides per second per replication fork (low speed comparing to the speed of the bacterial DNA Replication).But the human Genome can be copied only in a few hours because because many replication forks take place at the some time (multiple initiation sites). How Dna replication reacts to it's errors and describing how it was before and how I predict it will be after the speed ed up proofread process DNA polymerase enzymes are articular with respect to their choice of nucleotides during DNA synthesis, ensuring that the bases added to a growing strand are correctly paired with their complements on the template strand (i.e., A's with T's, and C's with G's). Nonetheless, these enzymes do make mistakes at a rate of about 1 per every 100,000 nucleotides. That might not seem like much, until you consider how much DNA a cell has. In humans, with our 6 billion base pairs in each diploid cell, that would amount to about 120,000 mistakes every time a cell divides!
Fortunately, cells have evolved highly sophisticated means of fixing most, but not all, of those mistakes. Some of the mistakes are corrected immediately during replication through a process known as proofreading, and some are corrected after replication in a process called mismatch repair. When an incorrect nucleotide is added to the growing strand, replication is stalled by the fact that the nucleotide's exposed 3′-OH group is in the "wrong" position During proofreading, DNA polymerase enzymes recognize this and replace the incorrectly inserted nucleotide so that replication can continue. Proofreading fixes about 99% of these types of errors, but that's still not good enough for normal cell functioning.
After replication, mismatch repair reduces the final error rate even further. Incorrectly paired nucleotides cause deformities in the secondary structure of the final DNA molecule. During mismatch repair, enzymes recognize and fix these deformities by removing the incorrectly paired nucleotide and replacing it with the correct nucleotide.
By Jessica Jolly Block 2 Mrs.Espinoza 12/13/2012 I'm going to start off by telling you the steps of DNA replication first , after that we will move on to answering the question what can we add , remove , or change to DNA replication for speeding up the process/making it more efficient . What is the "Fussy Thing " that you need to get rid off ? Or the "Great Idea" that you will need to add or increase to the process, to make it react more quick and efficiently. Intro Another way of speeding up the process of Dna Replication would be.......... Increase the accurate ~Proofreading Process--> The addition of more proofreading sources in dna replication making things more accurate as well as the addition of replication forks to speed up the process of Dna replication. Conclusion ~ I think the increasing the amount of replication forks and the increase of emphasis of the proofreading process in DNA replication and the adding of more complex eukaryotes will all play a big role in speeding up the process of DNA Replication making it more efficient for all of us . Adding more Replication Forks to speed up the process of DNA replication .^^ We need to add more replication forks , complex eukaryotes, and make the proofreading process more important as it is very useful . and the Changes along the way
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