By: Tosha Lee
Note: the stars (*) are definitions in the glossary
Note: the stars (*) are definitions in the glossary
What is DNA Replication?
DNA Replication is formed when the double helix* is unwound and each strand acts as a template for the next strand.
It is the process of producing two identical replica's from one original DNA molecule. This biological process occurs in all living organisms. It is the basis of biological inheritance. DNA replication is also quite accurate. About 1 in a billion base pairs made have a change in it. The number is kept so low by a proof-reading system that checks newly synthesized DNA for errors and corrects them when they are found. The DNA polymerase* also takes a part in keeping the change in a base pair low. The polymerase has a very high selectivity so that there are hardly any mistakes in the pairs.
DNA Replication is formed when the double helix* is unwound and each strand acts as a template for the next strand.
It is the process of producing two identical replica's from one original DNA molecule. This biological process occurs in all living organisms. It is the basis of biological inheritance. DNA replication is also quite accurate. About 1 in a billion base pairs made have a change in it. The number is kept so low by a proof-reading system that checks newly synthesized DNA for errors and corrects them when they are found. The DNA polymerase* also takes a part in keeping the change in a base pair low. The polymerase has a very high selectivity so that there are hardly any mistakes in the pairs.
Process of DNA Replication
When DNA replication happens it looks somewhat like a zipper. I guess you could call this process somewhat like a molecular zipper. DNA replication is semi-conservative. That means that each daughter DNA contains 1 strand from the parent and 1 complementary strand. The combination are identical DNA base pairs only pair with one other specific base. Adenine pairs with Thymine, Guanine pairs with Cytosine. So since one half comes from the parent, and the other half has to match it, the daughter will be equal to the parent.
Step 1: consists of the Topoisomerase*, altering the supercoiled form of a DNA molecule. The helicase* then unwinds the parental double helix.
Step 2: single-strand binding proteins stabilize the unwound parental DNA
Step 3: The leading strand* is synthesized continuously in the 5' ----> 3' direction by DNA polymerase
Step 4: The lagging strand* is synthesized discontinuously in the 3' ----> 5' direction. Primase Synthesis* a short RNA primer, which is extended by DNA polymerase to form an Okazaki fragment*.
Step 5: After the RNA primer* is replaced be DNA. DNA ligase* joins the Okazaki fragment to the growing strand.
When DNA replication happens it looks somewhat like a zipper. I guess you could call this process somewhat like a molecular zipper. DNA replication is semi-conservative. That means that each daughter DNA contains 1 strand from the parent and 1 complementary strand. The combination are identical DNA base pairs only pair with one other specific base. Adenine pairs with Thymine, Guanine pairs with Cytosine. So since one half comes from the parent, and the other half has to match it, the daughter will be equal to the parent.
Step 1: consists of the Topoisomerase*, altering the supercoiled form of a DNA molecule. The helicase* then unwinds the parental double helix.
Step 2: single-strand binding proteins stabilize the unwound parental DNA
Step 3: The leading strand* is synthesized continuously in the 5' ----> 3' direction by DNA polymerase
Step 4: The lagging strand* is synthesized discontinuously in the 3' ----> 5' direction. Primase Synthesis* a short RNA primer, which is extended by DNA polymerase to form an Okazaki fragment*.
Step 5: After the RNA primer* is replaced be DNA. DNA ligase* joins the Okazaki fragment to the growing strand.
Why do we need our DNA copied?
It's simple: Cells divide for an organism to grow or reproduce, every new cell needs a copy of the DNA or instructions to know how to be a cell. DNA replicates right before a cell divides.
It's simple: Cells divide for an organism to grow or reproduce, every new cell needs a copy of the DNA or instructions to know how to be a cell. DNA replicates right before a cell divides.
Human DNA has, with up to 80 base pairs in a chromosome. The replication process is going on simultaneously at hundreds of places in your body. The DNA is copied at approximately 50 base pairs per second. If there wasn't multiple places where the chromosome "unwinded" so that the replication process could begin, then the replication process would take a month rather than about an hour.