DNA replication

DNA is replicated during the cell division process to ensure that the daughter cells get an accurate copy of the genetic information

DNA replication:

1. DNA replication starts with an enzyme called Helicase unwinding the DNA strand at a spot called origins of replications

2. Initiator proteins bind to the origin and unwind the strand of DNA

3. The enzyme DNA Helicase unwinds the DNA by breaking the hydrogen bonds between the pairs

4. Single-Strand Binding Proteins bind to the DNA so that it does not coil back up again  

5. RNA primase adds a short RNA primer to the single-stranded DNA template. 

6. DNA polymerase binds to the RNA primer and begins adding complementary DNA nucleotides to the growing strand in the 5' to 3' direction. This process extends the DNA strand.

7. On the leading strand, DNA polymerase continuously synthesizes the DNA as the replication fork moves along. This strand is synthesized in the same direction as the unwinding.

8. On the lagging strand, the synthesis is more complex. It is synthesized in small fragments called Okazaki fragments. DNA polymerase adds nucleotides in the 5' to 3' direction, but because the lagging strand is oriented opposite to the leading strand, it must be synthesized in short segments.

9. After each Okazaki fragment is formed, RNA primers are removed by an enzyme called DNA polymerase and the gaps are filled with DNA nucleotides.

10. DNA ligase then seals the sugar-phosphate backbone of the DNA strand, joining the Okazaki fragments together to form a continuous strand.

11. Finally, the newly synthesized DNA strands are proofread and corrected by DNA polymerase to ensure accuracy and to fix any mistakes that may have been made during replication.

12. Once the replication is complete, the two identical DNA molecules are formed, each consisting of one original strand and one newly synthesized strand, a process known as semiconservative replication.

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