number the following steps of dna replication in the correct order
1. Initiation: The DNA helix unwinds and separates at the origin of replication.
2. Helicase binding: Helicase enzymes bind to the separated DNA strands and help in breaking the hydrogen bonds between the base pairs.
3. Priming: Primase synthesizes short RNA primers on each of the separated DNA strands.
4. DNA polymerase binding: DNA polymerase enzymes bind to the RNA primers and start adding complementary DNA nucleotides to the growing DNA strand.
5. Elongation: DNA polymerase continues to add nucleotides in a 5' to 3' direction, synthesizing new DNA strands in the leading and lagging directions.
6. Okazaki fragment synthesis: In the lagging strand, DNA synthesis occurs in short segments called Okazaki fragments.
7. DNA ligase binding: DNA ligase joins the Okazaki fragments together by sealing the phosphodiester bonds between adjacent nucleotides.
8. Termination: The replication process reaches the end of the DNA molecule, and replication is complete.
To number the steps of DNA replication in the correct order, we can follow these stages:
1. Initiation: The replication process starts at specific DNA sites called origins of replication. Proteins bind to these sites and initiate the unwinding and separation of the double-stranded DNA.
2. Helicase unwinding: Helicase enzymes unwind the double helix structure of the DNA molecule by breaking the hydrogen bonds between the nitrogenous base pairs. This creates two single strands of DNA, known as the template strands.
3. Priming: Primase enzyme synthesizes a short RNA primer on each template strand. This acts as a starting point for DNA synthesis.
4. Elongation: DNA polymerase binds to the RNA primer and adds complementary nucleotides to the template strand. It synthesizes new DNA strands by adding nucleotides in a 5' to 3' direction. The leading strand is synthesized continuously, while the lagging strand is synthesized in small fragments called Okazaki fragments.
5. Proofreading: DNA polymerase has a proofreading activity that checks for errors in the newly synthesized DNA strand. If any mistakes are found, it removes the corresponding nucleotide and replaces it with a correct one.
6. DNA ligase action: Once the DNA polymerase synthesizes all the new DNA strands, the RNA primers are removed, leaving small gaps between the fragments. DNA ligase seals these gaps by forming phosphodiester bonds, resulting in two complete and identical DNA molecules.
So, the correct order of these steps in DNA replication is:
1. Initiation
2. Helicase unwinding
3. Priming
4. Elongation
5. Proofreading
6. DNA ligase action