Understanding the Correct Order of Events in DNA Replication
What is the correct order of events in DNA replication?
Place the following events of DNA replication in order:
1. DNA strands separate
2. DNA polymerase binds
3. DNA helicase binds
4. Companion strand is assembled
5. DNA proofreading
Answer:
The correct order of events in DNA replication is: DNA strands separate, DNA helicase binds, DNA polymerase binds, companion strand is assembled, DNA proofreading.
The process of DNA replication involves several steps that must occur in a specific order to ensure accurate copying of genetic information. Understanding the correct order of events in DNA replication is crucial for maintaining the integrity of genetic material.
1. DNA Strands Separate
The first step in DNA replication is the separation of the two DNA strands. This is achieved by the enzyme DNA helicase, which breaks the hydrogen bonds between the nitrogenous bases, causing the double helix structure to unwind.
2. DNA Helicase Binds
After the DNA strands have separated, DNA helicase binds to the DNA molecule to facilitate the unwinding process. This enzyme plays a critical role in opening up the DNA molecule for replication.
3. DNA Polymerase Binds
Once the DNA strands are separated and unwound, DNA polymerase binds to the template strand. This enzyme is responsible for synthesizing the complementary strand by adding nucleotides according to the base-pairing rules.
4. Companion Strand is Assembled
As DNA polymerase adds nucleotides to the growing complementary strand, a new DNA molecule is formed. The companion strand is assembled in the 5' to 3' direction, following the direction of the template strand.
5. DNA Proofreading
After the companion strand is assembled, DNA proofreading occurs to ensure the accuracy of the replicated DNA molecule. This process involves checking for errors or mismatches in the nucleotide sequence and correcting them to maintain genetic fidelity.
By following the correct order of events in DNA replication, cells can accurately copy their genetic information and pass it on to subsequent generations. This process is essential for the growth, development, and maintenance of all living organisms.