Drag and drop the events that occur during DNA replication into the correct chronological order. Place the first event at the top and the last event at the bottom. DNA polymerase adds matching base pairs to template strands. An enzyme connects nucleotides at each gap on the lagging strand. RNA primers are added. Replication forks are formed. RNA primers are removed. Incorrect
The Correct Answer and Explanation is:
The correct chronological order of events during DNA replication is:
- Replication forks are formed.
- RNA primers are added.
- DNA polymerase adds matching base pairs to template strands.
- An enzyme connects nucleotides at each gap on the lagging strand.
- RNA primers are removed.
Explanation:
DNA replication is a highly orchestrated process that occurs in several steps. Here’s a breakdown of the stages:
- Replication Fork Formation:
The first step in DNA replication involves the unwinding of the double helix. The enzyme helicase unwinds the DNA at the origin of replication, creating replication forks, which are the sites where DNA is actively being copied. - RNA Primers are Added:
Primase synthesizes small RNA primers on both the leading and lagging strands. These primers provide a starting point for DNA polymerase, which can only add nucleotides to an existing strand. - DNA Polymerase Adds Matching Base Pairs:
With the RNA primers in place, DNA polymerase begins adding the complementary DNA nucleotides to the template strand. On the leading strand, this occurs continuously in the 5′ to 3′ direction. On the lagging strand, it occurs in fragments called Okazaki fragments due to the antiparallel nature of the DNA strands. - Enzyme Connects Nucleotides on the Lagging Strand:
On the lagging strand, after the DNA polymerase synthesizes each Okazaki fragment, DNA ligase comes in to connect the gaps between fragments, sealing the sugar-phosphate backbone. - RNA Primers are Removed:
Finally, the RNA primers are removed by RNase H, and the gaps are filled in with DNA nucleotides. DNA polymerase I then completes the final steps, ensuring that the replication process is finished.
This process ensures the accurate duplication of the DNA, which is critical for cell division and genetic inheritance.
