Why replication of human chromosomes would take so long?

The typical human chromosome has about 150 million base pairs that the cell replicates at the rate of 50 pairs per second. At that speed of DNA replication, it would take the cell over a month to copy a chromosome. The fact that it takes only one hour is because of multiple replication origins.

Why does DNA replication take so long?

In comparison, eukaryotic human DNA replicates at a rate of 50 nucleotides per second. In both cases, replication occurs so quickly because multiple polymerases can synthesize two new strands at the same time by using each unwound strand from the original DNA double helix as a template.

Why is replication fast and accurate?

The cell has multiple mechanisms to ensure the accuracy of DNA replication. The first mechanism is the use of a faithful polymerase enzyme that can accurately copy long stretches of DNA. … Stem cells have an extra safeguard to preserve the accuracy of their genetic information. DNA is double-stranded.

Why do chromosomes shorten after replication?

Why do telomeres get shorter? Your DNA strands become slightly shorter each time a chromosome replicates itself. Telomeres help prevent genes from being lost in this process. But this means that as your chromosomes replicate, your telomeres shorten.

What are the 4 steps of replication?

What are the 4 steps of DNA replication?

  • Step 1: Replication Fork Formation. Before DNA can be replicated, the double stranded molecule must be “unzipped” into two single strands.
  • Step 2: Primer Binding. The leading strand is the simplest to replicate.
  • Step 3: Elongation.
  • Step 4: Termination.
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Why does DNA polymerase go from 5 to 3?

DNA replication goes in the 5′ to 3′ direction because DNA polymerase acts on the 3′-OH of the existing strand for adding free nucleotides.

What are the 5 steps of DNA replication in order?

What are the 5 steps of DNA replication in order?

  • Step 1: Replication Fork Formation. Before DNA can be replicated, the double stranded molecule must be “unzipped” into two single strands.
  • Step 2: Primer Binding. The leading strand is the simplest to replicate.
  • Step 3: Elongation.
  • Step 4: Termination.
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