Here's why:
* Base pairing rules: DNA is composed of four nitrogenous bases: adenine (A), thymine (T), guanine (G), and cytosine (C). These bases pair specifically: A always pairs with T, and G always pairs with C. This strict pairing is the foundation of DNA replication.
* DNA polymerase: This enzyme reads the existing DNA strand and uses the base pairing rules to add complementary nucleotides to the new strand being synthesized.
* Template strand: One of the original DNA strands acts as a template for the new strand. The base pairing rules ensure that the newly synthesized strand is an exact copy of the template.
Other factors that contribute to faithful replication:
* Proofreading: DNA polymerase has a proofreading function that can identify and correct errors during replication.
* DNA repair mechanisms: Cells have complex mechanisms to repair any damage to the DNA that might occur.
* Origin of replication: Specific sites on the DNA molecule where replication begins.
* Replication fork: The point where the DNA strands separate during replication.
While other factors play a role, the base pairing rules are the fundamental principle that guarantees accurate DNA duplication.
