Here's why:
* Mitosis creates two identical daughter cells: The primary goal of mitosis is to produce two daughter cells that are genetically identical to the parent cell. This is crucial for growth, development, and repair in multicellular organisms.
* Each daughter cell needs a full set of chromosomes: Chromosomes, which carry the genetic information, are made of DNA. If DNA didn't replicate before mitosis, each daughter cell would only receive half the chromosomes, leading to genetic defects and potentially cell death.
* DNA replication ensures continuity: By replicating the DNA, the cell creates two complete sets of chromosomes, ensuring that each daughter cell receives a full set when the cell divides. This maintains the genetic integrity of the organism.
In essence, DNA replication before mitosis is like making a photocopy of the entire instruction manual for building the cell. Each daughter cell receives its own copy, allowing them to function independently and carry the same genetic information as the parent cell.
