The two new cells produced by mitosis are genetically identical to each other and to the original parent cell. Each one carries the same complete set of DNA, the same number of chromosomes (46 in humans), and roughly the same collection of internal structures. That said, “identical” has some important nuances depending on the type of cell division and the biological context.
Genetic Material Is Copied Exactly
Before a cell divides, it goes through a preparation phase where it duplicates every strand of its DNA. When the cell then splits during mitosis, the copied chromosomes are pulled apart so that each new cell gets one complete, identical set. In human cells, that means both daughter cells end up with 46 chromosomes, the same number the parent cell had. The genetic instructions in one daughter cell are a perfect match for the other.
This is fundamentally different from meiosis, the type of division that produces sex cells like sperm and eggs. Meiosis shuffles DNA between paired chromosomes through a process called crossing over, then divides twice to produce four cells that are genetically unique from one another and contain only half the original chromosome count (23 in humans). If your biology class is asking how “the two new cells compare,” the answer almost certainly involves mitosis, where the whole point is producing identical copies.
Internal Structures Are Split Roughly Evenly
A cell isn’t just DNA. It’s packed with energy-producing structures, protein-building machinery, and other components floating in a gel-like fluid. When a cell divides, all of these internal parts need to be distributed between the two new cells as well. Because most of these structures exist in large numbers and are spread throughout the cell, they get divided approximately equally when the cell pinches in half. The result is two cells that are functionally equipped in the same way, each with enough internal machinery to operate independently and continue growing.
Size Differences at Birth
The two new cells are not always the exact same size. In many organisms, cell division produces a slightly larger “mother” cell and a slightly smaller “daughter” cell. Research at Rockefeller University found that in yeast, the smaller daughter cell behaves as though it is about 20 percent smaller than its twin. Both cells carry the same genetic information, but the size difference means the smaller one typically needs more time to grow before it can divide again. In most animal cells undergoing standard mitosis, the size difference is minor, and both cells quickly grow to full size during the next growth phase.
How the Split Happens in Different Cell Types
The physical process of separating into two cells works differently depending on the organism. Animal cells divide by pinching inward from the outside, using a ring of protein fibers that contracts like a drawstring until the cell is squeezed in two. Plant cells can’t do this because they have rigid cell walls. Instead, they build a brand-new wall from the inside out, assembling it in the middle of the cell from small packages of building material until the two halves are completely walled off from each other. Despite these different methods, the end result is the same: two separate, intact cells.
When the Two New Cells Are Deliberately Different
There’s an important exception to the “two identical cells” rule. In a process called asymmetric division, a cell intentionally produces two daughter cells that differ in size, internal contents, or future function. This happens regularly in stem cells. For example, when a stem cell in the brain divides, one daughter cell remains a stem cell while the other becomes a specialized nerve cell precursor. The two cells receive the same DNA, but the parent cell distributes certain proteins and signaling molecules unevenly so that each daughter cell activates a different set of genes.
This pattern shows up across biology. In roundworm embryos, the very first cell division produces two cells that differ in both size and developmental fate. One gives rise to most of the body’s tissues, while the other follows a completely different path. These aren’t errors in the copying process. They’re a deliberate strategy that lets a single cell produce two daughters with distinct roles.
Chemical Markers Can Vary Slightly
Beyond the DNA sequence itself, cells carry chemical tags on their chromosomes that influence which genes are active or silent. These tags, part of what scientists call the epigenetic landscape, are generally copied during cell division so both daughter cells inherit the same pattern. However, the copying isn’t always perfect. Small differences in how these chemical marks are distributed can mean the two new cells don’t activate their genes in exactly the same way, even though their underlying DNA is identical. In most routine divisions this variation is minimal, but it becomes biologically significant in contexts like stem cell maintenance, where one daughter cell needs to “remember” its identity while the other takes on a new role.
The Short Answer for Biology Class
If you’re comparing the two new cells after mitosis: they have the same number of chromosomes, the same DNA sequence, a similar distribution of internal structures, and roughly the same size. They are essentially clones of the parent cell and of each other. The key distinction worth knowing is that this only applies to mitosis. Meiosis produces cells that are genetically different from each other and carry half the chromosome count. And in specialized cases like stem cell division, even mitosis can produce two cells destined for very different futures, despite sharing identical DNA.