About Mitosis & Meiosis
This animation steps a single cell through the ordered phases of cell division on a 2D canvas. In Mitosis mode it follows Interphase, Prophase, Prometaphase, Metaphase, Anaphase, Telophase and Cytokinesis; in Meiosis mode it adds two successive divisions (Meiosis I and II). Each phase has a fixed duration, and a normalised progress value t (0 to 1) is eased to interpolate chromosome positions, spindle assembly and the cleavage furrow.
The mode buttons switch between mitosis and meiosis, the Play/Pause button drives the timed animation, and Reset returns to Interphase. The Step buttons and clickable phase chips jump directly to any phase, while the Speed slider (0.2× to 3×) scales how fast the clock advances. Understanding these stages explains how organisms grow and repair tissue and how gametes acquire genetic variation through crossing-over.
Frequently Asked Questions
What is the difference between mitosis and meiosis?
Mitosis is a single division that yields two genetically identical diploid daughter cells, used for growth and tissue repair. Meiosis involves two consecutive divisions producing four genetically distinct haploid cells (gametes). The simulation lets you toggle between the two so you can compare their phases side by side.
What do the controls on this page do?
The Mitosis and Meiosis buttons choose the division type. Play animates through the phases, Reset returns to Interphase, and the two Step buttons move one phase forward or back. The phase chips below the mode buttons let you click straight to any stage, and the Speed slider scales playback from 0.2× to 3×.
What are the phases shown in mitosis?
The simulation shows Interphase, Prophase, Prometaphase, Metaphase, Anaphase, Telophase and Cytokinesis. Chromatin condenses in prophase, the nuclear envelope breaks down in prometaphase, chromosomes align at the metaphase plate, sister chromatids separate in anaphase, and the cytoplasm finally pinches apart in cytokinesis.
Why does the cell show four chromosomes?
The model uses 4n as a simple, readable diploid set (four colour-coded chromosomes) so the choreography of condensation, alignment and separation stays clear. Real human cells carry 46 chromosomes, but four is enough to demonstrate the principles without visual clutter.
What happens during crossing-over in meiosis?
In Prophase I homologous chromosomes pair into bivalents and exchange segments at points called chiasmata, drawn as an X over the homologue pair. This recombination shuffles alleles between maternal and paternal chromosomes and is a major source of genetic variation in the resulting gametes.
Why is the chromosome number halved in meiosis?
Meiosis I is a reductive division: homologous chromosomes, not sister chromatids, are pulled to opposite poles in Anaphase I. This halves the chromosome number so that when two gametes fuse at fertilisation the diploid count is restored rather than doubled each generation.
What is the metaphase plate?
The metaphase plate is the imaginary plane at the cell equator where chromosomes line up before separating. The simulation draws it as a dashed horizontal line during metaphase. Each chromosome is held there under balanced tension from spindle fibres attached to both poles, which is why metaphase is ideal for karyotyping.
How does the animation calculate movement?
Each phase has a set duration in seconds. A clock accumulates real elapsed time multiplied by the speed factor, advancing a progress value t from 0 to 1 within the current phase. That t is passed through an ease function, then used in linear interpolation to slide chromosomes, elongate the cell and grow the cleavage furrow.
Is this simulation biologically accurate?
It is a faithful schematic of the sequence, key events and chromosome counts of each phase, with explanatory text drawn from standard cell biology. It is a 2D teaching diagram rather than a molecular model, so it simplifies spindle dynamics, kinetochore behaviour and timing for clarity.
Why does meiosis produce four cells but mitosis only two?
Mitosis is one division of one cell, giving two daughters. Meiosis chains two divisions: Meiosis I produces two haploid cells, then Meiosis II separates the sister chromatids in each, doubling the count to four. The simulation visualises this by splitting the canvas into two and then four cells.