# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/DaeLqo-xe3v
- **Gondola URL:** https://gondola.cc/posts/67635471-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/c6542b1918.jpg
- **Posted:** 2026-07-07T00:30:35.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

Every second, your body completes millions of cell divisions, and almost none of them go wrong. That reliability is not luck. It is the product of one of biology’s most tightly policed sequences: the cell cycle.

Before a cell can split, it spends most of its life in interphase, quietly preparing:

- G1: the cell grows and checks whether conditions are right to commit
- S phase: the entire genome, roughly 6 billion base pairs, is copied with an error rate of about one mistake per billion letters
- G2: the cell proofreads that copy and repairs damage before proceeding

Only then does mitosis begin. Chromosomes condense from tangled metres of DNA into compact rods. A scaffold of microtubules, the mitotic spindle, extends from opposite poles and grips each chromosome at a protein structure called the kinetochore. By metaphase, every chromosome is aligned along the cell’s equator, held under tension, waiting.

Then the trigger. An enzyme severs the cohesin proteins gluing the sister chromatids together, and they are hauled to opposite ends in seconds. Two nuclei reform, and cytokinesis pinches the cytoplasm in two, yielding two daughter cells that each carry an identical genome and are ready to repeat the entire cycle.

What makes this remarkable is not the split itself but the checkpoints between every step. At each stage the cell asks one question before continuing: is everything correct? A single misaligned chromosome is enough to stall the whole process until it is fixed. When that surveillance breaks down, uncontrolled division is what we come to call cancer.

Life is not simply cells dividing. It is cells knowing precisely when they are permitted to.

#stemantics #cellbiology #mitosis #genetics #sciencefacts

## Stats

- **Views:** 3,106
- **Likes:** 121
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## Tags

mitosis, sciencefacts, genetics, cellbiology, stemantics

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