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One Cell Becomes Two
Age 15 · Biology
Before a cell divides, it copies every chromosome so there are two matching sets. The sets are pulled to opposite ends and the cell pinches in half, making two daughter cells with the same genetic instructions.
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In the picture
- Copied chromosomes lined up down the middle of the cell
- Spindle fibres pulling one full set toward each end
- The pinched waist where the membrane closes inward
- One of the two finished daughter cells, identical to its partner
Examples
- A scraped knee closing up as skin cells divide to fill the gap
- Fingernails and hair growing longer as cells at the root keep dividing
Key takeaways
- Chromosomes are copied first, so each new cell receives a complete set.
- This kind of division makes two cells genetically identical to the original.
Quiz: One Cell Becomes Two (Age 15)
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Before a cell divides in this way, it makes a copy of every chromosome. Why is that copying step necessary?
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A cell containing 46 chromosomes divides in this way. How many chromosomes does each of the two daughter cells contain?
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In this kind of division, one complete set of chromosomes is pulled to each end of the cell before the cell closes in and splits. What would go wrong if the sets were not separated properly first?
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