The Cell Cycle and Mitosis
A cell copies its DNA, then divides into two cells with identical chromosomes. Covers the stages of the cycle, what mitosis produces, and where in the body it is happening now.
What a learner can do afterwards
- Puts the stages of the cell cycle in order and says what happens to the chromosome number in each.
- States how many cells mitosis produces and how their genetic content compares with the parent cell.
- Names a place in the body where mitosis is going on and says what it is for.
1 · Read
The cell cycle has two great phases. In interphase the cell grows and copies its DNA, and in the mitotic phase it splits into two. DNA must be copied before the split, so each daughter gets a full set.
Interphase runs G1, S, then G2. The cell grows in G1, copies DNA in S, and checks everything in G2. Then mitosis lines the chromosomes up, pulls the sisters apart, forms two nuclei, and pinches the cell in two.
Mitosis makes two cells with chromosomes identical to the parent, which is how you grow and repair. The chromosome number stays the same. Your gut lining replaces cells every few days, and skin keeps dividing to replace worn-out cells, while nerves spend a lifetime resting instead, a pause called G0. Red blood cells carry no nucleus, so they cannot divide. Checkpoints halt faulty cells, and broken brakes can mean cancer.
Do not mix mitosis with making gametes. Mitosis gives two identical cells for growth and repair, and the chromosome number stays the same. Copy first, split second, same number throughout.
DNA is copied in S phase, then mitosis shares identical sets between two daughter cells.
2 · Watch
Take it off screen
Where it sits
Learn first
Nothing; this is a starting point.
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.