Science · Cells, genes & microorganisms
Cell Cycle, Mitosis, and Meiosis
Estimated time includes reading and one quiz. Take the time you need.
Start here: key ideas
- Interphase prepares a cell to divide.
- DNA is copied during S phase.
- Mitosis makes two genetically similar body cells.
- Meiosis makes four cells with half the chromosome number.
- Crossing over and independent assortment create variation.
What you’ll be able to do
- Put the main cell-cycle stages in order.
- Explain what checkpoints do.
- Compare the products of mitosis and meiosis.
- Explain how meiosis creates variation.
Learn how cells prepare for division and how mitosis differs from meiosis.
Optional review
If you’d like to review the basics, visit Cell Structure, Membranes, and Transport. You can start this lesson without completing those first.
The cell cycle prepares and controls division
The cell cycle is the ordered path from one cell division to the next. During interphase, the cell grows in G1, copies DNA in S phase, and prepares to divide in G2. DNA copying makes two sister chromatids joined together.
Checkpoints pause the cycle if DNA is damaged or the cell is not ready. These checks help prevent damaged DNA from passing to new cells.
Supporting detail: nondividing cells
Some cells leave the active cycle and enter G0. They perform normal jobs without preparing to divide. Some can return to the cycle after a signal; others remain in G0 for a long time.
Worked example. If DNA damage is found before S phase, a checkpoint can pause division before the damaged DNA is copied.
The cell cycle
G1: grow. S: copy DNA. G2: prepare to divide. Mitosis separates the copied chromosomes; cytokinesis splits the cell. G0 means the cell is not preparing to divide. Remember: DNA is copied before mitosis, not during it.
The cell cycle — OpenStax College, Anatomy & Physiology (2014 CC BY archive). CC BY 3.0. Original source image reproduced unchanged; explanatory caption added.
You've used your 1 free study guide
Your free topic allowance is shared across Reading, Math, Science and English. This first section is a preview. Unlock every study-guide
topic — full lessons, inline checks, the complete practice bank +
timed exam simulation — with a free trial.
Your one free topic stays free, always.
$0 today — card required to start your trial. Cancel anytime before day 3.
Already subscribed? Log in.