Cell division is about what happens to chromosomes, step by step. This page shows the order of the four lessons and where your next study session should start.
The chapter follows cells and organisation in SPM Biology, and it leads into inheritance and variation.
How do the four skills connect?
Mitosis comes first because it is the simpler process. Meiosis then adds a second division, and the last two lessons use both to answer counting and variation questions.
- Sequencing mitosis puts the stages in order and follows the chromosomes.
- Sequencing meiosis repeats that for two divisions and halves the number.
- Comparing chromosome and DNA changes tracks numbers through both processes.
- Explaining variation from meiosis uses the stages to justify why offspring differ.
What is the idea behind the counting questions?
Chromosome number counts the centromeres, and DNA amount counts the total genetic material. They are different quantities.
Take this example. A cell with 6 chromosomes enters interphase. After DNA replication, it still has 6 chromosomes, but each one now has two chromatids, so the DNA amount has doubled.
When the chromatids separate in mitosis, each daughter cell receives 6 chromosomes again. That is why a small two-row table, chromosomes and DNA, solves most of the chapter.
Where should you start?
Start with the stage your last answer got wrong.
- Stage order is shaky: open mitosis.
- You can do mitosis but meiosis mixes up: open meiosis.
- Numbers come out wrong: open the chromosome and DNA lesson.
- You want to check everything: try the cell division practice set.
Can one-to-one lessons help here?
They help when a student knows the words but cannot draw or count correctly. A teacher can watch you draw each stage and correct it on the spot, which a textbook cannot do. See online one-to-one Biology tuition.