IGCSE Biology / Cell division
Telling the two apart in the exam
Edexcel International GCSE Biology (4BI1), chapter 17: Cell division. Free lesson.
Read the revision notes · IGCSE Biology past papers
Mitosis and meiosis are two types of cell division with different outcomes and roles. Knowing how they differ helps you compare them, identify them in diagrams and explain when each is needed.
How many cells each process makes
The number of divisions determines how many daughter cells are produced. A daughter cell is a new cell formed by cell division. Mitosis has one division and produces two daughter cells. Meiosis has two divisions and produces four daughter cells.
How the daughter cells differ
Compare each daughter cell with the parent cell and with the other daughter cells. The chromosome number and genetic makeup distinguish the two processes. In mitosis, daughter cells have the same chromosome number as the parent cell and are genetically identical to it. In meiosis, daughter cells have half the chromosome number of the parent cell. They are all genetically different from the parent and from each other.
How to identify each process in a diagram
Look at how the chromosomes are arranged across the middle of the cell. This can identify the process even if the diagram does not show the final cells. A single line of chromosomes across the middle indicates mitosis. Homologous pairs lined up two abreast indicate meiosis. Homologous chromosomes are matching pairs, one of each pair from each parent.
Where each process happens and why
The two processes happen in different places because they have different roles in the organism. Mitosis happens almost everywhere in the body. It is used for growth, repair and asexual reproduction. Meiosis happens only where gametes are made. In animals, this is in the ovaries and testes. In flowering plants, it is in the anthers and ovules. Meiosis makes gametes, which are sex cells.
Apply the chromosome arrangement
If a diagram shows chromosomes in homologous pairs, two abreast, it shows the first division of meiosis. Although the diagram shows this stage, meiosis continues through a second division, producing four cells in total. Each of the four resulting cells has half the parent cell's chromosome number. The four cells are genetically different from one another.