Cell division: the stages of mitosis
Look at onion root-tip cells under the microscope, identify each stage of mitosis, put the stages in order, and compare mitosis with meiosis.
Core concept
In mitosis a cell copies its chromosomes and divides into two identical cells; meiosis makes four gametes with half the chromosomes
Topic: Cells and heredity
cell: The tiny building block that every living thing is made of. All key words divide so that living things can grow and repair themselves. In mitosis one cell divides into two new cells, each with exactly the same chromosomes as the parent. First the cell copies its DNA (interphase). Then the chromosomes coil up and become visible (prophase), line up across the middle of the cell (metaphase), have their two copies pulled to opposite ends (anaphase), and two new nuclei form (telophase). Finally the cytoplasm divides (cytokinesis). Meiosis is a different division, in the sex organs, that makes four gametes each with half the number of chromosomes: 23 instead of 46 in humans.
What you will learn
- Identify the stages of mitosis in microscope images.
- Put the stages of mitosis in order.
- Compare mitosis with meiosis.
Before you start
- Know that chromosomes are made of DNA and are found in the nucleus.
Materials
- Prepared slide of an onion root tip, stained
Equipment
- Compound microscope
Procedure
- Choose a stage card and look at what the chromosomes are doing under the microscope.
- Place each stage in order, from a resting cell to two new cells.