Why do cells need to divide?

Mitosis Sunday, 11 November 2018

Learning objectives All – recall that mitosis is when cells divide to produce two identical daughter cells Most – describe the different stages of mitosis Some – explain some of the problems that happen when mitosis goes wrong

http://www.bbc.co.uk/learningzone/clips/cell-division-by-mitosis-and-meiosis/6022.html

What happens before a cell divides?   What happens to the nuclear membrane? What happens to the chromosomes? What is special about the two cells produced?

Cut out the pictures and put them in the correct order. Try and write a caption for each one to explain what is happening.

A cell has 2 versions of each chromosome – one from each parent. We call this type of cell diploid.

To prepare for cell division, each chromosome is copied.

The chromosomes line up in the centre of the cell.

The two copies of each chromosome are pulled apart by spindle fibres.

The chromosomes move to different sides of the cell. Cytoplasm Divides. The cell begins to split in two.

The cell completely splits in two. There are now two cells, these are called daughter cells (both diploid). Each cell is genetically identical to each other, and to the original parent cell.

Asexual Reproduction Some organisms reproduce by mitosis. E.g. Strawberry plants form runners in this way which become new plants. This is an example of asexual reproduction. The offspring have exactly the same genes as the parent- therefore......

Where does mitosis happen? Most of the cells in the body divide by mitosis. Can you think of any exceptions? Some organisms can reproduce by mitosis. This is called asexual reproduction. Examples include yeast and the malaria parasite.

Cancer and Mitosis? Is there any link?

What happens when mitosis goes wrong? Usually cells only divide at certain times. Sometimes this control stops working and cells divide uncontrollably – this is cancer.

What is mitosis? Why is mitosis important? What would happen if mitosis didn’t take place? Suggest one advantage and one disadvantage of asexual reproduction. What is meant by a diploid cell? What cells in the body do you think are not diploid? How many parents does a cell that reproduces by sexual reproduction have? How many parents does a cell that reproduces by asexual reproduction have? Can you give an example of what happens when mitosis goes wrong?

Complete the questions on the sheet.