Learning Intentions I can state that the nucleus controls all the cells activities. I can state that cell division results in the increase in the number of cells in an organism. I can state that when a cell divides two new identical daughter cells are produced. I know what the human chromosome complement is I can state why the chromosome complement in daughter cells must be maintained I can describe the stages in cell division. I can state that cell division is essential to allow organisms to grow and repair damaged parts, e.g. cuts, bones and broken bones. Success Criteria Observe mitosis in plant cells I can put the stages of mitosis into the correct order I can confidently annotate and explain the stages of mitosis I can explain the use of mitosis for growth or repair in a body part. I can explain the need for the continuity of chromosome numbers.

From this…

To this

To this!!!

One chromosome

After chromosome replicates: one chromosome consisting of two chromatids

Make your own chromosomes

Why do we produce new cells? To repair damaged tissue –Eg wounded skin To grow –Eg bones, muscles etc To replace worn out tissue –Eg blood cells, skin etc.

Mitosis is the name for the way that a cell duplicates itself so that each daughter cell receives an identical copy of its genetic material. At the end of mitosis, there will be two cells instead of one. They will be identical to each other.

Mitosis in Onion Root Tips

Daughter Cells of Mitosis It is important that the chromosome complement of the daughter cells is the same as that of the parent cell. This is because the chromosomes contain the genetic information which controls the development and activities of the cell. Any change or loss of chromosomes would mean that the cell would not function properly. It is important that the chromosome complement of the daughter cells is the same as that of the parent cell. This is because the chromosomes contain the genetic information which controls the development and activities of the cell. Any change or loss of chromosomes would mean that the cell would not function properly. Identical to each other, but smaller than parent cell Identical to each other, but smaller than parent cell

46 Chromosomes Mother cell How many chromosomes will be in the human daughter cells? 46 Chromosomes Daugther cell 46 Chromosomes Daughter cell Therefore chromosomes must make an identical copy during cell division/mitosis How many chromosomes are in a human cell?

Mitosis Animation How many chromosomes will each daughter cell have?

Chromosomes make exact copies of themselves Chromosomes are long and thin, uncoiled and not easily visible

Chromosomes shorten and thicken and are visible under a microscope Chromosomes consist of two chromatids joined by a centromere. The number of chromosomes in a body cell is called the diploid number

Nuclear membrane disappears Spindle fibres form Chromosomes begin to line up at the equator

Chromatids pulled apart by spindle fibres to opposite poles

Nuclear membrane reforms around chromosomes

Cytoplasm divides and division is complete

1 Which cell structure controls all the cell activities including cell division? Nucleus

2 What is the chromosome complement of the following:

3 Why is it important that the chromosome complement of daughter cells in a multicellular organism is maintained? So that every cell has the necessary genetic instructions/genes Mitosis 4 What process maintains this continuity?

This controls cell activities including cell division The process by which a cell makes an exact copy of itself The number of chromosomes in a typical cell of an organism (eg in humans it is 46) During mitosis chromosomes make an exact copy to form two of these Where chromatids are joined together During mitosis, this pulls the chromatids apart from the equator of the cell Mitosis increases the number of these in an organism Cells which are identical to original parent cell (same chromosome complement)

NucleusThis controls cell activities including cell division MitosisThe process by which a cell makes an exact copy of itself Chromosome complement The number of chromosomes in a typical cell of an organism (eg in humans it is 46) ChromatidsDuring mitosis chromosomes make an exact copy to form two of these CentromereWhere chromatids are joined together Spindle fibreDuring mitosis, this pulls the chromatids apart from the equator of the cell CellsMitosis increases the number of these in an organism Daughter cells Cells which are identical to original parent cell (same chromosome complement)