6.2 QR mitosis

Question 1

What happens during prophase? 5 points

Answer 1

1. Chromatin fibres coil + condense to form
   chromosomes, nucleolus disappears, nuclear membrane begins to break down
2. Microtubules form spindle-shaped structures linking poles of the cell
3. 2 centrioles move to opposite poles of the cell (centrioles help formation of spindles)
4. Spindle fibres attach to centromeres + start to move chromosomes to the centre of cell
5. By end of prophase, nuclear envelope disappears

Question 2

What happens during metaphase?

Answer 2

Chromosomes moved by spindle fibres to form metaphase plate in the centre of cell + held in position

Question 3

What happens during anaphase?

Answer 3

1. Centromeres holding pairs of chromatids in each chromosome divide
2. Chromatids separated + pulled to opposite poles by shortening spindle fibres

Question 4

What happens during telophase?

Answer 4

• Chromatids have reached poles + now = chromosomes
• New chromosomes assemble at each pole + nuclear envelope reforms around them
• Chromosomes uncoil + nucleolus is formed

Question 5

What is cytokinesis?

Answer 5

Final stage of mitosis - cell divides into 2 separate cells