1. Cell Cycle and Mitosis

2. 1.Identify and summarise what happens in each phase of the cell cycle. 2.In G2 protein synthesis occurs to prepare the cell for mitosis. Which proteins would be synthesised? 1.Centriole 2.Proteins (microtubules) needed to make the spindle 3.Identify when the DNA can be seen as- 1.Unravelled/Uncoiled/Diffu se DNA? (Known as chromatin) 2.Condensed into two chromatids joined by a centromere 4.Q3.7 p114 CELL CYCLE - SNAB

5. 1.Identify chromatin- uncoiled/diffuse form of DNA 2.When in the cell cycle do the chromosomes condense? 3.When the chromosomes condense they become s__________ and t___________. Now they are v__________ down a microscope 4.Identify the chromatids 5.Label the centromere

7. Activity 3.8 The Cell Cycle

8. Mitosis stages http://www.sumanasinc.com/webcontent /animations/content/mitosis.html http://www.cellsalive.com/mitosis.htm

9. 1.Identify each stage 2.Label the cells.

12. StagesPhasesWhat happens? Amount of DNA in each cell (arbitrary units) DNA- condensed or diffuse (uncoiled)? Interphase G1 Interphase S Interphase G2 Mitosis Prophase Mitosis Metaphase Mitosis Anaphase Mitosis Telophase Cytokinesis

13. Activities Activity 3.9 Observing mitosis Activity 3.10 Mitosis Cell count in an onion root tip

14. Why is mitosis so important? Read page 119 How does mitosis ensure that the daughter cells are genetically identical to each other and the parent cell? – DNA replication occuring before mitosis (nuclear division) – The arrangement of chromosomes on the spindle so that sister-chromatids are pulled to opposite poles. What is mitosis useful for? – Growth – Repair – Asexual reproduction Q 3.13

15. Q3.5Write a definition for the following terms: totipotent, pluripotent and multipotent. _____________ stem cells are undifferentiated cells which can divide and give rise to all the cell types in an organism. Pluripotent stem cells are able to give rise to ____________, but not all cell types in an organism. Multipotent stem cells are _______________ cells which retain the ability to give rise to a variety of different cell types. For example, white blood cells in the ________________ can give rise to range of different types of blood cells.