1. 5.2 Mitosis Describe Interphase Know the phases of mitosis Know Cytokinesis

2. Cell Cycle 1.Interphase 2.Mitosis 3.Cytokinesis

3. Interphase (cell cycle) Not dividing Growth and preparation

4. Interphase (cell cycle) 1.G1 (gap 1) – growth 2.S (synthesis) – chromosomes replicate 3.G2 (gap 2) –new organelles

5. Interphase Chromosome replication 1.Chromatin coils/ twists to form a chromosome 2.Chromosome makes a copy 3.Sister chromatids formed

6. Question: What is a chromosome?

7. Answer: chromosomeDNAhistone protein chromatinA chromosome is made up of a DNA - histone protein complex called chromatin. Chromatin chromosomesChromatin is a long, thin fiber that is folded and coiled to form chromosomes. DNA double helix Histone proteins chromosome

8. Question: What is a replicated chromosome?What is a replicated chromosome?

9. Answer: chromosome chromatidssister chromatidsA replicated chromosome consist of two strands of identical chromosomal material called chromatids (sister chromatids). chromatid S phase: chromosomes replicate chromosome centromere

10. Question: When is a chromatid a chromatid?When is a chromatid a chromatid?

11. Answer: chromatidchromatid sisterchromatid centromereA chromatid is a chromatid as long as it is held in association with a sister chromatid at the centromere. chromatid centromere chromosome

12. Mitosis Follows Interphase in the cell cycle 1.Prophase 2.Metaphase 3.Anaphase 4.Telophase

15. Prophase - 1 Nuclear membrane breaksdown Centrioles move to poles Spindle fibers form Sister chromatids are held together centromeres

16. Metaphase -2 Centromeres attach to fibers Pull chromosomes to the center on the “metaphase plate”

17. Anaphase - 3 Centromeres divide sister chromatids Chromatids move to opposite poles of the cell

18. Telophase - 4 Chromosome fully divided into 2 new cells 2 nuclei and nuclear membrane form Chromosomes uncoil to form chromatin

19. Cytokinesis Follows mitosis in the cell cycle Cytokinesis = division of cytoplasm Cell membranes start to split 2 new cells are formed

21. Cytokinesis – Animal Animal cell – pinches off its membrane to form 2 new cells 24 hours after fertilization Plant cell – Cell wall is being formed between 2 plant cells Cell plate forms new cell membranes

23. Cytokinesis - plant Plant cell – Cell wall is being formed between 2 plant cells Cell plate forms new cell membranes