1. The Cell Cycle: A closer look!
Biology 12

2. Funny?

3. Review (from last Class):

4. Which stage is longest?

5. Interphase Aka the resting phase (but not really…)
Essentially, the cell is in between divisions and is carrying out maintenance activities of the cell
Made up of 3 sub-phases:
G1 phase
S phase
G2 phase

6. Interphase: G1 phase 1st growth phase
Cell mature by making more cytoplasm & organelles
Cell carries on its normal metabolic activities, such as synthesising proteins

7. Interphase: S phase Synthesis stage DNA is copied or replicated
Two identical copies of DNA
Original DNA

8. Interphase: G2 phase 2nd Growth Stage Occurs after DNA has been copied
All cell structures needed for division are completed (e.g. centrioles)
Both organelles & proteins continue to be synthesized

9. Mitosis Aka karyokinesis Division of the nucleus
Only occurs in eukaryotes
Made up of 4 phases:
Prophase
Metaphase
Anaphase
Telophase

10. Mitosis: prophase Early prophase: Late prophase:
Centrioles: make spindle fibres and move towards opposite plates
Chromosomes shorten and thicken (now visible under a microscope)
Late prophase:
Centrioles reach poles
Nuclear membrane (envelope) & nucleolus start to disappear

12. Mitosis: Metaphase Spindle fibres attach to centromeres
Sister chromatids (doubled chromosomes) line up at equator (middle of cell)
Guided by spindle fibers

13. Mitosis: Anaphase Centromeres divide in two
Spindle fibers contract and pull sister chromatids towards opposite ends of cell (pole)
Each pole (future daughter cells) will have an identical set of chromosomes

14. Mitosis: telophase Sister chromatids at opposite poles
Spindle disassembles
Nuclear membrane forms around each set of sister chromatids
Nucleolus reappears
Chromosomes loss their distinct outlines reappear as chromatin

15. In pictures:
Prophase
Metaphase
Anaphase
Telophase

16. Cytokinesis: Means division of the cytoplasm
Division of cell into two, identical halves called daughter cells
Would this happen the same way in plants and animal cells? Why or why not?
In plant cells, cell plate forms at the equator to divide cell
In animal cells, cleavage furrow forms to split cell

17. Cytokinesis Cleavage furrow in animal cell Cell plate in animal cell
Cleavage furrow is when the cell membrane pinches off

18. IPMATC Helpful hint? Interphase Prophase Metaphase Anaphase Telophase
Cytokinesis
IPMATC

19. Amimation:

20. To do: Mitosis colouring sheet Labelling sheet Nelson Bio 11 Book