1. Find your seats and take out your notebook.
Agenda for Tuesday March 22nd
Mitosis

2. Books and Resources www.glencoe.com Access Code: CCF2754895

3. Cellular Growth Cell Size limitations Ratio of surface area to volume
Difficulty providing nutrients and expel waste
Lower ratio = easier to maintain

4. Cellular Growth Cell size limitations Transport of Substances
Diffusion over a large area is slower & less efficient
Cellular communication
Too large means too hard to communicate

5. The Cell Cycle Cell reaches max size it stops growing or divides
Cells reproduce by growing and dividing = cell cycle
3 main stages of cell cycle
Interphase – cell grows, replicates DNA
Mitosis – cell nucleus and nuclear material divide
Cytokinesis – cell’s cytoplasm divides

7. 3 Stages of Interphase Gap 1 (G1)
Right after cell divides, cell carries out normal functions, prepares to replicate DNA
Synthesis (S)
Cell copies DNA
Chromosomes are structure that contain genetic material that is passed on
Chromatin is the relaxed form of DNA
Gap 2 (G2)
Cell prepares for mitosis

8. Mitosis Cell’s DNA separates
Creates 2 identical daughter cells
Same DNA
Same Number of Chromosomes in each cell
Increases number of cells as organisms grow
Replace damaged cells
4 Stages – Prophase, Metaphase, Anaphase, Telophase

9. 1. Prophase Longest phase
Chromatin condenses into chromosomes (X – shaped)
Chromosomes consist of two chromatids – identical copies of DNA
Chromatids are connected at a centromere

10. 1. Prophase Spindle fibers appear between poles
Centrioles appear at the ends of each cell
Aster fibers come out of the centrioles
Spindle fibers, centrioles, and aster fibers are called spindle apparatus
Helps move chromosomes

11. 2. Metaphase
Chromatids are pulled by motor proteins along spindle apparatus
Line up at center of cell

12. 3. Anaphase Chromatids pull apart
Spindle fibers start to shorten – causes chromosomes to move to end of cells

13. 4. Telophase Chromosomes arrive at the poles
Chromosomes start to unwind
Two nuclear membranes begin to form
Spindle apparatus disappears

14. Cytokinesis Divides cytoplasm Animal Cells Plant Cells
Microfilaments constrict/pinch the cytoplasm
Plant Cells
Cell plate forms between two daughter nuclei
Cell walls then form on either side of cell plate

16. Cell Cycle Regulation
Proteins called cyclins bind to enzymes called cyclin dependent kinases (CDK) to start different cell activities

17. Homework
Page 253 – 257
Questions 1 – 7 on page 257