Chapter 10 Cell Growth & Division

10-1 Cell Growth  Question: Are cells in a mouse and a whale the same size??  INTEREST GRABBER (10-1)  The larger a cell becomes, the more demands the cell places on its DNA. In addition, the cell has more trouble moving enough nutrients and wastes across the membrane

Limits to Cell Growth 1)DNA “overload”  DNA is unable to meet needs of a large cell 2)Surface area to volume ratio  Volume increases more rapidly than surface area 3)Exchanging Materials  The rate at which oxygen, food, & waste are used up depends on the cell’s volume  The rate at which oxygen, food, & waste diffuse across the membrane depends on the cell’s surface area

Division of the Cell  Before cells become too big, they divide forming two “daughter” cells.  The process of division is called cell division.

10-2 Cell Division  In eukaryotic cells, genetic information is passed on from one generation to the next by chromosomes.  Chromosomes are made of DNA  Human cells have 46 chromosomes

Purposes of Mitosis 1)Reproduction of unicellular organisms 2)Types of asexual reproduction 3)Growth / repair in multicellular organisms

The Cell Cycle TTTThe cell cycle is a series of event that cells go through as they grow and divide. DDDDuring the cell cycle, a cell … –G–G–G–Grows –P–P–P–Prepares for division –D–D–D–Divides to form 2 daughter cells EEEEach of which begin the cell cycle again!!

Events of the Cell Cycle  Interphase –Has three phases: G 1, S, and G 2 –Cell Grows –Chromosomes replicate

MITOSIS 1)P rophase LLLLongest Phase 55550 – 60% of the total time of Mitosis SSSSpindle Fibers Form NNNNuclear Envelope Disappears CCCChromosomes Coil up more tightly

2) Metaphase Chromosomes line up across the center of the cell

3) Anaphase  Sister chromatids separate and move to opposite ends of the cell

4) Telophase  Chromosomes uncoil  Nuclear Envelope reappears  Spindle fibers disappear

Cytokinesis  Splitting of the cytoplasm into two cells!

 Mitosis video (15 minutes) Mitosis

10-3 Regulating the Cell Cycle  READ pages 250 – 253!  Answer the following questions in your JOURNAL: 1.What is Cancer and what causes it? 2.Can cell division be turned on and off? 3.What does Cyclin do? 4.What are stem cells? 5.Do you believe stem cell research should be allowed? Briefly support your answer

Modeling the Phases of the Cell Cycle (pg. 254)