Chapter 10Chapter 10

Cell Growth & Cell Growth & DivisionDivision

10-1 Cell Growth10-1 Cell Growth QuestionQuestion: Are cells in a mouse and a : Are cells in a mouse and a

whale the same size??whale the same size?? INTEREST GRABBER (10-1)INTEREST GRABBER (10-1) The larger a cell becomes, the more The larger a cell becomes, the more

demands the cell places on its DNA. In demands the cell places on its DNA. In addition, the cell has more trouble moving addition, the cell has more trouble moving enough nutrients and wastes across the enough nutrients and wastes across the membranemembrane

Limits to Cell GrowthLimits to Cell Growth1)1) DNA “overload”DNA “overload”

DNA is unable to meet needs of a large cellDNA is unable to meet needs of a large cell2)2) Surface area to volume ratioSurface area to volume ratio

Volume increases more rapidly than Volume increases more rapidly than surface areasurface area

3)3) Exchanging MaterialsExchanging Materials The rate at which oxygen, food, & waste The rate at which oxygen, food, & waste

are used up depends on the cell’s volumeare used up depends on the cell’s volume The rate at which oxygen, food, & waste The rate at which oxygen, food, & waste

diffuse across the membrane depends on diffuse across the membrane depends on the cell’s surface areathe cell’s surface area

Division of the CellDivision of the Cell

Before cells become too big, they divide Before cells become too big, they divide forming two “daughter” cells.forming two “daughter” cells.

The process of division is called The process of division is called cell cell divisiondivision..

10-2 Cell Division10-2 Cell Division In eukaryotic cells, genetic information In eukaryotic cells, genetic information

is passed on from one generation to the is passed on from one generation to the next by chromosomes.next by chromosomes.

Chromosomes are made of DNAChromosomes are made of DNA Human cells have 46 chromosomesHuman cells have 46 chromosomes

Purposes of MitosisPurposes of Mitosis

1)1) Reproduction of unicellular organismsReproduction of unicellular organisms2)2) Types of asexual reproductionTypes of asexual reproduction3)3) Growth / repair in multicellular organismsGrowth / repair in multicellular organisms

The Cell CycleThe Cell Cycle The cell cycle is a series of event that The cell cycle is a series of event that

cells go through as they grow and divide.cells go through as they grow and divide. During the cell cycle, a cell …During the cell cycle, a cell …

– GrowsGrows– Prepares for divisionPrepares for division– Divides to form 2 daughter cellsDivides to form 2 daughter cells

Each of which begin the cell cycle again!!Each of which begin the cell cycle again!!

Events of the Cell CycleEvents of the Cell Cycle

InterphaseInterphase– Has three phases: GHas three phases: G11, S, and G, S, and G22

– Cell GrowsCell Grows– Chromosomes replicateChromosomes replicate

MITOSISMITOSIS1)1) ProphaseProphase

Longest PhaseLongest Phase 50 – 60% of the total 50 – 60% of the total

time of Mitosistime of Mitosis Spindle Fibers FormSpindle Fibers Form Nuclear Envelope Nuclear Envelope

DisappearsDisappears Chromosomes Coil Chromosomes Coil

up more tightlyup more tightly

2) Metaphase2) MetaphaseChromosomes line up across the center of Chromosomes line up across the center of

the cellthe cell

3) Anaphase3) Anaphase Sister chromatids separate and move to Sister chromatids separate and move to

opposite ends of the cellopposite ends of the cell

4) Telophase4) Telophase Chromosomes uncoilChromosomes uncoil Nuclear Envelope reappearsNuclear Envelope reappears Spindle fibers disappearSpindle fibers disappear

CytokinesisCytokinesis Splitting of the cytoplasm into two cells!Splitting of the cytoplasm into two cells!

Mitosis video (15 minutes) video (15 minutes)

10-3 Regulating the Cell Cycle10-3 Regulating the Cell Cycle READ pages 250 – 253!READ pages 250 – 253! Answer the following questions in your Answer the following questions in your

JOURNAL:JOURNAL:1.1. What is Cancer and what causes it?What is Cancer and what causes it?2.2. Can cell division be turned on and off?Can cell division be turned on and off?3.3. What does Cyclin do?What does Cyclin do?4.4. What are stem cells?What are stem cells?5.5. Do you believe stem cell research should be Do you believe stem cell research should be

allowed? Briefly support your answerallowed? Briefly support your answer

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