CELL GROWTH & CELL GROWTH & REPRODUCTION REPRODUCTION Chapter 8, Section 2 pg. 201Chapter 8, Section 2 pg. 201

Cell Size pg. 201-202Cell Size pg. 201-202 Small cells are more efficient (work better)Small cells are more efficient (work better) Easier to bring nutrients in and get waste outEasier to bring nutrients in and get waste out Small cells have a greater Small cells have a greater Surface Area-to-Surface Area-to-

Volume RatioVolume Ratio so that exchange of materials so that exchange of materials across the plasma membrane is more efficientacross the plasma membrane is more efficient

Cell Reproduction pg. 203Cell Reproduction pg. 203

Chromatin Chromatin = = uncondensed DNA, prior uncondensed DNA, prior to cell division.to cell division.

ChromosomesChromosomes = = condensed DNA, form condensed DNA, form when cell is ready to when cell is ready to divide divide

Made up of 2 halves Made up of 2 halves held together in the held together in the center by the center by the centromere pg. 205centromere pg. 205

Cell Cycle (Interphase & Cell Cycle (Interphase & Mitosis) pgs. 206 - 209Mitosis) pgs. 206 - 209 Cell CycleCell Cycle = sequence of growth & division of a = sequence of growth & division of a

cell, 2 partscell, 2 parts 1. Interphase1. Interphase 2. Cell Division2. Cell Division

MitosisMitosis CytokinesisCytokinesis

1. Interphase1. Interphase = growth period, majority of a cell’s = growth period, majority of a cell’s life – 3 parts life – 3 parts Cells grow (G1)Cells grow (G1) Chromosomes duplicate (S)Chromosomes duplicate (S) Prep for division (G2)Prep for division (G2)

2. Mitosis2. Mitosis = period = period of division, of division, 2 2 daughter cells get daughter cells get formed, each w/ a formed, each w/ a complete set of complete set of chromosomeschromosomes Divided into 4 PhasesDivided into 4 Phases

Phases of Mitosis pg. 207Phases of Mitosis pg. 207 1. Prophase1. Prophase Chromatin Chromatin coils into coils into

chromosomeschromosomes Sister ChromatidsSister Chromatids = two = two

halves of the halves of the chromosome, chromosome, chromatids are chromatids are genetically identicalgenetically identical

Nuclear Envelope Nuclear Envelope & & NucleolusNucleolus break downbreak down

CentriolesCentrioles start sending start sending out out Spindle FibersSpindle Fibers

2. Metaphase2. Metaphase Chromosomes Chromosomes line line

up in the center of up in the center of the cellthe cell

Spindle FibersSpindle Fibers attach attach the chromatidsthe chromatids

3. Anaphase3. Anaphase Separation of Separation of Sister Sister

ChromatidsChromatids

4. Telophase4. Telophase ChromatidsChromatids pulled to pulled to

opposite ends of the opposite ends of the cellcell

Nuclear Envelope Nuclear Envelope & & NucleolusNucleolus re-form re-form

CytokinesisCytokinesis pg. 209= division of the pg. 209= division of the cytoplasmcytoplasm Cleavage FurrowCleavage Furrow in animals in animals Cell PlateCell Plate in plants in plants

http://http://cellsalive.com/cell_cycle.htm

Cancer (Ch. 8, Sec. 3)Cancer (Ch. 8, Sec. 3) Results from uncontrolled cell division, over 200 Results from uncontrolled cell division, over 200

different typesdifferent types Cell division is controlled by enzymes. What Cell division is controlled by enzymes. What

controls enzyme production?controls enzyme production? If the DNA of a cell is damaged/altered, regulation If the DNA of a cell is damaged/altered, regulation

of cell division can be affectedof cell division can be affected What environmental factors can damage cells?What environmental factors can damage cells? Ultraviolet rays, exposure to toxic materials, Ultraviolet rays, exposure to toxic materials,

tobacco, obesitytobacco, obesity Other factors include genetics, lack of exercise, Other factors include genetics, lack of exercise,

obesity, unhealthy dietobesity, unhealthy diet

PracticePractice

Lung cancer is the leading cause of Lung cancer is the leading cause of death by cancer for males and females. death by cancer for males and females. Explain how this statistic can be easily Explain how this statistic can be easily reduced.reduced.