Chapter 10 Cell Growth And Division

I. Cell Growth –A. Limits to Cell Growth –2 reasons cells divide rather than continuing to grow indefinitely : 1) larger a cell grows,the more demands on its _______ –will not be making enough copies of DNA as size increases---This would cause an information crisis. 2) difficult to move waste and nutrients across cell which waste products leave cell depends on _______________________ of cell=total area of cell membrane DNA Surface area

which food and Oxygen are used up and waste produced depends on _____________________ –RATIO OF SURFACE AREA TO VOLUME- assuming a cube shape,surface area=l x w x 6…..volume= lx w x h…. ratio = SA /volume Cell volume

Cell Size Surface Area (length x width x 6) Volume (length x width x height) Ratio of Surface Area to Volume Ratio of Surface Area to Volume in Cells Section 10-1

Volume increases faster than surface area/CAUSING RATIO TO __________________..causing serious problems for cell decrease

B. Division of Cell -A cell divides into 2 daughter cells =_______________________________ –This happens before a cell can get too large –DNA ___________________before cell division,solving info crisis. Cell divisionreplicates

II. Cell Division ***simpler in prokaryotes –A. chromosomes –carries genetic info in eukaryotes –made up of ____________ and proteins –cells of every organism have a specific # of Chromosomes –humans have___ Chromosomes –fruit flies have 8 –usually not visible except in cell division,when they condense –___________________before cell division DNA 46 Replicates or copies

–each Chromosome consists of 2 identical __________________,which separate from each other in cell division –chromatids near middle chromatids centromere

B. Cell Cycle –________________________is in- between phase –______________________is the series of events that a cell goes through during growth and division….Where the cell grows,prepare for division,divides into 2 daughter cells interphase Cell Cycle

–4 phases M= _______________________________ S= ________________________________ G1 and G2= ______________________________________ __________________ Mitosis and cytokinesis Chromsomes replicate & DNA synthesis,some proteins synthesize G1=cell growth/G2= organelles and molecules produced

M phase G 2 phase S phase G 1 phase Figure 10–4 The Cell Cycle Section 10-2

ANAPHASE

1) Prophase –Longest phase –Chromosomes become visible –_______________________,2 tiny structures near nuclear envelope-separate and take positions on opposite ends of nucleus –Centrosome region helps organize __________________-microtubules that help separate chromosomes –Chromosomes attach to __________________________ end chromosomes coil tightly and nuclear envelope disappears centrioles spindle Spindle fibers

2 ) Metaphase- chromosomes line center Centromeres go to 2 poles 3) Anaphase- Centromeres split Chromatids separate and become individual _____________________ New chromosomes go to opposite poles and then stop moving chromosomes

4) Telophase- Chromosomes disperse into tangle of material New nuclear envelopes Spindle breaks apart Nucleolus becomes visible

D. Cytokinesis-divison of cytoplasm –Usually along w/ Telophase –Cell plate forms in plants that becomes the ______________________________ CELL WALL

III. _____________________= disorder in which some of the body’s cells lose the ability to regulate growth They do not respond to signals that regulate growth Divide uncontrollably,making ___________________(masses of cells) _____________=protein that regulates normal cell cycle (in eukaryotes) cancer tumors cyclins

Video Conten ts Videos Click a hyperlink to choose a video. Animal Cell Mitosis Animal Cell Cytokinesis

Video 1 Click the image to play the video segment. Video 1 Animal Cell Mitosis

Video 2 Click the image to play the video segment. Video 2 Animal Cell Cytokinesis