Chapter 10 Cell Growth And Division I Cell

Chapter 10 Cell Growth And Division

I. Cell Growth – – • DNA 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 rate @ which waste products leave cell depends on ____________ of cell=total area of cell membrane Surface area

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

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

• 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 division replicates

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 46 – humans have___ Chromosomes – fruit flies have 8 – usually not visible except in cell division, when they condense – __________before cell division Replicates or copies DNA

– each Chromosome consists of 2 identical _________, which separate from each other in cell division – chromatids attached @_________, usually 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= ________________ • G 1 and G 2= ___________________ Mitosis and cytokinesis Chromsomes replicate & DNA synthesis, some proteins synthesize G 1=cell growth/G 2= organelles and molecules produced

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

ANAPHASE

1) Prophase – – – centrioles 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 spindle Spindle fibers

• 2) Metaphase • • • chromosomes line up @ 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) tumors cancer cyclins

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

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

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