Image from http www bcps orgofficeslismodelslifeimagesgrow JPG CELL

Image from: http: //www. bcps. org/offices/lis/models/life/images/grow. JPG CELL GROWTH & DIVISION 10 -1 & 10 -2 Image by Riedell

2 Reasons why cells divide 1. ___________ As cell grows bigger demand on DNA “genetic library” becomes too great Ex: Small town library has 1000 books. As town grows and more people borrow books, there may be a waiting list to read the most popular titles http: //www. adc. state. az. us/images/Off-Library. JPG

2 Reasons why cells divide 2. ___________ As cell grows bigger demand for transport across membrane is too great http: //www. animationlibrary. com

Ability to transport of oxygen, food, waste across cell membrane depends on ________ Need for these depends on ______ As cell grows these DON’T increase at the same rate See relationship between volume and SA

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 Go to Section:

BIGGER CELLS NEED MORE FOOD and OXYGEN, but CAN’T TRANSPORT IT FAST ENOUGH or IN BIG ENOUGH QUANTITIES! http: //www. animationlibrary. com

Image from: http: //www. bcps. org/offices/lis/models/life/images/grow. JPG Image by Riedell Multicellular organisms grow mainly by increasing cell number

DNA CAN BE: SPREAD OUT IN NON-DIVIDING CELLS SCRUNCHED UP IN DIVIDING CELLS

DNA in PROKARYOTES • BACTERIAL DNA is CIRCULAR • HAVE ONE CHROMOSOME • NO NUCLEUS; ATTACHED TO CELL MEMBRANE http: //www. origin-life. gr. jp/3202121/fig 6. jpg

DNA in EUKARYOTES (Plants & Animals) • DNA is ROD-SHAPED CHROMOSOMES • MANY PAIRS • FOUND IN NUCLEUS http: //cellbio. utmb. edu/cellbio/chrom 2. jpg

Chromosome structure • __________ 2 identical arms • _________ constricted area holds chromatids together • _________ PAIR 2 of each chromosome (one from mom; one from dad)

HOMOLOGOUS CHROMOSOMES • SAME SIZE • SAME SHAPE • CARRY GENES for the SAME TRAITS • BUT _______! (Don’t have to have the SAME CHOICES) http: //arnica. csustan. edu/biol 3020/cell_division. htm http: //sps. k 12. ar. us/massengale/genetics%20 tutorial. htm

CELL DIVISION in PROKARYOTES Bacteria reproduce using _________________ http: //fig. cox. miami. edu/~cmallery/150/mitosis/fission. jpg

CELL CYCLE _______ = series of events that cells go through as they grow and develop cells alive cell cycle

CELL CYCLE INTERPHASE – non-dividing phase G 1 - Grow bigger Cell is “doing its job” DNA is spread out as chromatin S - Synthesis (copy DNA) & chromosomal proteins G 2 - Grow bigger, make organelles & molecules needed for cell division

CELL DIVISION MITOSIS – Nuclear division Prophase Metaphase Anaphase Telophase Cytokinesis – Cytoplasm divides G 0 – cell stops dividing (Ex: nerve cell)

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

INTERPHASE (G 1 - S - G 2) In between divisions Cells are in this phase most of the time Can see nucleus DNA spread out as chromatin Can’t see chromosomes DNA gets copied (S) Cell gets ready to divide

Pearson Education Inc publishing as Pearson Prentice Hall PROPHASE 1 st dividing phase http: //www. life. uiuc. edu/plantbio/102/lectures/08 mit&veg 102. html DNA scrunches into chromosomes Centrioles appear in centrosome region & move to poles Nuclear membrane & nucleolus disappear Spindle fibers form & attach to chromosomes

____ region organizes spindle Spindle MICROTUBULES are part of cytoskeleton http: //www. coleharbourhigh. ednet. ns. ca/library/organelle_worksheet. htm

METAPHASE Chromosomes line up in ______ Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall http: //www. science. siu. edu/plant-biology/PLB 117/JPEGs%20 CD/0247. JPG

ANAPHASE Centromeres split Centrioles pull chromatids_______ Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall http: //www. science. siu. edu/plant-biology/PLB 117/JPEGs%20 CD/0247. JPG

TELOPHASE (reverse prophase steps) See ______ nuclei Nuclear membrane & nucleolus return Chromosomes spread out as chromatin Centrioles disappear Spindle fibers disappear Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall http: //www 2. bc. ca. us/cnewton/Biology%2011/Mitosis. html

CYTOKINESIS Cytoplasm splits into 2 cells ANIMAL CELLS pinch cytoplasm in two with a ___________

CYTOKINESIS Cytoplasm splits into 2 cells PLANT CELLS can’t pinch because they have a sturdy ______ Plant cells separate cytoplasm by growing a ________ down the middle. http: //www. eastcentral. edu/acad/depts/BI/plant_mitosis_nolabels. html

Figure 10– 5 Mitosis and Cytokinesis Section 10 -2 Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Go to Section: Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Anaphase Metaphase

Videos Animal Cell Mitosis Animal Cell Cytokinesis

Concept Map Section 10 -2 Cell Cycle includes is divided into Go to Section: is divided into

Concept Map Section 10 -2 Cell Cycle includes Interphase M phase (Mitosis) is divided into G 1 phase Go to Section: S phase G 2 phase Prophase Metaphase Anaphase Telophase