Image from: Image by Riedell CELL GROWTH & DIVISION 10-1 & 10-2

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 DNA OVERLOAD

2 Reasons why cells divide 2. _____________________ As cell grows bigger demand for transport across membrane is too great Material exchange can ’ t keep up

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

BIGGER CELLS NEED MORE FOOD and OXYGEN, but CAN ’ T TRANSPORT IT FAST ENOUGH or IN BIG ENOUGH QUANTITIES!

Multicellular organisms grow mainly by increasing cell number Image from: Image by Riedell

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

DNA in PROKARYOTES BACTERIAL DNA is CIRCULAR HAVE ONE CHROMOSOME NO NUCLEUS; ATTACHED TO CELL MEMBRANE

DNA in EUKARYOTES (Plants & Animals) DNA is ROD-SHAPED CHROMOSOMES MANY PAIRS FOUND IN NUCLEUS

Chromosome structure ___________________ 2 identical arms __________________ constricted area holds chromatids together __________________ PAIR 2 of each chromosome (one from mom; one from dad) CHROMATIDS CENTROMERE HOMOLOGOUS

HOMOLOGOUS CHROMOSOMES SAME SIZE SAME SHAPE CARRY GENES for the SAME TRAITS BUT ______________! (Don ’ t have to have the SAME CHOICES) NOT IDENTICAL

CELL DIVISION in PROKARYOTES Bacteria reproduce using __________________________________ BINARY FISSION

______________ = 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)

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

PROPHASE 1st dividing phase Spindle fibers form & attach to chromosomes Nuclear membrane & nucleolus disappear DNA scrunches into chromosomes Centrioles appear in centrosome region & move to poles Pearson Education Inc publishing as Pearson Prentice Hall

________ region organizes spindle Spindle MICROTUBULES are part of cytoskeleton CENTROSOME

METAPHASE Chromosomes line up in ___________ middle Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall

ANAPHASE Centromeres split Centrioles pull chromatids_______ apart Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall

TELOPHASE (reverse prophase steps) See ______ nuclei Nuclear membrane & nucleolus return Chromosomes spread out as chromatin Centrioles disappear Spindle fibers disappear two Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall

CYTOKINESIS Cytoplasm splits into 2 cells ANIMAL CELLS pinch cytoplasm in two with a ______________________ CLEAVAGE FURROW

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. CELL PLATE CELL WALL

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

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

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

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

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

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

Videos Animal Cell Mitosis Animal Cell Cytokinesis

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

Go to Section: includes is divided into Concept Map Section 10-2 Cell Cycle M phase (Mitosis) Interphase G 1 phaseS phaseProphaseG 2 phaseMetaphaseTelophaseAnaphase