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CELL GROWTH & DIVISION 10-1 & 10-2
Image from: CELL GROWTH & DIVISION 10-1 & 10-2 The only time multiplication and Division mean the same thing! Image by Riedell
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2 Reasons why cells divide
DNA OVERLOAD 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
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2 Reasons why cells divide
Material exchange can’t keep up 2. _____________________ As cell grows bigger demand for transport across membrane is too great
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Need for these depends on ___________
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
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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
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BIGGER CELLS NEED MORE FOOD and OXYGEN, but CAN’T TRANSPORT
IT FAST ENOUGH or IN BIG ENOUGH QUANTITIES!
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mainly by increasing cell number
Image from: Image by Riedell Multicellular organisms grow mainly by increasing cell number
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DNA in PROKARYOTES BACTERIAL DNA is CIRCULAR HAVE ONE CHROMOSOME
NO NUCLEUS; ATTACHED TO CELL MEMBRANE
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CELL DIVISION in PROKARYOTES
Bacteria reproduce by simply getting larger, copying their DNA, and then splitting in two.
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DNA in EUKARYOTES (Plants & Animals)
DNA is ROD-SHAPED CHROMOSOMES MANY PAIRS FOUND IN NUCLEUS
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DNA CAN BE: SPREAD OUT IN NON-DIVIDING CELLS SCRUNCHED UP
IN DIVIDING CELLS CHROMATIN CHROMOSOMES
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Chromosome structure CHROMATIDS CENTROMERE
___________________ identical arms __________________ constricted area holds chromatids together CENTROMERE
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CELL CYCLE ______________ : the series of events that cells go through as they grow and develop
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CELL CYCLE INTERPHASE – non-dividing phase
G1- Grow bigger Cell is “doing its job” DNA is spread out as chromatin S - Synthesis (copy DNA) & chromosomal proteins G2- Grow bigger, make organelles & molecules needed for cell division M – Mitosis AND cytokinesis
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CELL DIVISION MITOSIS – Nuclear division (4 STAGES) Prophase Metaphase
Anaphase Telophase Cytokinesis – Cytoplasm divides G0 – cell stops dividing (Ex: nerve cell)
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Figure 10–4 The Cell Cycle Section 10-2 G1 phase M phase S phase
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INTERPHASE (G1 - S - G2) Can’t see chromosomes
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
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PROPHASE 1st dividing phase DNA scrunches into chromosomes
Pearson Education Inc publishing as Pearson Prentice Hall PROPHASE 1st dividing phase DNA scrunches into chromosomes Centrioles appear in centrosome region & move to poles Nuclear membrane & nucleolus disappear Spindle fibers form & attach to chromosomes
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METAPHASE middle Chromosomes line up in _____
Spindle fibers attach to centromeres
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ANAPHASE Centromeres split Centrioles pull chromatids_______ apart
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two 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
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CYTOKINESIS Cytoplasm splits into 2 cells CLEAVAGE FURROW
ANIMAL CELLS pinch cytoplasm in two with a ______________________ CLEAVAGE FURROW
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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 WALL CELL PLATE
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Figure 10–5 Mitosis and Cytokinesis
Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Figure 10–5 Mitosis and Cytokinesis
Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Figure 10–5 Mitosis and Cytokinesis
Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Figure 10–5 Mitosis and Cytokinesis
Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Figure 10–5 Mitosis and Cytokinesis
Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Figure 10–5 Mitosis and Cytokinesis
Section 10-2 Spindle forming Centrioles Chromatin Centromere Nuclear envelope Centriole Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Telophase Individual chromosomes Anaphase Nuclear envelope reforming
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Concept Map Cell Cycle Section 10-2 includes is divided into
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Concept Map Cell Cycle Section 10-2 includes M phase (Mitosis)
Interphase is divided into is divided into G1 phase S phase Prophase G2 phase Metaphase Telophase Anaphase
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