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

Section 10-1 Ratio of Surface Area to Volume in Cells 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/3202/3202121/fig6.jpg

DNA in EUKARYOTES

(Plants & Animals)

• DNA is ROD-SHAPED CHROMOSOMES • MANY PAIRS • FOUND IN NUCLEUS

http://cellbio.utmb.edu/cellbio/chrom2.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/biol3020/cell_division/cell_division.htm

http://sps.k12.ar.us/massengale/genetics%20tutorial.htm

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

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

G 1

CELL CYCLE

INTERPHASE – non-dividing phase - 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)

IN TERPHASE (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 PRO

PHASE

1st dividing phase http://www.life.uiuc.edu/plantbio/102/lectures/08mit&veg102.html

DNA scrunches into chromosomes Centrioles appear in centrosome region & move to poles Nuclear membrane & nucleolus disappear Spindle fibers form & attach to chromosomes

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

M

ETAPHASE

Chromosomes line up in ___________ Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall http://www.science.siu.edu/plant-biology/PLB117/JPEGs%20CD/0247.JPG

A

NAPHASE

Centromeres split Centrioles pull chromatids_______ Images from: Pearson Eduction Ince; Publishing as Pearson Prentice Hall http://www.science.siu.edu/plant-biology/PLB117/JPEGs%20CD/0247.JPG

T ELOPHASE (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://www2.bc.cc.ca.us/cnewton/Biology%2011/Mitosis.html

CYTO KINESIS Cyto plasm splits into 2 cells ANIMAL CELLS pinch cytoplasm in two with a ______________________

CYTO KINESIS Cyto plasm 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 reforming Nuclear envelope Chromatin

Interphase Cytokinesis

Centromere Chromosomes (paired chromatids)

Prophase

Spindle Centriole Centriole

Metaphase Telophase

Individual chromosomes

Anaphase

Go to Section:

Section 10-2 Concept Map

Cell Cycle includes is divided into is divided into Go to Section: