3.What is the advantage of cells being small? Materials move through cells by diffusion. Oxygen and food move into cells, while waste products move out of cells. How does the size of a cell affect how efficiently materials get to all parts of a cell? 1. On a sheet of paper, make a drawing of a cell that has the following dimensions: 5 cm x 5 cm x 5 cm. Then you should draw another cell about 2.5 cm x 2.5 cm x 2.5 cm. 2. Compare your drawings. How much longer do you think it would take to get from the cell membrane to the center of the big cell than from the cell membrane to the center of the smaller cell? 3.What is the advantage of cells being small? It would take twice the amount of time. If cells are small, materials can be distributed to all parts of the cell quickly.

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

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 http://www.adc.state.az.us/images/Off-Library.JPG

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

Need for these depends on ___________ Ability to transport 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

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

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

mainly by increasing cell number 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 CHROMATIN CHROMOSOMES

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

DNA is organized and packaged into structures called chromosomes. A human cell contains 46 chromosomes. (somatic cells) Chromosomes are composed of a substance called chromatin

Each strand of chromosomes is called a chromatid. Identical strands are called sister chromatids and are held together by centromeres. During cell division, the sister chromatids are seperated at the centromere, and one ends up in each daughter cell.

Chromosome structure CHROMATIDS CENTROMERE HOMOLOGOUS ___________________ 2 identical arms __________________ constricted area holds chromatids together CENTROMERE HOMOLOGOUS __________________ 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) NOT IDENTICAL 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 __________________________________ BINARY FISSION 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 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

CELL DIVISION MITOSIS – Nuclear division Prophase Metaphase Anaphase Telophase Cytokinesis – Cytoplasm divides G0 – cell stops dividing (Ex: nerve cell)

Figure 10–4 The Cell Cycle Section 10-2 G1 phase M phase S phase

INTERPHASE (G1 - S - G2) Can’t see chromosomes 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 DNA scrunches into chromosomes Pearson Education Inc publishing as Pearson Prentice Hall PROPHASE 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

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

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

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

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 http://www2.bc.cc.ca.us/cnewton/Biology%2011/Mitosis.html

CYTOKINESIS Cytoplasm splits into 2 cells CLEAVAGE FURROW 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 WALL CELL PLATE http://www.eastcentral.edu/acad/depts/BI/plant_mitosis_nolabels.html

http://highered. mcgraw-hill http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__mitosis_and_cytokinesis.html http://www.hybridmedicalanimation.com/work/animation/the-stages-of-mitosis/

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

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

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

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

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

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

Videos Animal Cell Mitosis Animal Cell Cytokinesis

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

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

SOUTH DAKOTA CORE SCIENCE STANDARDS LIFE SCIENCE: Indicator 1: Understand the fundamental structures, functions, classifications, and mechanisms found in living things 9-12.L.1.1. Students are able to relate cellular functions and processes to specialized structures within cells. Transport (ANALYSIS) cell membranes, homeostasis Cell life cycles (ANALYSIS) Examples: somatic cells (mitosis)

Core High School Life Science Performance Descriptors High school students performing at the ADVANCED level: predict the function of a given structure; predict the outcome of changes in the cell cycle; predict how homeostasis is maintained within living systems; PROFICIENT level: describe the relationship between structure and function explain how homeostasis is maintained within living systems; compare and contrast the cell cycles in somatic and germ cells; BASIC level recognize that different structures perform different functions define homeostasis; describe the life cycle of somatic cells;