Connect!

• How about those paper cuts? How do they “go away”?• How does a broken bone “get better”?• How did you start out life?• How many cells do you have now?• How did this happen…how did you grow?• How long do your cells last?• How does a single cell organism reproduce?• Describe how you think cells divide.

A. MITOSIS (MITOTIC CELL DIVISION)

• is when the nucleus divides. This divvies up the genetic material between the two cells.

• an exact copy of the set of chromosomes is made

• mitosis is important bc it makes cells that are diploid – meaning they have 2 copies of chromosomes in the nucleus (our body cells are diploid) – a complete set of directions!

• This is important bc every body cell needs a complete set of directions in order to function correctly.

• Before division can begin, each single-stranded chromosome replicates which results in a double-stranded chromosome

Chromosome Structure

• chromatids are the individual strands of a doubled chromosome

• centromere – connects chromatids

Steps of Mitosis

1. Interphase

2. Prophase

3. Metaphase

4. Anaphase

5. Telophase

Interphase• nucleus and

nucleolus are distinctly visible

• cell is carrying out normal life functions

• chromosomes are not visible

BUT• DNA is replicating

to prepare for mitosis

Prophase • chromosomes appear squiggly, like pasta

• nuclear membrane and nucleolus disappear

• chromosomes line up in the middle

• spindle fibers are formed (by centrioles in animal cells)

Metaphase

• chromosomes are pulled apart by spindle fibers

Anaphase

• nuclear membranes reappear

• cell membrane pinches in to start forming two

Telophase

Daughter cells• identical to

original cell

• same number of chromosomes

Contrasts Btwn Plants and Animals

1. centrioles are found only in animal cells and help form the spindle apparatus

2. animal cells pinch in while plant cells form a cell plate

• Remember…

mitosis is a continuous process…think of a video.

• Each diagram is like a freeze frame – just part of the process.

Animation of Mitosis

Click here: http://www.johnkyrk.com/mitosis.html

Here is another:

Cancer

• when abnormal cells divide uncontrollably

(“Cells Gone Wild”)

Chunk!

• What is mitosis?• Why is it important?• Describe a chromatid and centromere.• What is the first thing that happens?• What is the order of the phases?• Describe a cell in each phase.• What do spindle fibers do?• What do centrioles do?• How is mitosis in animal and plant cells different?• Why is the tip of a root a good place to look for mitotic

cells?• What is cancer?

•Explain this cartoon.

JFF!

Images• Cell dividing - www.historyoftheuniverse.com/celldivi.htm• Single to double - home.comcast.net/.../chromosomes_tips.htm • Chromatid - http://www.iupui.edu/~wellsctr/MMIA/images/chromosome_graphic.jpg• Fluorescent green series - http://www.sciencecentric.com/images/news/mitosis_300_364.jpg• Stages of mitosis – self-generated• Animal cytokinesis - http://www.mesoblast.com/images/images-mesoblast_cell_division_still.jpg• Plant cytokinesis - http://www.bio.txstate.edu/~dlemke/botany/1410lab/lab_exercises/lab3/

cell_cycle/cytokinesis.jpg• Cancer cells - http://images.google.com/imgres?imgurl=http://i3.photobucket.com/albums/y90/

hillaryk/CancerCells.jpg&imgrefurl=http://milesandhisfavorites.wordpress.com/category/science/&usg=__vC3yV-xfQkk47f4-P7e2IE4mB-g=&h=517&w=768&sz=192&hl=en&start=5&sig2=BlDO87EAV1vDS1gHwVa11Q&itbs=1&tbnid=V1eyETBoadi99M:&tbnh=96&tbnw=142&prev=/images%3Fq%3Dcancer%2Bcells%26gbv%3D2%26hl%3Den%26sa%3DG&ei=AS5rS_yFJdLi8Abyl4yNBg

• Cartoon - http://images.google.com/imgres?imgurl=http://www.ibiblio.org/Dave/Dr-Fun/collections/blobs/images/blobs-001.gif&imgrefurl=http://www.ibiblio.org/Dave/Dr-Fun/collections/blobs/blobs-archive-01.html&usg=__c3KcoaQT4MN6Ub15ne1D5xbt2d0=&h=480&w=640&sz=129&hl=en&start=11&sig2=xxTBwwtBiKZdFTZZAQA_nA&itbs=1&tbnid=Wf24vKWNBQVAyM:&tbnh=103&tbnw=137&prev=/images%3Fq%3Dmitosis%2Bcartoon%26gbv%3D2%26hl%3Den&ei=kSxsS-7VIMyV8AbMxomUBg

• Mitosis animation - biologycorner.com/resources/onionmitosis.jpg• Image may be subject to copyright.• Below is the image at: www.argohs.net/.../rgergitswebsite2004.htm