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Cell Division and Mitosis
http://www.johnkyrk.com/mitosis.html
http://www.sci.sdsu.edu/multimedia/mitosis/
http://www.bioteach.ubc.ca/TeachingResources/MolecularBiology/DNAReplication.swf
http://www.dnai.org/text/mediashowcase/index2.html?id=584
How do little elephants grow up to be BIG elephants?
By making more cells.
DNA
Because DNA stores genetic information and is replicated to pass information from cell-to-cell and generation-to- generation.
Why is DNA important?
Cell Division
1.Replication2.Mitosis3. Cytokinesis
Why do cells need to divide?
Why do cells need to divide?
1.To make new cells (if you are injured or growing)
2.Pass on your genes to next generation (sex)
Cell Cycle
1. Interphase
2. Prophase
3. Metaphase
4. Anaphase
5. Telophase
6. Cytokinesis
Which phases are part of mitosis?
Cell CycleWhich cycle is the longest?
Interphase
Interphase occurs before mitosis begins
• Chromosomes are __________ (# doubles)• Chromosomes appear as threadlike coils
(chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase
CELL MEMBRANENucleus
Cytoplasm
copied
InterphaseInterphaseAnimal Cell Plant Cell
What happens to the chromosomes during Interphase? The chromosomes double
INTERPHASE
DNA is replicated.
•During DNA replication the DNA separates into two strands and produces two new complementary strands. •Remember A binds to ___ and C binds to ___. T G
INTERPHASE
DNA is packed into ______________ after replication.
chromatin
duplicatedchromosome
Chromosomes
Chromosomes that are duplicated during Interphase are called?
INTERPHASEDNA condensed into visible Chromosomes
95% of the time DNA looks like this in the _________. Nucleus
Prophase 1st step in Mitosis
• Mitosis begins (cell begins to divide)
• ____________ (or poles) appear and begin to move to opposite end of the cell.
• Spindle fibers form between the poles.
CentriolesSister chromatids
Spindle fibers
Centrioles
Prophase
Animal Cell Plant Cell
Spindle fibers
Centrioles
Is the right picture or left picture of a Plant cell?
Metaphase 2nd step in Mitosis
• _____________(or pairs of chromosomes) attach to the spindle fibers.
CentriolesSpindle fibers
Chromatids
____________
Animal Cell Plant Cell
METAPHASE
Anaphase 3rd step in Mitosis
• ______________(or pairs of chromosomes) separate and begin to move to opposite ends of the cell.
Centrioles
Spindle fibers
Chromatids
____________
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
ANAPHASE
Telophase 4th step in Mitosis
• Two new _________form.
• Chromosomes appear as chromatin (threads rather than rods).
• Mitosis ends.
NucleiNuclei
Chromatin
nuclei
___________
Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
TELOPHASE
_____________occurs after mitosis
• Cell membrane moves inward to create two
daughter cells – each with its own nucleus with identical chromosomes.
CYTOKINESIS
Cytokinesis
Is this an animal or plant cell?
Cleave furrow in a dividing frog cell.
In Animal Cells, a Cleavage Furrow Forms and Separates Daughter Cells
Which process is pictured below?
-Cell Division-Mitosis or
-Cytokinesis
Cytokinesis
Is this an animal or plant cell?
Which phase has chromatids lined up in the middle?
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Which phase is first in the cell cycle?
Cell Cycle
30
The Cell CycleINTERPHASE - INTERMISSION
PROPHASE - PREPARE
METAPHASE - MIDDLE
ANAPHASE - APART
TELOPHASE – TWO NUCLEI
CYTOKINESIS - CELLS
30
Cell Cycle
Why does the cell cycle precisely divide the duplicated chromosomes into two?
interphase prophase
metaphase
To make each new cell identical with a complete set of genetic instructions.
Mitosis Precisely and Evenly Divides Duplicated Chromosomes
Is cytokinesis part of mitosis? No, neither is Interphase.
Mitosis in Action
What is the Blue stuff?
DNA
Cancer Progression• There are many different forms of cancer, affecting
different cell types and working in different ways. All start out with mutations in specific genes called “oncogenes”. The normal, unmutated versions of the oncogenes provide the control mechanisms for the cell. The mutations are caused by radiation, certain chemicals (carcinogens), and various random events during DNA replication.
• Once a single cell starts growing uncontrollably, it forms a tumor, a small mass of cells. No further progress can occur unless the cancerous mass gets its own blood supply. “Angiogenesis” is the process of developing a system of small arteries and veins to supply the tumor. Most tumors don’t reach this stage.
• A tumor with a blood supply will grow into a large mass. Eventually some of the cancer cells will break loose and move through the blood supply to other parts of the body, where they start to multiply. This process is called metastasis. It occurs because the tumor cells lose the proteins on their surface that hold them to other cells.