Cell Division and Mitosis. gResources/MolecularBiology/DN

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

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The Cell CycleINTERPHASE - INTERMISSION

PROPHASE - PREPARE

METAPHASE - MIDDLE

ANAPHASE - APART

TELOPHASE – TWO NUCLEI

CYTOKINESIS - CELLS

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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.