MITOSIS and the CELL CYCLE CELL DIVISION AND REPRODUCTION NOTEBOOK PAGES 54/55.

MITOSIS and the CELL CYCLE

CELL DIVISION AND REPRODUCTION

NOTEBOOK PAGES 54/55

How do little elephants grow up to be BIG elephants?

Why and how do animals shed their skin?

Cell Division is the answer! MITOSIS Asexual cell division

that duplicates a cell exactly with ALL the genetic material in the new cell

DIPLOID CELLS ARE CREATED

MEIOSIS Cell division of sex

cells that have only HALF the regular amount of genetic information in the new cell.

HAPLOID CELLS!

The process of cell division (MITOSIS) begins

after a sperm fertilizes an egg.

GENETIC INFORMATION LOCATED IN THE NUCLEUS

CHROMOSOMES- 46 in every normal human cell, DNA- carries info about all

cells and the organism

CENTROMERE- center where the nucleus and genetic material start to divide

CENTRIOLES- poles that appear at the sides or edges of the cell during mitosis

Three reasons why cells reproduce by asexual reproduction:

1. Growth 2. Repair 3. Replacement

Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun.

Cell that reproduce by asexual reproduction reproduce constantly.

Animated Mitosis Cyclehttp://www.cellsalive.com/mitosis.htm

• Interphase

• Prophase

• Metaphase

• Anaphase

• Telophase & Cytokinesis

I PAID MY ATTORNEY THOUSANDS(CONSTANTLY)

I- InterphasePAID- Prophase MY- Metaphase ATTORNEY- Anaphase THOUSANDS- Telophase(CONSTANTLY)- Cytokinesis

Interphase occurs before mitosis begins

resting periodCELLS ARE DIPLOID- FULL NUMBER OF

CHROMOSOMES (46)

• Chromosomes are copied (# 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

InterphaseInterphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Prophase 1st step in Mitosis

• Mitosis begins (cell begins to divide)• Centrioles (or poles) appear and begin to move to

opposite end of the cell. • Spindle fibers form between the poles.

CentriolesSister chromatids

Spindle fibers

Prophase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Spindle fibers

Centrioles

Metaphase 2nd step in Mitosis

• Chromatids (or pairs of chromosomes) attach to the spindle fibers.

Centrioles

Spindle fibers

Metaphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Anaphase 3rd step in Mitosis

• Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell.

Centrioles

Spindle fibers

Anaphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Telophase 4th step in Mitosis

• Two new nuclei form. • Chromosomes appear as chromatin (threads

rather than rods).• Mitosis ends.

NucleiNuclei

Chromatin

Telophase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Cytokinesisoccurs after mitosis

2 new cells have successfully

formed • Cell membrane moves inward to create two

daughter cells – each with its own nucleus with identical chromosomes.

Animal Mitosis -- Review

Interphase

Prophase

Metaphase

Anaphase

Telophase

Interphase

Plant Mitosis -- ReviewInterphase

Prophase

Metaphase

Anaphase

Telophase

Interphase

Cell Cycle

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The Cell Cycle

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- A review of the steps of Mitosis:

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