asexual reproduction

1 1

Asexual ReproductionMitosis

DSQ: Mitosis is the process in which the nucleus divides to form two new nuclei. How does mitosis differ in plants and animals?

Mrs. Camp

7th Grade Life Science

How do little elephants grow up to be BIG elephants?

Why do animals shed their skin?

The process of asexual reproduction (cell life cycle) begins after a sperm fertilizes an

egg.

Three reasons why cells reproduce by asexual reproduction:

1. Growth 2. Repair 3. ReplacementSkin 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 Cell Life Cyclehttp://www.cellsalive.com/mitosis.htm

Cell Life Cycle Stages

• Interphase

• M1- Prophase

• M2- Metaphase

• M3- Anaphase

• M4- Telophase

• Cytokinesis

Interphase occurs BEFORE mitosis begins

• Chromosomes and ALL organelles are copied.

• Chromosomes appear as threadlike coils (chromatin) at the start, but are almost invisible with a light microscope.

CELL MEMBRANENucleus

Cytoplasm

InterphaseWhat differences do you see?

Animal Cell Plant Cell

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

M1- Prophase 1st step in Mitosis

• Mitosis begins. Chromosomes visible.• Centrioles (or poles) appear and begin to

move to opposite end of the cell. (Not in Plants)

• Spindle fibers form between the poles.Centrioles

Sister chromatids

Spindle fibers

M1- ProphaseWhat differences do you see?

Animal Cell Plant Cell

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

Spindle fibers

M2- Metaphase 2nd step in Mitosis

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

Centrioles

Spindle fibers

M2- MetaphaseWhat differences do you see?

Animal Cell Plant Cell

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

M3- Anaphase 3rd step in Mitosis

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

Centrioles

Spindle fibers

AnaphaseWhat differences do you see?

Animal Cell Plant Cell

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

Telophase 4th step in Mitosis

• Chromosomes are at across ends of cell.• Chromosomes appear as chromatin

(threads rather than rods).• Two new nuclei form• Mitosis ends.

NucleiNuclei

Chromatin

TelophaseWhat differences do you see?

Animal Cell Plant Cell

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

Cytokinesisoccurs AFTER mitosis

• Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.

Animal Cell Life Cycle - Review

Interphase

M1-Prophase

M2- Metaphase

M3- Anaphase

M4- Telophase

Cytokinesis

Plant Cell Life Cycle -- ReviewInterphase

M1- Prophase

M2- Metaphase

M3- Anaphase

M4- Telophase

Cytokinesis Cell Wall Plate Forms

21

Cell Life Cycle- Animal Cell

22

- Cell DivisionThe Cell Cycle

22

Cell Life Cycle Animation

http://www.cellsalive.com/mitosis.htm