Mitosis and Asexual Reproduction Notes To be used with Mitosis and Asexual Reproduction Guided Notes

Cell Reproduction All of your body (somatic) cells are formed by mitosis Cell Reproduction is important when our bodies grow or when certain cells need replacement Cell typeLife span (days) Brain30-50 years Red blood Platelets Stomach lining Liver Intestine lining Skin

Stem Cells - cells taken from an early stage embryo that can differentiate (change into different cells)

Chromatin-Chromatid-Chromosome Genetic material - Contains DNA Chromatin Chromatid Chromosome DNA stands Coiled chromatin Replicated spaghetti & meatballs sister chromatids

The Cell Cycle - IPMAT 2 Parts: Interphase & Mitosis

The Cell Cycle - IPMAT Interphase Prophase Metaphase Anaphase Telophase Cytokenesis

Interphase 3 parts of Interphase –takes up about 90% of cell cycle G1 (growth one phase): –organelles grow S (synthesis phase): –replication of chromosome material G2 (growth phase two): –more organelle and cell growth

Interphase Chromatin: Immature chromosomes. Chromosomes are NOT distinguishable under microscope. Chromatin looks like spaghetti & meatballs. CENTRIOLES CHROMATIN NUCLEAR MEMBRANE

Mitosis - 4 phases Mitosis: is the second part of the cell cycle and is a type of cell division that results in two identical daughter cells. –The chromosome number in the daughter cell is the same as in the parent. -Humans have 46 chromosomes in each parent cell - their daughter cells will have 46 chromosomes. –Also called asexual reproduction or nuclear cell division –Only one parent is needed

Mitosis Each species has a specific chromosome number. OrganismNumber of Chromosomes Human Chimpanzee Dog Fruit fly Garden pea Adder’s fern Is the chromosome number related to the complexity of the organism??? NO WAY!

Phase1- Prophase 1. centrioles begin to separate 2. centrioles are connected by spindle fibers made of protein 3. nuclear membrane disappears 4. chromosomes appear coiled and become visible

Chromosome Structure chromatid: is one strand of a chromosome. two chromatids = one chromosome centromere: holds the chromatids together

Phase 2 - Metaphase 1. centrioles move to opposite poles of the cell connected by the spindle fibers. 2. each chromosome moves to the center of a cell along one spindle fiber. 3. the centromere attaches to a specific spindle fiber.

Phase 3 - Anaphase 1. cell is egg shape 2. centromeres replicate & separate 3. chromosomes separate 4. cytoplasmic division begin 5. cell membrane begins to pinch in

Phase 4 - Telophase 1. cell shape is figure 8 2. spindle fibers disappear 3. nuclear membrane reforms around chromosomes 4. centrioles replicate in late telophase 5. cell division begins in late telophase

Cytokenesis- -known as complete cell division -two identical daughter cells

The Cell Cycle: Interphase & Mitosis

Mitosis

Plant Mitosis How does mitosis differ in plants? –No centriole in plant cells –Plant cells do not pinch in half Cytoplasmic division is accomplished by a cell plate forming between 2 daughter cells

Mitosis In Plants: Interphase

Mitosis In Plants: Prophase

Mitosis In Plants: Metaphase

Mitosis In Plants: Anaphase

Mitosis In Plants: Telophase

Mitosis In Plants: Interphase

Results of Mitosis 1.The same chromosome number is retained from generation to generation 2.Each daughter cell receives an exact copy of the chromosomes of the parent cell

Results of Mitosis 3.Mutations are rare Cancer: uncontrolled cellular mitotic divisions Causes: Environment influences Viruses Smoking Radiation Prevention: Diet & exercise

Methods of Asexual Reproduction Binary fission: equal division of the cytoplasm and nucleus –results in two new organisms –Examples: paramecium, ameba, euglena

Methods of Asexual Reproduction Budding: nucleus of an organism's cell divides equally but the cytoplasm divides unequally –Examples: yeast, hydra, Sponge Bob

Sponge Bob

Methods of Asexual Reproduction Sporulation: the production of spores –Example: molds spores: single, specialized cells which are released from the parent –they are enclosed in a protective case and develop when environmental conditions are favorable

Sporulation

Methods of Asexual Reproduction Regeneration: the development of an entire new organism from part of an original organism –Example: starfish—one ray and part of central body –may also involve the restoration of lost body parts –invertebrates have greater powers of regeneration than do vertebrates

Regeneration

Patrick

Methods of Asexual Reproduction Vegetative Propagation: regeneration in plants –Complete new plants develop from part of the original plant –Example: Grafting

Asexual Reproduction Summary Individuals produced during asexual reproduction are genetically identical to their parents