Mitosis Asexual Reproduction 1 Mitosis What is it

Mitosis & Asexual Reproduction 1

Mitosis What is it? • A process of cell division in body cells (somatic cells). • Involves one replication and one division of genetic material (DNA) • Results in 2 daughter cells that are identical to each other. They have the same number of chromosomes.

How is Mitosis Used? • Mitosis is used for: – Growth – Replacements of cells – Asexual reproduction (in some organisms) 3

What is Reproduction? • The production of offspring (new organisms) • There are two types: – Asexual Reproduction – 1 parent • Offspring are genetically identical to the parent and to each other. - Sexual Reproduction – 2 parents • Offspring are genetically different and have different characteristics from parents. 4

Asexual Reproduction • Involves Mitosis – a process of cell division in body cells (somatic cells) • Involves one replication and one division of genetic material (DNA) – Results in two daughter cells that are identical to each other. They have the same number of chromosomes. 5

Mitosis Overview Telophase Interphase Prophase Anaphase Metaphase 6

The Phases of Mitosis Remember…IPMAT!! 1. Interphase Not a true phase of mitosis 2. Prophase 3. Metaphase 4. Anaphase 5. Telophase 7

The Phases of Mitosis - Interphase 1. Interphase – the period between cell divisions Not a true phase of mitosis • The cell grows and carries on normal metabolism • Genetic material (DNA) exists as chromatin – thin thread like coils of DNA. • Chromosomes replicate before division 8

What is Replication? • Each single stranded chromosome (chromatid) makes an exact copy of itself, resulting in a double stranded chromosome. • This is important to make sure each cell created through mitosis has the same amount of DNA chromatid Double stranded chromosomes are held together at the centromere 9

The Phases of Mitosis - Prophase 2. Prophase • Chromosomes become visible. • The nuclear membrane disappears. • Spindle fibers form between centrioles (in animal cells only). Early Prophase Late Prophase 10

The Phases of Mitosis - Metaphase 3. Metaphase • Double stranded chromosomes attach to spindle fibers at the centromere. • Chromosomes line up on the equator of the cell. 11

The Phases of Mitosis - Anaphase 4. Anaphase • spindle fibers shorten, pulling chromatids apart. • cell membrane begins to pinch in (animal cells only). • In plant cells a cell plate will form. 12

The Phases of Mitosis - Telophase 4. Telophase • Cell membrane begins to pinch in (animal cells only). • In plant cells a cell plate will form. • Cytokinesis occurs (division of cytoplasm) • New nuclear membranes form • Two new daughter cells are formed with identical nuclei. Cytokinesis Resulting Daughter Cells 13

Comparing Mitosis in Plant & Animal Cells Mitosis looks the same in plant and animal cells, except: • Only animal cells have centrioles • Animal cells pinch in • In plants a cell plate is synthesized to divide cytoplasm. 14

Comparing Mitosis in Plant & Animal Cells Plant cells develop a cell plate during Telophase Animal cells have centrioles 15

Mitosis and Disease Cancer: A group of diseases characterized by an uncontrolled division (mitosis) of abnormal cells. 16

Asexual Reproduction • • Asexual Reproduction involves 1 parent and produces genetically identical offspring. Types: 1. 2. 3. 4. 5. Binary Fission Budding Sporulation Regeneration Vegetative Propagation 17

Binary Fission • Mitosis followed by equal cytoplasmic division. Ameba Paramecium 18

Budding • Mitosis followed by unequal cytoplasmic division. Hydra Yeast Bud Parent 19

Sporulation • Special cells called spores are released from the parent and can develop into new individuals in a favorable environment. Bread Mold 20

Regeneration Sea Stars Planaria (worms) 21

Vegetative Propagation • New plants develop from the roots, stems, or leaves of another plant. – Occurs in some multicellular plants 22

Types of Vegetative Propagation Cuttings Tubers (Potatoes) Bulbs Runners 23

Vegetative Propagation • Grafting – part of one plant (scion) is attached to another plant (stock). Stock Multi-grafted Citrus Tree Scion 24

PROPHASE METAPHASE ANAPHASE TELOPHASE INTERPHASE 25

Photos of 5 Stages 26

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