Mitosis and Asexual Reproduction

Life Cycle of a Cell Mitosis Stage: this is the stage in which the cell’s nucleus duplicates and divides to form two new nuclei. It has four (4) stages or Phases. These are Prophase, Metaphase, Anaphase, and Telophase. Mitosis Stage: this is the stage in which the cell’s nucleus duplicates and divides to form two new nuclei. It has four (4) stages or Phases. These are Prophase, Metaphase, Anaphase, and Telophase.

Formation of Body Cells MITOSIS How do Cells reproduce? How do Cells reproduce? Cells reproduce through a process called Mitosis. Cells reproduce through a process called Mitosis.

Mitosis – Cell Division Mitosis is a kind of cell division that produces body cells. It started when you were conceived and it still continues now! Mitosis is a kind of cell division that produces body cells. It started when you were conceived and it still continues now! Each body cell divides to produce 2 new body cells with the same number of chromosomes (diploid). Each body cell divides to produce 2 new body cells with the same number of chromosomes (diploid). When a cell reproduces, one cell becomes two identical cells. When a cell reproduces, one cell becomes two identical cells.

Life Cycle of a Cell Interphase: the cell spends most of its time developing and maturing. It is getting ready to reproduce. This is the stage in which the chromatin in the nucleus develops into chromosomes. As the chromosomes begin to appear, the nuclear membrane disappears. Then the Chromosomes duplicate themselves!! This is called Replication. Interphase: the cell spends most of its time developing and maturing. It is getting ready to reproduce. This is the stage in which the chromatin in the nucleus develops into chromosomes. As the chromosomes begin to appear, the nuclear membrane disappears. Then the Chromosomes duplicate themselves!! This is called Replication.

Life Cycle of a Cell - Interphase

Stages of Mitosis Prophase: Chromosomes have duplicated to form 2 strands or a pair of chromatids (This is called Replication). These are called homologous chromosomes. Spindle fibers form and attach to the chromosomes. Prophase: Chromosomes have duplicated to form 2 strands or a pair of chromatids (This is called Replication). These are called homologous chromosomes. Spindle fibers form and attach to the chromosomes.

Prophase of Mitosis

Stages of Mitosis Metaphase: Chromosomes line up at the center or middle of the cell. Metaphase: Chromosomes line up at the center or middle of the cell.

Stages of Mitosis Anaphase: Chromosomes begin to pull apart. Spindle fibers pull them to opposite ends of the cell. Anaphase: Chromosomes begin to pull apart. Spindle fibers pull them to opposite ends of the cell.

Stages of Mitosis Telophase: The cell divides in half. Two identical daughter cells are formed, each having the same number of chromosomes as the parent cell. The division into two new cells is called Cytokinesis. Telophase: The cell divides in half. Two identical daughter cells are formed, each having the same number of chromosomes as the parent cell. The division into two new cells is called Cytokinesis.

Telophase of Mitosis

Life Cycle of a Cell Cytokinesis: this is the final stage of the cell’s life cycle in which the cell’s cytoplasm is equally divided for each new nucleus and the cell divides to form two new, identical cells. Cytokinesis: this is the final stage of the cell’s life cycle in which the cell’s cytoplasm is equally divided for each new nucleus and the cell divides to form two new, identical cells.

Cytokinesis

Asexual Reproduction This is Reproduction with only one parent. This is Reproduction with only one parent. Offspring (children) are identical to parent. Offspring (children) are identical to parent. Asexual Reproduction occurs in single-cell organisms, simple animals and plants. Asexual Reproduction occurs in single-cell organisms, simple animals and plants.

Asexual Reproduction The formation of a new individual from one parent. The formation of a new individual from one parent. Mini-me Mini-me (clones) (clones)

Who Reproduces asexually? Unicellular organisms (Ex: bacteria) Unicellular organisms (Ex: bacteria) Many simple animals (Ex: hydra) Many simple animals (Ex: hydra) Many plants Many plants

Asexual Reproduction It takes place by mitosis (new cells are identical to parent – clones). It takes place by mitosis (new cells are identical to parent – clones). It occurs rapidly and often, resulting in large numbers of offspring. It occurs rapidly and often, resulting in large numbers of offspring. Several methods include: Binary Fission, Budding, Spore Formation, Regeneration, and Vegetative Reproduction. Several methods include: Binary Fission, Budding, Spore Formation, Regeneration, and Vegetative Reproduction.

Asexual Reproduction Occurs by MITOSIS Occurs by MITOSIS Same hereditary material Same hereditary material Identical Identical Usually occurs fast Usually occurs fast Many offspring Many offspring No gametes involved (sex cells) No gametes involved (sex cells)

Methods of Asexual Reproduction Vegetative Reproduction Vegetative Reproduction Binary fission Binary fission Budding Budding Spore formation Spore formation Regeneration Regeneration

Methods of Asexual Reproduction 1) Binary Fission: this is the simplest form. 1) Binary Fission: this is the simplest form. One parent divides into two equal parts. Each daughter cell (new cells) becomes a separate individual and grows to normal size. One parent divides into two equal parts. Each daughter cell (new cells) becomes a separate individual and grows to normal size. No parent is left – it becomes two individuals. No parent is left – it becomes two individuals. Common in bacteria, protozoa, and algae. Common in bacteria, protozoa, and algae.

Example Binary Fission

Methods of Asexual Reproduction 2) Budding: 2) Budding: Parent divides into two Unequal parts. Parent divides into two Unequal parts. New individuals develop from buds on the outer surface of the parent organism. New individuals develop from buds on the outer surface of the parent organism. Common in yeast, hydra, sponges. Common in yeast, hydra, sponges.

Example of Budding Yeast Cells

Budding Hydra

Methods of Asexual Reproduction 3) Spores: these are special cells that are produced by special organisms. 3) Spores: these are special cells that are produced by special organisms. They are released by the parent, germinate. They are released by the parent, germinate. Spores are produced by fungi, algae, and protozoa. Spores are produced by fungi, algae, and protozoa. They are products of mitosis. They are products of mitosis. Common forms are bread mold and mushrooms. Common forms are bread mold and mushrooms.

Examples of Spores

Methods of Asexual Reproduction 4) Regeneration: 4) Regeneration: The ability of an organism to re-grow body parts. The ability of an organism to re-grow body parts. Examples are starfish, hydra, planaria, earthworms. Examples are starfish, hydra, planaria, earthworms.

Example of Regeneration

Methods of Asexual Reproduction 5) Vegetative Reproduction: this is also known as Propagation. 5) Vegetative Reproduction: this is also known as Propagation. It involves plants that reproduce asexually using vegetative parts (roots, stems, or leaves). It involves plants that reproduce asexually using vegetative parts (roots, stems, or leaves). Vegetative parts give rise to new plants. Vegetative parts give rise to new plants. This is a natural process that can also be produced Artificially!!! This is a natural process that can also be produced Artificially!!!

Natural Vegetative Reproduction This type occurs in Nature!! Some plants reproduce by Bulbs, Corms, Tubers, Runners or by Rhizomes. A) Bulbs: these are short underground stems surrounded by thick leaves. Examples are onions, garlic, tulips, and daffodils. (Corms do not have thick leaves.) A) Bulbs: these are short underground stems surrounded by thick leaves. Examples are onions, garlic, tulips, and daffodils. (Corms do not have thick leaves.)

Example of Bulbs

Example of Corms

Natural Vegetative Reproduction B) Tubers: these are enlarged parts of underground stems that contain food. Contain “eyes”, which are tiny buds. Examples are potatoes. B) Tubers: these are enlarged parts of underground stems that contain food. Contain “eyes”, which are tiny buds. Examples are potatoes.

Example of Tubers

Natural Vegetative Reproduction C) Runners: stems that grow sideways along the ground. Buds root and produce new plants. Example is strawberries. C) Runners: stems that grow sideways along the ground. Buds root and produce new plants. Example is strawberries.

Examples of Runners

Natural Vegetative Reproduction D) Rhizomes: stems that grow sideways underground that contain nodes. Nodes give rise to new plants. Examples are ferns, irises, cattails, waterlillies. D) Rhizomes: stems that grow sideways underground that contain nodes. Nodes give rise to new plants. Examples are ferns, irises, cattails, waterlillies.

Example of Rhizomes: ginger plant

Vegetative Reproduction Review Bulbs: short, underground stems surrounded by fleshy leaves (tulip) Bulbs: short, underground stems surrounded by fleshy leaves (tulip) Corms: same as a bulb without the fleshy leaves (crocus) Corms: same as a bulb without the fleshy leaves (crocus) Tubers: enlarged part of the underground stem which contain tiny buds called “eyes” Tubers: enlarged part of the underground stem which contain tiny buds called “eyes” Runner: a stem that grows sideways and has buds (strawberry, many grasses) Runner: a stem that grows sideways and has buds (strawberry, many grasses) Rhizome: a thick, underground stem that grows sideways Rhizome: a thick, underground stem that grows sideways

Artificial Vegetative Reproduction This type was developed by farmers and gardeners to grow plants with desirable traits. Methods include; Cutting, Layering, and Grafting.

Artificial Propagation Cuttings (leaf, stem, root) Cuttings (leaf, stem, root) Layering Layering Grafting Grafting

Artificial Vegetative Reproduction A) Cutting: a stem, leaf, or root used to produce a new plant. These parts are dipped in a hormone and placed in moist soil. Examples are grapevines, roses, African Violets. A) Cutting: a stem, leaf, or root used to produce a new plant. These parts are dipped in a hormone and placed in moist soil. Examples are grapevines, roses, African Violets.

Example of a Cutting

Artificial Vegetative Reproduction B) Layering: a stem is bent over and covered with soil to produce roots. Examples are raspberries, roses, honeysuckle. B) Layering: a stem is bent over and covered with soil to produce roots. Examples are raspberries, roses, honeysuckle.

Example of Layering

Artificial Vegetative Reproduction C) Grafting: Stems or buds are taken from one plant and joined to another stem of a related plant. Examples, Fruit trees. C) Grafting: Stems or buds are taken from one plant and joined to another stem of a related plant. Examples, Fruit trees.

Example of Grafting

Tree Grafting