Asexual reproduction ADJH- H. Aucoin

How do cells make new cells What happens when you cut a worm in half? Why do you think you can grow new skin over a cut on your hand but you can’t grow new fingers? ADJH- H. Aucoin

What is reproduction? Reproduction is the process by which organisms produce more of their own kind.  Think about it – Without reproduction, all life on earth would no longer exist. life on earth would no longer exist. ADJH- H. Aucoin

The cell cycle in your body  Cells don’t live forever, they eventually die.  Some cells life spans: Brain cells: 30 – 50 years Red blood cells: 120 days Stomach lining cells: 2 days Skin cells: 20 days  You need mitosis and cell division to replace these cells.  In your body about 3 billion cells die every minutes. ADJH- H. Aucoin

 Skin and bones can be healed because they undergo mitosis and can replace injured cells.  Research says that we age because as some cells die, they are not replaced or they are replaced more slowly, it is not known for sure. ADJH- H. Aucoin

Cancer  Cancer occurs when cells begin to divide uncontrollably.  Cancerous cells interfere with surrounding cells and disrupt their normal functioning.  Tumors/lumps are formed from the cells that pile up on each other. ADJH- H. Aucoin

 When you cut yourself, cells in that area over time multiply, fix the cut, and then slow their growth. Cancer stems from mutated cells who do not stop growing.  Cancerous cells start with a mutation in the cell's DNA. Mutations in a cells DNA can be caused by either genetic inheritance or the environment (ie. smoking, sunlight exposure, radiation, etc) mutationDNAMutationsmutationDNAMutations ( Cancer becomes malignant and fatal once its growth becomes intrusive on nearby tissues and organs, sometimes causing pain.[3] Also, further problems arise when metastasis occurs and cancer cells break away from the main growth and circulate in lymphatic and/or blood vessels. Once these renegade cells relocate, they can cause additional tumors.[7] [3][7][3][7] ADJH- H. Aucoin

 Once the mutation occurs, the cell begins to multiply at an increased rate, passing its mutated DNA on to further generations. They continue to grow and lead to an unwanted, benign cluster.  Cancer becomes malignant and fatal once its growth becomes intrusive on nearby tissues and organs. ADJH- H. Aucoin

What is Asexual Reproduction?  Only one parent is involved.  Offspring are genetically identical to their parents.  All cells that come from a single cell are genetically identical to it and to each other; they are all clones. ADJH- H. Aucoin

Types of Asexual Reproduction 1. Mitosis - is the exact duplication of the nucleus of a cell so as to form two identical nuclei during cell division. ADJH- H. Aucoin

Types of Asexual Reproduction 2. Binary Fission - occurs in one-celled organisms such as the ameba and paramecium. The nucleus divides by mitosis and the cytoplasm divides, forming 2 new daughter cells of equal size. ADJH- H. Aucoin

Types of Asexual Reproduction 3. Budding - Occurs in Hydra and yeast. The division of cytoplasm is unequal so one of the daughter cells is larger than the other. The daughter cells can separate or remain attached. A copy of the nucleus is made, then a tiny bud begins to form on the cell wall. This bud, containing the new nucleus continues to grow and eventually breaks away. ADJH- H. Aucoin

Types of Asexual Reproduction 4. Sporulation - occurs in molds, mosses, etc  Spores are produced in large numbers by mitosis.  Spores are surrounded by a tough coat to help them survive harsh environmental conditions. When mature, and the sporangium explode, and the spores can now float on air currents and begin the whole process over again. ADJH- H. Aucoin

Types of Asexual Reproduction 5.Regeneration - Refers to the replacement or regrowth of lost or damaged body parts ADJH- H. Aucoin

Types of Asexual Reproduction 6. Fragmentation – a small piece or fragment, breaks away from the main mass and grows into a new individual. ADJH- H. Aucoin

7. Vegetative Propagation Occurs only in plants. Meristemic cells (non specialized cells) help new plants to develop from the roots, stems, or leaves of the parent plant. Occurs only in plants. Meristemic cells (non specialized cells) help new plants to develop from the roots, stems, or leaves of the parent plant. Types of Asexual Reproduction ADJH- H. Aucoin

Runners- Runners are specialized stems called stolons. These stems grow horizontally outward and downward from plants and produce baby plants at their tips.. (ex. strawberries)  Grafting- horticultural techniques used to join parts from two or more plants so that they appear to grow as a single plant. ( For instance, a Macintosh seed will grow into an apple tree, but not into a Macintosh apple tree, which can only be achieved through grafting.) Types of Asexual Reproduction ADJH- H. Aucoin

Tissue Culture

Asexual reproduction– Brain Pop ADJH- H. Aucoin