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All living organisms are made of cells. Cells are the basic unit of structure and function in all living things. Cells come from pre-existing cells. Through both sexual and asexual reproduction. • Look at the picture to the right. • The green part of the potato will grow into a second potato exactly like the first one. It is BOTH parents. • Asexual reproduction is a type of reproduction in which a new organism is produced from only one parent and has the same DNA as the parent. • In humans it happens in most of our body cells. Interphase – DNA is replicated (copied) on each chromosome. This is the longest phase of the cell cycle and where the DNA “unzips” and makes two strands (1/2 old and ½ new). Mitosis - The big idea to remember is that mitosis is the simple duplication of a cell and all of its parts. It duplicates its DNA and the two new cells (daughter cells) have the same pieces and genetic code. Two identical copies come from one original. Cytokinesis - the cell splits into 2 new cells which are exact copies of each other, Interphase- The first stage of the cell cycle. Interphase happens BEFORE cell division and mitosis. Several things must occur first before the cell can divide. The most important thing is for the DNA to be copied or replicated so that each cell has a copy of the original DNA. The DNA is “unzipped” and base pairs match up to create 2 exact strands from the original. Mitosis- The stage of the cell cycle where the cell’s nucleus actually divides into 2 new nuclei resulting in an exact copy. Both cells now have the same genetic code. Two identical copies come from one original. Start with one cell and get two that are the same. Mitosis is divided into four stages of its own. Prophase Metaphase Anaphase Telophase This is how most of our somatic (body) cells are reproduced. Mitosis allows us to grow and develop. Cells have a limited lifespan. They eventually can’t function and need to be replaced. The cell cycle with mitosis is the beginning of the process by which the cells are replaced with exact clones of the old cell. Mitosis Video Clip Some simple organisms reproduce this way. Cancer and other diseases can happen when a mistake (mutation) is made in mitosis. For reasons that scientists are still trying to figure out, this mutated cell or group cells begins to replicate themselves very quickly. These abnormal cells then can spread to other parts of the body. Cancer Cell vs Normal Cell Growth Cytokinesis - the last stage of the cell division cycle. This happens AFTER mitosis and the second nucleus is completely formed. The animal cell membrane pinches in around the middle of the cell. A new cell wall is created in a plant cell. The plant or animal cell splits into two daughter cells. Each daughter cell ends up with an identical set of chromosomes. At the end of cytokinesis, each new cell enters interphase and the cycle starts over to make more cells. Asexual reproduction is a never ending cycle in your body. The whole cycle of somatic cell division typically lasts from 8 to 24 hours in humans. A type of reproduction in which a new organism is produced from one parent and has the same DNA or genetic material as the parent. This is also how somatic (body) cells are reproduced. Making an exact copy of a cell. To allow growth and development To replace old cells To repair damaged cells To create new organisms Brain Pop Asexual Reproduction Mitosis Cloning Budding Animal Regeneration