The Cell Cycle PDF

The Cell Cycle  Why do cells divide? For growth and repair To get food, water, and waste in and out of our bodies  What is the Cell Cycle? Series of events that take place from one cell division to the next Constantly  Interphase Period of growth and...

The Cell Cycle  Why do cells divide? For growth and repair To get food, water, and waste in and out of our bodies  What is the Cell Cycle? Series of events that take place from one cell division to the next Constantly  Interphase Period of growth and development Longest phase of the cell cycle Some cells never leave interphase such as nerve and muscle cells  Three things happen during interphase: Cell grows in size; makes an extra set of structures Cell makes a copy of its hereditary material. (DNA) Produces structures needed division (spindle fibers, centrioles)  DNA Deoxyribonucleic acid It is our hereditary material (passed on from our parents) Found in the nucleus of our cells as chromatin Chromosomes Human Karyotype  Chromosome #’s Humans-46 Carrot-18 Cat- 32 Dog-78 Earthworm-36 Fruit fly-8 Chimpanzee-48 Adder’s tongue fern-1,262  Mitosis Is the division of the nucleus Results in two new identical nuclei  Four Stages of Mitosis Prophase Metaphase Anaphase Telophase Prophase Chromatin condenses to form chromosomes. Centrioles move to opposite ends of the cell Spindle fibers form bridge between the ends of the cell. Nuclear envelope breaks down.  Metaphase Chromosomes line up in the center of the cell attaching to spindle fibers by a centromere. Anaphase Centromeres split Chromatids separate and become chromosomes. The new chromosomes move to opposite ends of the cell Cell begins to stretch out as the  Telophase Chromosomes stretch out New nuclear envelope forms around each region of chromosomes  Cytokinesis The cell membrane pinches in around the middle of the cell. The cell splits in two Each daughter cell ends up with an identical set of chromosomes and half of the organelles.  Cytokinesis The division of the cytoplasm Usually starts around the same time as telophase Results in two new identical cells (daughter cells) that have the same # of chromosomes as the original parent cell  Cytokinesis in Animal Cells Cell membrane pinches together around the middle of the cell creating two new cells Each daughter cell gets about half of the organelles Cytokinesis in Plant cells Cell plate forms down the center of the cell The cell plate gradually develops into a cell membrane New cell walls form around the cell membrane  http://www.youtube.com/watch?v=rg LJrvoX_qo&feature=related