Transcript Slide 1
Intro to topic 3 Notes There are 2 reasons cells divide rather than grow indefinitely. 1. The larger that cells become, the more demand the cell places on the DNA 2. the large the cell becomes the more trouble the cell has moving enough nutrients and wastes across the cell membrane Cell division is The process of DNA replication and the division of the cytoplasm to form 2 new identical cells Cell division reduces the volume, and increases the ratio between volume and surface area. you will need to be able to calculate surface area, volume and the ratio of surface area to volume http://www.youtube.com/watch?v=pv_RWaADwk&feature=related&safety_mode=true&pe rsist_safety_mode=1&safe=active Hw: Do Worksheet on cell growth Cell Division Chromosomes are not visible in most cells, except during ________________ Cell division When chromosomes become visible they consist of _________________ 2 sister chromatids _________________ connected at the _________________ centromere _____ Each pair of chromatids is attached at an area called the centromere ___________________________ The Cell Cycle is diagramed below: The period of growth between cell divisions is called Interphase ______________________________ The division of the nucleus during the M phase of the cell cycle is called ___________________. Mitosis Interphase is divided into 3 phases G1 Phase ____________________ S Phase _____________________ G2 Phase ____________________ During the G1 phase ________________________ Rapid growth Replication of Chromatids During the S phase ___________________ for mitosis During the G2 phasePrep _________________________ (make another centriole)_ The 4 phases of Mitosis are: 1. Prophase -- Chromosomes become visible, nucleus and nucleolus dissolve. Centrioles move to opposite ends and form microtubules( spindle) . Chromosomes Centrioles Microtubles/ spindle 2. Metaphase -- Chromosomes line up across the middle of the cell Microtubles/ spindle Chromosomes Centrioles 3. Anaphase -Chromosomes migrate to the 2 ends of the cell centrioles chromatids 4. Telophase -- New nuclear membrane forms, and the cell begins to divide by cytokinesis. prophase chromosomes Interphase spindle centriole Metaphase Nuclear membrane anaphase Cell membrane nucleolus centrioles telophase chromosomes Two new daughter cells chromosomes In animal cells Centrioles _______________________ located near the nucleus help separate the chromosomes Spindle fibers by forming ________________________. cytokinesis _____________________ is the process of the cytoplasm being divided in two pieces. Cell plate In pant cells a _____________________ forms midway of the cell. When an injury occurs the cells in the area begin to divide ____________________ When the injury is almost healed __________________________ the rate of cell division slows cyclins __________________ are responsible for regulating the cell cycle. Cancer is unregulated cell growth ___________________________ ______________ Cancer cells don’t respond to signals that regulate growth ___________ Cancer cells form masses of cells tumors called ___________________ Cancer cells break loose and spread throughout the body ___________________ Hw: 21 in workbook worksheet