Cell Division & Cell Cycle Study Guide :: essays research papers

CELL DIVISION Cell division involves 2 phases: 1- MITOSIS The process by which nuclear material is divided 2 identical daughter cells result 2- CYTOKINESIS the process by which the cytoplasm and its contents (organelles) separate into equal parts. cytokinesis begins before mitosis is complete cytokinesis differs in plant and animal cells ANIMAL CELLS the cell membrane pinches near the middle of the cell, dividing the cytoplasm into equal parts(2 new cells) PLANT CELLS a cell plate develops across the centre of the cell, creating a new cell wall between the 2 new cells Cells alternate between stages (phases) of dividing and not dividing. This sequence is called the cell cycle. The 2 major phases of the CELL CYCLE are: 1- DIVISION PHASE During this phase the cell undergoes mitosis (nuclear division) There are 4 phases of mitosis: Prophase Metaphase Anaphase Telophase 2- INTERPHASE During this phase, the cell takes in nutrients and builds proteins that are used by the cell for energy Chromosomes duplicate (DNA replication) This is the period of growth and repair for the cell (in preparation for the division phase) THE CELL CYCLE CELL CYCLE: the continuous process of mitosis, cell division, and interphase. HOW CELL GETS READY FOR MITOSIS Nucleus makes a copy of its chromatin(replication) Chromatin coils into double stranded chromosomes joined in the middle by a centromere 2 sets of DNA are bundled together nucleus is ready for mitosis to begin. Animal cell division: cell membrane pinches near the middle of the cell, dividing the cytoplasm into 2 new cells Plant cell division: a cell plate develops across the centre of the cell, forming a new cell wall between the 2 cells Original cellïÆ'  , parent cell New cellsïÆ'  , daughter cells # of chromosomes in the nucleus of each cell is identical to eachother and to the number in the original cell Why must nuclear membrane break down in mitosis? So that the contents of the cell can divide. The NUCLEUS controls the process of mitosis. REGENERATION: repair of injured cells or the making of lost body parts Normal Cell Replacement: cells die when they receive instruction to do so when they are no longer needed