http://www.ebsi.co.kr/ebs/lms/lmsx/retrieveSbjtDtl.ebs?sbjtId=S20180001026 /mnt/1T-5e7/mycodehtml/Biology/CSByun/Bio1_2020/007_Cell cycle_and_Cell_division_001/main.html ================================================================================ Cell cycle: - start of cycle: new cell after cell division - growth - end of cycle: new cell is performed cell division ================================================================================ Cell cycle ================================================================================ Interphase Mitotic phase ================================================================================ Interphase (growth of the cell) G1: - growth of the cell - number of cell organelle (such as ribosome, mitochondria, etc) increases recap that cell division is that one cell becomes 2 cells so, increasing number of cell organelle is required S (synthesis) - DNA replication G2 - growth of the cell - materials (which will consisit of spindle fiber) is synthesized ================================================================================ Interphase: - Most of the time during cell division process - You can see "nuclear membrane" and "phosphorus" in the interphase period of the cell - chromonema instead of chromosome - spindle fiber is not observable - spindle fiber is observable in mitotic phase (prophase) - centrosome (which is source point of spindle fiber) is observable ================================================================================ Mitotic phase - prophase (pre) - chromonema gets dense into chromosome - "nuclear membrane" and "phosphorus" disappear - spindle fiber is becoming observable - metaphase (intermediate) - best period to observe the chromosome - anaphase (late) - telophase (end) - chromosome gets losen into chromonema - "nuclear membrane" and "phosphorus" start to show - spindle fiber disappears ================================================================================ - You can see 2 step of mitotic phases - This is meiosis - There is no "interphase" between meiosis1 and meiosis2 ================================================================================ - G1 and G2 in interphase period are too short to draw them - SMSM is observed in the cleavage (which is observed in initial cell division of fertilized egg) 2 cells -> 4 cells -> 8 cells ================================================================================ Most of cell stays at G1 When new cell should be generated, cell cycle starts ================================================================================ ================================================================================ Interphase ================================================================================ Mitotic phase prophase (pre) - chromonema gets dense into chromosome - "nuclear membrane" and "phosphorus" disappear - spindle fiber is becoming observable - 2n=4 in above case ================================================================================ Mitotic phase metaphase (intermediate) - Chromosomes are arranged in the center line - centrosome moves to the both end locations - centrosomes emit the spindle fiber - spindle fiber is attached to kinetochore of the each chromosome - best period of the cell to observe and anlyze the "chromosome" and the "nuclear phases" ================================================================================ Mitotic phase anaphase (late) - Separation of chromatid in the "somatic cell division" - Note that it's not separation of homologous chromosome which is observed in meiosis process - spindle fiber becomes short and then chromatid is separated ================================================================================ Mitotic phase telophase (end) - Completion of separation - chromosome gets losen into chromonema - "nuclear membrane" and "phosphorus" start to show - spindle fiber disappears - You can see 2 daughter nucleus in the one cell - After completion of separtion of 2 daughter nucleus, cytoplasm should be divided ================================================================================ Division of cytoplasm - Animall cell - Cytoplasmic inclusion - Dividing force: from outside to inside - Plant cell - Dividing force: from inside to outside - by creating cell plate - cell plate becomes cell wall afterwards ================================================================================ When somatic division is performed - Development and growth - Recover mechanism from the damange - Asexual reproduction ================================================================================