New Cells

HideShow resource information
View mindmap
  • New Cells
    • Mitosis
      • Prophase
        • Chromosomes spiralise and condense (supercioling). They are visable, thick and short threads
          • The Nuclelus shrinks, centrioles move to opposite poles in the cell
            • Spindle Fibres from in the regions of the centrioles
              • Each chromosome can be seen as 2 chromatids joined at the centromere
                • Each pair of sister chromtids are duplicated chromosomes
                  • Nuclear envelope begins to disintergrate
          • In this state, chromosomes can take up stains to be seen under light microscope
      • Metaphase
        • Spindle fibres have grown accross the cell
          • the chromosomes have lined up independantly along the equator
            • the spindle has sttached to each chromosomes centromere
      • Anaphase
        • Centromeres divide into two, separating sister chromatids
          • fibres shorten, pulling each chromosome to separate poles
            • V shape because they are pulled by centromere
      • Telophase
        • Chromosomes begin to uncoil into chromatin
          • Spindle fibres disintergrate, cell constricts along its central axis
            • Nuclear envelope begins to from around each set of chromosomes
              • Cytokinesis
                • division of the cytoplasm into two genetically identical daughter cells
          • When coiled, the chromosomes cannot complete their functions, so the length of time they are coiled needs to be as short as possible
      • Interphase
        • cell prepares for division, DNA replicates, centrioles replicate, 2 pairs of homologous chromosomes
      • Most animal cells, in plants only meristem cells can
        • Plants don't have centrioles, tunulin protien required is made in cytoplasm
          • In plant cells cytokinesis begins with the formation of a cell plate
      • Please-Pro Make-Meta Another-Ana Two-Tele
    • Needed For:
      • replacement an old cell
      • Growth of tissue
      • Development
    • Chromosomes
      • in nucleus of eukaryotic cells
      • each contains one molecule of DNA - including specific sections Genes
        • the molecules of DNA that make up each chromosome are wrapped around proteins called histones
          • The DNA of eaach chromsome is replicated - producing 2 replicas, a pair of sister chromatids) held at the centromere
      • Varies depending on species - human 46, dogs 78 etc
      • Chromatin threads are about 30nm thick, after supercioling a chromosome is about 500nm thick
    • Mutations
      • can occur if DNA is not replicated correctly
      • can cause the cell not to function correctly
    • Time
      • varies between species and type
      • affected by availability of nutrients
    • Mitosis is only a small portion of the cell cycle
      • interphase - s phase and growth phase


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Cellular processes and structure resources »