cell division

• Cells use the process of DNA replication prior to cell division to make an identical copy of their DNA. Each daughter cell formed receives a full complement of DNA which is identical to the parent cell.

  
• Prokaryotic cells


  Divide by binary fission

  
• Prokaryotic cell division


  1. Circular chromosome replicates

  2. Chromosome attaches to cell membrane

  3. Cell divides into two new cells

  
• Mitosis


  Division of the nucleus to form two identical daughter cells

  
• Eukaryotic cells


  Divide by mitotic division which involves division of the nucleus (mitosis) and division of the cytoplasm (cytokinesis)

  
• Mitosis


  1. Prophase

  2. Metaphase

  3. Anaphase

  4. Telophase
• Anaphase in mitosis


  Pairs of chromatids are separated and moved by the spindle to opposite poles of the cell

  
• Chromosomes in eukaryotic cells are linear
• The purpose of cell division is for new cells to arise, as one cell must divide (separate into two new cells)
• In unicellular organisms, cell division allows for species to reproduce
• In multicellular organisms, cell division allows for the organism to grow, replace damaged or dead cells, and leads to sexual reproduction
• Parent cell


  The original cell
• Daughter cells


  The new cells
• For a cell to be able to divide, they need to replicate their DNA

  
• DNA replication


  The process of copying the DNA

  
• DNA replication ensures that the daughter cells have identical DNA to the parent cells
• Binary fission


  Division of prokaryotic cells

  
• Steps in binary fission

  1. Single, circular DNA chromosome is replicated

  2. Each chromosome attaches to the cell membrane

  3. The parent cell elongates so the chromosomes are separated

  4. The cell membrane grows inwards at the cleavage site and a new cell wall forms

  5. The parent cell has successfully divided into two identical daughter cells

  
• All multicellular organisms consisting of animal cells reproduce through sexual reproduction
• Diploid cells


  Cells that have two copies of each chromosome, one from the mother and one from the father

  
• Homologous pairs


  The maternal and paternal chromosomes

  
• Somatic cells


  Diploid cells
• Gametes


  Sex cells (egg and sperm)
• Stages of the cell cycle

  1. Interphase

  2. Prophase

  3. Metaphase

  4. Anaphase

  5. Telophase

  6. Cytokinesis