Producing New Cells

• Ate + sodium


  Chemical reaction
• Specialisation of cells


  Leads to formation of systems
• Chromosomes


  Thread-like structures made up of DNA, found in the nucleus of a cell
• Chromosome Complement


  Different species have different numbers of chromosomes within their nuclei
• Diploid cells


  Contain 2 matching sets of chromosomes (2n)
• Haploid cells


  Contain 1 copy of each chromosome (n)
• Humans have 46 chromosomes, arranged into 23 pairs
• Diploid cells have two copies of each chromosome
• Haploid cells have one copy of each chromosome
• Cell Division


  Mitosis provides new cells for growth and to replace damaged cells
• During cell division, the nucleus of the parent cell divides to produce two daughter cells with the same number of chromosomes
• Stages of Mitosis


  • Chromosomes become visible in the nucleus
  • Each chromosome copies itself to form pairs of chromatids
  • Spindle fibres attach to each pair of chromatids
  • Spindle fibres pull chromatids apart back into chromosomes
  • A new nuclear membrane forms around each group of chromosomes forming 2 nuclei
  • Cytoplasm divides to produce 2 genetically identical daughter cells
• Stem cells


  Unspecialised cells that can divide to self-renew and make more stem cells or specialise into different cell types
• Types of stem cells

  • Embryonic stem cells
  • Adult stem cells
• Specialised cells


  Work together to create more complex structures
• Cell organisation


  Cells -> Tissues -> Organs -> Organ systems -> Organism