DNA, Chromosomes and mitosis

• cell need to divide because of

  • growth
  • repair
  • development
• the process through which cells are regenerated is called the cell cycle
• Mitosis is the process when one cell divides into two genetically identical daughter cells
• mitosis

  • the cell grows in size and increases number of subcellular structures
  • the DNA is duplicated, the DNA stays with the original DNA and forms a X shape
  • all the chromosomes lines up in the middle of the cell and spindle fibres from the sides of the cell attach themselves to the chromosomes and pull them apart
  • now cytokinesis happens when the cell membrane and cytoplasm divides forming two genetically identical daughter cells
• DNA is spread out in long strands but when the cell is preparing for mitosis it condenses into chromosomes (coiled up dna). the DNA contains large number of genes which controls our characteristics. Humans have 23 pairs of chromosomes
• binary fission is the process when prokaryotic organisms divide and reproduce
• binary fission

  • grow
  • replicate genetic material
  • and then gets pulled apart but one offspring might get more plasmids since they are random
  • it grows new cell wall through the middle which allows it to divide
• division cycles:

  number of mins in total/mean division time

  number of cells: starting number of bacteria * 2^number of rounds