The cell cycle

• What is the cell cycle?


  The cell cycle is the time from when a cell is formed by division to the time when it itself divides.
• What two main phases are part of the cycle?


  Interphase and mitosis.
• What is the exception to the rule, what cells don't divide again once fully formed?


  Guard cells around leaf stomata and mammalian neurons.
• What happens during interphase?


  G1, S and G2
• What happens during G1


  It is the first phase of growth, the cell increases in size, additional organelles are synthesized, protein synthesis takes place- it could last a few hours or many moths.
• What happens during S ?


  It is the DNA synthesis phase, chromosomes are replicated, once the cell has entered this phase it will go on to mitosis- this phase can take minutes or hours to complete.
• What happens during G2?


  It is the second phase of growth, more new organelles are synthesised, the cell double checks that duplicated chromosomes are free of error, any repairs to errors from from DNA duplication are made.