Interphase is the phase of the cell cycle in which the cell spends the majority of its time and performs the majority of its purposes. During interphase the cell obtains nutrients, and it is considered as the living phase of the cell. Most eukaryotic cells spend most of their time in interphase. Interphase is not a resting phase as once thought.
There are 3 stages of interphase:
G1, in which the cell grows and functions normally. During this time, a lot of protein synthesis occurs and the cell "grows" - more organelles are produced and increasing the volume of the cytoplasm. If the cell is not to divide again, it will remain in this phase.
synthesis (S), in which the cell duplicates its DNA (via semi-conservative replication).
G2, in which the cell ensures that its chromosomes and organelles are ready for mitosis. The proteins necessary for cell division are also made (e.g. the proteins needed for the microtubules to form the spindle fibres).
Duration is variable and depends on the function of the cell. Some human cells divide every 24 hours; in this case interphase takes about 22 hours and mitosis the remaining 2.
Interphase is the period during which the cell's organelles carry out their functions, causing the nucleolus to increase in size. The time that mitosis takes therefore depends on the variety and size of the cell.
In interphase, the cell gets itself ready for Mitosis or Meiosis. Somatic cells go through mitosis and gametes go through meiosis. Interphase is not the first stage of mitosis but prophase is, due to conterary belief.
Details on specifics of Interphase source: AS Level Biology compiled by Phil Bradfield, John Dodds, Judy Dodds and Norma Taylor. (Published by Longsman)
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