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1., , G1 (gap1) phase:, , The first stage of interphase is called the, , G1 phase (first gap) because, from a microscopic, aspect, little change is visible. However, during, the G1 stage, the cell is quite active at the, biochemical level., , It is characterized by a change in chromosome, from condensed state to more extended state, and series of metabolic events that leads to, initiation of DNA replication. During G1 phase,, chromatin fibres become slender, less coiled and, fully extended and more active for transcription., The transcription results in synthesis of RNAs, (tRNA, MRNA and rRNA) ad series of proteins, molecules required for initiation of DNA, replication., , The length of G1 phase varies from cell to cell, and also the length of G1 phase is more than, other three phase in cell cycle., , G1 phase represents 25-40% of generation time, of a cell., , G1 phase is very significant phase of cell cycle as, the cell grows and accumulates the building, blocks of chromosomal DNA and the associated, proteins as well as sufficient energy reserves to, complete the task of replicating each, chromosome.