Interphase

Interphase is the longest part of the cell cycle but its length is extremely variable between cell types. Under the microscope the nucleus during interphase can look deceptively quiet, but this is misleading: the chromosomes that were visible as condensed thread-like structures during the previous division have now dispersed into their extended chromatin form, and for most of interphase they are actively being transcribed to direct protein synthesis. Interphase is where the DNA content of the cell is quantified using the C-value, defined as the amount of DNA, measured in picograms, contained in a haploid nucleus; tracking how many C-values of DNA a cell holds (2C at the start, rising to 4C after replication) is the standard way biologists describe progress through interphase. Interphase itself is subdivided into three named phases - G1, S and G2 - each with a distinct job: G1 is for general growth and metabolic activity, S is when the DNA is actually copied, and G2 is a second grow …