Anaphase: Chromosomes (blue), kinetochores (pink), microtubules (green). Simplified diagram to compare with the photomicrograph above. Previously, during metaphase, spindle fibers (which are microtubules) attach themselves to the centromere of each chromosome.
These onion root tip plant cells are in interphase, prior to the start of mitosis. The cell nucleus, nuclear membrane, nucleolus, and chromatin are visible. Ed Reschke/Photolibrary/Getty Images Before a dividing cell enters mitosis, it undergoes a period of growth called interphase.
Preprophase is an additional phase during mitosis in plant cells that does not occur in other eukaryotes such as animals or fungi. It precedes prophase and is characterized by two distinct events: The formation of the preprophase band, a dense microtubule ring underneath the plasma membrane.
Prometaphase is the phase of mitosis that begins when the nuclear envelope begins to break down and mitosis is the part of the cell cycle that involves the separation of chromosomes and other cellular constituents into two daughter cells. Prometaphase can be split up into early and late phases. During early prometaphase, the following occurs:
Early during prophase, the first stage of mitosis, the chromosomes become visible with a light microscope as they condense (that is, as they shorten, coil, and thicken). Also, a spindle apparatus (blue strands in the upper two figures at left) begins to extend outward from each of the two centrosomes.