MEDRADSC 2X03 Lecture Notes - Lecture 7: Interphase, Reticulocyte, G1 Phase

• School: McMaster University
• Department: Medical Radiation Sciences
• Course: MEDRADSC 2X03
• Professor: Sandra Charbonneau

Document Summary

Non-lethal damage reparable: non-reparable cell-cycle time (tc) time needed to complete one cell cycle (all cells are different) Mitotic cycle time : vartiations in tc of mammalian cells is mainly due to difference in duration of g1 phase. Dna synthesis (s phase) within 15 hours. Cells in all 4 phases (g1, s, g2, m) are present. Proportion in each is stable over time: mitotic index: fraction of cells in mitosis. In vitro cells: normally asynchronous, synchronized population can be produced in lab. At different parts of the cycle, different cyclins are secreted into the cell. They tell the cell when to move into the next cell cycle, they will only do that when they have the right parts. Division delay can occur in both non-lethal and lethal damage. Disturbs mitotic index of asynchronous population of cells initial decrease following irradiation: mitotic overshoot follows (the pause starts up again and the cell catches up plus the normal divisions.