The fundamental sequence of events in mitosis is the same as in meiosis (in meiosis it happens twice). Both processes include the breakdown of the nuclear membrane, the separation of genetic material into two groups, followed by cell division and the reformation of the nuclear membrane in each cells.
Making rough estimate of physical quantities is useful because it allow us to have an idea of how big or small a quantity is, it gives us the near result of the real quantity a matter contains. The approximate quantity obtained will give us information about the size of the quantity.
A central carbon atom bonded to an amino acid group and an R group.