Binary Fission

Binary Fission

1. Prokaryotic Cells Replicate by Binary Fission

   • In binary fission, the cell splits into two
   • The circular DNA and plasmids replicate
     • The cell gets bigger and the circular DNA strands move to opposite 'poles' (ends) of the cell
       • The cytoplasm begins to divide and new cell walls begin to form
         • The cytoplasm divides and two daughter cells are produced
           • Each daughter cell has one copy of the circular DNA, but can have a variable number of copies of the plasmids
   • Bacteria can divide very quickly if given the right conditions
     • However, if conditions become unfavourable, the cells will stop dividing and eventually begin to die

2. You Can Calculate the Number of Bacteria in a Population

   • The mean division time is the average amount of time it takes for one bacterial cell to divide into two
     • If you know the mean division time of a cell, you can work out how many times it has divided in a certain amount of time
       • And therefore the number of cells it has produced in that time
   • Make sure both times are in the same units
     • Divide the total time that the bacteria are producing cells by the mean division time
       • This gives you the number of divisions
         • Multiply 2 by itself for the number of divisions to find the number of cells