Binary Fission

• Prokaryotic cells can reproduce using a type of simple cell division called binary fission. In binary fission, the cell splits into two.
• In binary fission, 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 plasmid(s).
• Bacteria can divide very quickly if given the right conditions (eg. a warm environment and lots of nutrients). Some bacteria, such as E. coli, can take as little as 20 minutes to replicate in the right environment. However, if conditions become unfavourable l, the cells will stop dividing and eventually begin to die.
• The mean division time is just 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 so the number of cells it has produced in that time.