Binary Fission and Viral Replication

Binary Fission

• The single, circular DNA molecule undergoes DNA replication

• Any plasmids present undergo DNA replication

• The parent cell divides into 2 cells, with the cytoplasm roughly halved between the 2 daughter cells

• The 2 daughter cells each contain a single copy of the circular DNA molecule and a variable number of plasmids

• If a daughter cell doesn’t receive the singular circular DNA molecule or at least 1 copy of a plasmid they die

Binary Fission diagram

Name the 4 ideal conditions for binary fission to occur

• Warm

• Moist

• Good pH conditions

• Oxygen

Describe the stages of the diagram

Lag phase:

• Constant population size

Binary Fission hasn’t started yet

Experimental Growth Phase:

• Population size double every 20 mins in ideal conditions (log phase)

  Stationary phase:

• Population size is constant

• Max pop. the environment can sustain

  Death Phase:

• Pop. size decreases

• Bacterial cells dying

• Lack of Oxygen

• Build up of CO₂ - reduced the pH

• Acidic conditions kill bacterial cells