11_Binary fission

Binary fission process and comparison with mitosis

How does binary fission begin? (2)

• Semi conservative replication begins at the ori

• Helicase unzips DNA by breaking hydrogen bonds between complementary bases of the 2 strands

How is bacterial chromosome replicated in binary fission? (3)

• Parental strands used as templates for synthesis of daughter strands

• Free deoxyribonucleotides CBP with bases on parental strand

• DNA polymerase catalyses formation of phosphodiester bonds between adjacent deoxyribonucleotides

How are daughter strands separated from parental strands in binary fission?

• 2 newly formed ori move to opposite poles of the cell and attach to plasma membrane

• Cell elongates to prepare for division

• Topoisomerase cuts, separates and reseals the 2 DNA molcs

How does bacteria split into 2 cells in binary fission?

Invagination of plasma membrane and deposition of new cell wall divide parent cell into 2 daughter cells

Compare the end products of binary fission and mitosis

Both produce 2 genetically identical cells

Compare the amount of DNA of parents and daughter cells in binary fission and mitosis

Both are the same in each daughter cell as compared to parent cell

Contrast between DNA replication of binary fission and mitosis

Binary fission: occurs during binary fission (duh)

Mitosis: occurs during S phase of interphase before mitosis

Points for contrasting of behaviour of chromosomes in binary fission and mitosis

1. Attachment of chromosomes to plasma membrane?

2. Entanglement of DNA molcs?

3. Condensation of chromosomes to sister chromatids?

4. Specific positioning of chromosomes at different stages?

Spindle fibres are involved in ___ but are not involved in ___

mitosis, binary fission