Microbial genetics 1.pptx

Microbial genetics

1. Microbial genetics

2. introduction Genetics ; is the science concerned with the cell charateristics,and how they are passed from one generation to the next

3. Molecules of genetics The main main molecules of genetics are called nucleic acid . All the genetics information are stored as asequence of bases through nucleic acids. Mainly in dna and in rna in some rna virus

4. transfer of genetics material in prokariyotics [ bactriria ] Three types of replication hapend in bactria . transmation Trans duction conjugation

5. Conjugation Conjugation is a mechanisms of dna exchange mediated by plasmid . The bactria that contain transmmissible plasmid are called donor cell and other that receive plasmid are known as recipient cells. Most of the transfer of f factor [ fertility factor] plasmid in e. coli Cells in which f factor is present is represented by f+ [ it functions as donor ]. Cell without, f factor are denoted by f - [ recipient cells]

6. the first step in conjugations is establishment of contact between cell of opposite strains. Recipient cells f- receive the donor plasmid . it become f+ cell . f+ cell and plamid intigrated and become high frequency recombinant [ hfr ] cells hfr and other f – cells replicat parental chromosome is transfer to recipient cells. This cell is called recombinant f- cell

7. transformation It was discovered by frederick griffith [1928] in mixture of two strains of diplococcus while experimenting with laboratory mice Those cells in which transformation can be affected are known competent cells That part of dna which quality of transformation lies is called transfer fector

8. Differences between trans forming and conjugation transformation in trans formation exchange of genetics materials takes place between the members of the same species. genetics characters incorporates in a transformed cell are permanent conjugation conjugation occurs between the members of two different genera ex. Salmonella and serratia conjugation are temporary in it large amount dna transfer, therefore the conjugation important in increasing genetics diversity

9. transductions Transductions is special mathod of genetics recombination in which genetic material is transferred from donor to the recipient cell by means of a tempratev bacteriophage it was discovered by zinder and lederberg in salmonella

10. Difference between transformaton and transduction transduction Transfer of genetics materials from donor to recipient cell is through a temperate page there isno effect of this enyme transformation transfer through the solution deoxyribonuclease completely checks the process of transformation

11. Multiplication of virus Lytic cycle infection synthesis of phage component Assembly of new phage paricle Liberation of phage particle from the host

12. lysogenic cycle it phage do not cause death of the host cell when they multiply Linear phages dna become circular and integrates with in the bectrial chromosome by recombination . the inserted phage dna is now called prophage