In: Biology
what is the difference between the lytic and lysogenic cycles? what are the steps?
Ans. In lytic cycle, the bacteriophage replication occurs independently inside bacterial cell and reproduce many viral particles. In case of lysogenic cycle, viral DNA integrates into bacterial genome and replicates along with the host bacterial DNA and reproduce.
Steps in lytic cycle: Bacteriophage binds to the bacterial cell (host) surface -----> Bacteriophage DNA enters into the bacterial cell ------> Digestion of host DNA -----> New phase DNA formed by utilizing nucleotides from digested bacrerial DNA-----> Transcription and translation of phage DNA producing phage proteins ------> new phage particles assembled and lysis of bactrial cell by phage encoded enzyme ----> New phase particles released and infect new bacterial cells to perform lytic cycle again.
Steps in lysogenic cycle: Bacteriophage binds to the bacterial cell (host) surface -----> Phage DNA enters the host cell ----> Integration of phage DNA into the host DNA ----> Replication of bacterial chromosome with integrated phage DNA and cells continue division for many cycles producing many bacterial cells with the integrated phage DNA (prophage DNA) ------>Under stress condition, the phage DNA (prophage DNA) gets excised from the daughter bacterial chromosomes and enter lytic cycle infecting new bacteria.