HEAD DNA CAPSULE TAIL SHEATH TAIL TAIL PLATE TAIL CORE TAIL FIBERS Figure Bacteriophage Bacteriophage
Figure Bacteriophage
Each phage attaches to a specific cell surface molecule (usually a bearina that receptors protein)and so only cell can be infected by a given phage
Each phage attaches to a specific cell surface molecule (usually a protein) and so only cells bearing that “receptor” can be infected by a given phage
Two Basic Types 1.Lytic phage: eg T phage infect a bacterial cell DNA replication coat proteins expression host cell lysed to release the new phage
Two Basic Types 1.Lytic phage: eg. T phage infect a bacterial cell DNA replication coat proteins expression host cell lysed to release the new phage
The lytic growth cycle 2-p lage bacterial e chromosome 个② phage structural parts cell fragments Figure 21-1
Figure 21-1 The lytic growth cycle
2. Temperate phage: eg, Phage A Lysogeny(溶源途径)一 the phage genome integrated into the bacterial genome and replicated passively as part of the host chromosome, coat protein genes not expressed The phage is called a prophage. Daughter cells are lysogens
2. Temperate phage: eg. Phage λ ◼ Lysogeny (溶源途径)—the phage genome integrated into the bacterial genome and replicated passively as part of the host chromosome, coat protein genes not expressed. • The phage is called a prophage. • Daughter cells are lysogens