MICRO 6
What are the benefits of using bacteriophages to control bacterial infections in humans?
They only attack bacteria, they are easier to find, they can go deeper into infected areas
How can bacteriophages synthesize necessary components during their replication cycle?
They use the host cell to provide all necessary components in order to replicate
What is a virion?
A complete and fully developed viral particle
What is the difference between a lytic or viulent, and a latent or temperate phage?
A latent phage goes through the lysogenic cycle before going through the lytic cycle, the latent cycle phage is replicated within the host until an environmental factor forces the phage into the lytic cycle
What are the steps of Latent lambda phage integration replication in E.coli?
Attachment, penetration, integration, binary fission
What are the steps in Latent lambda phage integration--> lytic cycle replication?
Attachment, penetration, integration, binary fission, excision of phage DNA, transcription, replication of viral DNA and viral proteins, assembly, release
What are the steps of Productive T4 phage replication in E.coli?
Attachment, penetration, transcription, replication of viral DNA and viral proteins, assembly, release
Why can't a lytic bacteriophage cause disease in humans?
Bactiophages require specified receptors produced by bacteriophages that attach to the surface of their receptor cells, Eukaryotic cells don't have receptors bacteriophages need to connect to host cells.
What are the advantages and disadvantages of using bacteriphage therapy in treating antibiotic resistant bacteria infections?
Disadv: more expensive, and takes more research, Adv: less toxic for the host
What macromolecule makes up the bacteriophage genome?
DNA and RNA
What are some common human diseases that are caused by bacteria carry a prophage?
Diptheria toxin, erythrogenic toxin, staphylococcal enterotoxin A, pyrogenic toxin, botulinum neurotoxin
What are practical solutions of the serial dilution technique?
It is more accurate when counting colonies, and makes isolation of bacteria easier
What enzyme is carried within the capsid of a bacteriophage and what is its function?
Lysozyme, it penetrates the cell membrane allowing viral DNA to enter
Explain the steps of Latent lambda phage viral replication in the integration, lytic cycle
Phage attaches to host cell, phage uses lysozyme to inject DNA into host cell, phage DNA circularizes and enters lysogenic cycle, cell divides by normal binary fission with integrated phage DNA in chromosome, because of environmental factors, phage DNA is removed from chromosome and released in host, phage DNA is transcribed in host, phage DNA is replicated, and new phage DNA and proteins are made and assembled into virions, cell lyses and releases phage virions
What is a prophage?
Phage DNA inserted into host cell's DNA
Explain the process of Latent lambda phage viral replication in E.coli
Phage attaches to host cell and injects DNA, phage injects DNA into host cell using lysozyme, phage DNA circularizes and enters bacterial chromosome by recombination becoming a prophage, the lysogenic bacterium reproduces normally by binary fission creating more copies of the phage
Explain the process of productive T4 phage viral replication in E.coli
Phage attaches to host cell, penetrates the host by using enzyme lysozyme and injects DNA, phage DNA is copied within the host, phage DNA is copied and replicated, viral components are assembled into virions, host cell lyses and new virions are released
How is plaque formed?
Plaques are formed when bacteriophage sample is mixed with host and poured on petri plate, the virus bacteria mixture solidifies, when phage lysis occurs, plaque forms on agar
What are the forms in which the genome of a bacteriophage can exist within a cell?
Prophage**********
What macromolecule makes up the capsid of a bacteriophage?
Protein and capsomeres
Why is it more advantageous being a temperate phage than being a lytic phage?
Temperate phage has more multiplication of bacteria, where lytic destroys the host
How can you tell if bacteria are resistant to a phage?
The bacteria never lyse and no observable changes occur in the phenotype
What determines the host range of a bacteriophage?
The specific attachment site on the host cell surface and availability of host celular factors
Describe why infection of a bacterium by a temperate bacteriophage may contribute to the virulence of a bacterium?
The transfer of genes such as toxins may occur