10941447
Descrição
FlashCards por Francisco Sacadura, atualizado more than 1 year ago
|
Criado por Francisco Sacadura
aproximadamente 8 anos atrás
|
|
| Questão | Responda |
| What are functions of phages? | Minimal: -protect NA (capsid, envelope) -deliver NA -convert host to produce phage -release phage/lysis |
| Which one, phage T4 or filamentous phage, has limited amount of DNA? Why? | T4 => DNA has to fit inside protein shell (icosahedral head), whereas in filamentous, DNA just added to ends => no restriction |
| Describe the 4 phases of lytic growth | 1) Infection - tail binds host cell surface R - DNA injected 2) Early dev - may make own Pol but mostly hijacks host Pol => replication 3) Late dev - genomes, heads, tails made - DNA packaged in heads, tails attach 4) Lysis - cell broken to release new phages |
| Describe the 3 phases of lysogenic growth | 1) Infection 2) Integration phage DNA into host DNA Replicates dormant state (w/ host DNA) Immunity to further infection (repressor) 3) Induction: phage DNA released => lytic cycle |
| Define: 1 - Virulent 2 - Temperate 3 - Lysogen 4 - Prophage 5 - Immunity 6 - Induction | 1 - only lytic 2 - can switch between lytic/lysogenic 3 - host cell w/ phage DNA 4 - phage DNA integrated in cell DNA 5 - lysogen protected from infection by phage from same species (repressor) 6- conditions that drive latent phage to become active |
| How does phage decide lysis or lysogeny? | Depends on conditions: lysogeny favoured by low level nutrients and high MOI (multiplicity of infection=#phage/#bacteria) |
| New bacteria arrive to the lab. You want to figure out if they are virulent or temperate. How would you proceed? | 1) introduce high [virus] in2 bacteria lawn 2) phage infection => lytic burst => patch 3) plaque appearance - clear or turbid - clear => virulent - turbid => temperate (low MOI => lytic growth => clear patch => high MOI => lysogeny => bacteria replicate immune 2 infections => turbid centre) |
| Is lamb DNA ss or ds and linear or circular? | Linear dsDNA inside icosahedral head but circular inside host (12bp cohesive ends anneal when injected in host) |
| How long is lamb DNA? How many genes? | 48,500bp 46 genes identified |
| Is the fact that the lamb DNA becomes circular inside the host a feature or a bug? | If DNA not circular replication not work bc extreme operon - genes clustered by function & functional groups expressed in same transcript |
Quer criar seus próprios Flashcards gratuitos com GoConqr? Saiba mais.