1. no independent reproduction 2. no metabolism (can't generate ATP) 3. no growth 4. no independent movement (moved via phomytes) 5. no cellular organization 6. crystallization
1. Irritability?-detect a stimulus and act appropriately 2. Adaptability-evolve b/c they have DNA or RNA
Baltimore Classification System
Class I dsDNA-bacteriophage (herpes) Class II ssDNA Class III dsRNA-+ sense=mRNA (easily translatable) produces RNA dependent RNA pol; - sense: compliment of + sense Class IV ssRNA-RNA directed RNA synthesis. distinguished by what their genome is used for. ribosomes use this template to make proteins. no DNA intermediate just RNA Class V ssRNA-RNA directed RNA synthesis; + sense, DNA intermediate. have reverse transcriptase (DNA-RNA hybrid); retrovirus (lasts forever)
Balt. Class. System cont'd.
Class VI ssRNA-DNA needed by host Class VII dsDNA-requires RNA intermediate to make protein; reverse transcriptase used to go from RNA-> DNA (RNA dependent DNA synthesis)
virus structures (4)
1. helicol-genome plus protein 2. polihedral-contains glycoproteins: means by which virus identifies a host 3. bacteriophage-invaded bacteria -polihedral plus helicol 4. enveloped-surrounded by an envelope that is made up of phospholipid bylayer
Bacteriophage Infection Cycles (2)
Virulent Phage: lytic (death) cycle-kill host cell; integrated by endonucleases; has tail fibers that fit into receptor proteins
Temperate Phage: lysogenic cycle (lambda bacteriophage); integrase capabilities; integration of viral genome of host, transcription of the viral genome, synthesis of viral proteins, host cell reproduction, NOT provirus formation
Phage 1. why haven't they succeeded in invading bacteria?
-bacterial DNA: methylated (attaches to methyl group) 1. capsule-covers up receptors that phage could get to 2. restriction enzymes-recognize/destroy viral DNA before it can be transcribed 3. endospore-thick walls a phage can't get to -protease: enzyme that cuts the protein