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28 Cards in this Set
- Front
- Back
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virus |
"poison" nonliving agents, genetic elements tiny complex virus- unusual looking prone to mutations dependent on host cell |
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obligate intercellular parasites |
need host cell take over host cell function |
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virion |
complete virus particle, multiply and reproduce |
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bacteriophage |
bac cell virus RNA or DNA, not both, double/single stranded nucleocapsid- nucleic acid surrounded by capsid (protein coat), basic unit of virus multiply inside host cell and use resources |
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host range |
very specific about host cell attachment side facilitate attachment leads to infection |
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viral structure |
capsid (shell of protein) can be helical- twisted or polyhedral- many sides capsomeres- subunits spikes- attachment, change, define what virus envelope (bilayer) lipid- like host cell membrane but with viral protein
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envelope |
enveloped- additional coat from host cell nonenveloped- just capsid (naked), resistant to disinfectant |
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function of capsid/envelope |
protection from host enzymes/ chemicals (from host, either carry all or none) stimulate immune response- protect against infections binding/attachment and penetration host cell- cell needs surface receptors for attachment and growth
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bacteria life cycle (multiplication of bacteriophages) |
1. pierces hole- bac lysozome (cell wall dissolved) 2. push gen info inside cell, rest stays on outside can shut down bac cell, dictated by virus gen material produce enzyme, bac DNA destroyed 3. synthesis-replicate (more gen info), multiply (make more virus), eclipse- no virus particles detected in host cell |
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bacteria life cycle |
4. assembly 5. release- infect other cells lytic cycle ends in lyse of cell |
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look at pic lytic vs lysogenic cycle |
lysogenic- virus and bac coexist prophage- changes bac genetic structure (lysogenic conversion) produce respiratory tract toxin (kills cells-pathogens) form pseudomembrane |
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generalized transduction |
mistakenly injecte bac DNA instead of viral gene transfer, act like carriers and infect bac DNA random DNA error in packaging, suppose to pick up own DNA but pick up bac host DNA any gene can be transferred by virulent/temp phage |
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specialized transduction |
only temp phages can transfer specific bac genes viral DNA pops out, pull out piece of bac DNA (specific DNA) |
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terms |
lytic cycle- ends in death of cell temp phage- not perm, become part of bac DNA latent- silent lysogen- bac cell, infected by temp phage, DNA piece can pop out prophage- extra DNA piece, integrated bac virus |
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animal virus |
DNA (nuc)- need enzyme to multiply/replicate RNA (cyto)- prone to mutations, replicate mutations not fixed, passed on, stick/change + stranded- directly go to RNA - stranded- make +, translated |
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exceptions |
poxvirus- large DNA virus, carries all enzymes for multiplication/replication (happens in cyto not nuc) hepadnavirus- transcribes RNA strand and uses reverse transcriptase to make DNA mol (in body long time) retrovirus- RNA used rev trans to make DNA integrated as provirus in host chromosome |
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provirus |
integrated animal virus permanent |
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animal cell entry |
1. attachment, virion attaches to host cell 2. entry/uncoating- virion enters, DNA uncoated 3. portion viral DNA transcribed, prod mRNA 4. biosyn- viral DNA replicated, proteins made 5. late translation, capsid protein synthesized 6. maturation- virions mature 7. release- virions rel (exocytosis/budding) cell will eventually die |
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fusion |
separation of capsid and DNA released uncoating- separation of capsid and genetic material endocytosis/fusion- envelope only very difficult to treat- once integrated immune system can not reach |
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carriers |
animals humans, may not have symptoms but can transmit disease |
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acute infections |
short duration, virus goes through productive cycle ended in the lysis of cell, late complications follow, sickness then recovery, immune system gets rid of all of virus, best to get measles |
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latent infections |
quiet/dormant, delay between infection and symptoms, entry by mouth, 3-9 day recovery, heal, virus not slim-just dormant in nerve cells, can reactivate cold sore, fever blister, herpes varicella- caused by herpes, chicken pox/shingles |
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chronic infection |
infectious virus present at all times, carrier may have no obvious symptoms but can pass it on- Hep B gradual increase in virus over long period of time- AIDS, mad cow disease virus is always present (not dormant) |
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tumor |
abnormal growth benign- remains in defined area, noninvasive malignant- uncontrolled growth, metastasis |
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normal cells |
grow in monolayer (single layer) contact inhibition- multiply/divide, stop dividing when in contact with each other apoptosis- program cell death- does not divide forever, body gets rid of |
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cancer cells |
pile on top of each other multiplier grows indefinitely virus can transform cells from normal to cancer- transformation |
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normal cell become cancerous |
oncogenic DNA and RNA viruses- cancer causing Hep B/C (DNA)- carsination of liver Epstein Barr (DNA)- mono virus, nasal vary cancer HPV (RNA)- sex transmitted, AIDS (RNA)- cancer of blood vessel lining |
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plant viruses |
prions- no nucleic acid, entirely protein, hard to get rid of, tougher than virus/endospore viroids- small circular single stranded RNA molecules, infect plants tulip breaking virus- streaky, genetic color change |
