Term
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Definition
| simple,acellular,contain DNA or RNA, obligate intracellular parasite, lack enzymes necessary for protein and NA synthesis, unaffected by antibiotics. |
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Term
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Definition
| protein shell/coat that encloses NA genome. |
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Term
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Definition
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Term
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Definition
| lipid membrane that surrounds virus particle |
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Term
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Definition
| virus encoded glycoproteins exposed on surface of envelope |
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Term
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Definition
| protein + nucleic acid complex |
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Term
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Definition
| complete infective virus particle |
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Term
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Definition
| virus particle functionally defective |
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Term
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Definition
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Term
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Definition
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Term
| measurement is done through? |
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Definition
membrane filteration
ultracentrifugation
electron microscopy |
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Term
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Definition
protein coat
protects the NA from enzymes, composed of capsomers
introduces genome into host cell
3 types: helical,icosahderal,complex. |
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Term
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Definition
shaped like hollow tubes with protein walls
NA determins length
Rigid helix-TMV, flexible - animal virus
Tobacco Mosaic Virus: 15-18 nm, 300 nm
encloses RNA genome. |
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Term
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Definition
Regular polygon with 20 facets and 12 vertices.
Capsomers - pentamers/hexamers
Pentamers-vertices(12) & hexamers- facets
Some RNA viruses- both pentamers & hexamers have one type of protein
Other viruses: protein vary of pentamers and hexamers
exception - DNA virus with pentamers- Simian virus 40. |
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Term
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Definition
largest animal virus
seen under a phase contrast/bright field. |
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Term
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Definition
complex internal structure with ovoid-brick shaped exterior.
Bacteriophages - head(icosahedron) tail(helical) |
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Term
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Definition
| DNA/RNA ss or ds 4000 nuc lineal/circular |
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Term
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Definition
sequence identical to viral mRNA
polio virus, TMV, Rous sacrcoma |
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Term
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Definition
complementary sequence to viral mRNA
Rabies, mumps, measles,influenza |
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Term
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Definition
more then 1RNA strand within a capsid
each segment codes for one protein. |
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Term
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Definition
associated with envelope/capsid- influenza neuraminidase
located within capsid- RNA dependent RNA polymerase, reverse transcriptase. |
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Term
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Definition
outer cover derived from host cell membrane
lipoprotein- hostel cell and protein
animal virus envelopes- host cell nuclear/ plasma membrane
envelope proteins project - spikes/ peplomers. |
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Term
| Example of enveloped virus(pleomorphic) |
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Definition
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Term
| enveloped virus-susceptible to ether |
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Definition
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Term
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Definition
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Term
| Susceptibility to Temperature |
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Definition
with seconds at 56C
Minutes at 37 C
stable at low temperature
frozen at 70C or lyophilization: long term storage. |
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Term
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Definition
| 5-9 too acid or too basic kills |
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Term
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Definition
enveloped viruses are sensitive
naked viruses are resistant. |
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Term
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Definition
formaldehyde, B-propiolactone are virucidal
chlorination of drinking water kills most viruses except hep A and polio.
Viruses are resistant to phenol |
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Term
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Definition
inactivated by sunlight, UV and ionizing radiation
Autoclave,dry heat, ethylene oxide, gamma irradiation, sodium hypoclorite, formaldehyde, ethanol |
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Term
| Step 1 of Virus Replication |
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Definition
Attachment
interaction of virion with receptor site
receptors- glycoproteins
specific
initiate innversible structural changes |
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Term
| Step 2 of virus replication |
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Definition
Penetration
virus particle taken up inside cell
receptor mediated endocytosis/direct penetration/fusion of virion envelope with plasma membrane. |
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Term
| Step 3 of virus replication |
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Definition
Uncoating
occurs after penetration
genome is released as free NA/nucleocapsid
acidic pH in endosomes. |
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Term
| Step 3 of virus replication |
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Definition
Uncoating
occurs after penetration
genome is released as free NA/nucleocapsid
acidic pH in endosomes. |
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Term
| Synthesis of viral proteins |
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Definition
viral n.a, capsid, enzymes regulator proteins
DNA virus synthesize NA in host cell nucleus
except: pox virus
RNA virus synthesize all compoents in cytopolasm: except- orthomoxvirus some paramyxovirus and retro virus.
virus protein synthesized in cytoplasm. |
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Term
| The steps involved in DNA replication are |
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Definition
transcription of mRNA from viral NA
translation to early proteins
replication of viral NA
synthesis of late proteins |
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Term
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Definition
| enters host cell nucleus - transcription(using host enzymes) |
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Term
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Definition
| enter host cells nucleus- converted into ds DNA- transcription occurs. |
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Term
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Definition
| transcribed to mRNA by viral polymerases. |
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Term
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Definition
| viral RNA acts as mRNA- translation occurs. |
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Term
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Definition
| transcribed to mRNA using RNA polymerase. |
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Term
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Definition
ssRNA converted to RNA-DNA hybrid by reverse transcriptase ds DNA synthesis from hybrid
integrates into the host cell chromosome- provirus. |
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Term
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Definition
1. assembly takes places in host cell nucleus/cytoplasm
2.non enveloped virus- complete virions
3. enveloped virus- nucleocapsid is complete. |
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Term
envelopes- derived from host cell membrane during budding
envelope- modified by insertion of virus specific antigens. |
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Definition
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Term
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Definition
Release
budding
bacteriophage- lysis of host cell
animal virus- no lysis. |
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Term
| replication cycle in bacteriophages |
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Definition
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Term
| time for replication cycle in animal viruses |
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Definition
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