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40 Cards in this Set
- Front
- Back
virus |
aninfectious particle consisting of genes packaged in a protein coat |
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Plasmids, transposons, and viruses |
mobilegenetic elements (3) |
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tobacco mosaic disease |
stuntsgrowth of tobacco plants and gives their leaves a mosaic coloration |
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Adolf Mayer |
discoveredthat he could transmit the disease by rubbing sap extracted from one diseasedleaf to a healthy plant |
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Dimitri Ivanowsky |
passed the sap through a filterdesigned to remove bacteria. |
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Martinus Beijerinck |
Hereasoned that the agent was smaller and simpler than bacteria and is creditedwith the concept of a virus |
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wendell Stanley |
confirmedthis hypothesis by crystallizing the infectious particle, now known as tobaccomosaic virus (TMV) |
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-Nucleic acid -Capsid -capsomeres -membranous envelope |
A virus is a very small infectiousparticle consisting of |
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viral envelopes |
(derivedfrom membranes of host cells) surround the capsids of influenza viruses andmany other viruses found in animals |
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bacteriophages |
viruses that infect bacteria |
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host range |
alimited number of host cells that it can infect |
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lytic cycle |
aphage replicative cycle that culminates in the death of the host cell |
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virulent phage |
A phage that reproduces only by thelytic cycle |
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restriction enzymes |
Bacteria defense against phages that recognize and cut up certainphage DNA |
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lysogenic cycle |
§replicatesthe phage genome without destroying the host |
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prophage |
integrated viral DNA |
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temperate phages |
Phages that use both the lytic andlysogenic cycles |
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parvovirus |
ex. of single-stranded DNA virus |
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herpes |
ex. of double-stranded DNA virus |
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rhinovirus |
ex. of single-stranded RNA virus |
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rotavirus |
ex. of double-stranded RNA virus |
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retroviruses ex. HIV produces AIDS |
use reversetranscriptase tocopy their RNA genome into DNA |
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provirus |
The viral DNA that is integratedinto the host genome and does not leave the host cell |
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mutations |
creates adaptive changes inproteins |
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genetic recombinations |
transfers DNA from one bacteriumto another |
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transformation |
bacterial cell takes up DNA from dead cells outside and combines it with itsown DNA |
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transduction |
infecting bacterial virus (phage)introduces DNA from previous hosts |
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conjunction |
transfer of specific plasmids from onebacterium to another |
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rearrangement of transposons |
affects overall gene expression |
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feedback inhibition or gene regulation |
A cell can regulate the productionof enzymes by |
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operon model |
One mechanism for control of geneexpression in bacteria is (Discovered by Francois Jaciband Jacques Monod in 1961) |
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operator |
Acluster of functionally related genes can be coordinately controlled by asingle “on-offswitch” called |
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operon |
theentire stretch of DNA that includes the operator, the promoter, and the genesthat they control |
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repressor |
The operon can be switched off by aprotein ______. -preventsgene transcription by binding to the operator and blocking RNA polymerase |
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corepressor |
§amolecule that cooperates with a repressor protein to switch an operon off |
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repressible operon |
operon thatis usually on; binding of a repressor to theoperator shuts off transcription (trp) |
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inducible operon |
operon that is usuallyoff;a molecule called an inducer inactivates the repressor and turns ontranscription (lac) |
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inducer |
inactivatesthe repressor to turn the lacoperon on |
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catabolic pathways |
Inducibleenzymes usually function in _______ _________; their synthesis is induced byachemical signal |
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anabolic pathways |
Repressibleenzymes usually function in _________ __________; their synthesis is repressed byhigh levels of the end product |