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Another one !

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Clozapine
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01/24/07 - 02:28 PM

Some viruses are characterized by helical symmetry of the viral nucleocapsid. Which of the following statements about viruses with helical symmetry is most accurate?

(A) All enveloped viruses with helical symmetry are classified into the same virus family
(B) Helical nucleocapsids are found primarily in DNA-containing viruses
(C) All human viruses with helical nucleocapsids possess an envelope
(D) Excess empty helical particles containing no nucleic acid are commonly produced in infected cells

Ancylostoma
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01/24/07 - 02:39 PM

I think its c. Not sure , I cant really remember all the positive sense viruses but I know all the ned sense rna viruses are helical and enveloped.

Clozapine
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01/24/07 - 02:46 PM

+ve sense RNA viruses

T - Toga
C - Corona
R - Retro
P - Picorna
C - Calici
R - Reo

and Flavi

PCR don have envelopes

PCR, Toga and Flavi are icosahedral

babydoc4usmle
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01/24/07 - 02:54 PM

if virus helical - it can be only ENVELOPED.
so answer C is definitely correct

Ancylostoma
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01/24/07 - 02:56 PM

no I know their names , call "pico and flow to come rightaway". I cant remember their shapes, becuase some are helical, or a couple are , some are cubic.

I use pcr for uneveloped too

ahh but pcrTf would be the positive sense icosahedrals . Thanks

freshdoc

02/22/07 - 06:22 PM

The answer is C . Envelopped helical viruses are mostly RNA virus and most of them are ( - ) sense

sixfeet
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03/21/07 - 11:27 AM

therefore all-ve sense virusese are helical .. corona is +ve sense and helical..all dna & +ve sense viruses are icosahedral..
DNA VIRUSES:
all dna visuses are ds.. except parvo
all are linear except.. papova and hepadna..
PAP ARE NAKED.
-VE RNA:
ALL ARE SS LINEAR EXCEPT:
ORTHOMYXO =8 SEGMENTS
ARENA=2,CIRCULAR
BUNYA=3,CIRCULAR
DELTA=CIRCULAR

+VE RNA:
ALL ARE SS LINEAR EXCEPT.... REO IS DOUBLE STRANDED WITH 10 FRAGMENTS... HIV IS DEPLOID...
ALL ARE ICOSAHEDRAL EXCEPT CORONA... AND ALL VE ENVELOPE EXCEPT PCR..

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