NBME 23 Enveloped (NBME Answers)

Retired NBME 23 Answers

nbme23/Block 4/Question#18 (reveal difficulty score)
An investigator is conducting a study to ...
Enveloped 🔍 / 📺 / 🌳 / 📖
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submitted by ∗drsquarepants(20)

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I found this helpful, enveloped vs. nonenveloped

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drsquarepants Chart on slide 22 +7

megaera13 Thank you. Definitely need to note this down somewhere. +2

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submitted by ∗thomasalterman(181)

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Envelopes benefit the virus in that the virus will look like the host, facilitating fusion. However, an enveloped virus is generally less stable than a naked icosahedral virus (naked viruses are generally icosahedral).

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docred123 So do these patients have h.Flu? What was the giveaway? Thanks +2

mousie I chose Enveloped simply bc it said dies when heated, not sure if there where any other clues to narrow this down or make me feel more confident in my choice but I went with it anyway +17

eclipse I don't think they expected us to narrow down the answer to a specific virus. Enveloped viruses tend to be less stable (?) than the non-enveloped ones and don't survive as well under harsher environments (outside human's body, heat, etc.) +2

peridot To add on, I also have no idea what virus this could be but the question stem does say "A previously unidentified virus is recovered from urine specimens" making me think that it's not something we're supposed to have know about, unless I'm totally understanding it wrong. +1

chaosawaits My dumbass diagnosed her properly, then confidently chose "genome consisting of RNA," forgetting the conditions of the characteristic in question, that it's responsible for the virus being susceptible to heat. FML +

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submitted by ∗lamhtu(139)

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A possible integration to help with answering this question: Sketchymicro states one possible way to inactivate arenaviruses is heat. Arenaviruses are enveloped. If you can remember this, you can keep straight that enveloped viruses are heat-labile (sensitive)

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submitted by ∗brise(86)

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AKA the reason why covid can be killed with heat! B/c it is enveloped!

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madamestep And alcohol! Look at us with our increased knowledge of virology due to the global fall of normal society :') +

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submitted by ∗underd0g(14)

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My last-ditch reasoning was that SPORES are heat-resistant; therefore enveloped viruses must not be.

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cmeacham Spores = Bacteria (C. diff mostly for USMLE) +

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submitted by ∗imgdoc(183)

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Differences between Naked and Enveloped viruses:

IS THE VIRUS: Inactivated by heat, detergents, acid and organic solvents like ether and alcohols?

YES = ENVELOPED, the lipid envelope basically holds the proteins needed to attach to the human cells, by dissolving the envelope, the virus loses its ability to infect and therefore survive.

NO = NAKED

Got this from Kaplan

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submitted by ∗amy(4)

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The non-enveloped virus are tougher than enveloped virus (think HAV and HEV vs HBV)
Heat labile: Microorganism destroyed at 60C Heat stable: Microorganism survive 100C for 1h

In this question, viral infectivity is destroyed at 60C, which mean it is not as tough, so envoloped.

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