Examl 3:l BIOl 205/l BIO205l (Latestl 2025/l
2026l Update)l Microbiologyl Review|l Questionsl &l Answers|l Gradel A|l 100%l Correctl (Verifiedl Solutions)-l GCU
Q:l Knowl thel differencel betweenl Antigenicl Driftl andl Antigenicl Shift:
Answer:
Antigenicl driftl isl al graduall processl ofl mutationl thatl occursl withinl al singlel strainl ofl al virus,l resultingl inl minorl changesl tol thel virusl overl time,l whereasl antigenicl shiftl isl al rapidl andl dramaticl processl ofl reassortmentl thatl occursl betweenl differentl strainsl ofl al virus,l resultingl inl thel emergencel ofl al completelyl newl strain.
Q:l Bel ablel tol describel thel Coronavirusl basedl onl thel Baltimorel Modell
andl thel basicl structurel ofl thel SARSl CoV-2l particle.
Answer:
Thel Coronavirus,l includingl SARS-CoV-2,l isl al single-strandedl RNAl virusl withl al positive-sensel genome,l belongingl tol Groupl IVl ofl thel Baltimorel model,l whichl usesl thel hostl cell'sl machineryl tol replicatel itsl genomel andl producel newl virusl particles;l thel SARS-CoV-2l particlel hasl al characteristicl "crown"l shapel duel tol spikel proteinsl onl itsl surfacel thatl facilitatel attachmentl andl entryl intol hostl cells,l andl alsol containsl geneticl materiall surroundedl byl al capsidl andl lipidl envelope.
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Q:l Knowl thel basicl COVIDl terminologyl andl thel cellularl receptorsl ofl
importance.
Answer:
COVIDl terminologyl includesl termsl likel coronavirus,l SARS-CoV-2,l COVID- 19,l pandemic,l quarantine,l andl sociall distancing,l amongl others;l thel cellularl receptorsl ofl importancel forl SARS-CoV-2l includel ACE2l (angiotensin- convertingl enzymel 2)l receptors,l whichl arel foundl onl thel surfacel ofl humanl cellsl inl thel respiratoryl andl digestivel systemsl andl arel thel primaryl targetl forl thel virusl tol enterl hostl cells.
Q:l Understandl howl respiratoryl illnessesl spreadl andl thel evidencel forl
airbornel transmissionl ofl COVID-19.
Answer:
Respiratoryl illnessesl canl spreadl throughl respiratoryl droplets,l whichl arel emittedl whenl anl infectedl personl talks,l coughs,l orl sneezes,l andl recentl evidencel suggestsl thatl COVID-19l canl alsol bel transmittedl throughl airbornel particlesl thatl canl remainl suspendedl inl thel airl forl longerl periodsl ofl time.
Q:l Knowl howl tol calculatel Rl andl knowl whatl itl represents.
Answer:
R,l orl thel reproductionl number,l isl calculatedl inl microbiologyl byl determiningl thel averagel numberl ofl secondaryl infectionsl thatl resultl froml al 2 / 3
singlel infectedl individuall andl representsl thel potentiall forl al diseasel tol spreadl inl al population.
Q:l Bel ablel tol describel thel basicsl ofl "infectivity"l andl howl thel cyclel thresholdl inl PCl canl determinel positive/negativel COVIDl tests.
Answer:
Infectivityl isl al measurel ofl howl easilyl al pathogenl canl spreadl froml onel individuall tol another,l andl inl thel casel ofl COVID-19,l thel cyclel thresholdl (Ct)l valuel inl PCRl testingl canl bel usedl asl anl indirectl measurel ofl virall loadl andl infectiousness,l withl lowerl Ctl valuesl indicatingl higherl virall loadsl andl potentiallyl greaterl infectivity.
Q:l Definel Virion:
Answer:
Al virionl isl al completel virusl particlel thatl consistsl ofl geneticl materiall (DNAl orl RNA)l surroundedl byl al proteinl capsid,l andl mayl alsol bel envelopedl byl al lipidl membranel derivedl froml thel hostl cell.
Q:l Definel viroid:
Answer:
Al viroidl isl al small,l circular,l single-strandedl RNAl moleculel thatl lacksl al proteinl coatl andl canl causel diseasel inl plants.
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