PCBl 3023l Examl 1l Latestl 2026l 2027l

PCBl 3023l Examl 1l (Latestl 2026/l 2027l Update)l Review|l 100%l Verifiedl Questionsl &l Answersl |l Gradel A

Q:l intronsl are...

Answer:

-l noncodingl regionsl ofl mRNAl molecule

Intronsl arel thel noncodingl regionsl onl DNAl andl Extronsl arel thel codingl regionsl onl DNA

Q:l Thel processesl ofl replicationl willl bel bestl describedl as...

Answer:

-l al fastl errorl pronel processl thatl reliesl onl repairl mechanisms

Q:l retroviruses...

Answer:

-l codel forl anl enzymel calledl reversel transcriptase -l codel forl proteinl whichl whichl providel forl al protectivel coding -l codel forl globall geneticl elements

Q:l whichl ofl thel followingl willl involvel anl unfavorablel reaction?

Answer:

-l pyrimidinel dimerization

Q:l whichl ofl thel followingl constitutesl al horizontall transferl ofl DNA?

Answer: 1 / 4

-l actuationl ofl environmentall DNAl byl bacterial cell

Q:l thel enzymaticl activityl ofl manyl proteinsl canl bel alteredl byl additionl ofl phosphatel groupl byl classl ofl enzymesl called...

Answer:

-l Kinases

Proteinl Kinasesl phosphorylatel ;l Proteinl Phosphatasesl dephosphorylate

Q:l thel hydrolysisl ofl ATPl is...

Answer:

-l Hasl al NEGATIVEl deltal Gl value

ATPl hydrolysisl isl thel breakdownl ofl thel ATPl bond,l whichl willl releasel energy,l thisl isl al favorablel reaction.l Favorablel reactionsl increasel entropy,l andl isl representedl byl al -Gl (Gibsl Law)

Q:l Whichl ofl thel followingl replicationl isl energeticallyl unfavorable?

Answer:

-l associationl ofl al singlel strandedl bindingl proteinl tol thel exposedl singlel strand.

DNAl wantsl tol bel inl itsl lowestl energyl state,l whichl isl beingl twistedl inl itsl doublel helixl form.l Thel singlel strandedl bindingl proteinsl functionl tol preventl thel strandsl froml twisting,l thisl isl whyl itsl unfavorable.

Q:l Polarl covalentl bond

Answer:

-l sharingl ofl electronsl betweenl twol atomsl ofl differentl electronegativity

• / 4

Q:l cellsl oftenl assemblel largel complexesl froml al smallerl preforml molecule.l Thel advantagel ofl thisl is?

Answer:

-l efficientl controll ofl assembly -l fewl genesl required -l lessl energyl required

Q:l phosphorylationl ofl anl enzymel canl affectl proteinl functionl by?

Answer:

-l alteringl ofl thel proteinsl conformation -l openingl andl closingl bindingl sitesl elsewherel onl thel protein.

Phosphorylation=conformationall change l -l affectsl bothl activel andl regl sites

Q:l thel corel ofl al nucleosomel isl composedl of?

Answer:

-l al diskl shapedl proteinl octamer

Histones:l complexl ofl 8l proteins:l 4l kindsl ofl 2l each

Q:l whichl enzymel isl directlyl responsiblel forl activationl ofl GTPl bindingl proteins?

Answer:

-l Guaninel nucleotidel exchangel factor

GEF-inducesl releasel ofl GDP l -inducesl GTPl bindingl tol vacatedl GDPl site l -activation

Q:l thel deltal Gl valuel ofl anl unfavorablel reactionl canl bel madel negativel by... 3 / 4

Answer:

-l Increasingl thel concentrationl ofl thel reactants

Whenl al reactionl releasesl heatl (-Deltal H)l orl increasesl thel entropyl ofl thel system,l thesel factorsl makel Deltal Gl morel negative.

Q:l Whatl isl NOTl anl electrostaticl interaction?

Answer:

-l Hydrophobicl interaction

Q:l electrostaticl interactions

Answer:

-l ionicl bonds -l hydrogenl bonds -l vanl derl waalsl attractions

Q:l alphal helicesl andl betal pleatedl sheathsl arel veryl commonl proteinl structuresl becausel they...

Answer:

-l involvel interactionsl betweenl peptidel bonds

Involvel H-bondl betweenl N-Hl ofl onel peptidel bondl andl C=Ol ofl another.

Q:l Prokayotes

Answer:

-l single,l circularl DNA -l celll wall -l nol organelles -Eubacterial andl archaea

• / 4