Nucleic Acids - Janella Jane Ilag

7/23/2019 Nucleic Acids - Janella Jane Ilag

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NUCLEIC ACIDS

Ilag, Janella*Jane R.

ChE-4102


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Transcription: RNA

Synthesis

Transcription

is the process by which D! "irects thesynthesis o# hnR! $ %R! %olec&les

that carry the co"e" in#or%ation nee"e"#or protein synthesis.

'essenger R! pro"&ction (iatranscription is act&ally a )two stepprocess in which an hnR! %olec&le isinitially pro"&ce" an" then is e"ite" toyiel" the"esire" %R! %olec&le.


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Geneis a seg%ent o# a D! stran" thatcontains the base se+&ence #or the

pro"&ction o# a specic hnR! $ %R!%olec&le.

Human Genome Project

a "eca"e long internationally base"research proect to "eter%ine the locationan" base se+&ence o# each o# the genesin the h&%an geno%e.

Genome

is all o# the genetic %aterial /the totalD! containe" in the chro%oso%es o# an

organis%.


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Steps in theTranscription Process

1. ! portion o# the D! "o&ble heli &nwin"s,eposing so%e bases /a gene. he&nwin"ing process is go(erne" by the

en3y%e R! poly%erase rather than byD! helicase /replication en3y%e.

2. ree ribon&cleoti"e, one n&cleoti"e at ati%e, align along one o# the epose"

stran"s o# D! bases, the te%platestran"s, #or%ing new base pairs. In thisprocess, 5 rather than aligns with ! inthe baising process.


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6. R! poly%erase is in(ol(e" in

the lin7age o# ribon&cleoti"es,one by one to the growing hnR!%olec&le.

4. ranscription en"s when the R!poly%erase en3y%e enco&nters a

se+&ence o# bases that is rea" asa sop signal.


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!era"" Process o#Transcription o# DNA


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Temp"ate Stran$

stran" o# D! &se" #or hnR!$%R!synthesis.

it is copie" procee"ing in the 68to98"irection

In#ormationa" Stran$ the other D! stran" /the non-

te%plate stran" :i(es the base se+&ence present in

the hnR! stran" being synthesi3e".


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D! te%plate ;tran"< 98 !--:-C-C-! 68

D! in#or%ational ;tran"< 68 -!-C-:-:- 98a

hnR! ;tran"< 68 5-!-C-:-:-5 98

=ase ;e+&ence in R!< 98 5-:-:-C-!-5 68

ro% the base se+&ence 98!--:-C-C-! 68in a D!te%plate stran", "eter%ine the base se+&ence in thehnR! synthesi3e" #ro% the D! te%plate stran".

=ase >airing !ssociate" with theranscription >rocess


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E%ercise:

ro% the base se+&ence 98-!-!-C-C- 68in a D! te%plate stran", "eter%ine thebase se+&ence in the hnR!synthesi3e" #ro% the D! te%plate

stran".

D! te%plate ;tran"< 98 -!-!-C-C- 68

D! in#or%ational ;tran"< 68!-5-5-:-:-! 98

hnR! ;tran"


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Post&Transcription Processin':(ormation o# mRNA

he R! pro"&ce" #ro% a gene thro&ghtranscription is hnR!, the prec&rsor #or%R!.

Con(ersion o# hnR! to %R! in(ol(espost-transcription processing o# the hnR!.

E%on ) is a gene seg%ent that con(eys

/co"es #or genetic in#or%ation.Intron ) is a gene seg%ent that "oes not

con(ey /co"e #or genetic in#or%ation.

- D! seg%ents that interr&pt a genetic

%essage.


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! gene consists o# alternating eon an"intron seg%ents.

Eon Intron Eon Intron EonhnR!

Introns arec&t o&t

Eons areoine"together

snR!

snR!

%R!


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;plicing

is the process o# re%o(ing introns

#ro% an hnR! %olec&le an" oiningthe re%aining eons together to #or%an %R! %olec&le.

- this in(ol(es snR! %olec&leswhich is ne(er #o&n" #ree in a cell an"is always #o&n" co%plee" withproteins in particles calle" s%alln&clear ribon&cleo-protein %olec&lescalle" snR>8s /prono&nce" as)sn&rps


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Sma"" nuc"earri*onuc"eoprotein partic"e is a co%ple #or%e" #ro% an

snR! %olec&le an" se(eral

proteins.Sp"iceosome

- is a large asse%bly o# snR!

%olec&les an" proteins in(ol(e"in the con(ersion o# hnR!%olec&les to %R! %olec&les.


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A"ternati!e Sp"icin'- is a process by which se(eral"i?erent proteins that are

(ariations o# a basic str&ct&ral%oti# can be pro"&ce" #ro% asingle gene.


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Eon !

Intron

Eon =

Intron

Eon C

Intron

Eon D

%R! #or#o&rth >rotein

%R! #orthir" >rotein

%R! #orrst >rotein

%R! #orsecon">rotein

hnR!

hnR!

A"ternati!e Sp"icin'


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The Human Transcriptome

Transcriptome is all o# the %R!%olec&les that can be generate" #ro%the genetic %aterial in a geno%e.

The Genetic Co$eCo$on is a three n&cleoti"e se+&ence inon %R! %olec&le that co"es #or a

specic a%ino aci".Genetic Co$e is the assign%ent o# the@4 %R! co"ons to specic a%ino aci"s/or stop signals.


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The Genetic Co$e Ta*"e


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Remar+a*"e (eatures o#Genetic Co$e Ta*"e

1.he genetic co"e is highly "egenerate,that is %any a%ino aci" are"esignate" by %ore than one co"on.

Co"ons that speci#y the so%e a%inoaci" are calle" synony%s.

2.here is a pattern to the arrange%ento# synony%s in the genetic co"e table.

6.he genetic co"e is al%ost &ni(ersal.

4.!n initiation co"on eits. he eistenceo# )stop co"ons /5!:, 5!! an" 5:!

s&ggests the eistences o# )startco"ons.


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5sing the genetic co"e, "eter%ine the se+&ence o#a%ino aci"s enco"e" by the %R! co"on se+&ence

98 :CC-!5:-:5!-!!!-5:C-:!C-CC! 68

%R!< 98 :CC-!5:-:5!-!!!-5:C-:!C-CC! 68>epti"e< !la-'et-Aal-Bys-Cys-!sp->ro

5sing the :enetic Co"e an" %R!co"ons to >re"ict !%ino !ci"

;e+&ences


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E%ercise5sing the genetic co"e, "eter%ine the se+&enceo# a%ino aci"s enco"e" by the %R! co"onse+&ence.

98 C!5-CC5-C!C-!C5-:55-5:5-5:: 68

Ans,er:

is->ro-hr-Aal-Cys-rp


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;ection !, C, an" E o# the #ollowing basese+&ence section o# a D! te%plate stran"are eons an" sections = an" D are introns.

D!< 98!-C:-:--CCC-!:-:CC 68 ! = C D

E

Relating Eons an" Introns to hnR!an" %R! ;tr&ct&res


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a. hat is the str&ct&re o# the hnR!transcribe" #ro% this te%plate

D!< 98 !-C:-:--CCC-!:-:CC 68 ! = C DE

hnR!< 68 5!!-:C!-!C!-!!!-:::-5C!-C:: 98

! = C DE

hnR!< 98 ::C-!C5-:::-!!!-!C!-!C:-!!5 68 E D C = !

b. hat is the str&ct&re o# the %R! obtaine"by splicing the hnR!

%R!< 98 ::C-!!!-!C!-!!5 68 E C !


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E%ercise

;ection !,C, an" E o# the #ollowing basese+&ence section o#a D! te%plate stran"are eons an" sections = an" D are introns

D!< 98C:C-C:-!:-::-CCC-::!-::! 68! = C D E

a. hat is the str&ct&re o# the hnR!transcribe" #ro% this te%plate

b. hat is the str&ct&re o# the %R!obtaine" by splicing the hnR!


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Ans,er:

a.D! 98C:C-C:-!:-::-CCC-::!-::! 68

hnR! 68:C:-:C!-5C!-!CC-:::-CC5-CC5- 98

hnR! 98 5CC-5CC-:::-CC!-!C5-!C:-:C: 68

b. %R! 98 5CC-5CC-CC!-:C: 6E D C

! = C D E

! = C DE

E D C =!


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he str&ct&re i# an %R! seg%ent obtaine" #ro% D!te%plate stran" is

%R! 68 !55-CC:-5!C-:!C 9F

hat polypepti"e a%ino aci" se+&ence will besynthesi3e" &sing this %R!

%R! 98 C!:-C!5-:CC-55! 68

-en" :ln-is-!la-Be& C-en"

Re"atin' Protein Amino Aci$Se-uence to the Directiona"ity o# anmRNA Se'ment


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E%amp"ehe str&ct&re o# an %R! seg%ent

obtaine" #ro% a D! te%plate stran" is%R! 68 !C:-!:C-CC5-C55 9F

hat polypepti"e a%ino aci"

se+&ence will be synthesi3e" &sing this%R!

Ans,er:

%R! 68 !C:-!:C-CC5-C55 9F%R! 98 55C-5CC-C:!-:C! 68

-en" >he ;er !rg !la C en"


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Antico$ons an$ tRNA .o"ecu"es

tR! %olec&les #&nction as inter%e"iaries that"eli(er a%ino aci"s to the %R!.

!ll tR! %olec&les ha(e the sa%e general

shape an" this shape is cr&cial to how they#&nction.

wo-"i%ensional )clo(erlea# is the shape

pro"&ce" by the %olec&les #ol"ing an" twistinginto regions o# parallel stran"s an" regions o#hairpin loops.


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T,o (eatures o# thetRNA Structure

1. he 68en" o# the open part o# theclo(erlea# str&ct&re is where an a%inoaci" beco%es co(alently bon"e" to the

tR! %olec&le thro&gh an ester bon".2. he loop opposite the open en" o# the

clo(erlea# is the site #or a se+&ence o#three bases calle" an antico"on.

!ntico"onis a three-n&cleoti"e se+&enceon an tR! %olec&le that isco%ple%entary to a co"on on an %R!%olec&le.


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!nswerro C-ter%inal en"


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E%ercise:! D! te%plate stran" is rea" as #ollowshe-Aal-yr-is-C-en"


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Trans"ation: ProteinSynthesis

Trans"ation

he process by which %R! co"ons are"eciphere" an" a partic&lar protein %olec&le is

synthesi3e".he s&bstances nee"e" #or the translationphase o# protein synthesis are %R!%olec&les, tR! %olec&les, a%ino aci"s,

riboso%es an" a no. o# "i?erent en3y%es.Riboso%e rR! protein co%ple that ser(es asthe site #or the translastion phase o# proteinsynthesis.


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(i!e Genera" Steps to theranslation>rocess

/0 Acti!ation o# tRNA

!n a%ino aci" interacts with !> tobeco%e highly energi3e". It then #or%s aco(alent bon" with the 68en" o# a tR!%olec&les. !%ino aci"s tR! paring isgo(erne" by en3y%es.

10 Initiationthe %R! attaches to a riboso%e so that

the rst co"on /!5: is at the > site. ! tR!carrying %ethionine attaches to rst co"on.


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20E"on'ation ) !nother tR! withsecon" a%ino aci" bin"s at the ! site.

he %ethionine trans#er #ro% the >-siteto the ! site. he riboso%e shi#ts to thenet co"on, %a7ing it8s a site a(ailable.

30Termination)the polypepti"e chaincontin&es to lengthen &ntil a stopco"on appears on the %R!. he new

protein is cleare" #ro% the last tR!.40Past&Trans"ation Processin' )

clea(age o# 'et /the initiation co"on&s&ally occ&rs ;-; bon"s between Cys&nits also can #or%.


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.utations ) is an error in base se+&ence in a gene that isrepro"&ce" "&ring D! replication.

.uta'en ) is a s&bstance or agent that ca&ses a change

in the str&ct&re o# a gene.

T,o Types o# .uta'ens

1 Ra"iation in the #or% o# &ltra(iolet light, G-rays,ra"ioacti(ity an" cos%ic rays.

2 Che%ical agents /H2 ca&ses "ea%ination o#heterocyclic nitrogen bases.

Point .utation ) a %&tation in which one n&cleoti"e iss&bstit&te" #or another.

Hriginal D! ! : C ! C >oint '&tate" D! ! C C ! C

he e?ect o# a point %&tation can (ary #ro% no e?ect to achange in pri%ary str&ct&re to ter%ination o# protein

synthesis.

C has replace":


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a. 5n%&tate" base se+&ence

:!: CC C5C Be&

e%plate In#or%ational %R! a%ino aci"

stran";tran"

'&tate" base se+&ence

:!! C C55 Be&

e%plate In#or%ational %R! a%ino aci"stran";tran"

Si"ent .utation )a%ino aci" i"entity is not a?ecte", as both

%R! co"ons co"e #or the sa%e a%ino aci".

>re"ict the change that occ&rs in a%ino aci" i"entitywhen each o# the #ollowing point %&tations occ&r on 68to 9

D! base seg%ents.

a. :!: is point %&tate" to :!!

b. !!! is point %&tate" to !!

c. !! is point %&tate" to !

>re"icting the E?ect o# a >oint '&tation


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b. 5n%&tate" base se+&ence

!!! 555>hee%plate In#or%ational %R! a%ino aci"

stran" ;tran"

'&tate base se+&ence!! ! 55! Be&e%plate In#or%ational %R! a%ino aci"

stran" ;tran"

he point %&tation has pro"&ce" a co"on that co"es #or a"i?erent a%ino aci".

c. 5n%&tate" base se+&ence

!! ! 5!5 yre%plate In#or%ational %R! a%ino aci"

stran" ;tran"

'&tate" base se+&ence! !! 5!! stop co"on

e%plate In#or%ational %R!a%ino aci"

stran" ;tran"

he point %&tation has pro"&ce" stop co"on res&lting in

ter%ination o# protein synthesis.


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E%ercise:>re"ict the change that occ&rs in a%ino

aci" i"entity when each o# the #ollowingpoint %&tation occ&r on to 68 to 98 D!base seg%ents.

a. C! is point %&tate" to C

b. C:! is point %&tate" to ::!

c. :C is point %&tate" to !C

Ans,ers:a. !sp beco%es :l&

b. !la beco%es >ro

c.

:ln beco%es a stop co"on


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Nuc"eic Aci$s an$ 5iruses

5iruses ) a (ery s%all "isease ca&sing agentsthat are consi"ere" the lowest or"er o# li#e.

- is a s%all particle that contains D! or R!/b&t not both s&rro&n"e" by a coat o# protein

an" that cannot repro"&ce witho&t the ai" o# ahost cell.

- "o not posses the n&cleoti"es, en3y%es, a%inoaci"s an" the other %olec&les necessary toreplicate their n&cleic aci" or to synthesi3e

proteins.

- their only #&nction is #or repro"&ction, (ir&ses"o not generate energy.


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Retro!irus )R! containing (ir&s

- re(erse synthesis is go(erne" by the

en3y%es re(erse transcriptase !ID; (ir&sin on e. o# retro(ir&s.

He"per T&ce"" ) (ir&s has anity #or aspecic type o# white bloo" cell, an

i%portant part o# the bo"y8s i%%&nesyste%.

5accine )is a preparation containing aninacti(e or wea7ene" #or% o# a (ir&s orbacteri&%.

I# a (ir&s contains D!, the host cellreplicates the (iral D! in a %anner

si%ilar to the way it replicates to its own


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Recom*inant DNA an$Genetic En'ineerin'

Genetic En'ineerin'

- is the process whereby an organis% is intentionally changeat the %olec&lar /D! le(el so that it ehibits "i?erent traits.

- the rst organis%s to be genetically engineere" werebacteria in 1K6 an" %ice in 1K4.

- Ins&lin pro"&cing bacteria were co%%erciali3e" in 1L2,an" genetically %o"ie" crops ha(e been a(ailable since1K4.

6aci""us thurin'iensis ) on insect resistant that is obtaine"#ro% the presence o# a gene obtaine" #ro% the soil bacteria.

& amy"ase ) an en3y%e that rapi"ly brea7s "own starchinto gl&cose.


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Recom*inant DNA 7rDNA8

- is D! that contains genetic %aterial

#ro% two "i?erent organis%s.

6acterium E0 co"i

) #o&n" in the intestinal tract o# h&%ansan" ani%als is the organis% %ost o#ten&se" in reco%binant D!.

-- contain D! in the #or% o# s%all,

circ&lar, "o&ble stran"e" %olec&les calle"plas%i"s.


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Se"ecte$ Human Proteins Pro$uce$ Usin'Recom*inant DNA Techno"o'y an$ their Use

Protein Treatment

Ins&lin Diabetes

Erythropoietin /E>H !ne%ia

&%an growth hor%ones /: ;ti%&late growth

Interle&7ins ;ti%&late i%%&ne syste%

Inter#erons Be&7e%ia an" other cancers

B&ng s&r#actant protein Respiratory "istress

;er&% alb&%in >las%a s&pple%ent

&%or necrosis #actor / Cancers

iss&e plas%inogen acti(ator/>!

eart attac7s

Epi"er%al growth #actor ealing o# wo&n"s an" b&rns

ibroblast growth #actor &lcers


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-ED H RE>HR-

Nucleic Acids - Janella Jane Ilag

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