Biotechnology and Gene Tech Answers F215 (1)
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Transcript of Biotechnology and Gene Tech Answers F215 (1)
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1. (i) plasmid cut by restriction enzyme;at specific sequence;same enzyme as used to cut (insulin) gene;sticky ends / described;ref. complementary sticky ends;ligase seals (sugar-phosphate) backbone / AW; ma !
(ii) credit any two from the following"
# antibiotic resistance (gene) introduced and sur$i$ors ha$e plasmid;
% fluorescent marker (gene) introduced and glo&ing bacteria ha$e plasmid;
' identify bacteria producing insulin using antibodies; %[6]
2. referring to pig insulin:ethical / religious reasons;incompatibility / lack of tolerance / immune response; oranot eactly the same as / less effecti$e than human insulin; ora
referring to human insulin from bacteria:
engineered insulin is cheaper; oragreater supply of engineered insulin; ora #
[1]
3. (i) (penicillin) secondary metabolite ;produced at start of / during stationary phase / end of gro&th phase ; Alogphase ref to production (at maimum) &hen kept short of nutrients/ nutrients depleting / factors limiting gro&th ;
continuous culture maintains in log / rapid gro&th phase ; % ma
(ii) to pro$ide respiratory substrate / energy ; Afor respiration
to maintain culture / keep culture ali$e / pre$ent (premature) death ofculture ;
(limited) maintains in stationary phase / pre$ents rapid gro&th ;
A* ; Rglucose as carbon source % ma[4]
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4. 1 genetic testing / screening;
2 for inherited disease / AW;
3 (test to see if) indi$idual is carrier;
4 premarital testing / predict if (potential) offspring may inherit the disease;
5 antenatal testing;6 ref to termination;
7 embryo selection (to ensure embryo healthy);Rselection of se
8 (test for genes that contribute to) diseases that de$elop later in life ;
9 those &ith genes gi$en ad$ice to limit effects / counselling;
10 faster / earlier diagnosis;
11 de$elop more effecti$e / efficient drugs (to combat disease) ;
12 drugs ha$e direct effect on genes / protein made from specific gene code;
13 gene therapy / correct the base sequence of faulty gene;14 economic implications / AW;
15 A*; e.g. ref. to method used / use of gene probes / biopsy
16 A*;allo&s targeting of drug treatment ! ma[4]
5. AA+,,, / adenine adenine thymine cytosine cytosine cytosine ; (first )[1]
6. can fi nitrogen;does not deplete soil nitrogen / impro$es nitrogen content of soil (o$er time);allo&s culti$ation of poor soil;reduces use of fertilisers;higher yield;A*; e.g. reduce contamination of en$ironment by fertilisersqualified cost ref.ref. leaching of nitrate % ma
[2]
7. (a) odd number of sets of chromosomes / AW ;
homologous pairs not formed ; Aref to difficulties in pairing
during meiosis ; allow point if reference made to causing problemsduring meiosis
does not form seeds ; ma %
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(b) ref to sterile conditions / aseptic techniques ;
(small) piece of plant tissue remo$ed ; Atake cuttings
ref to named tissue ; e.g. meristem aillary / (apical) buds
eplant ;
orleaf remo$ed ;
enzymes / cellulases / pectinases to remo$e cell &all ;
protoplasts formed ;
gro&th on nutrient medium ;
plant gro&th regulators / named gro&th regulator ; Rhormones
rooting ;
incubation in light ;
plantlets ;subdi$ide ;
handling medium / sterile soil ;
A* ;
A* ; e.g. remo$e &a from lea$es
callus culture / mass of undifferentiated cells forms
ref. auin to cytokinin ratio
urashige and koog ( 0 ) medium
further detail of culture method / aseptic technique ma 1
(c) max 4 for either
advantages
many plants ;
genetically identical ;
(so) all ha$e desired characteristics / genotypes / phenotypes ;
no need for (artificial) selection ;
can be obtained in short space of time / AW ;easy to transport / store ; Aref to space sa$ing
easy to genetically engineer ;
disease / $irus free ;
disadvantages
genetically identical qualified in terms of disad$antage ;
susceptible to disease ;
loss in genetic di$ersity (as cloned plants are gro&n eclusi$ely) ;
farmers ha$e to buy plants from suppliers / AW ;ref to economic problems for de$eloping countries ; e.g. start up costs
patented property ;
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A* ;
A* ; e.g. no quarantine required ref. to cost qualified not labour intensi$e (ad$antages)genetically unstable (disad$antage) ma 1
[12]
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8. (a) pro$ides oygen for aerobic respiration ;
any detail e.g. oidati$e phosphorylation ;
sterile to pre$ent contamination ;
mies fungus &ith substrate / pre$ents settling / bubbles help stirring / AW ; %
(b) (i) carbon 2 glucose / lactose ;
nitrogen 2 amino acids / nitrate ions / ammonium ions / yeast etract ;
A corn steep liquor for either but not both %
(ii) &ater is for cooling / remo$ing ecess heat ;
maintains constant / optimum temperature ;
respiration produces heat ;
&hich &ould denature enzymes / kill cells ;
heat also produced by stirrer / motor ; ma '(iii) &ill affect enzyme action / metabolic rate ; Adenature enzymes
addition of buffer / acid / alkali / base ; %
(c) (i) 3 hours ; #
(ii) Xincludes rapid / eponential / main gro&th phase ; ora
&hen primary products are made / penicillin is a secondarymetabolic product ;
ecess of nutrients in Xorpenicillin produced &hen nutrients
limited / depleted ; '
(d) filter (to remo$e fungus) ;
fungus &ashed (to remo$e penicillin) ;
continuous countercurrent / chemical etraction ;
concentration ;
addition of potassium ions ;
precipitate crystals / (potassium) salts ;
sol$ents used to purify penicillin ;A* ; e.g. dried some are chemically modified 33.14 pure ma '
(e) can genetically engineer microorganisms ;
ref to risk of infection ; e.g. ,56 &ith 78
a$oids problem &ith side effects / allergic effects ; Aref. toimmune response
large amount of product ;
gro& microorganisms in small area / $olume ; Aless space required
can be cultured any&here in &orld ;
ethical ad$antages qualified ;
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ref to cost qualified ; e.g. insulinuses cheaper feedstock (than forrearing pigs)
A* ;
A* ; e.g. high replication / gro&th rate
etraction of 78 from brains slo& process ma !
[20]
9. (a) (i) temperature ;
concentration of substrate / sugars /carbohydrates ; R$olumes / amounts
concentration of yeast ; R$olume / amount
p8 / carbon dioide concentration ;
oygen a$ailability ;
concentration of alcohol / ethanol / toic &aste ;
A* ; ma '
(ii) carbon dioide ; A,9%
#
(b) (i) one mark for slow, fast, slow / nothing
initial gas production slo& ref to time ;
rapid rate ref to time ;
little gas production ref to time ;ref to actual $olumes ;
any rate calculated ; ma !
(ii) ref to (aerobic / anaerobic) respiration ;
slow gas production
transport of glucose into yeast cells takes time ; Aabsorbed / takenup by yeast detail ; e.g. ref to carriers
rapid rate of respiration
high substrate concentration in yeast cells ;
rate slows
substrate runs out ;
or other factor(s) / named factor affect the rate ;
A* ; e.g. increase in number of yeast cells increases rate ofrespiration qualified ref to time taken for ad:ustment toconditions (in slo& production) ma !
(c) slower rate of respiration
enzymes(s) to metabolise / hydrolyse / digest / breakdo&n maltosenot present ;
genes s&itched on ;
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time for enzymes to be synthesised ;
ref to membrane transport / ease of passing through membrane ;
A* ; e.g. facilitated diffusion ma %[14]
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10. (i) fe&er genetically engineered mosquitoes pass parasites across midgut; Afigures
fe&er g e mosquitoes ha$e parasites in sali$ary glands ; Afigures
fe&er g e mosquitoes can infect (uninfected) mice ; Afigures
less good as vectors instead of all of first three points = only
use of comparati$e figures ; ma '
(ii) benefitone of follo&ing ;
reduce use of insecticide / drug
safer than insecticide / drug
A* ma #
ha!ardone of follo&ing ;
parasite may de$elop resistance
gene may pass to other species
A* ma #[5]
11. (i) adding / using &ater ;
breaking bond / ester bond (in molecule) ; Abreakdo&n into smallermolecules %
(ii) matri protects / stabilises (immobilised) enzyme / lipase ; allow once
so &ill function at optimal rate / more efficiently (than soluble) at highertemperature / !1 , ; Agreater acti$ity / AW
ref to soluble lipase begins to denature (reducing acti$ity) ; ora
continues to &ork at optimal rate / more efficiently at lo&er p8 ;
ref to presence of fatty acids changing p8 ;
ref to ionic bonds breaking (in soluble lipase) ; ora
A* ; e.g. ref to industrial uses ref to effect on < groups ma ![6]
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12. (i) attached to an insoluble material / AW ; #
(ii) (micro)encapsulation / (trapped) in alginate beads ;
adsorption / stuck onto e.g. collagen / clays / resin / (porous) glass ;
cross linkage or co$alent / chemical bonding to e.g. cellulose /collagen fibres ;
gel entrapment / trapped inside gel e.g. silica (lattice / matri) ;
partially permeable membrane (polymer) microspheres ; ma %
(iii) urine can be processed / no problem of remo$ing urine / AW ;
pure / drinkable / useable &ater produced ; A&ater recycled
space sa$ing / less &ater needs to be taken into space ;
payload limit / &eight reduction / AW ;
no need to take more enzymes into space / enzymes reusable ; Aenzymes
reco$erable
no problem in separating enzyme from products / product not contaminated ;
ref to longer shelf-life of enzyme ;
A* ; e.g. larger surface area of enzyme eposed more stable at etremes
ref to ease of use (of bioreactor) ma '[6]
13. (i) ref to r6=A / recombinant 6=A ;
restriction enzyme(s) ;
cut 6=A at specific site(s) ;
detail site(s) ;
ref to $iral 6=A and human 6=A / 6=A of gene ;
ref to sticky ends ;
complementary binding ;
detail of binding ; A > + / , > 7 / hydrogen bonds
ligase to seal ?nicks@ in (sugar-phosphate) backbone ; ma !
(ii) has effect &hen added to genome ;
not masked ;
no need to remo$e / inacti$ate recessi$e / mutant allele ; ma %[6]
14. (i) 6=A from t&o different sources ;
combined / :oined / AW ; %
(ii) restriction enzymes cut 6=A ;at specific sites ;
detail of sites ;
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may gi$e sticky ends ;
complementary sticky ends :oin ;
terminal transferase / enzyme adds sticky ends ;
ligase :oins gaps / nicks ; ma '[5]
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15. (a) 1 pre$ent self-pollination / un&anted pollination of flo&ers ;
2 detail of pre$ention ;
3 cross-pollinate t&o $arieties ; Acrossed / mated / hybridised
4 detail pollination ;
5 isolate plants / flo&ers ;6 collect seeds and so& ;
7 in high salt concentration ;
8 select plants &hich sur$i$e / can tolerate high concentration ;
9 and ha$e large tasty tomatoes ;
10 interbreed these plants ;
11 repeat selection ;
12 ref many generations ;
13 cross &ith $ariety &ith large tomatoes to impro$e size ;14 cross &ith $ariety &ith good fla$our to impro$e taste ;
15 ref backcrossing &ith original $ariety for salt tolerance ;
16 A* ;
17 A* ; ma
e.g. ref background genes / hybrid $igour / heritability /
effect on $igour / ref setting up pure-breeding initial lines
QWC legible text with acc!ate "#elli$g% #$ctati&$
a$' g!a((a! ; #
(b) (i) acti$e transport ;
(energy from) A+* / respiration ;
against concentration gradient ;
ref binding site for ion / AW ;
ref change of shape of protein ; ma '
(ii) 7B quick(er) / C slo&(er) ;
(tolerance) in one generation ($. many generations) ;
ref one gene / rest of genome unaltered ($. hybridisation) ;
background genes intact ($. need for backcrossing) ;
different $arieties engineered for different conditions ;
no problem re interbreeding ;
can select transporter system / AW / from another species/ named taon ;
can select transporter system / AW / for maimum efficiency ;
A* ; ma '
[15]
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16. aniety about (future) health / may not &ant to kno& / AW;many diseases &e can test for ha$e no treatments;discrimination by employers;discrimination by insurance companies / banks;reliability of tests in question;Afalse positi$e / negati$e resulteample of disease gi$en in contet;
cost to =8 / go$ernment;rich people can benefit / poor &ill not benefit;A*;;e.g. moral issues associated &ith embryo selection
eugenicsparents feelings to&ards childpresence of allele may not cause disease / ref to multifactorialdiseasesref to storage of data and freedom of information / in$asionof pri$acy / question of paternity
R?playing 7od@ / cloning ! ma[4]
17. (i) restriction (enzyme) / endonuclease; #
(ii) this may be answered in the context of inserting into a plasmid"
cut 6=A &ith restriction enzyme;ref to sticky ends;complementary;
base pairs / ,,, and 777 / , pairing &ith 7 / alternati$e;(6=A) ligase / ligation;ref to bonding / AW; e.g. hydrogenorphosphodiester / sugar-phosphate
A*; e.g. add sticky ends to blunt endscut both at the same place ' ma
(iii) codes for %protein / polypeptide / enzyme;Aref to protein synthesis / transcription / translation
(enzyme) catalyses / causes % condensation / formation of glycosidicbonds / reaction (bet&een %mannose / sugars); %
[6]
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18. cheaper;ref to compatibility / less chance of re:ection / fe&er side effects;stated ethical issue; e.g.don@t need to kill animals / remo$es religiousob:ectionsref to contamination / easier to purify / ref to disease;consistent quality;
more effecti$e (as human in origin);production le$el can meet demand / reliability of supply / faster production;ignoregreater production % ma
[2]
19. (a) (i) amylase ; #
(ii) glycosidic ; < glucosidic #
(iii) alpha / D ; #
(b) (i) encapsulation / trapped in alginate beads ;
adsorption orstuck onto collagen / clays / resins ;
cross linkage or co$alent / chemical bonding to cellulose (fibres) ;
gel entrapment / trapped in silica gel ;
partially permeable membrane microspheres ; ma %
(ii) does not mi &ith / does not contaminate / stays separate from theproduct ; ref to no / less / easier do&nstream processing ;
reco$erable / not lost during processing ;
reusable / cost effecti$e ;
matri stabilises / protects the enzyme ;
so acti$ity not affected by changes in temperature / p8 orrun ata high temperature / &ider range of p8 ;
longer use / shelf-life ;
so suitable for continuous culture / cost effecti$e / greater yield ;
A* ;
points can interchange if valid ma !
(c) not necessary to start &ith a pure enzyme ;
keeps the enzyme a&ay from oygen ;
more enzymes in$ol$ed ;
cell produces enzymes ;
A* ; e.g. enzyme(s) may be epensi$e / difficult to isolate
simultaneous processes can occur ma %[11]
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20. (a) (i) penicillin ; Aother named antibiotic #
(ii) (comple organic molecules) produced after / not produced duringthe (log / rapid / main) gro&th phase ;
not essential for normal cell gro&th / reproduction ; ma #
(iii) batch / fed batch ; #
nutrients only added at start ;
short / rapid gro&th phase ;
required product made during stationary phase / late in lifecycle ; ora
Rdeath phase
shortage / depletion of nutrients / named nutrients ;
cell di$ision / reproduction no longer occurring ;
ref to addition of glucose / lactose at inter$als
(to a$oid death of culture) ; ma %
(b) 1 air pressure &ill push the medium into the culture $essel ;
2 medium / nutrients added to the culture at a constant rate / AW ;
3 algae / cells / #hlorella remo$ed / har$ested from the sample port ;
4 at the same rate as / to match the nutrients added ;
5 so $olume in fermenter remains constant ;
6 remo$al of &aste / toic products ;
7 that could affect gro&th / reproduction ;8 (cells kept in) eponential / log / rapid / main gro&th phase ;
9 algae are photosynthetic ;
10 light energy required ;
11 ref to use of fluorescent light to a$oid o$erheating ;
12 ref to monitoring temperature ;
13 ref to optimum conditions ; A?conditions for maimum gro&th@
14 air bubbles to mi culture &ith nutrients / AW ;
15 air bubbles to allo& algae to get sufficient light ;16 air bubbles pro$ide oygen for (aerobic) respiration ;
17 and ,9%for photosynthesis ;
18 air flo&ing into the culture $essel flo&s out through an outflo& tube ;
19 pre$enting build-up of pressure ;
20 A* ; e.g. sampling to check for mass of #hlorella ma
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(c)
factorstalen$ironmengcontrollin
ofdifficultytorefformarkone
;p8constantagmaintainindifficulty
;emperatureconstant tagmaintainindifficulty
heating / cooling qualified ;
foaming ;
blocking of inlet / outlet tubes ;
difficulties &ith miing / stirring ;
contamination / keeping it sterile ;
conditions need to be continuously monitored ;
nutrient requirements may change ;
A* ;
A* ; e.g. algal gro&th on glass
difficulties in pro$iding sufficient light
errors lead to loss of se$eral days production of #hlorella ma ![15]
21. (a) plasmid $%& protein
nucleotides / sugar E phosphate E base ; amino acids ;
! different subunits ; %F different subunits ;
phosphodiester bonds ; Aphosphoester peptide bonds / polypeptide ;contains * ; contains / disulphide bonds ;
double-stranded / double heli ; may ha$e !G structure ;
circular ; ref to %G / 'G structure / AW ;
A* ; e.g. role of 8 bonds ' ma
(b) (i) stimulates immune response / production of antibodies / + or C cells ; #
(ii) stimulate cell-mediated immunity / + cells ;
antigen remains in body longer / continuously produced ;antigens in blood only stimulate humoral immune system / C cells ;
antigens (in blood) lost in urine / broken do&n in li$er ;
ref to 8, ; # ma
(c) (i) binds
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A* ; cheaper / reduces number of $accinations % ma
(iii) 7olgi modifies protein / polypeptide / AW ;
forms glycoproteins / add sugars orcarbohydrate ;
7olgi forms $esicles ;
incorporated into cell membrane ; Reocytosis
A* ; % ma
(d) cells that take up $%& vaccine might
1 function less &ell ;
2 be killed by immune system / trigger auto-immune response ;
3 ha$e genes disrupted / mutation ;
4 ne& gene might be inherited / AW ;
5 plasmid could enter bacteria ;
6 superbug / create ne& disease / AW ;
7 effects unkno&n / ne& technology / no human trials ;
8 A* ; ref ethics ref irre$ersible ' ma[14]
22. increase in use of 7 crop / 7B crop / Ct cotton ;
no / less insecticide needed ;
reduced number of cases of pesticide poisoning ;
ref to figures (e.g. by !.!) ;
reduced cost (insecticide) ;
ref to figures (e.g. by F.% HI kg-#
/ J #.') ;
ref to limitations of sur$ey ;
A* ;
Are$erse arguments ma ![4]
23. (a) (i) gradual process / AW ;
to impro$e traits ;
to achie$e homozygosity / AW ;
best in each generation interbred ;
ref to artificial selection ;
ref to se$eral traits in$ol$ed / may be additi$e / polygenic ; ma %
(ii) ref to mitosis ;
chromosomes replicated ;
failure of spindle / cell di$ision ; ma %
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colchicine / other method ;
(iii) self-pollination pre$ented ;
pollination by foreign pollen pre$ented ;
pollen transfer ;
practical detail ; ma %
(i$) 'n ;
meiosis fails ;
ref to synapsis / homologous pairs ; ma %
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(b) (i) sterile eplant ;
sterile nutrient medium ;
ref to plant gro&th regulators ;
callus ;
subdi$ided ;medium &ith different plant gro&th regulators ;
plantlets / embryoids ;
hardening medium / sterile soil ;
A* ; e.g. appropriate plant gro&th regulators ma 1
(ii) callus can be di$ided ;
large numbers of identical plants ; Aclone
in short time ;
bulk up sterile hybrid ;bulk up master hybrid lines ;
no need for making more !n ; ma %[15]
24. (i) type of starch ;
concentration of starch / suspension ;
$olume of starch / suspension ; Ramount
ref to flo& rate ;
size of beads ; Anumber / mass / $olume of beads in column Ramounttemperature ;
length / diameter of column ;
yeast concentration ;
p8 ;
A* ; e.g. age of culture ' ma
(ii) add Cenedict@s (reagent) and boil / heat ; A,u9!in alkaline solution
different densities / colours (of precipitates) formed ; Aturbidities
use of a colorimeter in correct contet ;
Afiltering and &eighing precipitate
)R
use of ,linisti / 6iasti (strips) ;
different colours obtained ;
colour compared to chart ;
accept other valid methods e"g" reference to use of biosensors % ma
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(iii) agree
not all yeast cells successfully entrapped / AW ;
(in product) yeast cells respiring / metabolising / using sugar as anenergy source ;
(so) lo&er le$els of sugar (in product) ;
not agree
yeast cells entrapped (in beads) / immobilised so product not contaminated/ yeast not present to affect product ;
yeast cells unable to pass through glass &ool / filter ;
only $ery lo& numbers of yeast cells (so unlikely to ha$e great effect) ; % ma[7]
25. any three acceptable e"g"disease / $irus free ;
genetically identical / clone ;
maintain fa$ourable characteristics / ad$antageous phenotypes ;
faster method ;
produces many plants ;
allo&s long-term storage of plant tissue ;
easily genetically manipulated / eample of genetic manipulation ;
easier echange bet&een countries as no quarantine ;enables optimal production of useful secondary products (e.g. codeinefrom poppy) ;
no eternal en$ironmental influences ;
no influence of seasonal $ariation ;
A* ; e.g. use for sterile / infertile plants
A* ; named eample of ad$antageous phenotype e.g. gro& more $igorously
use for rare or endangered plants
rele$ant eample of genetic manipulation ' ma[3]
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26. answers referring to insulin production can also be credited in mp ',(,4
1 )scherichia coli; A)" coli
genetic engineering ' ma
2 amino acid sequence (of 878) kno&n / analysed ;
3 gene coding for 878 synthesised ;4 using triplet code / genetic code ;
*+
5 m
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27. (a) r6=A > 6=A from t&o sources ;
both 6=As cut &ith restriction enzyme / named restriction enzyme ;
gi$ing sticky ends ;
or gi$ing blunt ends to &hich sticky ends added ;
complementary binding of sticky ends ;8 bonds / e.g. A to + / e.g. , to 7 ;
nicks in (sugar-phosphate) backbone sealed by ligase ; ' ma
(b) percentage / proportion of muscle fibres &ith central nuclei / dying muscle
fibres increases in control &ith time ;
percentage / proportion of muscle fibres &ith central nuclei / dying musclefibres reduced by treatment ;
ref to comparati$e figures &ith percentages and day ; '
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(c) advantages
1 can identify presence of disorder ;
2 remo$es uncertainty ;
3 allo&s early treatment ;
4 &hich may impro$e life epectancy / quality of life ; Aa$oidunncessary suffering
5 allo&s informed choice about ha$ing children / planning healthyfamily ;
6 allo&s KL and embryo screening / preimplantation geneticdiagnosis (*76) ;
7 allo&s fetal testing and termination ;
8 choice re donation / adoption ;
9 A* ; e.g. detail of donation" AK(6) / egg donation / embryodonation
(axi(( 5 &$ a'*a$tage"
disadvantages
10 false positi$es / negati$es ;
11 may not be test for all mutations ;
12 only small number tests a$ailable / not a$ailable for all conditions ;
13 simple presence may not result in condition ;
14 confirmed presence gi$es stress / fear ;
15 problem re telling / testing rest of family ;
16 discrimination by employers / insurers ;
17 ethics of termination ;
18 A* ; e.g. detail of problem of test risk of test procedurediagnosis and elimination rather than treatment increasein intolerance / discrimination of disabled ?designer@
problem (axi(( 5 &$ 'i"a'*a$tage"
ma
QWC clea! well &!ga$i"e' "i$g "#eciali"t te!("; #
must include both advantages and disadvantages and two terms
such as
life epectancy quality of life
KL *76 *78 AK(6)
amniocentesis
, karyotype
false positi$e false negati$e[15]
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28. award marks if diagram clearly annotated
reser$oir for storage of nutrients ;
ref to method for addition of nutrients and remo$al of &aste / products ;
Asubstrate
ref to more detail of nutrient addition / product remo$al at a constant rate /continually / throughout fermentation period ;
idea of rate of product remo$al equal to addition of nutrients ;
Akeep $olume constant
use of probes / sensors / monitors ; Athermometer (for temperature)
(to monitor) any t&o of temperature / p8 / oygen le$els ;
method to maintain p8 e.g. use of buffers tube to add acid / alkali ;
addition of antifoam ;
ref. to need to maintain sterility (to a$oid contamination) ;
method to maintain constant temperature e.g. (thermostatically-controlled) &aterbath cooling :acket ; Rheat echanger
A* ; e.g. use of stirrer method to a$oid clumping of cells / blocking of inlet oroutlet pipe(s) ! ma
[4]
29. (a) a$oid attracting a mate of a different species ; ora
ensure reproducti$e isolation ; # ma
(b) (i) diffusion ; #
(ii) so that they do not recei$e oygen constantly ;
there are mitochondria bet&een them and the cell surface ; # ma
(c) mitochondria / aerobic respiration / oidati$e phosphorylation inhibitedonly briefly ;
oygen concentration decreases again ;
pre$enting action of luciferase / production of light ;
each flash short ; orae.g. so not continuously lit
A* ; % ma
(d) acti$e transport ; Ae.g. =aE/M
Epump
protein synthesis ;
synthesis of named substance ;
mo$ement of organelles ;
phosphorylation of glucose ;
A* ; ; ; e.g. transcription translation anabolic reaction
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Rrespiration 6=A replication chromosome mo$ement mitosis ' ma
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(e) cells / membranes damaged / disrupted ;
nitrous oide released ;
mitochondria stop using oygen ;
oygen allo&s light production / reaches light-producing organelles ;
in unlimited quantities / continuously so light is brighter ;respiration / oidati$e phosphorylation ceases ;
no more A+* / =A68%;
luciferin synthesis / regeneration stops ;
A* ; ' ma
(f) li$e bacteria respire / produce A+* ; ora #
(g) m
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31. (a) (i) # mutation ;% random / spontaneous / chance / pre-eisting ;' natural selection ;! drug / insecticide is selecti$e agent / selecti$e pressure ;1 resistants ha$e selecti$e ad$antage ; resistants sur$i$e / susceptibles die ;
N pass allele / mutation to offspring ; Rgene / resistance allele frequency increases ;3 rapid because multiplicati$e phase / short generation time / large#F numbers offspring / many breeding sites ; ma 1
(ii) lasmodium inside li$er cell / red blood cell ;antibodies cannot reach target / cannot be detected by immune system ;large genome ;antigenic $ariation / AW ;$ariation from meiosis ;detail ; e.g. independent assortment / crossing o$er
parasite s&itches bet&een different $ersions of proteins ;ref var gene ; ma '
(b) (i) marks in pairs - one pair onlymutation ; &ith lack of production ;
examples
in, promoter / on switch . so not transcribed .
to give premature stop codon . so, no useful / shortened, product .
deletion . with loss of allele / different product .
frameshift . so, different / no useful, m+%& / product .
in initiation codon . so m+%& not translated .& mutation . & lack of production; ma %
(ii) marks in pairs - one pair only
no membrane receptor / AW ; so no binding / internalisation ;no channel / carrier / pump ; so lack of essential nutrient / ion ;do not multiply in li$er ; so not a$ailable to infect red blood cells ;A* protein ; problem ; ma %
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(c) #FF4 protection &ith % boosters ;irrespecti$e of dosage ;NF4 &ith # booster ;no e$idence &ith 1F FFF &hether &orks &ith one booster ;ref to memory cells ;needs large numbers of parasite / ref #F FFF ' ;
safe / &ill not cause disease / does not kill mice ;might mutate back to &ild type ;can infect li$er cells e$en if no further de$elopment ;may need drug to remo$e from li$er ;data relates only to mice / may not be applicable to humans ;A* ; e.g. no data comparing results &ith standard antigenic (AW)
$accine ma '[15]
32. (a) (i) t&o recessi$e alleles/homozygous recessi$e/t&o of allele %;
no normal dominant/allele #;homozygous same allele as affected child; %
(ii) deletion remo$es base pairs;shorter/lighter pieces of 6=A mo$e further in electrophoresis;to&ards anode;so allele % shorter/lighter than allele #; ma '
(b) F.%1/%14/# in !; #[6]
33. (a) m
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(iii) eplant of meristematic / cambium / totipotent / pluripotent cells/ tissue ;
eplant (surface) sterilised / sterile nutrient ;
appropriate hormone to stimulate mitosis / di$ision ;
callus formed ;
subdi$ided ;
appropriate hormone to stimulate differentiation ;
plantlet formed ;
hardening medium / sterile soil ! ma
(i$) genetically identical ;
genotype does not affect result ;
easily genetically engineered ;
plants deri$ed from it identically genetically engineered / AW ;
large numbers easily obtained ;
early stages compact ; ' ma
so easily kept in identical conditions ;[15]
34. # restriction enzyme to cut gene from genome ;
% and plasmid / artificial chromosome / 6=A of $ector ;' same restriction enzyme ;! if cut &ith sticky ends then :oin ;1 if cut &ith blunt ends then sticky ends / nucleotides added ; Rbases &ith , bases one end and 7 bases other ;N requires terminal transferase ; (6=A) ligase needed to seal nicks in 6=A backbone ;3 ref to :oin phosphate - sugar / adds phosphate ;#F 6=A may be produced by re$erse transcriptase ;## from m
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[9]
35. (i) ! - base pairs ;palindromic / AW ;
specific sequence ; ma %
(ii) yes same sticky ends / sticky ends sho&n ; 7A+, / ,+A7complementary (bases) ;hydrogen bond ;A &ith + ;, &ith 7 ; ma '
(iii) t&o correct cuts ;G| A T T C A G A A T T T C G| A A T C
C T A A |G T C T T A A A G C T T A |G #[6]
36. (i) adding / using &ater to break bond / ester bond (in molecule);Abreakdo&n into smaller molecules #
(ii) matri protects / stabilises enzyme / lipase;
functions at optimal rate / more efficiently at higher temperature / !1 ,;Agreater activity / &3
ref. to soluble lipase begins to denature (reducing acti$ity); ora
functions at optimal rate / more efficiently at lo&er p8;ref. to presence of fatty acids changing p8;ref. to ionic bonds breaking (in soluble lipase) ; ora
A* ; e.g. ref to industrial usesref to effect on < groups ma !
[5]
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37. (a) 1 gene bank ;
2 ref to &ild type ;
3 maintain genetic di$ersity ;
4 ref to loss of alleles / genetic erosion ;
5 may ha$e appropriate trait for breeding ;6 for future use ;
7 requirements of breeders change ;
8 in case climate change / different conditions ;
9 ref to temperature / global &arming ;
10 ref to p8 tolerance / acid rain ;
11 as yet unkno&n traits may be useful ;
12 in case other named change ;
13 may lose trait if interbred ;14 may form part of food &eb / community ;
15 that cannot be replaced ;
16 adapted for habitat / niche ;
17 hybrids less &ell adapted ;
18 ref to etinction ;
19 A* ; e.g. need to maintain population for leisure fishing
20 A* ; ma
QWC legible text with acc!ate "#elli$g% #$ctati&$ a$'g!a((a!; #
(b) (i) enzyme from bacterium ;
break do&n 6=A of in$ading (bacterio)phages ;
ref to specific site of 6=A ;
detail of site (! - bp / palindromic) ;
cut 6=A ;
lea$ing blunt ends ;
or sticky ends ; ' ma
(ii) crucian carp# (thick) band in correct position (see diagram) ;
hybrid goldfish x common carp '(thin) bands in correct position ;
hybrid common carp x crucian carp '(thin) bands in correct position ; '
g o l d f i s h c o m m o n c a r p c r u c i a n c a r p h y b r i dg o l d f i s h x
c r u c i a n c a r p
h y b r i dg o l d f i s h x
c o m m o n c a r p
h y b r i dc o m m o n c a r p x
c r u c i a n c a r p
[15]
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38. tissue
# meristematic ;% undifferentiated / totipotent / able to de$elop into any cell type /
unspecialised ;' (cells) can still di$ide / undergo mitosis ;! $irus free ; max '
sterilising agent1 aseptic technique ; pre$ent gro&th of / contamination by bacteria / fungi ;N could o$er&helm / gro& faster than / compete &ith plant tissue ;
AAW max '
cytokinins, auxins
plant gro&th !eglat&! , #!&(&te! , h&!(&$e;3 cytokinins stimulate shoot / stem gro&th / many branches ;#F auins stimulate gro&th of root / root hairs ; max '
magnesium, nitrate ions, sucrose## magnesium for chlorophyll / photosynthesis ;#% nitrate (ions) needed for protein / enzyme / chlorophyll / named chemical ;#' sucrose con$erted to glucose / fructose / monosaccharide ;#! used in respiration / release energy ; max (
#1 A* ; e.g. further detail e.g. cytokinins stimulate cell di$isionno $ascular tissue therefore disease free ma
QWC clea! well &!ga$i"e' "i$g "#eciali"t te!("; #
award 23# mark if three of the following terms are given in correct
contextmeristematicundifferentiatedtotipotentmitosisasepticcontaminationregulator
promoterhormonechlorophyll
photosynthesis
respiration[7]
39. (a) (i) co& supero$ulated ;treated &ith hormone / L8 / named proprietary brand ;&ashed out of o$iduct (Auterus) / collected from o$ary ;detail &ashing ;detail collection ; ma '
(ii) ref to mitochondrial 6=A ;detail ; e.g. circular / self-replicatingmitochondria in cytoplasts fused &ith darted buffalo cell ; Aorganelle
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embryo has miture of buffalo and co& mitochondria ;nuclear / chromosomal 6=A is buffalo ;ref to bacterial contamination ; ma %
(iii) for correct phase of cycle ;ref to synchronisation ;
to prepare uterus for (implantation of) embryo ;ref to increased thickness of uterine lining ;ref to increased $ascularisation of uterine lining ; ma '
(b) increases rate of reproduction ;does not require species@ eggs ;so does not require fertile female ;does not require female for pregnancy / uses surrogate ;female not put at risk in tra$el / mating / pregnancy ;successfully formed embryo can be subdi$ided / cloned ;can use adult cells from all eisting animals to maintain di$ersity ; ma !
(c) sperm bank ;oocytes / eggs ; gametes5 > # mark onlyembryos ;tissue ;zoo / reser$e / game park ; ma '
[15]
40. max 7 for the process of genetic engineeringmax 2 for the advantages
1 identify / find gene (for insulin) / length of 6=A coding for insulin;
2 obtain / isolate / etractgene / length of 6=A (for insulin);obtain / isolate / etractm
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6 ref to complementary ends / sticky ends / described;
7 insert gene / AW into plasmid;
8 recombinant 6=A;
9 plasmid uptake by bacteria;
10 identify those bacteria that ha$e taken up the plasmid;11 pro$ide &ith ra& materials / nutrients;
12 fermenter / bioreactor;
13 bacteria produce insulin;
14 etract and purify / do&nstream processing;
15 A*;e.g.. detail of uptake by bacteriamethod of identifying those that took up plasmid*,
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complementary binding;8-bonds bet&een bases;A to + and , to 7;nicks in sugar-phosphate backbone sealed/AW;
by ligase; ma ![7]
43. (i) indicates the range of results;on either side of the mean;indicates $ariability/(standard) de$iation/(standard) error;indicates if data sets significantly different; % ma
(ii) no/small increase/figs. quoted;lag phase;ad:ust to conditions/detail of ad:ustment;
produce enzymes;A*; % ma
(iii) more rapid gro&th in non-deficient cells/ora;figures in support from both aes of graph;lo& ribose in 7*6 deficient cells/ora;less a$ailable to parasites/lasmodium;less production of
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45. benefits
a$oids in:ections / pain of in:ections / children@s fear of in:ections ;mimics normal pancreatic beha$iour ;more stable homeostasis / reduced highs and lo&s in blood sugar ;less chance hypoglycaemia / hyperglycaemia ;less restriction on lifestyle ;
no need to measure blood sugar ;A* ; max (
problems
re:ection ;cells could lodge else&here ;may take longer to act ;A* ; e.g. rat data may not be applicable to humans
transgene may ha$e unforeseen effect max ( ma ![4]
46. humans are eukaryotes /)scherichia coli is a prokaryote ;
humans / eukaryotes have 7accept ora8
larger proteins / genes ;introns ;?:unk@ 6=A / non-coding 6=A ;repeating sequences ;centromeres / telomeres ;fossil genes ;
)" coli cell much smaller ; oraselection for less &aste of space / more compact genome ; % ma
[2]
47. insulin is polypeptide / protein ;(promoter) s&itches on transcription or makes gene produce m
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48. meristematic/pluripotent/totipotent/cambial/undifferentiated tissue;sterile conditions;nutrient medium to encourage di$ision/mitosis;
produces callus;subdi$ided;different (nutrient) medium to encourage differentiation;
detail of either medium; e.g. named nutrient or plant growth substancegro&s to plantlet;hardening medium/sterile soil; ma 1
[5]