1. GCE Biology Mark Scheme June 2005 (1)

8/13/2019 1. GCE Biology Mark Scheme June 2005 (1)

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MS3 WELSH JOINT EDUCATION COMMITTEE3.00 CYD-BWYLLGOR ADDYSG CYMRU

General Certificate of E!cation T"#t"#$rif A"#$ G"ffreinol

Advanced Subsidiary/Advanced Uwch Gyfrannol/Uwch

MAR%ING SCHEMES

SUMMER 2005

BIOLOGY


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INTRODUCTION

The marking schemes which follow were those used by the WJEC for the Summer 2005

examination in CE !iology" They were finalised after detailed discussion at examiners#

conferences by all the examiners in$ol$ed in the assessment" The conferences were heldshortly after the %a%ers were taken so that reference could be made to the full range of

candidates# res%onses& with %hotoco%ied scri%ts forming the basis of discussion" The aim of

the conferences was to ensure that the marking schemes were inter%reted and a%%lied in the

same way by all examiners"

't is ho%ed that this information will be of assistance to centres but it is recognised at the

same time that& without the benefit of %artici%ation in the examiners# conferences& teachers

may ha$e different $iews on certain matters of detail or inter%retation"

The WJEC regrets that it cannot enter into any discussion or corres%ondence about these

marking schemes"


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BIOLOGY

ASSESSMENT UNIT BI&

'!e#tion An#(er)E*+lanator" Note# Mar,#

Aaila.le

(" )ibosome mark scheme

*i+ ( mark for decent diagram showing 2 clear subunits

( mark for any label large subunit

small subunit

groo$e which /),- fits into

t),- binding site 2

*ii+ ),-.)ibosomal ),-

/rotein

*not amino acids.nucleic acid+

(

(

*iii+ *rough+ endo%lasmic reticulum (

*i$+ %rotein.%oly%e%tide synthesis (

*$+ nucleolus.nucleolus and cyto%lasm

*not nucleus.cyto%lasm+

(

Total 0 /ar,#

(


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Aaila.le

2" 1i%id mark scheme

*i+

Tri$l"cerie 12o#+2oli+i

Structural

difference (

fatty acids 2 fatty acids

Structural

difference 2

*lycerol head only+ lycerol 3 %hos%hate

head

*not %hos%horus+

Where com%ound

is found in

organisms

4nder

skin.subcutaneous.

blubber

-round body organs

ur.feathers

,er$e cells

Smooth

E).golgi.$esicles

seeds

chloro%lasts

Cell.%lasma

/e/.rane#

*not hydro%hilic.hydro%hobic.%olar.non6%olar.fat un7ualified+One /ar,

+er ro( 3 4

*ii+ Stearic.Saturated has more 8 or con$erse"

Stearic has no double bonds *in 2"rocar.on c2ain.double

C-Cbonds+ or con$erse"

Stearic acid is a straight hydrocarbon chain.not kinked.bent

or con$erse"(

*iii+ Stearic acid.saturated *fatty acid+" (

Total 5 /ar,#

2


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Aaila.le

" enetic finger%rinting 9 mark scheme

*a+ *i+ enetic.:,- finger%rinting.:,- %rofiling" (

*ii+ blood.sali$a.skin.hair.semen any 2

*not finger%rints.body fluids.urine.sweat+

(

*iii+ sus%ect 2 (

*i$+ it is the only one which has the banding %attern which

exactly matches the one at the scene of the crime"

*allow sam%les are the same+

(

*b+ *i+ 4sed to cut the :,- *into sections"+

*not genes+

(

*ii+ Se%aration of :,- fragments" (

*c+ /aternity suits.e7 (

Total 0 /ar,#


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Aaila.le

;" Cell di$ision mark scheme

*a+ Correct ': of 1S root


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Aaila.le

5" !eetroot 9 mark scheme

*i+ ?$ery little increase.06@ unitsA u% to ?;0BC.first ;

tem%eratures

ra%id rise at 50BC.rise from @ to D0 at 50BC

small rise from D0 to (00 units from 50 to @0BC"

higher tem%erature& darker solution.higher reading

2

*ii+ =embrane *%roteins+ are stable between (0 and ;0BC.at low

tem%eratures

*-%%earance of the red %igment means that+ the *tono%last

and+ cell membrane has been damaged between ;0 and 50BC.at high tem%eratures

*meaning+ %igment has leaked out of cells.sa% $acuole.

change in membrane %ermeability.damaged membrane

%roteins change sha%e.denature and come out of bilayer

%hos%holi%ids bilayer has become too fluid.cannot retain

%roteins"

*iii+ :issol$es %hos%holi%ids.destroys cell membrane structure

*So+ %igment leaks out"

*not ref" to higher or lower readings+

(

Total 7 /ar,#

5


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Aaila.le

@" 'mmobilised en


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Aaila.le

D" Cystic fibrosis mark scheme

*a+ %rotein.ca%sid

nucleic acid.:,-.),- 2

*b+ gene thera%y (

*c+ 4se of li%osomes

Transfer of non C gene *into %lasmid+

Coated in *s%heres of+ %hos%holi%ids.li%id *bilayer+

!reathed into lung $ia aerosol.inhaler"

*d+ ets into nucleus

'nsertion into genome.chromosome

Transcri%tion.e7 *in context+

Translation.e7" *in context+ 2

*e+ -cti$ation of oncogenes

4nex%ected disease caused.leukaemia

-llergic res%onse"

*not side effects un7ualified+

(

Total 9 /ar,#

D


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Aaila.le

G" *a+ En


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'!e#tion An#(er)E*+lanator" Note# Mar,#Aaila.le

G" *b+ :,- re%lication.transcri%tion essay mark scheme

DNA re+lication

a :,- re%lication has to occur %rior to cell di$ision.duringinter%hase

b */arental+ :,- helix unwinds *has to be clear that this is allthe :,-& not Hust a section+

c Com%lementary strands se%arate due to breaking of *weak+86bonds (could be given in transcription

d !ase %airing *-T& C+ occurs between the bases of the both

tem%late strands and free nucleotides

e :,- %olymerase se%arates the 2 :,- strands.Hoining of:,- nucleotides

f /roduces %air of identical helices.strands

g Semi6conser$ati$e re%lication.one new chain& one original

h =ention of =eselson and Stahl ex%t.correct details ofex%eriment

Tran#cri+tion

i >ccurs during %rotein synthesis

H !ase se7uence of a *cistron+ gene is con$erted to /RNA*not :,- is con$erted+

k ene *only+.short section *e7+ unwinds

l ),- %olymerase attaches to the :,-.Hoins ),-nucleotides

c :,- unne strand acts as a tem%late

n ree ),- nucleotides align themsel$es o%%osite thecom%lementary base.mention of uracil instead of thymine&uracil %airs with adenine

% Com%lete m),- %eels off and exits *nucleus+ through anuclear %ore.:,-


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ASSESSMENT UNIT BI :

'!e#tion An#(er#)E*+lanator" Note# Mar,#

Aaila.le

(" *a+ dia%hragm (

*b+ diffusion (

*c+ em%hysema (

*d+ asthma (

*e+ tidal (

;5xygen to water+ (

*ii+ it takes u% . remo$es hydrogen . %rotons . forms water (

*i$+ %rotons flow down gradient . diffusion (

through *a channel in+ -T/ synthetase . -T/ase . stalked

%articles

(

the energy is used to make -T/ *from -:/+" (

;&5

Documents

1. GCE Biology Mark Scheme June 2005 (1)