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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 2007
BIOLOGY
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INTRODUCTION
The marking schemes which follow were those used by the WJEC for the Summer 2007
examination in CE !"#$#%& They were finalised after detailed discussion at examiners'
conferences by all the examiners in(ol(ed in the assessment& The conferences were held
shortly 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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AS MODULE B!
&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
./ amylose+ ,7-
al)ha.+
glycosidic+
water./2#+
beta.+
hydrogen./+
microfibrils+
0/ a1 + ,3-
4+
C+
+/+
b1 50 60+ 1
2 8+ 1
,2-
c1 )roduction of ha)loid gametes+
not9 half :;. half number of chromosomes1
so di)loid number regained in
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
4/ a1 i1 )rotein+ ,-
ii1 correct )art labelled.circled+ ,-
iii1 com)lementary sha)e to glucose. similar sha)e to
substrate and acti(e site+
substrate.glucose will fit into.binds with acti(e site1.
en
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
5/ a1 cell wall ?+ ,5-
(acuole ? ?+
nuc mem ? +
chloro)lasts ? ?+
mesosomes ? ?+
mitochondria ? +
b1 i1 collection.number.many similar cells+ ,2-
working together.carrying out a function+
ii1 yes because many cells+ =ax ,2-
identical in structure+
working together to mo(e.raise forearm+
no because other tissues.blood (essels.ner(es. connecti(etissue )resent+
therefore is an organ+
Total 1.23
6/ a1 i1 cyto)lasm.rough endo)lasmic reticulum+ ,-
ii1 ribosome+ ,6-
)rotein+
not9 amino acid1
ribosomal.r@:;+
iii1 transfer.t@:;+
messenger.m@:;+ ,2-
b1 i1 )e)tide bond formed+ =ax ,6-
amine grou) linked to carboxyl grou)+
molecule of water eliminated+
condensation reaction+
)oints two and three can be shown on labelled diagram1
ii1 ;TA.en
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
7/ a1 :;. )lasmid cut o)en+ =ax ,8-
at certain base seBuences+
generating blunt.sticky ends+
use of restriction endonuclease1. en
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
9/ b1 ; diffusion+ ,0-
! high to low concentration.down a conc& gradient+
C )assi(e )rocess.no energy.;TA in(ol(ed+
facilitated diffusion+
E reBuires use of carrier.channel )rotein.molecule+
not9 intrinsic1
4 osmosis
mo(ement of water from high to low water )otential+
not9 water concentration1
/ acti(e trans)ort+
" ;TA de)endent+
J against.u) a concentration gradient+
D )rotein carriers in membrane reBuired+
$ endo.exocytosis.bulk trans)ort+= acti(e.energy ;TA de)endent )rocess+
: )inocytosis liBuid.)hagocytosis solid+
# in(ol(es breakage of membrane.in(agination+
not9 )inching off1
3
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AS MODULE B2
&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
./ a1 ?ylem
b1 =ass flow hy)othesis
c1 :itrates not9 nitrogen.formula1
d1 Counterflow.countercurrent
e1 Tissue fluid Total 6
0/ a1 i1 Aotometer
ii1 rate of1 water u)take by the shoot.(olume of water taken
u)
iii1 mo(ement of bubble indicates (olume of water taken u)
by the shoot1
b1 i1 cut shoot under water+
kee) lea(es dry+
set u) a))aratus under water.full of water
make sure >oints are airtight =ax& 2
ii1 to return bubble to
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
4/ a1 ; :itrogen fixation
! ecay.)utrefaction.decom)osition
C :itrification
Aenalty if bacteria mentioned1
b1 Stimulates )lant growth.algal bloom+
Which then die )lus the reason lack of light.nutrient de)letion1+
ecom)osition by bacteria+
Which increase in number+
#2 le(el decreases because #2 used by bacteria.higher
!#.res)iration+
eath of fish.in(ertebrates in context of )re(ious )oint1
=ax& 8
Total 9
7
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
5/ a1 i1 Symmetrical and correct way u)
$abels correct using names in table
Correct )ro)ortions
ii1 not all of organism eaten+
dead organisms not eaten+
loss of undigested material+
loss of C#2.res)iration.loss of heat+
$oss as urine.urea.excretion =ax& 2
b1 ead organisms may not be collected.only li(ing organisms
collected+
@oots.)art of organisms not collected+
:ot re)resentati(e areas sam)les+
Time of collection.seasonal (ariation+
ariable water content unless dried.dry biomass+
;nimals may be at more than one tro)hic le(el& =ax& 2
c1 @eflected+
$ight )asses through leaf.does not get absorbed by a chloro)last+
Con(erted to heat energy+
Some wa(elengths not absorbed by )lant )igments.eB&
not9 ref& to short wa(elengths+ not all hits the )lant1
=ax& 2
Total :
F
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
6/Inspiration Expiration
External intercostal
Muscles
Contracted @elaxed
Movement of ribcage G) and outwards own and inwards
diaphragm Contracts flattens1 @elaxes dome sha)ed1
Volume of thorax "ncreases.high ecreases.less
Pressure in thorax ecreases.less "ncreases.high
Direction of movement of
air
"n to lungs1 #ut of lungs1
#ne mark )er row& 5
b1 i1 ; H !
800 x 81 x 6 H18*F00 c;3
ii1 C H
000 x 01 x 6 I 160*000 c;3
No !nit# < . ;ar+ onl" if ot= an#'er# correct/
c1 "ncreases number of breaths )er minute.unit time in %&
"ncreased (olume of each breath in %
;ny use of figures
e&g& "ncrease in breaths from 8 to 0 in 20 secs1.eB in %
"ncrease in (olume from 800 to 000cm6in %
3 secs )er breath in ?* 2 secs )er breath in %com)arison reBuired1
d1 ol breathed in.out )er breath would be less
Time taken for each breath would be longer =ax&
Total .0
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
7/ a1 i1 ays 23 H 60
ii1 "ncrease in.high )redator numbers+
"ncreased )redation by higher )redator )o)ulation1
not9 ref& to carrying ca)acity1
b1 i1 ecrease due to lack of )rey
not9 food1
ii1 "ncrease1 due to lack of )redators
c1 i1 ;dd more )redatory mites at inter(als1
ii1 =aintain Aredator numbers or descri)tion linked marks1
d1 S)ecific to one )est1+
$ong term+
oes not de(elo) resistance+
:o en(ironmental damage.ref& to insecticide damage.no
bioaccumulation&
not9 not using harmful chemicals1
=ax&
Total 9
0
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
9/ a1 ; ;granulocyte.lym)hocyte.monocyte
! ranulocyte.)hagocyte.neutro)hil
4or A an Bif W!C's.$eucocytes #:E =;@D #:$%
C Erythrocytes.@ed cor)uscles.red blood cells
b1 !i conca(e disc increases S;9 ol1 for #2u)take+
not9 flattened1
:o nucleus lea(es more s)ace for /b+
Contains /b which has an affinity for.combines with #2+
4lexible sha)e.elastic membrane allows cells to sBuee
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
8/ a1 ;& /eart muscle is myogenic.contraction is initiated from
within the muscle itself
not9 heart1
!& "nitiated at the S;:.)acemaker&
C& Wa(e of de)olarisaton.im)ulses.excitation1 )ass o(er atria
walls causing contraction of atria&
& Cannot )ass to (entricles because of layer of non
conducti(e.insulati(e1 tissue.collagen fibres&
E& @ight left1 both atria contract simultaneously.eB&
4& e)olarisaton.im)ulses con(erges on.arri(es at the ;:&
& =ention of delay&
/& So that atria contract before (entricles&
"& e)olarisation )asses down se)tum walls&
J& Through Aurkyne.Aurkin>e tissues.!undles of /is&
D& To a)ex of heart&
$& e)olarisaton )asses u)wards through (entricle
walls.muscle&
=& So heart contracts from a)ex u)wards&
:& So )ushing blood into the arteries.A;.;orta&
#& Some mention of ner(ous su))ly to heart.mention of effect
of adrenaline&
.2 ;ar+# fro; t=e a,ailale .6
2
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
b1 ;& Aores in the leaf e)idermis* bordered by guard cells
!& "nner wall thicker than outer
C& Aresence of chloro)lasts
& 4ully labelled1 reasonable diagram
E& C change sha)e to allow o)ening and closing.labelled
diagrams
4& ;llow gas exchange
& Control loss of water (a)our from leaf
/& O*enin$I DK)um) acti(ely trans)orts DKions into C
not9 ref& stomata1
"& AS causes C#2le(els to fall.)/ rises
J& and en
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AS MODULE B"
&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
./ a1 suitable tem)+ suitable )/+ nutrient source+ water+ oxygen
not9 warmth.air1
,-
;ny t=reeof abo(e
b1 Sha)e of Cells drawn :ame of rou)
round Coccus.cocci
rod !acillus.bacilli
mark )er column but must match horio#iti,e or
ne$ati,e
A (iolet )ositi(e
B )ink negati(e
Correct colours ,-
Correct grou)s ,-
iii1 Arotein ,-
$i)o)olysaccharide ,-
Total ;ar+# 183
8
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
0/ a1 i1 & ingestion MMMMM& 2& digestion MMMMMM ,2-
6& absor)tion MMMM&& 8& egestion MMMMMM
8 correct
6 correct mark
ii1 The breakdown of large* insoluble molecules into small
soluble ones
,-
b1 En?";e S!#trate >ro!ct# Si#e ofsecre#ion
)e)sin
)rotein.
)oly)e)tide
)e)tides
stomach.
gastric )its
)e)tidases )e)tides
amino acids
Aancreas.
small
intestine
li)ase li)ids fatty acids
and
glycerol
)ancreas
sali(ary1
amylase starch.amylose
maltose sali(ary
gland
mark for each correct row ,8-
c1 i1 rawing showing brush border labelled ,-
rawing showing goblet labelled ,-
ii1 Correct function of brush border cell ,-
Correct function of goblet cell ,-
iii1 =icro(illi.brush borderlarge surface area.mitochondria
for acti(e trans)ort.'goblet' to store mucus.any feature of
secretion* e&g& (esicles
,-
Total ;ar+# 1.03
3
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
4/ a1 i1 Chloro)hyll a+ chloro)hyll b+ xantho)hyll* carotene*
carotenoid
,-
;ny t=reeof abo(e
ii1 ;llows light of different wa(elengths to be absorbed ,-
b1 i1 @ate of )hotosynthesis+ ,-
at different wa(elengths ,-
ii1 ;xis correctly labelled* rate of )hotosynthesis ,-
$ine drawn to show )eaks that coincide ,-
iii1 The wa(elengths of light most absorbed are the
wa(elengths used in the biochemical reactions owtte&
,-
c1 i1 )hotosystems ,-
ii1 )hotolysis ,-
iii1 ? :;A ,-
% water ,-
N oxygen ,-
i(1 ) electrons ,-B )rotons ,-
(1 ;cce)ting or donating electrons ,-
(i1 ?/2.:;A/2 ,-
(ii1 Source of reducing )ower.to reduce C#2.adding hydrogen
to A; to form ;$A1&
,-
Total ;ar+# 1.93
5
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
5/ a1 i1 ;TA.adenosine tri)hos)late ,-
ii1 Aurine base correctly circled on diagram ,-
iii1 ;A.adenosine di)hos)hate ;: )hos)hate ,-
i(1 "t occurs in all cells. all organisms. all metabolic reactions ,-
b1 i1 ; intermembrane s)ace ,-
! matrix ,-
ii1 lycolysis.$ink reaction.Dreb's cycle ,-
;ny two mark each ,-
iii1 A )um) )rotons from matrix into intermembraces)ace.ref& acti(e trans)ort ,-
C carry electrons from )um) to )um)1. electrontrans)ort
,-
i(1 Aro(ide energy for )um)s ,-
(1 ;TA synthetase.synthase acce)t ;TA ase1not9 stalked )articles1
,-
(i1 con(erts ;AKAi1 to ;TA+ ,-
Gsing energy from )rotons mo(ing down
electrochemical1 gradientchemiosmosis Bualified
,-
Total Mar+# 1.53
6/ a1 i1 " humoral ,-
"" cell mediated ,-
ii1 ? ! lym)hocyte.cell ,-
% T lym)hocyte.cell ,-
iii1 !one marrow ,-
i(1 =emory cell ,-
Aroliferate.)roduce antibodies immediately1 on nextcontact with the s)ecific antigen. )athogen
,-
(1 /el)er cell1* killer cell1* su))ressor cell1* memory cell1 ,2-
;ny 6 of abo(e for 2 marks 2 for mark1not9 abbre(iations1
(i1 Stimulate )roduction of ! cells.cytotoxicity.Switch off
cell mediated res)onse at end of immuneres)onse.)roliferate on next contact. destroy )athogens bylysis
,-
7
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
b1 i1 T cells.lym)hocytes multi)ly in res)onse to )resence of
(irus. antigen. )art of )rimary res)onse
not9 )rimary res)onse unBual1
,-
ii1 irus )articles are inside T cells.T cells destroy (irus )articles
not9 ref& to antibodies1
,-
iii1 They do not ha(e enough T cells to defend against
)athogens& owtte
not9 immune system weakened1
,-
c1 The antibodies raised in the immunisation will also attack human
cells. cell membranes&
,-
Total ;ar+# 1.53
F
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
7/ a1 ;& ;ll materials are added at start.not during the )rocess+ ,-
!& Sterile a))aratus+ ,-
C& Aure culture1 ofPenicillium (notatum); ,-
& Sterile nutrient medium+ ,-
E& ;eration method.oxygen for res)iration+ ,-
4& )/ ad>ustment.buffer+ ,-
& 4ilters for introduction of sterile air.oxygen+ ,-
/& =ethod of mixing Bualified+ ,-
"& Water >acket to control tem)erature.Bualified+ ,-
J& ;llow growth )hase to take )lace.lucose is de)leted
during growth )hase+
,-
D& Aenicillin is secondary metabolite+ ,-
$& Aenicillin is )roduced.har(est after growth )hase. during
stationary )hase. after nutrient de)letion+
,-
=& 4ilter culture fluid. se)arate fungus+ ,-
:& Aurify filtrate.chemically modify antibiotic+ ,-
#& ;A e&g& )enicillin )roduction in nature )ossibly to reduce
com)etition. com)arison with continuous culture&
,-
=aximum 0 from 3 a(ailable&
b1 ;& Aarasite in sali(ary gland of mosBuito. ref& to sali(a+ ,-
!& Aasses into blood stream when mosBuito bites+ ,-
C& "n(ades li(er cells+ ,-
& "n(ades red blood cells+ ,-E& Taken in when mosBuito feeds+ ,-
4& Aasses to sali(ary gland of mosBuito+ ,-
& Are(ent adult biting+ ,-
/& :ets.clothing.re)ellants+ ,-
"& Control mosBuito )o)ulation+ ,-
J& "nsecticide Bualified.T to kill adults or lar(ae+ ,-
D& rain.co(er standing water to )re(ent egg laying.lar(ae
de(elo)ing+
,-
$& S)ray oil.detergent on water to drown lar(ae+ ,-
=& 4ish to eat.bacteria to infect lar(ae.biological control+ ,-
:& Sterilisation.infertile males to )re(ent re)roduction+ ,-#& Correct reference to difficulty of treating.(accinating in
order to reduce )ool of infected humans. ref& to
)ro)hylaxis
,-
=aximum 0 from 3 a(ailable&
Total ;ar+# 1.23
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AS MODULE B$
&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
./ a1 i1 ; I Aetals acce)t Corolla
! I Stigma
C I ;nther not 9 )ollen.stamen1
I Se)als acce)t calyx not 9 bract1
E I #(ary not 9 car)el.o(ule1 ,3-
ii1 $arge )etals+
Stamens.anther.stigma inside flower+
not 9 high stigma1
car)el inside flower+
nectary+,=ax 2-
b1 i1 rowth1 organised.controlled by tube nucleus+
En
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
4/ a1 Long haired bron short haired blac!
hhbb //!!
not 9 if ga) or colon etc between letter )airs1
hb /!
4 /h!b
4 Short hair !lack
no error carried forward1
,2-
,-
,-
,-
b1 /!& /b& h!& hb ,-
Short haired !lack //!!+ //!b+ /h!!+ /h!b
Short haired !rown bb//+ bb/h+
$ong haired !lack& !!hh+ !bhh
$ong haired !rown bbhh ,F-
%&o#al
!"'
5/ a1 mark each correct label and )osition of cell body
Sensory9 into dorsal root with ganglion in grey matter&
@elay9 in grey matter with cell body in grey matter
=otor9 cell body in grey matter* out of (entral root on same side
as sensory&
,6-
b1 White matter axons and dendrons1 myelin sheath.no cell bodies
;cce)t ora grey matter* cell bodies no myelin sheath
,-
c1 Syna)tic (esicles.rece)tor sites only on )resyna)tic.one side of
syna)se+
Ex)lanation of refractory )eriod Bualified+
,2-
d1 a1 Slow it down+
b1 e)olarisation . action )otential at the node not 9 im)ulse1+
c1 from one node of @an(ier1 to next called Saltatory
conduction1+
d1 !ecause sodium and )otassium ions cannot )ass across
myelin sheath+
e1 :o myelin sheath local circuit conduction+
,=ax 8-
%&o#al!0'
2
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22
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
6/ a1 ; efinition of s)ecies+
! Are(enting allele . gene flow . interbreeding+
C ifferences arise because1 mutation random1+
Selection )ressures are different or described+
E eogra)hical.allo)atric Bual+
4 !eha(ioural Bual+
mor)hological.mechanical Bual+
/ sym)atric Bual.seasonal isolation+
" /ybrid sterility+
J 4ittest sur(i(e+ term needed1
D Aass on fa(ourable alleles+ not 9 genes1
$ :atural selection+ term needed1
= e&g& ala)agos finches+
: :o com)etition for a(ailable niches+
# ;da)ti(e radiation term needed in context1
A ;A& e&g& ref enetic drift* founder )rinci)le ex)lained
=ax 0
26
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
b1 ; @ef& )oints ! in )roximal con(oluted tubule& "f two of
following used in context+
! Water absorbed by #smosis+
C lucose absorbed by cotrans)ort acce)t ;TA reBuired .
acti(e trans)ort+
Some substances absorbed by diffusion* e&g& it ; D E
chloride ions+ exam)le needed1
E Selecti(e reabsor)tion . selecti(e absor)tion+
4 Water )otential of filtrate decreases not 9 ref& to
surrounding tissue1+
Aressure dro)s+
/ @ef& to )oints " = in escending1 loo) of /enle if two
used in context+
" :aKle(els u).water mo(es out by osmosis if not abo(e1+
not 9 salt1
J Water )otential down+
D ;scending loo) :aKout . chloride out.walls im)ermeable
to water+
$ Water )otential u)+
= @ef counter current+
: ;/ acts on collecting duct.distal con(oluted tubule+
# so water absorbed ex)lained.because of increased
)ermeability+
A ;A e&g& ref urea out from ACT or from collecting duct to
lower WA.@ef& secretion creatinine* )enicillin into
ACT.aBua)orins&
28
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
7/ a1 i1 @:; . nucleotides+ not 9 t@:;.r@:;1 ,-
ii1 ;cti(e site ,-
iii1 Secondary.al)ha /elix not 9 coil.s)iral1
Tertiary 6 dimensional folding acce)t globular
not 9 ref& SS bridges etc.more than one 6 structure i&e&
Buaternary1
,-
,-
b1 i1 @e(erse transcri)tase uses @:; as a tem)late 1 to make
:; 1
,2-
ii1 ifferent amino acid seBuence1 made+
ifferent (iral1 )rotein will be made+
iral1 Arotein is an antigen;ntigen changes+
;ntibodies are s)ecific.do not recognise new antigen+,6-
c1 i1 ;ttaches to en
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&!e#tion An#'er#(E)*lanator" Note# Mar+#
A,ailale
9/ a1 i1 Con(erted into a form which is useable by li(ing
organisms&
,-
ii1 :itrogen fixing bacteria or exam)le
"ndustrial fixation . /aber )rocess .
Electrical storms+
;ny two for mark& not 9 root nodules1
,2-
iii1 enitrifying bacteria con(ert nitrates into atmos)heric
nitrogen.less nitrates in water logged soils.)lants don't rely
on soil nitrates+
"nsecti(orous )lants digest )rotein and absorb amino acidsuse nitrogen from these acce)t ref :;+ ,-
b1 i1 Carry out chemical reaction . named+ ,-
ii1 Electron transfer chain . cytochromes.electron carriers+
not 9 ETC.)hotosystems1
,-
iii1 Gsed to )um) )rotons+
"nto bacterial cell1 wall+
Creates )roton gradient . )roton moti(e force.
electrochemical gradient . )/ radient . high concentration
)rotons in wall ,2 =ax-
i(1 Arotons mo(e down gradient into cyto)lasm1+
Through stalked )articles* )roteins.)rotein channels+
Causes ;TA synthetase . synthase+
To )roduce ;TA from ;A and iA.)hos)horylation of ;A+
,=ax 6-
c1 /ydrogen from reduced :;+
is used to reduce carbon dioxide.donate to glycerate 6 )hos)hate+
using energy from ;TA+
to make glucose.triose )hos)hate+
not 9 sugar1
,=ax 6-
CE !iology =arking Scheme Summer 20071.E
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