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1. Photosynthesis is a complex metabolic process whicPhotosynthesis is a complex metabolic process whic h can be influenced by h can be influenced by many differentmany different environmental factors.
environmental factors. (a
(a) ) ExExplplaiain n ththe e tetermrm limiting factorlimiting factor with reference to photosynthesis.with reference to photosynthesis.
……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… (2) (2) (b)
(b) An invAn investigestigation ination into the eto the effect offect of lighf light intent intensity asity and carnd carbon dibon dioxide oxide concenconcentration tration onon photosynthesis was carried out using pond weed. The pond weed was placed in a test tube photosynthesis was carried out using pond weed. The pond weed was placed in a test tube
that contained pond water and a quantity of sodium hydrogencarbonate. The light was that contained pond water and a quantity of sodium hydrogencarbonate. The light was provided by a lamp. The oxygen bubbles produced by the pond weed were directed into a provided by a lamp. The oxygen bubbles produced by the pond weed were directed into a
length of capillary tubing. length of capillary tubing.
The graph below shows how the rate of oxygen production of the pond weed changed The graph below shows how the rate of oxygen production of the pond weed changed with light intensity when immersed in two different concentrations of sodium
with light intensity when immersed in two different concentrations of sodium hydrogencarbonate. hydrogencarbonate. 00 .. 88 00 .. 77 00 .. 66 00 .. 55 00 .. 44 00 .. 33 00 .. 22 00 .. 11 00 00 55 00 11 00 00 11 55 00 22 00 00 22 55 00 33 00 00 33 55 00 44 00 00 RR a ta t e o f o x y g e ne o f o x y g e n pp r o dr o d uu c t ic t i oo nn / / c m c m 33 mm ii nn –– 11 – – 33 – – 33 0 . 0 . 5 5 mm o l o l d m d m s os o d id i u mu m h y d r o g e n c a r b o n a t e h y d r o g e n c a r b o n a t e 0 . 0 . 1 1 mm o l o l d m d m s os o d id i u mu m h y d r o g e n c a r b o n a t e h y d r o g e n c a r b o n a t e
(i)
(i) ExplaExplain thin the she shape ape of thof the grae graph bph between etween a liga light inht intensitensity of ty of 0 an0 and 40d 400 ar0 arbitrarbitraryy units in the sodium hydrogencarbonate concentration of
units in the sodium hydrogencarbonate concentration of 0.5 mol dm0.5 mol dm –3 –3..
……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… (4) (4) (ii)
(ii) DescrDescribe anibe and expd explain thlain the effee effect of ct of increaincreasing sing the cthe concenoncentratiotration of n of sodiusodiumm hydrogencarbonate, on the rate of oxygen production.
hydrogencarbonate, on the rate of oxygen production.
……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… (3) (3) (iii)
(iii) A number A number of precauof precautions would tions would need to need to be taken be taken while carrying while carrying out thisout this investigation in order to obtain reliable data. Describe
investigation in order to obtain reliable data. Describe oneone precaution and explainprecaution and explain why this precaution is necessary.
why this precaution is necessary.
……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… ……….………..…… (2) (2)
(c)
(c) During During the ligthe light-deht-dependependent stagnt stage of phe of photosyotosynthesnthesis, oxis, oxygen iygen is prods produced buced by phoy photolysitolysis.s. Describe the process of photolysis and explain
Describe the process of photolysis and explain its role.its role.
……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… (3) (3) (Total 14 marks) (Total 14 marks) 2.
2. (a) (a) The The rate rate of pof photoshotosyntheynthesis sis can bcan be lime limited ited by a by a numbenumber of r of factofactors.rs. Explain why temperature can be a limiting factor in photosynthesis. Explain why temperature can be a limiting factor in photosynthesis.
……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… (2) (2) (b)
Name the parts labelled A, B and C. Name the parts labelled A, B and C.
A ……….……… A ……….……… B ……….……… B ……….……… C ……….……… C ……….……… (2) (2) (c)
(c) The fThe flow dilow diagram agram below below showshows soms some of te of the prhe processocesses whes which ocich occur in cur in the lithe lightght independent reaction of photosynthesis.
independent reaction of photosynthesis. 5 c a r 5 c a r b o n c o mb o n c o m p o u n d + Xp o u n d + X YY TT rr ii o s e p h oo s e p h o s p h a t es p h a t e GG ll u c o s e p h o s p h au c o s e p h o s p h a tt ee RR e g ee g e n e r a tn e r a t ii o no n NN AA DD P H P H + H+ H AA TT PP ++ (i)
(i) Name Name the the subssubstancetances s reprerepresented sented by by the the letterletters s X X and and Y.Y.
X ..……….……… X ..……….……… Y ..……….……… Y ..……….……… (2) (2) (ii
(ii) ) StaState te the the oriorigin gin of of the the NADNADPH PH + + HH++and the ATP used in the light-independentand the ATP used in the light-independent
reaction. reaction. …..……….……… …..……….……… (1) (1)
(d)
(d) DescrDescribe hoibe how the w the prodproducts ucts of phof photosyotosynthesnthesis are is are transtransported ported in the in the plant.plant.
……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… ……….……… (5) (5) (Total 12 marks) (Total 12 marks) 3.
3. The diagram below shows an The diagram below shows an outline of the light-independent stage outline of the light-independent stage of photosynthesis, together of photosynthesis, together with some of the products.
with some of the products.
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(a)
(a) Using Using the infthe informaormation prtion provided ovided in the in the diagrdiagram, ideam, identify ntify substsubstances ances X and Y aX and Y and stand state thete the number of carbon atoms present in each.
number of carbon atoms present in each. X X ... Y Y ... (2) (2) (b)
(b) ExplaExplain in how how subssubstance tance Y iY is s conveconverted rted to to triose triose phospphosphate.hate. ... ... ... ... ... ... ... ... (2) (2)
(c)
(c) TriosTriose phose phosphate phate is conis converted verted to a phto a phosphosphorylatorylated 6-caed 6-carbon rbon sugar sugar which iwhich in turn n turn can becan be converted to a number of
converted to a number of products such as sucrose and glucose. Sucrose is products such as sucrose and glucose. Sucrose is translocatedtranslocated around the plant in phloem.
around the plant in phloem.
Describe how phloem tissue is adapted for this function. Describe how phloem tissue is adapted for this function. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (6) (6) (Total 10 marks) (Total 10 marks) 4.
4. The diagram below shows one pair of electrons being passed between the molecules of theThe diagram below shows one pair of electrons being passed between the molecules of the electron carrier system (A, B, C and D) during part of the light-dependent reactions of electron carrier system (A, B, C and D) during part of the light-dependent reactions of photosynthesis.
(a
(a) ) ((i) i) ExExplplaiain n hhow ow ththe e ppaiair r of of elelececttrorons ns mmovove e ffrorom m chchlolororophphylyll l to to ththee electron carrier system.
electron carrier system. ... ... ... ... ... ... ... ... (2) (2) (ii)
(ii) ExplaExplain in how how electroelectrons ns lost lost from from chlorchlorophylophyll arl are re replaceeplaced.d. ... ... ... ... ... ... ... ... (2) (2) (iii)
(iii) Explain hExplain how ATP ow ATP is syis synthesised nthesised when electrons when electrons pass bpass between electron etween electron carriers carriers BB and C. and C. ... ... ... ... ... ... ... ... (2) (2)
(b)
(b) Describe Describe the the Calvin Calvin cycle. cycle. You You should should answer answer this this question question in in continuous continuous prose.prose. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (6) (6) (Total 12 marks) (Total 12 marks) 5.
5. Simazine is a herbicide that kills plants by disrupting the flow of electSimazine is a herbicide that kills plants by disrupting the flow of elect rons in the membranes of rons in the membranes of chloroplasts.
chloroplasts.
An investigation was carried out into the effects of Simazine on photosynthesis. Two samples of An investigation was carried out into the effects of Simazine on photosynthesis. Two samples of plants were grown under the same controlled conditions. One sample was treated with water and plants were grown under the same controlled conditions. One sample was treated with water and
the other with a solution of Simazine. Both samples were supplied with radioactive carbon the other with a solution of Simazine. Both samples were supplied with radioactive carbon dioxide (14CO2) in a well lit, sealed chamber for an hour.
dioxide (14CO2) in a well lit, sealed chamber for an hour.
The plants were removed from the chamber and killed immediately. The mass of radioactive The plants were removed from the chamber and killed immediately. The mass of radioactive carbon
(a
(a) ) SuSugggegestst oneonecondition which should have been controlled while the plants were growing.condition which should have been controlled while the plants were growing. ... ... ... ... (1) (1) (b)
(b) ExplaExplain why in why the pthe plants lants were kwere killed illed immediimmediately aately after thfter they werey were reme removed oved from from thethe chamber. chamber. ... ... ... ... (1) (1) (c)
(c) The The resuresults lts of of the the experexperiment iment are are given given in in the the table table below.below. Radioactive carbon fixed / mg Radioactive carbon fixed / mg Pla
Plants nts tretreated ated with with watewater r Plants Plants tretreateated d witwith h SimaSimazinzinee 1
100..6 6 11..44
Suggest an explanation for the effect of Simazine on the mass of radioactive carbon fixed Suggest an explanation for the effect of Simazine on the mass of radioactive carbon fixed in the plants. in the plants. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (5) (5) (Total 7 marks) (Total 7 marks)
6.
6. The carbohydrates in green plants are The carbohydrates in green plants are formed during the light-independent stage of formed during the light-independent stage of photosynthesis. They are synthesised from glycerate 3-phosphate (GP).
photosynthesis. They are synthesised from glycerate 3-phosphate (GP). (a)
(a) State pState precisrecisely whely where there the sye synthesnthesis of is of carbocarbohydrahydrates tates takes pkes place dlace during uring the lithe light- ght-independent stage of
independent stage of photosynthesis.photosynthesis. ...
...
(1) (1)
(b)
(b) Name Name the the products products of of the the light-dependent light-dependent stage stage of of photosynthesis photosynthesis used used during during thethe synthesis of carbohydrates. synthesis of carbohydrates. ... ... ... ... (2) (2) (c)
(c) DescrDescribe thibe the role e role of ribof ribulose ulose bisphbisphosphaosphate (Rte (RuBP) iuBP) in the n the light-light-indepindependenendent stagt stage of e of photosynthesis. photosynthesis. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2)
(d)
(d) An invAn investigestigation oation of phof photosyntosynthesis thesis in cells in cells taken taken from a from a green green alga walga was carras carried ouied out.t. Samples of the algal cells were taken at 1 minute intervals over a period of 6 minutes. Samples of the algal cells were taken at 1 minute intervals over a period of 6 minutes. The quantities of GP and RuBP in these cell samples were measured.
The quantities of GP and RuBP in these cell samples were measured. At the start of the investigation, the algal cells
At the start of the investigation, the algal cells were kept in an atmosphere with 1%were kept in an atmosphere with 1% carbon dioxide. After 3 minutes, the concentration of carbon dioxide was decreased to carbon dioxide. After 3 minutes, the concentration of carbon dioxide was decreased to 0.003%.
0.003%.
The graph below shows the results of this investigation. The graph below shows the results of this investigation.
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Time / minutes Time / minutes (i)(i) DescrDescribe tibe the efhe effects fects of tof the dhe decreasecrease in e in the the concenconcentration tration of cof carbon arbon dioxiddioxide on e on thethe quantities of GP and RuBP.
quantities of GP and RuBP. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2)
(ii)
(ii) SuggesSuggest explt explanatioanations fons for the r the effeceffects yots you havu have dese described cribed in pin part (iart (i).). ... ... ... ... ... ... ... ... ... ... ... ... (2) (2) (Total 9 marks) (Total 9 marks) 7.
7. An experiment was carried out to investigate the effect of light iAn experiment was carried out to investigate the effect of light i ntensity on the rate of ntensity on the rate of photosynthesis of an aquatic plant, using t
photosynthesis of an aquatic plant, using t he apparatus shown below.he apparatus shown below.
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(a)
(a) ExpExplailain n whawhat t is is meameant nt by by the the tertermm limiting factor.limiting factor. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2)
((bb) ) SSttaattee twotwoenvironmental conditions, other than light intensity, which would need to beenvironmental conditions, other than light intensity, which would need to be controlled.
controlled.
Describe how each of
Describe how each of these environmental conditions could be controlled.these environmental conditions could be controlled. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (4) (4)
(c)
(c) The aqThe aquatic uatic plant plant was alwas allowed lowed to cato carry orry out phut photosyotosynthesnthesis fois for 10 r 10 minuteminutes. Des. Describscribe howe how this apparatus could be used to determine the
this apparatus could be used to determine the raterate of oxygen production (mmof oxygen production (mm33minmin – – 11).). ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (4) (4) (d)
(d) DescrDescribe hoibe how you w you could could modify modify this athis apparapparatus ttus to deto determine ermine the ethe effect ffect of diof differenfferentt wavelengths
wavelengths of light on photosynthesis.of light on photosynthesis. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2) (Total 12 marks) (Total 12 marks)
8.
8. The diagram below shows some of the stages in the Calvin cycle.The diagram below shows some of the stages in the Calvin cycle.
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2 2 (a)(a) Some sSome stages tages of thof the Calve Calvin cyin cycle recle require quire energy energy from from ATP. DATP. Describescribe in oe in outline utline how AThow ATPP is made available by reactions in the chloroplast.
is made available by reactions in the chloroplast. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (5) (5)
FBPase is an enzyme involved in one step of the pathway used to re-form the CO
FBPase is an enzyme involved in one step of the pathway used to re-form the CO22acceptor acceptor molecule RuBP.
molecule RuBP.
In an investigation, plants were modified by introducing a gene which reduces the activity of In an investigation, plants were modified by introducing a gene which reduces the activity of FBPase. The graph below shows the effect of this treatment on the sucrose content of the leaves FBPase. The graph below shows the effect of this treatment on the sucrose content of the leaves of treated and untreated plants.
of treated and untreated plants.
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(b)(b) DescrDescribe thibe the effee effect of ct of reducreduced FBed FBPase aPase activitctivity on y on the suthe sucrose crose contencontent of t of leavesleaves.. ... ... ... ... ... ... ... ... (2) (2) (c)
(c) SuggeSuggest an est an explanaxplanation fotion for the dr the differifference in ence in sucrsucrose coose content ntent of the of the leaves leaves of treof treated anated andd untreated plants. untreated plants. ... ... ... ... ... ... ... ... (2) (2)
(d)
(d) SuggeSuggest st potenpotential tial benefbenefits its of of plants plants modifmodified ied in in this this way.way. ... ... ... ... ... ... ... ... (2) (2) (Total 11 marks) (Total 11 marks) 9.
9. The diagram below shows a root hair cell.The diagram below shows a root hair cell.
(a)
(a) Describe Describe how thhow the se shape ohape of a f a root root hair hair cell increases cell increases the the efficiency efficiency of abof absorption sorption of of water water and mineral ions from the soil solution.
and mineral ions from the soil solution. ... ... ... ... ... ... ... ... (1) (1)
(b)
(b) MineraMineral ions l ions can bcan be takee taken up n up by roby root haot hair celir cells and ls and may amay accumuccumulate alate at hight higher er
concentrations than in the soil solution. Explain how mineral ions are taken up by root concentrations than in the soil solution. Explain how mineral ions are taken up by root hair cells. hair cells. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (4) (4) (c)
(c) PhospPhosphate ihate ions aons are reqre required uired for tfor the syhe synthesnthesis of is of many many imporimportant mtant molecuolecules in les in plantsplants.. Name
Name twotwoproducts of the light-dependent stage of photosynthesis that require products of the light-dependent stage of photosynthesis that require phosphatephosphate ions in their molecular structure.
ions in their molecular structure. ... ... ... ... ... ... ... ... (1) (1)
(d)
(d) Describe Describe a sa simple procimple procedure edure by wby which yohich you couu could uld use minese mineral culture ral culture solutions solutions to to find thefind the effect of a lack of phosphate ions on plant growth.
effect of a lack of phosphate ions on plant growth. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (3) (3) (Total 9 marks) (Total 9 marks)
10.
10. (a) (a) In thIn the spae space bece below, dlow, draw a raw a diagrdiagram of am of a chloa chloroplasroplast shot showing twing the mahe main fein features atures of of this organelle.
this organelle.
On your diagram indicate the location of the dependent reactions and the On your diagram indicate the location of the dependent reactions and the light-independent reactions.
independent reactions.
(4) (4)
(b)
(b) DesDescricribe be the the proprocescess s of of non-cyclic non-cyclic photophosphphotophosphorylationorylation.. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (4) (4) (c)
(c) DescrDescribe ibe what what happehappens ns to to the the produproducts cts of of non-cyclic non-cyclic photophosphophotophosphorylationrylation.. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2) (Total 10 marks) (Total 10 marks)
11.
11. The diagram below shows a chloroplast.The diagram below shows a chloroplast. BB
DD CC
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((aa) ) ((ii) ) NNaamme e tthhe e ppaarrtts s llaabbeelllleed d AA, , BB, , C C aannd d DD.. A A ... B B ... C C... D D... (2) (2) (ii)
(ii) State thState the part oe part of the chf the chloroploroplast, slast, shown ohown on the dn the diagraiagram, wherm, where oxyge oxygen is pen is producroduced.ed. ...
...
(1) (1)
(iii)
(iii) Explain Explain how how oxygen oxygen is is produced produced in in chloroplasts chloroplasts during during photosynthesis.photosynthesis. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (3) (3) (b)
(b) OxygeOxygen inhn inhibits ibits the ethe enzyme nzyme that cthat catalysatalyses thes the fixe fixing oing of carbf carbon don dioxideioxide. High. High concentrations of oxygen, within a chloroplast, can
concentrations of oxygen, within a chloroplast, can reduce the rate of reduce the rate of photosynthesis.photosynthesis. Describe and explain the effect of high concentrations of oxygen on the rate of
Describe and explain the effect of high concentrations of oxygen on the rate of carbohydrate production in a chloroplast.
carbohydrate production in a chloroplast. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (3) (3)
(c
(c) ) SuSugggegestst twotwoenvironmental conditions which could increase the environmental conditions which could increase the rate of oxygenrate of oxygen production by plants. production by plants. 1 1 ... 2 2 ... (2) (2) (Total 11 marks) (Total 11 marks) 12.
12. One of the reactions One of the reactions of photosynthesis can be summarised as shown below.of photosynthesis can be summarised as shown below.
water
water →→ hydrogen ions + oxygen gas + electronshydrogen ions + oxygen gas + electrons
(a)
(a) NamName e the the reareactioction n shoshown.wn. ...
...
(1) (1)
((bb) ) GGiivvee oneone other factor, not shown above, that would be required for this reaction to occur other factor, not shown above, that would be required for this reaction to occur in a chloroplast. in a chloroplast. ... ... (1) (1) (c)
(c) DescrDescribe thibe the role e role of thof the elece electrons trons in the in the light light dependependent rdent reactioeaction of n of photophotosynthsynthesisesis.. ... ... ... ... ... ... ... ... ... ... ... ...
(d)
(d) DescrDescribe and ibe and explaiexplain how tn how the prohe products ducts of the of the light light dependdependent reaent reaction ction are invare involved iolved in then the production of glyceraldehyde-3-phosphate (GALP).
production of glyceraldehyde-3-phosphate (GALP). ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (4) (4) (e)
(e) GALP dGALP does noes not accot accumulaumulate in a te in a chlorchloroplasoplast durt during ping photoshotosyntheynthesis. sis. ExplaExplain how in how GALP iGALP iss used following its production.
used following its production. ... ... ... ... ... ... ... ... (2) (2) (Total 12 marks) (Total 12 marks)
13.
13. The diagrams below show the absorption spectra and the action spectrum that were produced inThe diagrams below show the absorption spectra and the action spectrum that were produced in an investigation of photosynthesis in a
an investigation of photosynthesis in a flowering plant.flowering plant. AA bb ss o r po r p tt ii oo n n ss pp e ce c tt r ar a
44
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(a)
(a) Using Using the inthe informaformation in tion in the twthe two grao graphs, phs, explaexplain the in the relatiorelationship nship betwebetween the en the absorabsorptionption and action spectra for this flowering plant.
and action spectra for this flowering plant. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (3) (3) (b)
(b) State pState precisrecisely whely where there the chle chlorophorophyll pyll pigmentigments wous would be ld be found found in a chin a chloroploroplast olast of af a flowering plant. flowering plant. ... ... (1) (1) (c)
(c) DescrDescribe hoibe how chrw chromatoomatography graphy could could be usbe used to ed to identidentify thify the chloe chloroplasroplast pigmet pigments fnts fromrom the leaves of a flowering plant.
the leaves of a flowering plant. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (4) (4)
(d)
(d) ExplaExplain why fin why flowerinlowering plang plants grots grown in swn in soil whoil which is dich is deficieficient in ment in magnesagnesium ionium ions oftes oftenn have leaves with pale yellow patches between the veins.
have leaves with pale yellow patches between the veins. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2) (Total 10 marks) (Total 10 marks) 14.
14. The diagram below summarises the The diagram below summarises the light dependent reactions of photosynthesis.light dependent reactions of photosynthesis.
L I
L I GG HH TT PP rr oo dd uu cc tt AA
CC hh ll oo rr oo pp hhee yyll eell llcc tt rr oo nnEE ssll ee cc tt rr oo n ccn e le l eeaa rr rr ii eecc tt rr oorr ss nn PPss rr oo dd uu cc
(a)
(a) Give tGive the prhe precise ecise locatlocation wiion within a thin a chlorochloroplast plast where where this this sequesequence once of reacf reactions tions occuroccurs.s. ...
...
(2) (2)
(b)
(b) Give Give the the names names of of produproduct ct A A and and produproduct ct B.B. Product Product A A ... Product Product B B ... (2) (2)
chloroplast. chloroplast. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (4) (4) (e)
(e) AtraziAtrazine ne can can be be used used as as a a weedkweedkiller.iller. (i)
(i) ExplaExplain hin how thow the pre presenesence oce of wef weeds eds can can reduce reduce the the yield yield of cof crop rop plantplants.s. ... ... ... ... ... ... ... ... (2) (2) (ii)
(ii) A chaA change in nge in a sina single ggle gene cene can altean alter the r the electrelectron caon carrierrriers so s so that athat atrazintrazine ise is ineffective. Suggest how crop plants unaffected by atrazine could be used to ineffective. Suggest how crop plants unaffected by atrazine could be used to increase crop yields.
increase crop yields. ... ... ... ... ... ... ... ... (2) (2) (Total 13 marks) (Total 13 marks) 15
15.. DaData fta for uor use wse witith thh the que quesestitionons ths that fat folollolow.w. Fig
Phytoplankton are microscopic single-celled plant-like organisms which live in Phytoplankton are microscopic single-celled plant-like organisms which live in vast numbers in the sea floating just below the surface where they
vast numbers in the sea floating just below the surface where they carry outcarry out photosynthesis.
photosynthesis.
Marine phytoplankton account for over 50% of the world’s primary Marine phytoplankton account for over 50% of the world’s primary productivity.
productivity.
Figure 2.
Figure 2. CalanusCalanusis a herbivorous small animal which makes up most of the zooplanktonis a herbivorous small animal which makes up most of the zooplankton
of the North Sea
of the North Sea and feeds on phytoplankton.and feeds on phytoplankton. CalanusCalanusappears in the North Seaappears in the North Sea
in March and starts to breed, but its
in March and starts to breed, but its numbers do not reach a maximum untilnumbers do not reach a maximum until July. Between late August to early October they leave
July. Between late August to early October they leave the North Sea and returnthe North Sea and return to the deep waters of the
to the deep waters of the North Atlantic Ocean to spend the winter.North Atlantic Ocean to spend the winter. CalanusCalanusareare
the main food source of many small fish
the main food source of many small fish as well as the young of larger as well as the young of larger fish suchfish such as herring and cod.
Fig
Figurure e 3.3. SaSandndeeeelsls..
Sandeels are small fish which make up almost a
Sandeels are small fish which make up almost a half of the mass of fish in half of the mass of fish in thethe North Sea. They feed on zooplankton, particularly
North Sea. They feed on zooplankton, particularlyCalanusCalanus. They are an. They are an
important part of the diet of many of
important part of the diet of many of the larger fish such as cod and the larger fish such as cod and herringsherrings caught for human food. Sandeels are also important in the diet
caught for human food. Sandeels are also important in the diet of many seaof many sea birds such as puffins and kittiwakes. Sandeels are caught in vast numbers to birds such as puffins and kittiwakes. Sandeels are caught in vast numbers to make fish-meal food used for farm animals.
make fish-meal food used for farm animals.
Fi
Figugure re 4.4. PrPrododucuctitivivity ty dudue te to po phyhytotoplplananktkton on in in NoNortrth Sh Sea ea ovover er a ta twewelvlve me mononthth period. period.
J
J
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F
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A
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O
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D
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3
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5
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3
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2
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P P r r i i m m a a r r y y p p r r o o d d u u c c t t i i v v i i t t y y / / g g C C m m m m o o n n t t h h l l y y t t o o t t a a l l – – 2 2Fi
Figugure re 5.5. MeMean an sesea sa sururfaface ce tetempmpererataturure oe of tf the he NoNortrth Sh Sea ea ovover er a ta twewelvlve me mononthth period. period.
J
J
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F
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8
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M M e e a a n n m m o o n n t t h h l l y y s s e e a a t t e e m m p p e e r r a a t t u u r r e e d d e e g g r r e e e e s s C C FigurFigure 6.e 6. BreedBreeding stock bing stock biomasiomass of two specs of two species of fish in the Noies of fish in the North Sea. Herth Sea. Herring storring stockscks fell so low that from
fell so low that from 1978 until 1982, fishing for this species in the 1978 until 1982, fishing for this species in the North SeaNorth Sea was banned. In 2000 the EU negotiated a reduction in fishing for
was banned. In 2000 the EU negotiated a reduction in fishing for cod butcod but scientists believed that the ‘fishing quotas’ agreed by the EU were too
scientists believed that the ‘fishing quotas’ agreed by the EU were too high tohigh to allow cod to recover to
allow cod to recover to a sustainable level.a sustainable level. 2 2 , , 5 5 0 0 00 2 2 , , 0 0 0 0 00 1 1 , , 5 5 0 0 00 1 1 , , 0 0 0 0 00 t t a a l l b b r r e e e e d d i i n n g g m m a a s s s s / / t t o o n n n n e e s s C C o o dd H H e e rr
Figure 7. Location map. Figure 7. Location map.
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N N o o rr ww a ay y Acknowledgements AcknowledgementsBased on data in ‘Phytoplankton, biomass a
Based on data in ‘Phytoplankton, biomass a nd production in the southern North nd production in the southern North Sea’.Sea’.
Joint
Joint
,,I. and Pomroy
I. and Pomroy
,,A. (1993) Marine Ecology Progress Series.
A. (1993) Marine Ecology Progress Series.
9999: 169–182.
: 169–182.
Based on Zhihong Li, Holt M. and Osborne, J. (2000) ‘A baroclinic model of the NW European Based on Zhihong Li, Holt M. and Osborne, J. (2000) ‘A baroclinic model of the NW European shelf seas’.
shelf seas’.
http://www.google.co.uk/search?sourceid=navclient&ie=UTF-8&rls=GGLG,GGLG:2006-16,GGLG:en&q=north+sea+temperature+annual+cycle 8&rls=GGLG,GGLG:2006-16,GGLG:en&q=north+sea+temperature+annual+cycle http://www.aslo.org/photopost/showphoto.php?photo=1007&papass=&sort=1&thecat=500 http://www.aslo.org/photopost/showphoto.php?photo=1007&papass=&sort=1&thecat=500 http://www.statistics.gov.uk/cci/nugget.asp?id=367 http://www.statistics.gov.uk/cci/nugget.asp?id=367
Read and use the data above, and your own knowledge, to answer the following questions. Read and use the data above, and your own knowledge, to answer the following questions. ((aa) ) ((i) i) CCoonnssttrruucct t aan n aapppprroopprriaiatte e ffooood d wweeb b ddiaiaggrraam m tto o sshhoow w tthhe e ffeeeeddiningg
relationships between the organisms referred to in the data booklet and which relationships between the organisms referred to in the data booklet and which shows the trophic levels each
shows the trophic levels each organism occupies.organism occupies.
(3) (3)
(ii)
(ii) ExplaExplain why in why the tothe total biomtal biomass of ass of cod in cod in the Nothe North Sea rth Sea is nois normally rmally much lemuch less thass thann the total biomass of sand eels.
the total biomass of sand eels. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2)
((bb) ) ((ii) ) SSuuggggeesstt twotwoadvantages to the phytoplankton of being advantages to the phytoplankton of being concentratedconcentrated just below the sea surface (Figures 1 and 4).
just below the sea surface (Figures 1 and 4). ... ... ... ... ... ...
(ii)
(ii) Like Like land land plants, plants, phytoplankton phytoplankton require require mineral mineral salts. salts. Suggest Suggest why why phosphates phosphates areare essential for the growth of
essential for the growth of phytoplankton.phytoplankton. ... ... ... ... ... ... (1) (1) (c
(c) ) ((i) i) IIn n FiFigugure re 44, , ththe e ununitits s usused ed to to exexppreresss s prprimimaary ry pproroduductctivivitity y araree abbreviated as
abbreviated as gCm
gCm –2 –2
..
Given that ‘C’ stands for organic carbon and the other letters are commonGiven that ‘C’ stands for organic carbon and the other letters are common metric units, suggest what gCmmetric units, suggest what gCm –2 –2 stands for by writing it out in full.stands for by writing it out in full. ...
...
(1) (1)
(ii)
(ii) With rWith refereneference to Fce to Figureigures 4 and s 4 and 5, disc5, discuss tuss the exthe extent to went to which mhich mean seean sea sura surfaceface temperature controls the primary productivity of
temperature controls the primary productivity of phytoplankton.phytoplankton. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (3) (3)
(iii)
(iii) Measurements Measurements show that show that the mean the mean light intensity light intensity for the for the months May months May and Jand July isuly is the same, but the mean sea surface temperature is 8oC higher in July than in May. the same, but the mean sea surface temperature is 8oC higher in July than in May. Suggest why, in spite of this, primary productivity is similar in these two months. Suggest why, in spite of this, primary productivity is similar in these two months. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2) (d
(d) ) ThThe e nunumbmberers s of of
Calanus
Calanus
in the North Sea have been decreasing since 1960 and there isin the North Sea have been decreasing since 1960 and there is some evidence that this may be due to climate change. The distribution ofsome evidence that this may be due to climate change. The distribution of
Calanus
Calanus
finmarchicus
finmarchicus
, one of the most , one of the most abundant species, seems to be shifting northwards,abundant species, seems to be shifting northwards, becoming more common off the coast of Norway. Suggest whybecoming more common off the coast of Norway. Suggest why
Calanus
Calanus
may not succeedmay not succeed so well in warmer water.so well in warmer water. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2)
(e
(e) ) ((i) i) ThTherere e aare re ssevevereraal l rreaeasosons ns whwhy y cocommmmererciciaalllly y imimpoportrtanant t sstotockcks s of of ffisishh,, such as cod and herring, are under threat in the North Sea. Using information in such as cod and herring, are under threat in the North Sea. Using information in Figure 6 explain why over-fishing by humans is almost certainly part of the Figure 6 explain why over-fishing by humans is almost certainly part of the problem. problem. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2) (ii)
(ii) Nets uNets used bsed by fisy fishermen hermen in the in the North North Sea arSea are reque required tired to havo have a mee a mesh sish size whze whichich catches larger fish but allows the smaller (younger) fish to escape. This acts as a catches larger fish but allows the smaller (younger) fish to escape. This acts as a selection pressure on the cod population. Explain
selection pressure on the cod population. Explain the effects this selection pressurethe effects this selection pressure might have on the
might have on the phenotypes of these cod in future phenotypes of these cod in future generations.generations. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2) (Total 20 marks) (Total 20 marks)
16.
16. (a) (a) The The electroelectron min microsccroscope ope image image below below showshows pas part ort of a f a chlorchloroplasoplast.t.
The table below gives one function of each of the three structures labelled
The table below gives one function of each of the three structures labelled AA,, BB andand CC onon the electron microscope image. Complete the table below by writing in the appropriate the electron microscope image. Complete the table below by writing in the appropriate letter and the name of each structure.
letter and the name of each structure. F
Fuunnccttiioonn LLaabbeel l lleetttteerr NNaamme e oof f ssttrruuccttuurree Photophosphorylation Photophosphorylation Stores non-carbohydrate Stores non-carbohydrate organic material organic material Carbon fixation Carbon fixation (3) (3) (b)
(b) The eThe equatioquation ben below slow summariummarises tses the phe procesrocess of s of photophotolysis lysis of wof water.ater. 2H
2H22OO→→4H4H+++ 4e+ 4e – – + O+ O22
(i)
(i) ExplaExplain in what what happehappens ns to to the the electrelectrons ons releasreleased ed by by photphotolysisolysis.. ... ... ... ... ... ... ... ...
(ii)
(ii) The eleThe electronctrons are las are later inter involved volved in the rin the reduceduction of tion of NADP. ExNADP. Explain tplain the imphe importancortancee of reduced NADP in
of reduced NADP in the light-independent reactions of photosynthesis.the light-independent reactions of photosynthesis. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... (3) (3) (c)
(c) The rThe rate at ate at which which plants plants prodproduce cauce carbohyrbohydrate drate by phby photosyotosynthesnthesis is is is known known as gras grossoss primary productivity.
primary productivity.
Put a cross in the box next to the equation that
Put a cross in the box next to the equation that shows the relationship between grossshows the relationship between gross primary productivity (GPP), net primary productivity (NPP) and respiration (R). primary productivity (GPP), net primary productivity (NPP) and respiration (R).
GPP + R = NPP GPP + R = NPP GPP + NPP = R GPP + NPP = R GPP = NPP + R GPP = NPP + R GPP = NPP – R GPP = NPP – R (1) (1) (d)
(d) The tabThe table belole below showw shows the nes the net primat primary prory productivductivity in fity in four dour differifferent ecoent ecosystesystems. Tms. Thehe ecosystems in the table are listed in order of increasing distance from the equator, starting ecosystems in the table are listed in order of increasing distance from the equator, starting with tropical rainforest.
with tropical rainforest.
Ecosystem
Ecosystem Net primary productivityNet primary productivity / kJ m
/ kJ m –2 –2yearyear –1 –1 T
Trrooppiiccaal l rraaiinnffoorreesst t 337 7 880000 T
Teemmppeerraatte e ffoorreesst t 225 5 220000 B
Boorreeaal l ffoorreesst t 114 4 770000 P
(i)
(i) It is It is estimaestimated thted that 85at 85% of % of the ethe energy nergy availaavailable tble to pro primary imary consuconsumers mers will will not bnot bee available to secondary consumers. Calculate the energy that will be available to the available to secondary consumers. Calculate the energy that will be available to the secondary consumers in the
secondary consumers in the tropical rainforesttropical rainforest. Show your working.. Show your working.
Answer ... kJ m
Answer ... kJ m –2 –2year year –1 –1
(2) (2)
(i
(ii) i) SuSuggggesestt twotwo reasons for the differences in the net primary productivity as thereasons for the differences in the net primary productivity as the distance from the equator increases.
distance from the equator increases. ... ... ... ... ... ... ... ... ... ... ... ... (2) (2) (Total 13 marks) (Total 13 marks)
