The answers/markschemes are below each question in italics. You can reorganize the document so that you do not see the answer/markschemes answer/markschemes when you answer the questions.
1.
Seed dispersal is important in the migration of plants plants from one area to another area. Plants have evolved many methods, both physical and biological, by which to disperse their seeds. 50 maple seeds, which are wind dispersed, were dropped one at a time from two different heights, 0.54 m and 10.8 m respectively. The histograms below show the distribtion of the distance the maple seeds travelled. 18
18
1)
1!
$ e ig h t % 0 .5 4 m
15
14
1"
1"
10
10
# m b e r of seeds
5 4
4
*
*
"
"
$ e ig h t % 1 0 .8 m
1!
14
# m b e r 8 of seeds !
1)
1
0
(
8
)
! 4
5 4 *
*
"
1
1
0
& is t a n c e t r a v e ll e d ' cm
& is t a n c e t r a v e l le d ' m
+Sorce stdent e-periment, ralnic/
a2
3or each each heig height, ht, ident identify ify the the distanc distancee travell travelled ed by the the greate greatest st nmber nmber of of seeds. seeds. i2
$eight $eight % 0.54 0.54 m m ........... ................. ........... .......... .......... .......... .......... .......... .......... .......... ........... ........... .......... .......... .......... .......... .......... ....... ..
ii2
$eight $eight % 10.8 m ............ ................. .......... .......... .......... .......... .......... .......... .......... .......... ........... ........... .......... .......... .......... .......... .......... ....... .. (1)
b2 b2
State State the the eff effec ectt of hei heigh ghtt on seed seed dispe dispers rsal al.. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (1)
c 2
Sggest two reasons for the effect of the drop height on the distance travelled by the seeds. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. 1
(2)
2
The following graphs show the rate and timing of seed release from different species of grass in the same area dring the smmer. 100
100 F e s t u c a r u b r a
H o l c u s l a n a t u s
a te o f seed fall ' 50 n m b er 1 wee/ 1 0 0 c m "
a te o f seed fall ' 50 n m b er 1 wee/ 1 0 0 c m "
0
0 14
"1 "8
5
6ne
1"
1(
"!
"
6ly
1!
*0
14
7 g st
"1 "8
5
6ne
1"
1(
"!
"
6ly
1!
*0
7 g st
400 A g r o s t i s s t o l o n i f e r a
!00
P o a t r i v i a l i s *00
a te o f seed fall ' 400 n m b er w e e / 1 1 0 0 c m " " 0 0
a te o f seed fall ' n m b er "00 w e e / 1 1 0 0 c m " 1 0 0 0
0 14
"1 "8
6ne
5
1"
1(
6ly
"!
"
1!
7 g st
*0
14
"1 "8
5
6ne
1"
1(
6ly
"!
"
1!
*0
7 g st
+Sorce 6 $arper, Population $arper, Population Biology Biology of Plants, Plants, 7cademic 7cademic Press $arcort 9race 6ovanovich2 1((), page 5)
d2
:denti :dentify fy the the grass grass speci species es which which prod prodce cess the most most seeds seeds in this this area. area. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (1)
e2
:denti :dentify fy the the gras grasss specie speciess which which prodc prodces es the the most most seed seedss in 6ne. 6ne. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (1)
3
f2
;ompar ;omparee seed seed prodc prodctio tion n for all speci species es relat relative ive to to the timi timing ng of thei theirr releas release. e. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (3)
g2
Sggest two benefits for these plants in the timing ti ming of seed release. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (2)
4
9iological seed dispersal is sally dependent on the ntritional content of the seed or frit. The following table gives the ntritional content for frits of different species in temperate and tropical climates. Percentage by &ry
Protein
ipid
;arbohydrate
&ispersal 7gents
Temerate
;ranberry (Vaccinium)
*
!
8(
9irds
$awthorn (Crataegus)
"
"
)*
9irds
Pin cherry (Prunus)
8
*
84
9irds
Po/eberry (Phytolacca)
14
"
!8
9irds
Strawberry (Fragaria)
!
4
88
9irds
Troical
9ird palm (Chamaedorea)
14
1!
55
9irds
3ig (Ficus)
)
4
)(
9ats
=istletoe (Viscum)
!
5*
*8
9irds
=on/ey frit (etragastris)
1
4
(4
=on/eys
"
!*
(
9irds
+Sorce $ $owe and
-ford ?niversity Press 1(88, page 1"1
h2
;ompare ;ompare tropic tropical al frits frits to tempera temperate te frits frits in in relation relation to the the mean mean vales vales for lipid, carbohydrate and protein content. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (2)
5
i2 i2
@-pl @-plai ain n which which fr frit it wol wold d have have the the highe highest st ener energy gy con conte tent nt.. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (2)
A2
Sggest one advantage and one disadvantage of dispersal of seeds by animals. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (2) (Total 1! marks)
a2
height height 0.54 0.54 m m !0)( !0)( cm ' 0.!0 0.!00.) 0.)( ( m from from the plant2 plant2 and height 10.8 m 0".( m from the plant2B #nits needed for both parts of the ans$er% b2 b2 c2
the the grea greater ter the the heig height ht from from which which the the seed seed fel fell, l, the frther it travelled from the parent plant
1
1
at the greater height& seed can catch the wind to travel frther ' pdrafts ' more wind at greater heightB farther to the grond and does not travel straight down ' more time to be blown before hitting the grondB at lo$er height seed can fall straight downB seed can hit downdraft and fall fasterB Any point must e'plain the difference difference in distance travelled from the t$o heights%
" ma-
d2
Agrostis stolonifera
1
e2
Poa trivialis
1
f2
Poa prodces Poa prodces seed earliest in the smmer ' 6neB Holcus prodces Holcus prodces most seed in 6lyB prodce seed in late 6ly to2 7gstB Agrostis and Agrostis and Festuca Festuca prodce Holcus and Holcus and Poa Poa have have a pea/ time of seed fall ' short period of seed fallB Agrostis and Agrostis and Festuca Festuca may may contine to increase in seed prodction to SeptemberB Accept any of these points made conversely as an alternative alternative .
(g)
* ma-
A$ard [1] each each for any t$o of the follo$ing . to avoid predation 6
(h)
(i)
(2)
disperse at times $hen other species are dispersing their seeds to avoid competition late in the year to allo$ seeds to germinate over $inter better germination conditions better dispersal conditions more $ind animals for dispersal photoperiod * re+uired re+uired day length for flo$ering flo$ering more energy stored at the end of the summer for seed production more light $armth better conditions for seedling photosynthesis gro$th
ma'
A$ard [1] each each for any t$o of the follo$ing . tropical fruits have higher lipid content than temperate fruits temperate fruits (-./) have greater carbohydrate content than tropical fruits (00/) protein levels are similar in both groups of fruits slightly higher in temperate fruits than tropical fruits (must ma1e it clear that the difference is slight)
ma'
mistletoe high proportion of lipid and carbohydrate (lipid has appro'imately t$ice the energy content of protein and carbohydrate)
A$ard [1] for for advantage and [1] for for disadvantage . animal dispersal advantage& travel further digestion crac1s seed coat for better germination deposited in feces $ith organic matter better in areas $ith little $ind animal dispersal disadvantage& predation seeds eaten deposited deposited in poor environment buried too deep buried too shallo$ (if deposited $ith feces) animal might become e'tinct scarce
ma' [17]
2.
&escribe the metabolic events of germination in a starchy seed. (Total " marks)
absorption of $ater (embryo) increases respiration (embryo) secretes 3A to (aleurone layer) (stimulates) production of amylase digestion of starch to smaller sugars maltose mobili4e to tissues transport of foods nutrients to embryo
3.
arge air spaces
9.
arge nmbers of stom tomata
;.
$airs on the leaves
&.
edced roots
C 7
(Total 1 mark)
#.
The leaves of plants are adapted to absorb light and se it in photosynthesis. &raw a labelled diagram to show the arrangement of tisses in a leaf. (Total $ marks)
A$ard A$ard [1] for for each of the follo$ing structures, sho$n in the correct relative position and labelled% 5ndividual cells are not not needed but do not penali4e if they are are sho$n . pper epidermisB palisade layer ' mesophyllB spongy layer ' mesophyllB lower epidermisB -ylem in a maAor or minor vein2B phloem in a maAor or minor vein2B vein2B collenchyma in the midrib2B gard cellsB do do not accept stoma stomata only2 only 2 [6]
".
@-plain how maniplation of day length is sed in the prodction of flowers. ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ ........................................................... ......................................................................................... ............................................................ ...................................................... ........................ (Total $ marks)
8
some flowering plants are short-day plants; others are long-day plants; important variable is length of darkness / photoperiod; some plants grown in greenhouses with controlled light conditions; short-day plants kept in the dark during daylight hours; long-day plants artificially lit during the night; using an appropriate wavelength wavelength / far-red light / 730 nm; possible to expose expose only for brief brief periods to keep keep costs down but long enough to interrupt the dark period; involves interaction of phytochromes phytochromes with metabolic reactions; controlled by the plant’s biological clock; [6]
$.
lcosinolates are chemicals fond in some vegetables, which are responsible for the taste of horseradish, wasabi and broccoli. There are two types of glcosinolate, aliphatic and indolyl. They have been fond to have many positive health effects, inclding carcinogen deto-ification and antio-idant properties. &ifferent varieties of broccoli vary in their content of glcosinolates as shown in the graph below. esearchers have fond that !1D of the variation in aliphatic glcosinolate concentration is de to genetic factors compared with 1"D for indolyl glcosinolates. % ey&
"5
p r o g o i t r i n a l i p h a t i c 2 g l c o r a p h a n in a lip h a ti c 2 g l c o b r a s s i c in in d o l y l 2
"0 l c o s in o la te 15 c o n c e n t r a ti o n ' m o l g 1 d r y m a s s 10 5 0
9 rig a d ie r
Pac/m an
Petro
E a r ie t y o f b r o c c o l i +Sorce @ $ 6effery et al ., 6utrition ., 6utrition oday oday,, "00"2, 3!, page "082
a2
?sing the graph, graph, compa compare re the the amont amont of aliphatic aliphatic glcosinola glcosinolates tes among the different different varieties of broccoli. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. .............
9
.......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (3)
b2
?sing ?sing the data, data, e-pla e-plain in how how otbree otbreedin ding g cold cold be sed sed to deve develop lop a new new variety variety of of broccoli with increased glcosinolate content. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (3) (Total $ marks)
(a)
in Brigadier Brigadier and and Pac1man, Pac1man, glucoraphan glucoraphanin in higher higher in concen concentratio tration n than than progoitri progoitrin n progoitrin appro'imately appro'imately e+ual in Pac1man and Brigadier greatest greatest in Petro Petro Brigadier has highest total glucosinolate concentration Brigadier has highest glucorphanin concentration Pac1man has lo$est total glucosinolate concentration concentration Pac1man has lo$est glucorphanin concentration concentration 7 ma'
(b)
(outbr (outbree eedin ding g is) repr reprod oduct uction ion invol involving ving fusi fusion on of gamet gametes es produc produced ed by genetically unrelated individuals individuals can increase aliphatic glucosinolate concentration because more variation is due to genetic factors Brigadier and Petro have more aliphatic glucosinolates cross Brigadier $ith Petro Pet ro because because Brigadier Brigadier has more more glucorap glucoraphinin hinin and Petro Petro has has more more progo progoitrin itrin
7 ma' [6]
!.
7n e-periment was carried ot to investigate the effect of water stress on ccmber Cucumis Cucumis sativus2 sativus2 seedlings. ;otyledons were detached from for day old seedlings and treated with polyethylene glycol P@2, a water absorbing compond. compond. β Famylase Famylase activity was measred in cotyledons treated with P@ at concentrations of 0, "0, *0, 40 and 50D. This enGyme catalyses the conversion of starch into maltose. The mean reslts are shown in the graph.
10
0 .*
8 F a m y l a s e a c t i v i t y p e r p a i r o f c o t y l e d o n s ' H m o l m a l t o s e m i n 1
0 ."
0 .1
0 0
1
"
*
& r a tio n o f tr e a tm e n t ' d a y s +Sorce & Toda/, et al ., ., "0002, 9ournal "0002, 9ournal of of !'perimental !'perimental Botany, Botany, 51, pages )*()45
a2 a2
:den :denti tify fy the the mama-im imm m acti activi vity ty of β Famylase Famylase in the 50D treatment. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (1)
b2
;ompare the β Famylase Famylase activity in the cotyledons treated with "0D P@ wit h those treated with *0D P@. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (2)
c2
&edce &edce the the relative relative free free sgar sgar conte content nt of the the cotyled cotyledons ons treate treated d with "0D "0D P@ compar compared ed to those treated with *0D P@. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (1)
11
d2 d2
Sgg Sggest est reas reason onss for for the the chan change ge in in acti activi vity ty of of β Famylase Famylase dring water stress. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (2) (Total 6 marks)
(a)
*;
.%: (± .%.;) .%.;) µ mol mol maltose min (u ( units needed)
;
(b)
no substa substanti ntial al incre increase ase in acti activit vityy in the ./ ./ trea treatme tment nt over over the five five days days of the the e'periment 7./ sample reaches ma'imum activity t$o days after start of treatment higher level of activity at all times for f or 7./ treatment compared $ith ./ treatment activity appro'imately si' times higher for 7./ treatment than for ./ . / treatment on day t$o any other appropriate numerical e'ample ma'
(c)
7./ treatm treatment ent $ill $ill have have gre greate aterr amount amount of of free free sugar sugarss (malto (maltose) se) than than ./ treatment
(d) (d)
;
$ate $aterr stres stresss $ill $ill trig trigge gerr synth synthesi esiss of pro proteins teins β
'.
?se and conservation preferences for savanna trees were investigated i nvestigated in a
1
1
"
5
0
5
0
0
0
0
0
0
1
1
"
5
0
5
0
0
0
0
0
0
1
1
"
5
0
5
0
0
0
0
0
0
1
1
"
5
0
5
0
0
0
0
0
0
1
1
"
5
0
5
0
0
0
0
0
0
1
1
"
5
0
5
0
0
0
0
0
0
1
1
"
5
0
5
0
0
0
0
0
0
1
1
"
5
0
5
0
0
0
0
0
A d a n s o n i a d i g i t a t a A t 4 e l i a a f r i c a n a A n n o n a s e n e g a l e n s i s B a l a n i t e s 4 e g y p t i a c a B o m b a ' c o s t a t u m = e t a r i u m m i c r o c a r p u m = i o s p y r o s m e s p i l i f o r m i s F i c u s s y c o m o r u s 3 a r d e n ia e r u b e s c e n s > a n n e a m i c r o c a r p u m P a r 1 i a b i g l o b o s a P e r i c o p s i s t a ' i f l o r a P i l i o s t i g m a t h o n n i n g i i P l e r o c a r p u s e r i n a c e u s ? t e r c u l i a s e t ig e r a ?trychno s spinosa a r n a r i n d u s in d i c a V i te l la r i a p a r a d o ' a V i te ' t d o n i a n a @ i m e n i a a f r i c a n a @dible frits
% ey&
do not /now
Eegetable sace
; on s tr c tio n
n o t im p o rta n t
3 ire w oo d
= e d ic in e
; om m er c e
m o d e r a te ly im p o r ta n t
3ield trees
; on s e r v a tio n p r i o r i t y
v e r y im p o r ta n t
12
+Sorce !conomic +Sorce !conomic BotanyB BotanyB Iristensen and y//e, reprinted by permission from !conomic Botany, Botany, vol. 5) 22, pages "0*"1), Iristensen and y//e. ;opyright "00*, The #ewJor/ 9otanical arden, 9ron-, #ew Jor/
a2
:denti :dentify fy the most most impor importan tantt tree tree spec species ies to the the vill village agers. rs. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (1)
b2
State State the categ category ory of of se for whic which h village villagers rs have have most diff difficl iclty ty in findin finding g sefl sefl species. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (1)
13
c2
;ompar ;omparee the sefl seflnes nesss of species species in provi providin ding g edible edible frit frit with their their sef seflne lness ss for vegetable sace. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (2)
d2
&eterm &etermine ine the percen percentag tagee of of spec species ies that that are are val valed ed entirely as Kvery importantL in at least three categories. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (1)
e2 e2
Sgg Sgges estt a pro prope pert rty y of of the the wood wood from from P% P% erinaceus that erinaceus that ma/es it one of the preferred species for se in bilding hoses. .......................................................... ........................................................................................ .............................................................. ............................................. ............. .......................................................... ........................................................................................ .............................................................. ............................................. ............. (1) (Total $ marks)
(a)
Vitellaria parado'a
;
(b)
construction
;
(c)
7 specie speciess A% digi digitata tata,, P% P% biglob biglobosa osa,, V% V% donian doniana a very important in both categories ;. species ran1ed very important for edible fruits and species for vegetable sauce overall the . tree species $ere slightly more valuable for edible fruits than for vegetable sauce @imenia africana more useful as edible fruit but not as vegetable sauce vice versa for Bomba' costatum in both categories there $ere no do not 1no$ responses
* (d)
"0
×
100 = 15D
=o not need to sho$ $or1ing (e)
ma'
;
strength resistance to insect attac1 eg termites attractiveness 14
resistant to decay fle'ible not too heavy easy to cut tradition
; ma' [6]
.
:n order to prevent transfer of pollen from an anther of one plant to the stigma of the same plant selfFpollination2, the snflower Helianthus spp2 spp2 anther sheds its pollen before the stigma is matre enogh to receive it. @arly in the morning the anther is e-posed by elongation of the filaments. The anthers open at this time to release their pollen anthesis2. The stigma appears above the anthers by late afternoon, and by the following morning it is flly receptive. To see how the filament 32 and the style S2 are affected by light, their lengths were measred at time intervals starting 1" hors before anthesis −1"2. Some plants were grown in continos white light "42 and some plants grown nder cycles of 1! hors white light followed by 8 hors dar/ 1!'&82. The reslts are shown in the graph.
+Sorce obello et al, 9ournal of !'perimental Botany , "0002, "1, pages 140*−141"
a2
3ilame 3ilaments nts of the the plant plantss grown grown in conti contino nos s white white light light incr increase eased d in length length by 0."5 0."5 mm in the "8 hors after anthesis. ;alclate how mch the filaments of the plants grown in alternating white light and dar/ increased dring the same period.
15
.......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ (1)
b2
;ompare ;ompare the the increa increase se in the length of the the style style in the plants grown in contino continos s white white light with those grown in alternating white light and dar/. .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ (2)
The table compares the percentage of ovles that have been fertiliGed and developed into seeds in snflower plants grown nder continos white light with those grown nder alternating light and dar/. The nmbers represent the mean ± one standard deviation.
c2
ight treatments
*ercentage o+ +ertilized o,ules
;ontinos white light "42
11.40 ± ).)!
7lternating light and dar/ 1!'&82
58."! ± 4.0!
@-plain @-plain the the differen differences ces in the the percenta percentages ges of ovles ovles fertiliGed fertiliGed sing the data data in the the graph graph abot the growth of filaments and styles. .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ (3)
16
d2
@-plai @-plain n how stan standar dard d deviat deviation ion S&2 S&2 show shown n in this this table table can can be sed sed to help help in comparing the effect of light treatments on the fertiliGation of ovles. .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ (3)
To analyse analyse the effect of growth reglators on filament elongation, frther e-periments were performed in the dar/, white light light and red light. The flowers were treated with a-in or with gibberellic acid and compared to a control with no growth reglator. The reslts are shown in the bar chart below.
17
e2
:dentify :dentify,, with with reasons reasons,, which which factors factors promote promote and and which which factors factors inhibit inhibit the elongation elongation of filaments. .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ (3)
f2
@-plai @-plain n the the disadv disadvant antage agess to to a plan plantt of of self selfFpo Fpolli llinat nation ion.. .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ (2) (Total 1# marks)
(a)
%: ( ± .% .%) mm (units re+uired)
;
(b)
cyclic cyclic light light ma1e ma1ess style style gro$ gro$ almo almost st immedi immediate ately ly $hile $hile $ith $ith cont continu inuous ous light it ta1es longer to start to gro$ >; =- starts gro$ing in first hour $hile >D style starts gro$ing after hours gro$th is more gradual in >D $ith continuous light the style gro$s less continuous (>D) gro$s to :%- mm $hile cyclic (>; =-) gro$s to ;.% mm little difference after - hours in both cases gro$th only starts $ith anthesis ma'
(c) (c)
D/ more more ferti fertili li4ed 4ed ovul ovules es in in cyc cycli licc ligh light t filament gro$s more in cyclic light than continuous pollen closer to stigma so pollination more probable in continuous light anthers do not become e'posed Accept converse $ording% $ording%
(d)
(e)
standa standard rd devi deviati ation on is a measu measure re of of variab variabilit ilityy indicate indicatess the spre spread ad of values around the mean continuous light data is more variable (because it has a higher standard deviation) helps to decide $hether the difference bet$een t$o means is significant -/ of values are ; ?= from mean difference bet$een means is appro'imately D appears t o be significantly different light treatment ma1es a significant difference
7 ma'
7 ma'
dar1ne dar1ness ss prom promote otess $hite $hite light light inhib inhibits its beca because use fila filamen ments ts shorter shorter than than in in dar1ness red light inhibits because filaments shorter than in dar1ness au'ins promote because filaments are longer than in control in $hite and red light
18
gibberellic acid inhibits because because filaments are shorter in continuous $hite light dar1ness 7 ma' "eason must be present to receive receive the mar1% Accept if converse converse $ording% (f)
self
ma' [14]
1-.
Sweet pepper Capsicum Capsicum annuum2 annuum 2 is an important widespread agricltral crop. Scientists stdied the transport and distribtion of sodim in sweet pepper by growing plants in sodim chloride soltions. The graph below shows the sodim ion concentration in plant parts of sweet pepper grown in 15 m= sodim chloride for three wee/s. *0 "8 "! "4 "" "0 18 S o d i m io n c o n c e n t ra tio n ' m = / g 1
1! 14 1" 10 8 ! 4 " 0 oot
eaves
3 r it
S te m
P la n t P a r t +Sorce = 9lomFMandstra 9lomFMandstra et% al ., ., KSodim fl-es in sweet pepper e-posed to varying sodim concentrationsL, 9ournal of of !'perimental !'perimental Botany 1 #ovember 1((82, vol. 4(, isse *"8, pp. 18!*18!8, by permission permission of >-ford ?niversity Press Press
a2 a2
i2 i2
Stat Statee the the conc concen entr trat atio ion n of sod sodim im ions ions in fr frits. its. ......................................................... ......................................................................................... .............................................................. .................................. .... (1)
19
ii2 ii2
;alcl ;alclate ate the perce percenta ntage ge increas increasee in sodim sodim ion concen concentra tration tion betwe between en root root and stem. ......................................................... ......................................................................................... .............................................................. .................................. .... (1)
20
b2
Sggest Sggest why why a high high sodim sodim ion ion concen concentra tration tion in in the cells cells of the the stem stem is impor importan tantt in providing spport to this type of plant. plant. .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ (1)
c 2
State one possible se of sodim in plants. .......................................................... ........................................................................................ .............................................................. ............................................ ............ (1)
d2
Scientists Scientists also also fond fond that the concen concentratio trations ns of of sodim sodim ion in in cells cells of the stem and and in in -ylem sap were the same. @-plain why this led the scientists to believe there was no active transport between -ylem and stem. .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ (2)
e 2
Sggest one possible method of transport of sodim ions between -ylem and stem. .......................................................... ........................................................................................ .............................................................. ............................................ ............ (1)
21
The graph below shows the sodim ion concentration of the -ylem sap in relation to the distance from the base. Two e-periments were performed. @-periment @-periment 1 plants grown grown in in 15 m= m= sodim chloride chloride soltion soltion only @-periment @-periment " plants grown grown in 15 m= sodim sodim chloride chloride soltion soltion and and then transferr transferred ed to a sodimFfree soltion for an e-tra wee/ % ey&
e - p e rim e n t 1
e - p e rim e n t "
18 1! 14 1" 10
S o d i m i o n c o n c e n t r a ti o n ' m =
8 ! 4 " 0
40
!0
80
100
1"0
140
& is ta n c e f ro m b a s e ' a r b i t r a ry n i ts +Sorce = 9lomFMandstra 9lomFMandstra et% al ., ., KSodim fl-es in sweet pepper e-posed to varying sodim concentrationsL, 9ournal of of !'perimental !'perimental Botany 1 #ovember 1((82, vol. 4(, isse *"8, pp. 18!*18!8, by permission permission of >-ford ?niversity Press Press
f2
State State the rela relation tionshi ship p between between sodi sodim m ion conce concentr ntrati ation on and and distanc distancee from the the base base of the the stem in e-periment 1. .......................................................... ........................................................................................ .............................................................. ............................................ ............ (1)
g2 g2
i2 i2
State State the the sod sodim im conc concen entr trat atio ion n whe when n the the stem stem is 50 arbi arbitr trary ary nits nits from from the the base base in plants for each of the following. @-periment 1 .......................................................... ........................................................................................ ....................................... ......... @-periment " .......................................................... ........................................................................................ ....................................... ......... (1)
22
ii2
@-plain @-plain the the differ difference ence in the the sodim sodim ion ion concent concentration ration in this this part part of of the the stem in plants of e-periment 1 and e-periment e-periment ". ......................................................... ......................................................................................... .............................................................. .................................. .... ......................................................... ......................................................................................... .............................................................. .................................. .... ......................................................... ......................................................................................... .............................................................. .................................. .... ......................................................... ......................................................................................... .............................................................. .................................. .... (2)
h2
;ompar ;omparee the distr distrib ibtio tion n of sodim sodim ions ions in the the stems stems of plants plants in both both e-per e-perime iments nts.. .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ (3)
+Sorce ;ortesy of Professor Mlma @ Ngolo, 5nstituto =ar$inion =ar$inion,, 9enos 7ires, 7rgentina
i2 i2
i2 i2
&raw &raw a lin linee sho showi wing ng the ma-im a-imm m leng length th of th the sto stom matal atal pore pore.. (1)
23
ii2 ii2
;alcl ;alclate ate the the real real siGe siGe of of the the stomat stomatal al pore. pore. Show Show yor yor wor/ wor/ing ing.. ......................................................... ......................................................................................... .............................................................. .................................. .... (1)
A2
@-plain two abiotic factors that affect transpiration rate in this leaf. .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ .......................................................... ........................................................................................ .............................................................. ............................................ ............ (2) (Total 1' marks)
(a)
(i)
;
mE 1g
(units re+uired)
;
"8 − 102 × 100 (ii)
;-. (% ) or
10
(b) (b)
cell cellss in stem stem abso absorb rb $ate $aterr (by (by osm osmos osis is)) prov provid idin ing g turg turgid idit ityy turg turgor or pres pressu surre
(c)
main mainta tain in osmo osmoti ticc ba balanc lance e help to maintain turgidity assist active transport
(d)
; ; ; ma'
active active trans transpor portt means means movem movement ent aga against inst a conc concent entrat ration ion grad gradien ient t there is no concentration gradient concentration in 'ylem should be lo$er than stem (but it is not)
(e)
diffusion facilitated diffusion
;
(f)
sodium sodium ion concen concentra tration tion decre decrease asess as you get furthe furtherr a$ay a$ay fro from m the the base vice versa
;
(g)
(i)
e'periment ;& ;mE e'periment & mE
;
Both ans$ers must be correct to receive receive [1] . (ii)
(h)
in e'perim e'periment ent ; (conc (concent entrat ration ion of of sodium sodium ions ions is high high becaus because) e) sodium sodium is continually ta1en up it is lo$er in e'periment because sodium is lost by diffusion into medium ($hen no sodium in medium) in e'periment there is more $ater upta1e (by osmosis) ma'
sodium sodium ion ion conc concent entrat ration ion in e'per e'perimen imentt ; is high higher er close close to base base (moving a$ay from base) sodium ion concentration decreases in e'periment ; but remains constant decreases slightly in e'periment sodium ion concentration rises in e'periment after ;.. arbitrary units but continues to decline in e'periment ; same sodium ion concentration in both e'periments at ;.0 arbitrary arbitrary units lo$er sodium ion concentration in e'periment ; compared $ith e'periment $hen close to the top far from base 7 ma' 24
(i)
(i)
;
A$ard A$ard mar1 if line dra$n off the image but it must be ;( ± ; ±;) ) mm% (ii) (ii)
real eal si4 si4ee G len lengt gth h of of line line dra$ dra$n n ÷ 7... 7... G .%..( ± ±. %...0)mm
;
#nits are re+uired, allo$ for !CF% Also Also accept ans$er in cm% (2)
humidi humidity ty decre decrease asess transp transpira iration tion rate becaus becausee atmosp atmospher heree is satu saturat rated ed temperature increases transpiration rate because there is more 1inetic energy light increases photosynthesis $hich opens stomata increasing the rate of transpiration $ind air movement lo$ers concentration outside leaf ma' [18]
25
