IB Biology textbook

11 The enzyme aspartate carbomoyltransferase (ACTase) is a key regulatory enzyme in nucleotide metabolism
in bacteria.The activity of this enzyme was studied in the bacterium Helicobacter pylori, an important human
pathogen.ACTase activity and the growth of H. pylori were measured at different concentrations of carbomoyl
aspartate (CAA), the end product of the reaction catalysed by ACTase.

@Zn
&%% &%% 68IVhZ VXi^k^in

>$ fobeh_ \gdli]

,* ,*
68IVhZ VXi^k^in$ d[ Xdcigda
<gdli]$ d[ Xdcigda
*% *%

'* '*

%%
% &% '% (% )% *% +%
8dcXZcigVi^dc d[ XVgWVbdna VheVgiViZ $ bbda YbÄ(

hdjgXZ/ 7jgch! [j Wb#! 8_ebe]_YWb FheY[Zkh[i Edb_d[! &..- !
]iiee/$$lll#W^dad\^XVaegdXZYjgZh#Xdb

a i State the growth of H. pylori at a CAA concentration of 30 mmol dm–3. (1)
ii Calculate the change in ACTase activity between CAA concentrations of 20 and 40 mmol dm–3. (1)

b Compare the effect of increasing CAA concentration on the growth of H. pylori and ACTase activity. (2)

c Explain the effect of CAA on ACTase activity. (2)

d Suggest a direct medical application of this information. (1)

(total 7 marks)
© IB Organization 2009

, CJ8A:>8 68>9H 6C9 EGDI:>CH &.(

- 8Zaa gZhe^gVi^dc VcY e]didhnci]Zh^h

Notation in biochemical >cigdYjXi^dc
pathways
Respiration and photosynthesis are two key biochemical
Photosynthesis and respiration pathways in ecosystems. Light energy from the Sun is trapped
involve large organic molecules. as chemical energy in photosynthesis and then the energy
For simplicity, these are often is transferred through food chains and released back to
identified by the number of the environment as heat energy from respiration.The two
carbon atoms they contain.Thus pathways can be simply written as:
glucose, C6H12O6, is simplified to
C6.A biochemical pathway may photosynthesis
be written as C3 n C3 so that
nothing appears to have happened 6CO2 + 6H2O + energy C6H12O6 + 6O2
but the number of oxygen and/or
hydrogen atoms in the second C3 respiration
molecule will have changed. Both
photosynthesis and respiration There are a number of similarities between the two pathways,
have linear and cyclic components which will be examined in this chapter.The basics of
in their pathways. Many of photosynthesis and respiration are covered in Chapter 3, and it
the compounds involved are would be useful to review this chapter before proceeding.
abbreviated to their initials.
-#& 8Zaa gZhe^gVi^dc

6hhZhhbZci hiViZbZcih

r State that oxidation involves the loss of electrons from an element, whereas reduction involves a gain of electrons; and

that oxidation frequently involves gaining oxygen or losing hydrogen, whereas reduction frequently involves losing
oxygen or gaining hydrogen.

r Outline the process of glycolysis, including phosphorylation, lysis, oxidation and ATP formation.
r Draw and label a diagram showing the structure of a mitochondrion as seen in electron micrographs.
r Explain aerobic respiration, including the link reaction, the Krebs cycle, the role of NADH + H+, the electron

transport chain and the role of oxygen.

r Explain oxidative phosphorylation in terms of chemiosmosis.
r Explain the relationship between the structure of the mitochondrion and its function.

gZYjXZY dm^Y^hZY Dm^YVi^dc VcY gZYjXi^dc
bdaZXjaZ & bdaZXjaZ '
Cell respiration involves several oxidation and reduction reactions. Such
dm^Y^hZY gZYjXZY reactions are common in biochemical pathways.When two molecules react,
bdaZXjaZ & bdaZXjaZ ' one of them starts in the oxidised state and becomes reduced, and the other
starts in the reduced state and becomes oxidised, as shown in Figure 8.1.
;^\jgZ -#& Dm^YVi^dc VcY gZYjXi^dc VgZ
a^c`ZY egdXZhhZh Ä Vh dcZ bdaZXjaZ ^h There are three different ways in which a molecule can be oxidised
gZYjXZY Vcdi]Zg ^h dm^Y^hZY ^c V gZYdm or reduced, as outlined in Table 8.1. In biological oxidation reactions,
gZVXi^dc# addition of oxygen atoms is an alternative to removal of hydrogen atoms.
Since a hydrogen atom consists of an electron and a proton, losing
hydrogen atoms (oxidation) involves losing one or more electrons.

&.)

Oxidation and reduction occur together in biochemical reactions.As Dm^YVi^dc GZYjXi^dc
one compound loses electrons, for example, another gains. In the simple
equation for respiration, glucose is oxidised as hydrogen atoms, and adhh d[ ZaZXigdch \V^c d[ ZaZXigdch
therefore electrons, are gradually removed from it and added to hydrogen adhh d[ ]nYgd\Zc \V^c d[ ]nYgd\Zc
acceptors (the oxygen atoms on the left side of the equation), which \V^c d[ dmn\Zc adhh d[ dmn\Zc
become reduced.
IVWaZ -#& 8]Vc\Zh ^ckdakZY ^c dm^YVi^dc VcY
C6H12O6 + 6O2 n 6CO2 + 6H2O + energy gZYjXi^dc#

Chemical reactions like this are referred to as redox reactions. In redox An easy way to remember
reactions, the reduced molecule always has more potential energy than the oxidation and reduction is to think
oxidised form of the molecule. Electrons passing from one molecule to of the words OIL RIG:
another carry energy with them.
OIL = Oxidation Is Loss (of
GZhe^gVi^dc electrons)

Cell respiration is the controlled breakdown of food molecules such RIG = Reduction Is Gain (of
as glucose or fat to release energy, which can be stored for later use.The electrons)
energy is most commonly stored in the molecule adenosine triphosphate,
or ATP. The respiration pathway can be divided into four parts: Bisphosphate and diphosphate

r glycolysis Although both these molecules
r link reaction contain two phosphate groups,
r Krebs cycle the phosphates are joined in
r electron transfer chain and chemiosmosis. different ways. In a diphosphate
molecule such as ADP, the two
<anXdanh^h phosphates are joined to each
other; in a bisphosphate molecule
Glycolysis is the first stage in the series of reactions that make up such as hexose bisphosphate, each
respiration. It literally means ‘breaking apart glucose’.The glycolysis phosphate is joined to a different
pathway occurs in the cytoplasm of the cell. It is anaerobic (that is, it can part of the hexose molecule.
proceed in the absence of oxygen) and produces pyruvate and a small
amount of ATP. One molecule of the hexose sugar glucose is converted to NAD+ is a hydrogen carrier that
two molecules of the three-carbon molecule called pyruvate with the net accepts hydrogen atoms removed
gain of two molecules of ATP and two molecules of NADH + H+.The during the reactions of respiration.
process is shown in detail in Figure 8.2 (overleaf ). During glycolysis, two hydrogen
1 The first steps are to add two phosphate groups from ATP, in a process atoms are removed and NAD+
accepts the protons from one of
called phosphorylation.A hexose bisphosphate molecule is produced. them and the electrons from both
(This appears contrary to the purpose of respiration, which is to make of them.
ATP, but the two lost ATPs are recovered later.)
2 The hexose bisphosphate is now split into two triose phosphates in a NAD++ 2H n NADH + H+
reaction called lysis. Note that NADH + H+ must be
3 Now, another phosphorylation takes place but this time an inorganic written in this way and should not
phosphate ion, Pi, is used and not ATP.Two triose bisphosphates are be simplified to NADH2.
formed.The energy to add the Pi comes from an oxidation reaction.
The triose bisphosphate is oxidised and at the same time NAD+ is
reduced to NADH + H+.
4 There now follows a series of reactions in which the two phosphate
groups from each triose bisphosphate are transferred onto two
molecules of ADP, to form two molecules of ATP – this is ATP
formation.A pyruvate molecule is also produced.

- 8:AA G:HE>G6I>DC 6C9 E=DIDHNCI=:H>H &.*

& E]dhe]dgnaVi^dc \ajXdhZ gZaVi^kZan jcgZVXi^kZ \ajXdhZ ^h
888888 VXi^kViZY Wn gZVXi^dc l^i] 6IE

' 6IE

' Anh^h e]dhe]dgnaViZY +"XVgWdc hj\Vg
]ZmdhZ W^he]dhe]ViZ
888888
EE

e]dhe]dgnaViZY +"XVgWdc
hj\Vg hea^ih id [dgb ild ("
XVgWdc hj\Vg e]dhe]ViZh

' ("XVgWdc hj\Vg e]dhe]ViZ
' ig^dhZ e]dhe]ViZ

888 888
E E

( Dm^YVi^dc E^ E^ ' C69
) 6IE [dgbVi^dc ' C69= =
888 888 :cZg\n
EE EE ) 6IE gZaZVhZY Vh
]nYgd\Zc ^h
igVch[ZggZY id
i]Z ]nYgd\Zc
VXXZeidg VcY
jhZY id [dgb
6IE bdaZXjaZh#

' engjkViZ ("XVgWdc hj\Vg
e]dhe]ViZ bdaZXjaZh VgZ
888 888 XdckZgiZY id engjkViZ

;^\jgZ -#' I]Z hiV\Zh d[ \anXdanh^h# CdiZ i]Vi [dg ZVX] bdaZXjaZ d[ \ajXdhZ! ild
bdaZXjaZh d[ 6IE VgZ jhZY VcY [djg VgZ [dgbZY! hd i]ZgZ ^h V cZi \V^c d[ ild 6IEh#

Four molecules of ATP are formed by converting one molecule of
glucose to two molecules of pyruvate. However, two molecules of ATP
were required to start the pathway and so there is a net gain of two
molecules of ATP per glucose. In addition two NADH + H+ are formed.

To summarise, the net products of glycolysis per glucose molecule are:

r 2 ATP
r 2 NADH + H+
r 2 molecules of pyruvate.

& A^hi i]gZZ lVnh ^c l]^X] V hjWhiVcXZ XVc WZ gZYjXZY#

' L]Vi bdaZXjaZ ^h jhZY id e]dhe]dgnaViZ \ajXdhZ Vi i]Z hiVgi d[ \anXdanh^h4

( HiViZ i]Z cVbZ d[ i]Z egdXZhh i]Vi hea^ih i]Z ]ZmdhZ W^he]dhe]ViZ
bdaZXjaZ ^cid ild ig^dhZ e]dhe]ViZ bdaZXjaZh#

) L]Vi ^h jhZY id e]dhe]dgnaViZ ZVX] ig^dhZ e]dhe]ViZ bdaZXjaZ [daadl^c\
i]Z VWdkZ gZVXi^dc4

* >c i]Z \anXdanh^h eVi]lVn! l]^X] bdaZXjaZ ^h dm^Y^hZY Yjg^c\ Vc
dm^YVi^dc$gZYjXi^dc gZVXi^dc4

+ L]Vi ^h i]Z cZi \V^c d[ 6IE [gdb \anXdanh^h eZg \ajXdhZ bdaZXjaZ4

&.+

I]Z a^c` gZVXi^dc VcY @gZWh XnXaZ

If oxygen is present, pyruvate formed during glycolysis moves into
the mitochondrial matrix by facilitated diffusion.The structure of a
mitochondrion is shown in Figures 8.3 and 8.4.

djiZg ^ciZg"bZbWgVcZ bVig^m Xg^hiV ^ccZg
bZbWgVcZ heVXZ g^WdhdbZ bZbWgVcZ

;^\jgZ -#( :aZXigdc b^Xgd\gVe] d[ V b^idX]dcYg^dc ,' %%% #

I]Z [aj^Y bVig^m XdciV^ch i]Z I]Z ^ccZg bZbWgVcZ ^h [daYZY id Increasing area
ZconbZh gZfj^gZY [dg i]Z a^c` [dgb Xg^hiVZ! l]^X] ^cXgZVhZ i]Z
gZVXi^dc VcY @gZWh XnXaZ# hjg[VXZ VgZV [dg gZVXi^dch# I]^h Just as the inner lining of the small
bZbWgVcZ XdciV^ch i]Z egdiZ^ch intestine is folded to increase its
cZZYZY [dg i]Z ZaZXigdc igVch[Zg surface area to absorb food, so the
X]V^c VcY Vahd 6IE hnci]VhZ# inner mitochondrial membrane is
folded into cristae to increase its
Xg^hiVZ g^WdhdbZ surface area.The cristae provide
a large area for the enzymes and
6IEVhZ molecules used in the electron
transport chain (see page 199).
I]Z djiZg bZbWgVcZ I]Z heVXZ WZilZZc i]Z ^ccZg VcY djiZg bZbWgVcZh!
ZcXadhZh i]Z b^idX]dcYg^dc `cdlc Vh i]Z ^ciZg"bZbWgVcZ heVXZ! ^h ^bedgiVci ^c
VcY `ZZeh ^i hZeVgViZ [gdb X]Zb^dhbdh^h Vh ^i ^h hbVaa VcY ZcVWaZh V ]^\]
i]Z XnideaVhb# XdcXZcigVi^dc d[ egdidch id VXXjbjaViZ#

;^\jgZ -#) 9^V\gVb d[ V b^idX]dcYg^dc ^c adc\^ijY^cVa hZXi^dc#

The link reaction and the Krebs cycle pathways occur in the
mitochondrial matrix, shown in Figure 8.5 (overleaf ).
1 The link reaction converts pyruvate to acetyl CoA using

coenzyme A, and a carbon atom is removed as carbon dioxide.This is
called a decarboxylation reaction.At the same time as the carbon
dioxide is removed, pyruvate is oxidised by the removal of hydrogen.The
hydrogen atoms are removed by NAD+ to form NADH + H+.

- 8:AA G:HE>G6I>DC 6C9 E=DIDHNCI=:H>H &.,

[VX^a^iViZY Y^[[jh^dc
[gdb i]Z XnideaVhb

i]Z a^c` gZVXi^dc engjkViZ C69 & 9ZXVgWdmnaVi^dc
8D' 888 C69= = VcY dm^YVi^dc
gZVXi^dch
VXZina 8d6 XdZconbZ 6
88

, 8nXaZ WZ\^ch XdZconbZ 6 ' 8dZconbZ 6 ^h
V\V^c gZXnXaZY

)"XVgWdc VX^Y
8888

X^igViZ
888888

C69= =

+ Dm^YVi^dc C69 @gZWh
gZVXi^dch XnXaZ
Vahd `cdlc Vh i]Z X^ig^X VX^Y XnXaZ
;69=' C69

* 6IE ;69 )"XVgWdc VX^Y C69= = ( 9ZXVgWdmnaVi^dc
[dgbVi^dc 6IE 8888 8D' VcY dm^YVi^dc
gZVXi^dch
69E E^ 8D'
*"XVgWdc VX^Y
88888

) 9ZXVgWdmnaVi^dc C69= =
VcY dm^YVi^dc C69
gZVXi^dch

;^\jgZ -#* I]Z a^c` gZVXi^dc VcY @gZWh XnXaZ#

2 Acetyl CoA now enters the Krebs cycle to continue the processes
of aerobic respiration. Immediately, the coenzyme A is removed to be
recycled.

3 The two carbons that enter with acetyl CoA also leave as carbon
dioxide from two decarboxylation reactions.

4 One molecule of ATP is formed.
5 Hydrogen is removed during oxidation reactions to the two hydrogen

carriers NAD+ and FAD+.
6 Since the Krebs cycle is a cyclic process, what enters must eventually

leave so that the cycle begins and ends with the same substances.
Because each molecule of glucose forms two molecules of pyruvate
during glycolysis, each glucose molecule requires two link reactions and
two rotations of the Krebs cycle.Thus, when working out the products

&.-

of the cycle we must consider two sets of products. So, to summarise, the Note that the correct method to
products of the link reaction and Krebs cycle, per glucose molecule, are: show reduced FAD is FADH2.

r 8 molecules of NADH + H+
r 2 molecules of FADH2
r 2 molecules of ATP
r 6 molecules of CO2.

I]Z ZaZXigdc igVchedgi X]V^c! dm^YVi^kZ e]dhe]dgnaVi^dc VcY
X]Zb^dhbdh^h

Most of the ATP produced from glucose breakdown occurs in the
last phase of respiration at the end of the electron transport chain.
Reactions take place on the inner mitochondrial membrane of the
cristae and in the inter-membrane space between the inner and outer
membranes.The inner membrane holds molecules called electron
carriers, which pick up electrons and pass them from one to another in
a series of oxidations and reductions.The pathway is called the electron
transport chain (ETC) because electrons from hydrogen are moved along
it. Several protein molecules are electron carriers and the three key ones
are shown in Figure 8.6.

Electrons from NADH + H+ are transferred onto the first electron
carrier.As they pass through the carrier, they lose energy and this is used
to pump a proton (H+) from the matrix to the inter-membrane space,
lowering the pH of the space.The electrons are then transferred to two
further carriers and the process is repeated.As the electrons from one
NADH + H+ pass along the chain, a total of nine protons are pumped

Xnidhda d[ XZaa egdidc XnidX]gdbZ
ejbeh dm^YVhZ

djiZg ]nYgd\Zc ^dch
b^idX]dcYg^Va egdidch VXXjbjaViZ
bZbWgVcZ = = = = = ==== = ]ZgZ XgZVi^c\ V
^ciZg"bZbWgVcZ = = ediZci^Va Y^[[ZgZcXZ
heVXZ = = = = == = = VXgdhh i]Z bZbWgVcZ
^ccZg = ==
b^idX]dcYg^Va
bZbWgVcZ 'ZÄ 'ZÄ 'ZÄ
bVig^m d[
b^idX]dcYg^dc 'ZÄ 'ZÄ egdidc X]VccZa
= = 6IE hnci]VhZ
ZaZXigdc XVgg^Zgh d[
i]Z ^ccZg C69 '= &' D'
b^idX]dcYg^Va C69= =
bZbWgVcZh ejbe
]nYgd\Zc ^dch ='D 69E E^ 6IE
egdidch [gdb i]Z
bVig^m id i]Z ^ciZg" =
bZbWgVcZ heVXZ
Vh egdidch Y^[[jhZ Ydlc i]Z
XdcXZcigVi^dc \gVY^Zci WVX` id i]Z
bVig^m k^V 6IE hnci]VhZ! ZcZg\n
^h ]VgcZhhZY [dg 6IE hnci]Zh^h

;^\jgZ -#+ I]Z ZaZXigdc igVchedgi X]V^c h]dl^c\ dm^YVi^kZ e]dhe]dgnaVi^dc VcY X]Zb^dhbdh^h#

- 8:AA G:HE>G6I>DC 6C9 E=DIDHNCI=:H>H &..

Chemiosmosis into the inter-membrane space.At the end of the chain, the electrons are
Osmosis is the passive flow combined with protons and oxygen atoms to make water, in the oxidative
of water molecules down a part of oxidative phosphorylation.
concentration gradient through
a partially permeable membrane. The space between the membranes is very narrow and allows for a
Chemiosmosis is similar but instead rapid increase in the concentration of the protons that are pumped into it
of water moving, it is protons during the electron transfer reactions.The protons in the inter-membrane
that pass down a concentration space create a concentration gradient between the space and the matrix.
gradient. These protons can now flow passively down this concentration gradient
back into the matrix, through a very large integral protein.This is called
As Table 8.2 shows, the net chemiosmosis.The large protein contains the enzyme ATP synthase,
production of ATP from one which joins ADP and Pi to form ATP. Three protons flowing through
molecule of glucose is, in theory, this enzyme results in one ATP being formed. Since the electrons from
36. Biochemists have discovered one NADH + H+ pump nine protons into the inter-membrane space,
that the actual production is closer each NADH + H+ results in the formation of three ATP. This is the
to 30 ATPs and propose that this phosphorylation part of oxidative phosphorylation.
discrepancy occurs because some
protons are used to transfer ATP FADH2 also supplies electrons to the electron transport chain but
from the matrix to the cytoplasm. further down the chain than NADH + H+, missing the first protein
Only about 30% of the energy in a pump. FADH2 allows the production of just two ATPs.
glucose molecule generates ATP.
DkZgVaa 6IE egdYjXi^dc Yjg^c\ VZgdW^X gZhe^gVi^dc
'%%
Together, glycolysis, the link reaction and the Krebs cycle yield 36
ATP molecules for each molecule of glucose broken down by aerobic
respiration, as summarised in Table 8.2.

HiV\Z 6IE jhZ 6IE n^ZaY

\anXdanh^h ' 6IE jhZY Vi i]Z hiVgi ' 6IE ) 6IE
' C69= = ) 6IE
a^c` gZVXi^dc 6IE [dgbVi^dc + 6IE
@gZWh XnXaZ ' C69= = ' 6IE
6IE [dgbVi^dc &- 6IE
cZi ZcZg\n n^ZaY + C69= = ) 6IE
' ;69=' (+ 6IE

IVWaZ -#' HjbbVgn d[ 6IE egdYjXi^dc Yjg^c\ VZgdW^X gZhe^gVi^dc#

, L]ZgZ egZX^hZan Yd i]Z a^c` gZVXi^dc VcY i]Z gZVXi^dch d[ @gZWh XnXaZ
iV`Z eaVXZ4

- L]ZgZ egZX^hZan Yd i]Z gZVXi^dch d[ i]Z ZaZXigdc igVchedgi X]V^c iV`Z
eaVXZ4

. >c i]Z a^c` gZVXi^dc! ^h engjkViZ dm^Y^hZY dg gZYjXZY4

&% CVbZ i]Z bdaZXjaZ i]Vi ZciZgh i]Z @gZWh XnXaZ#

&& 9jg^c\ dcZ gdiVi^dc d[ i]Z @gZWh XnXaZ! ]dl bVcn bdaZXjaZh d[ XVgWdc
Y^dm^YZ VgZ [dgbZY4

&' 9jg^c\ dcZ gdiVi^dc d[ i]Z @gZWh XnXaZ! ]dl bVcn bdaZXjaZh d[ 6IE VgZ
[dgbZY Y^gZXian Wn i]Z XnXaZ4

&( L]Vi ^h i]Z ejgedhZ d[ i]Z [daY^c\ d[ i]Z ^ccZg b^idX]dcYg^Va bZbWgVcZ4
&) L]Vi ^h i]Z [jcXi^dc d[ i]Z ZaZXigdc igVchedgi X]V^c :I8 4
&* L]Vi ]VeeZch id i]Z e= d[ i]Z ^ciZg"bZbWgVcZ heVXZ Vh ZaZXigdch

bdkZ Vadc\ i]Z :I84
&+ =dl bVcn bdaZXjaZh d[ 6IE VgZ egdYjXZY [gdb dcZ C69= = 4
&, CVbZ i]Z bdaZXjaZ i]Vi i]Z egdidch eVhh i]gdj\] \d^c\ [gdb i]Z ^ciZg"

bZbWgVcZ heVXZ id i]Z bVig^m#

-#' E]didhnci]Zh^h

6hhZhhbZci hiViZbZcih

r Draw and label a diagram showing the structure of a chloroplast as seen in electron micrographs.
r State that photosynthesis consists of light-dependent and light-independent reaction.
r Explain the light-dependent reactions.
r Explain photophosphorylation in terms of chemiosmosis.
r Explain the light-independent reactions.
r Explain the relationship between the structure of the chloroplast and its function.
r Explain the relationship between the action spectrum and the absorption spectrum of photosynthetic pigments in

green plants.

r Explain the concept of limiting factors in photosynthesis with reference to light intensity, temperature and

concentration of carbon dioxide.

I]Z gZVXi^dch d[ e]didhnci]Zh^h The light-dependent and light-
independent reactions
Photosynthesis is the process by which light energy is harvested and stored
as chemical energy, primarily in sugars but also in other organic molecules Both of these reactions are part of
such as lipids. It occurs in green plants, algae and some bacteria.All these photosynthesis and can only occur
organisms are known as autotrophs, which means they can make their when there is sufficient light.The
own food. light-independent reactions do not
have to take place during darkness.
Photosynthesis can be divided into two parts:

r the light-dependent reaction
r the light-independent reaction.

The light-dependent reaction produces compounds that are used in the
light-independent reaction.

Both the light-dependent and the light-independent reactions take
place in the chloroplasts of plant cells (Figures 8.7 and 8.8, overleaf ).
The stroma contains the enzymes required for the light-independent
reaction and the stacks of thylakoid membranes increase the surface area
for the light-dependent reaction.

- 8:AA G:HE>G6I>DC 6C9 E=DIDHNCI=:H>H '%&

\gVcjb hiVgX]
higdbV \gV^c
aVbZaaV
X]adgdeaVhi
ZckZadeZ

;^\jgZ -#, :aZXigdc b^Xgd\gVe] d[ V X]adgdeaVhi '% %%% #

djiZg bZbWgVcZ X]adgdeaVhi
^ccZg bZbWgVcZ ZckZadeZ

g^WdhdbZh a^e^Y YgdeaZi
hiVgX] \gV^c

higdbV

aVbZaaV

i]naV`d^Y
\gVcjb hiVX` d[ i]naV`d^Yh

;^\jgZ -#- 9^V\gVb d[ V X]adgdeaVhi#

I]Z a^\]i"YZeZcYZci gZVXi^dc

The light-dependent reaction occurs on the thylakoid membranes
of the chloroplast and is powered by light energy from the Sun. Each
thylakoid is a flattened sac so the space in the middle is narrow.The
thylakoid membranes form stacks called grana, which may be joined
together by intergranal membranes. Light is absorbed by photosynthetic
pigments such as chlorophyll, which are found on the granal membranes.
There are several pigments found in plants and each one absorbs light of
a slightly different wavelength.The pigments are associated with proteins
that are involved in electron transport, proton pumping and chemiosmosis.

The photosynthetic pigments are combined into two complex groups
called photosystems I and II, which absorb the light energy and use
this to boost electrons to a higher energy level so that they become
‘excited’, as shown in Figure 8.9.

'%'

Cdc"XnXa^X e]dide]dhe]dgnaVi^dc ZÄ ]^\]"ZcZg\n
ZaZXigdc
]^\]"ZcZg\n
ZaZXigdc X]V^c d[
ZaZXigdc XVgg^Zgh
ZÄ 69E E^

6IE
ZcZg\n aZkZa
e]didhnhiZb >> a^\]i ZÄ C69E =
VWhdgWZY 'ZÄ
e]didhnhiZb >
='D C69E=
a^\]i ZÄ
VWhdgWZY

& D' '= 'ZÄ ZÄ
'

8nXa^X e]dide]dhe]dgnaVi^dc

69E E^ ]^\]"ZcZg\n
ZaZXigdc

ZÄ

@Zn bdkZbZci d[ ZaZXigdch ZcZg\n aZkZaX]V^c d[6IE
WZilZZc ZaZXigdc XVgg^Zgh e]didhnhiZb >ZaZXigdc
X]Vc\Z ^c ZcZg\n XVgg^Zgh a^\]i
d[ ZaZXigdch VWhdgWZY

ZÄ

ZÄ

;^\jgZ -#. I]Z a^\]i"YZeZcYZci eVi]lVn d[ e]didhnci]Zh^h#

1 The first step in the light-dependent reaction is the photoactivation
of photosystem II. Pigment molecules in the photosystem absorb light
energy and boost electrons in a molecule of chlorophyll to a higher
energy level.The electrons are accepted by a carrier protein molecule at
the start of the electron transport chain.

2 Photosystem II has to replace these lost electrons and it does this by
taking them from water.Water is split into electrons, protons (hydrogen
ions) and an oxygen atom. Since the splitting is brought about by light
energy, it is called photolysis.The oxygen is released as an excretory
product.

3 Excited electrons travel along the electron transport chain into
photosystem I.As they do this, they lose energy but this is used to
pump protons into the thylakoid interior (in a similar way as occurs
in the electron transport chain in the mitochondrion).The thylakoid
interior is small and so a proton concentration gradient builds up
quickly.The protons then flow out through a large channel protein,

- 8:AA G:HE>G6I>DC 6C9 E=DIDHNCI=:H>H '%(

NADP+ is very similar to NAD+ almost identical to the one in mitochondria, which contains the
– it simply has a phosphate group enzyme ATP synthase.This time though, the formation of ATP is called
attached.An easy way to remember photophosphorylation and it occurs between photosystems II and I
that photosynthesis uses NADP+ (Figure 8.10).
is to note that they both have a 4 Absorption of light energy causes photoactivation in photosystem I,
letter ‘P’. boosting more electrons to an even higher energy level.The electrons
that arrive from photosystem II replace those that are displaced.The
electrons at the higher energy level are combined with protons in the
hydrogen carrier NADP+ to form NADPH + H+.
The two products of the light-dependent reaction,ATP and NADPH +
H+,are used to drive the light-independent reaction.

8nXa^X VcY cdc"XnXa^X e]dide]dhe]dgnaVi^dc
When ATP is produced using energy from excited electrons flowing from
photosystem II through photosynthesis I and on to NADP+, the process is
called non-cyclic photophosphorylation.

When light is not a limiting factor, the light-independent reactions
may proceed more slowly than the light-dependent reaction, so that the
supply of NADP+ runs out.This means the electrons boosted up from
photosystem I have no acceptor available to take them.They rejoin the
electron transport chain near the start and generate more ATP for the
light-independent reaction.This alternative pathway is called cyclic
photophosphorylation (Figure 8.9).

i]naV`d^Y ^ciZg^dg i]naV`d^Y ^ciZg^dg

='D '= = = ==
==
& D'
'

e]didhnhiZb >> =
e]didhnhiZb > =
6IE hnci]VhZ
C69E 6IE
C69E=

higdbV =
69E E^
=

;^\jgZ -#&% 8]Zb^dhbdh^h ^c e]didhnci]Zh^h#

'%)

I]Z a^\]i"^cYZeZcYZci gZVXi^dc

The light-independent reaction occurs in the stroma of the chloroplast
and is a cyclic pathway called the Calvin cycle.The pathway is shown
in Figure 8.11. (Large organic molecules have been simplified to show
just the number of carbon atoms they contain.) ATP and NADPH + H+
formed during the light-dependent stage supply energy and reducing
power for the Calvin cycle.The final product of the cycle is carbohydrate.

During each turn of the Calvin cycle one molecule of carbon dioxide is
used so Figure 8.11 shows three cycles combined together.As this is a cycle,
what goes in must leave, so three carbons enter in three molecules of carbon
dioxide and three carbons leave in one molecule of triose phosphate, which
can be used to form glucose or other organic compounds.
1 At the start of the cycle, the acceptor molecule ribulose bisphosphate

(RuBP) combines with incoming carbon dioxide from the air to form
glycerate 3-phosphate (GP).This reaction is called carbon fixation. It
is catalysed by RuBP carboxylase, an enzyme that is sometimes called
rubisco.
2 The ATP and NADPH + H+ from the light-dependent reaction
convert the glycerate 3-phosphate into triose phosphate (TP). Glycerate
3-phosphate therefore becomes reduced to triose phosphate. No more
phosphate is added so the only input from ATP is energy.
3 Six molecules of triose phosphate are produced but only five are
needed to reform the ribulose bisphosphate to keep the cycle going.
The extra triose phosphate leaves the cycle and since it takes a
phosphate with it, this is replaced in the cycle from ATP.

+ 69E + E^ + C69E= = ' 6IE VcY C69E= =
+ C69E [gdb i]Z a^\]i"
+ 6IE YZeZcYZci gZVXi^dc
XdckZgi i]Z \anXZgViZ
("e]dhe]ViZ <E ^cid
ig^dhZ e]dhe]ViZ IE #

& 8VgWdc [^mVi^dc Ä ZVX] + \anXZgViZ ("e]dhe]ViZ! <E + ig^dhZ e]dhe]ViZ! IE
g8^DW'j aXddhbZ WW^^cheZ]h dlhe^i]]ViZ
id bV`Z ' bdaZXjaZh
d[ \anXZgViZ ("
e]dhe]ViZ <E #

8Vak^c XnXaZ

( 8D' ( g^WjadhZ W^he]dhe]ViZ! Gj7E ig^dhZ e]dhe]ViZ! IE
( DcZ ig^dhZ e]dhe]ViZ IE
) I]Z [^kZ gZbV^c^c\ * ig^dhZ e]dhe]ViZ! IE
ig^dhZ e]dhe]ViZh VgZ 6IE aZVkZh i]Z XnXaZ VcY ^h
XdckZgiZY WVX` id jhZY ^c i]Z hnci]Zh^h d[
i]gZZ g^WjadhZ \ajXdhZ VcY di]Zg
W^he]dhe]ViZh l^i] dg\Vc^X bdaZXjaZh hjX]
i]Z VYY^i^dc d[ Vh Vb^cd VX^Yh#
dcZ e]dhe]ViZ
[gdb 6IE# 69E E^

;^\jgZ -#&& I]Z a^\]i"^cYZeZcYZci eVi]lVn d[ e]didhnci]Zh^h#

- 8:AA G:HE>G6I>DC 6C9 E=DIDHNCI=:H>H '%*

Six ‘turns’ of the Calvin cycle produces two triose phosphate molecules,
which can be combined to form the final product, glucose. Some triose
phosphate molecules will follow other pathways to make other organic
carbohydrate molecules, such as sucrose or cellulose, or other molecules
that the plant needs, such as amino acids, fatty acids or vitamins.

&- L]ZgZ YdZh i]Z a^\]i"^cYZeZcYZci gZVXi^dc iV`Z eaVXZ4
&. L]ZgZ YdZh i]Z a^\]i"YZeZcYZci gZVXi^dc iV`Z eaVXZ4
'% L]Vi ^h i]Z cVbZ \^kZc id i]Z VWhdgei^dc d[ a^\]i Wn i]Z e]didhnhiZbh4
'& L]^X] Xdadjg d[ i]Z a^\]i heZXigjb ^h cdi VWhdgWZY Wn eaVcih4
'' L]Vi ^h i]Z a^\]i ZcZg\n jhZY [dg l]Zc ^i ^h VWhdgWZY Wn i]Z

e]didhnhiZbh4
'( L]Zc e]didhnhiZb >> adhZh ZaZXigdch! l]Vi bdaZXjaZ ^h jhZY id gZeaVXZ

i]Zb4
') L]Vi ^h i]Z cVbZ d[ i]Z egdXZhh ^c fjZhi^dc '(4
'* CVbZ i]Z lVhiZ egdYjXi [gdb i]Z a^\]i"YZeZcYZci gZVXi^dc#
'+ CVbZ i]Z ild egdYjXih [gdb i]Z a^\]i"YZeZcYZci gZVXi^dc i]Vi VgZ

cZZYZY [dg i]Z a^\]i"^cYZeZcYZci gZVXi^dch#
', CVbZ i]Z hiVgi^c\ VXXZeidg bdaZXjaZ ^c i]Z 8Vak^c XnXaZ! l]^X] gZVXih

l^i] XVgWdc Y^dm^YZ#
'- CVbZ i]Z egdYjXi d[ i]^h gZVXi^dc#
'. I]Z bdaZXjaZ cVbZY ^c fjZhi^dc '- gZVXih l^i] i]Z bdaZXjaZh cVbZY ^c

fjZhi^dc '+# CVbZ i]Z egdYjXi d[ i]^h gZVXi^dc#
(% L]Vi ^h i]Z cVbZ \^kZc id i]Z [dgbVi^dc d[ 6IE ^c i]Z a^\]i"YZeZcYZci

gZVXi^dc4
(& CVbZ i]Z eVi]lVn l]ZgZ ZaZXigdch [gdb e]didhnhiZb > VgZ gZXnXaZY

WVX` ^cid e]didhnhiZb >#

8gZVi^kZ ZcYZVkdjg

Occasionally, the answer to a
question about an unknown biochemical
pathway is discovered as a result of
designing an investigation that is simple and
elegant.To find the steps involved in the
light-independent reaction, a team led by
Melvin Calvin (1911–1997) designed what
he called the ‘lollipop’ apparatus.

FjZhi^dc id Xdch^YZg
To what extent could an elegant scientific
protocol be considered a work of art?

'%+

I]Z VXi^dc heZXigjb VcY i]Z VWhdgei^dc heZXigjb Chlorophyll is the most important
and abundant plant pigment used
The spectrum of colours that humans can perceive is just part of the to capture light for photosynthesis.
electromagnetic spectrum.The range of wavelengths in visible light is from There are several forms of
400 nm to about 700 nm. Light provides the energy for photosynthesis but chlorophyll and each selectively
not all wavelengths are absorbed equally by the chloroplasts. If white light absorbs certain wavelengths of
is shone onto chloroplasts, the wavelengths they absorb depend on the light at the red and blue ends of
pigments present in them. Figure 8.12 shows an investigation in which the spectrum, while reflecting
the pigments from chloroplasts have been extracted and form a solution. green light.Terrestrial plants and
They are illuminated by light that has passed through a prism, so that the green algae contain two forms of
whole spectrum is visible.As the spectrum of wavelengths passes through the pigment, chlorophyll a and b,
the solution, the red and blue colours are lost, because they have been but diatoms contain a third type
absorbed by the pigments.The green part of the spectrum is not affected, known as chlorophyll c instead of
as chlorophyll does not absorb green light. chlorophyll b.

The investigation in Figure 8.12 can be made more sophisticated by Plants also contain several other
filtering white light so that only a precise wavelength is shone onto the pigments, including carotenoids,
chlorophyll solution.The proportion of each wavelength that is absorbed which are orange in colour, and
by the solution can be measured and an absorption spectrum, which anthocyanins, which are red.These
shows the relative amounts of each wavelength that is absorbed, can be pigments also selectively absorb
built up. Each pigment has a characteristic absorption spectrum, as shown certain wavelengths and reflect
in Figure 8.13 (overleaf ). others.Absorbed light may be
used in chemical reactions, and
The rate of photosynthesis can be measured in several ways, one the reflected light determines the
of which is to measure the volume of oxygen released. Rapid oxygen colour of the plant and can be
production indicates a high rate of photosynthesis. If the rate is measured important in attracting pollinators
for a range of wavelengths, a graph known as an action spectrum can to flowers.
be built up. Chlorophyll is more sensitive to some wavelengths of light
than others and produces excited electrons at the highest rate at these
wavelengths.The more excited electrons are produced, the faster the rate
of photosynthesis.A typical action spectrum shows that blue and red light
are used most efficiently.

l]^iZ a^\]i heZXigjb dcan \gZZc
hdjgXZ d[ k^h^WaZ h]VYZh eVhh
a^\]i i]gdj\] i]Z
XVgY eg^hb X]adgde]naa
l^i] hdaji^dc
V ha^i X]adgde]naa ZmigVXi
hdaji^dc ^c V i]^c
\aVhh [aVh`

;^\jgZ -#&' Dcan \gZZc a^\]i eVhhZh i]gdj\] V X]adgdeaVhi ZmigVXi hdaji^dc0 gZY VcY
WajZ lVkZaZc\i]h VgZ VWhdgWZY#

- 8:AA G:HE>G6I>DC 6C9 E=DIDHNCI=:H>H '%,

X]adgde]naa W

6WhdgWVcXZ X]adgde]naa X
XVgdiZcd^Yh

)%% )*% *%% **% +%% +*% ,%%

WajZ LVkZaZc\i] d[ a^\]i$cb gZY
a^\]i a^\]i

;^\jgZ -#&( 6Whdgei^dc heZXigV [dg e]didhnci]Zi^X e^\bZcih Ä X]adgde]naah W VcY X"
VcY XVgdiZcd^Y e^\bZcih#

Figure 8.14 shows action and absorption spectra plotted on one graph.
The degree of correlation between the light energy absorbed at different
wavelengths and the rate of photosynthesis indicates that absorbed light is
used in the photosynthetic pathways.

Absorption and action spectra vary for different species of plant. Some
plants contain different pigments such as carotene and xanthophylls, which
absorb wavelengths that chlorophyll cannot.These pigments, known as
accessory pigments, absorb some yellow and green light and account for
the photosynthesis that occurs in this range.

&%% &%%
VXi^dc heZXigjb
[dg e]didhnci]Zh^h

-% -%
GViZ d[ e]didhnci]Zh^h!
Vh eZgXZciV\Z d[ gViZ Vi +,% cb$

EZgXZciV\Z VWhdgWVcXZ$
+% +%

)% )%

'% '%

% +%% ,%% %
)%% *%% LVkZaZc\i]$cb X]adgde]naa X

@Zn XVgdiZcd^Yh
X]adgde]naa W

;^\jgZ -#&) 6Whdgei^dc VcY VXi^dc heZXigV hjeZg^bedhZY#

'%-

A^b^i^c\ [VXidgh GViZ d[ e]didhnci]Zh^h

Like all metabolic processes, the photosynthetic pathway requires a %% 6
number of components to make it work. If any of these components is in A^\]i ^ciZch^in
short supply, it limits the rate at which photosynthesis works.
;^\jgZ -#&* GViZ d[ e]didhnci]Zh^h ^h
Photosynthesis requires a suitable temperature, and sufficient light egdedgi^dcVa id a^\]i ^ciZch^in! jci^a ed^ci 6!
energy and carbon dioxide – any one of these can become a limiting l]Zc hdbZ di]Zg [VXidg ^h a^b^i^c\#
factor and change the rate of photosynthesis.

When one step in photosynthesis is slowed down, the whole process
slows down. If light intensity is increased, the rate of photosynthesis
increases until a certain point when increasing light has no further effect,
as shown in Figure 8.15.

At low light intensities, there may be a shortage of the products of the
light-dependent reaction so photosynthesis is slow.At point A, the plant is
saturated with light and cannot photosynthesise at a faster rate even with
more light.This indicates that some other factor is limiting the reaction.

Temperature affects enzymes that catalyse the reactions of
photosynthesis so that if the temperature is too low the reactions
may proceed very slowly and a graph of temperature versus rate of
photosynthesis would look similar to Figure 8.16.At low concentrations
of carbon dioxide there may be insufficient carbon dioxide to be fixed in
the Calvin cycle.At higher carbon dioxide concentrations, another factor
may limit the reaction.
r In Figure 8.16, experiment 1 shows that as light intensity increases so

does the rate of photosynthesis between the points A and B on the
graph.At these light intensities, light is the limiting factor. Between
points B and C another factor has become limiting.
r In experiment 2, where the temperature has been increased to 20 °C,
the line has not changed, showing that it is the carbon dioxide
concentration that is the limiting factor – a change in temperature has
had no effect.

; < ZmeZg^bZci ) Ä %#& 8D'! (% •8

GViZ d[ e]didhnci]Zh^h 9 : ZmeZg^bZci ( Ä %#& 8D'! '% •8
7
8 ZmeZg^bZci ' Ä %#%) 8D'! '% •8
ZmeZg^bZci & Ä %#%) 8D'! &* •8

%6
% A^\]i ^ciZch^in

;^\jgZ -#&+ I]Z Z[[ZXi d[ iZbeZgVijgZ VcY 8D' XdcXZcigVi^dc dc i]Z gViZ d[
e]didhnci]Zh^h#

- 8:AA G:HE>G6I>DC 6C9 E=DIDHNCI=:H>H '%.

Water is also essential for r In experiment 3, raising the carbon dioxide concentration causes the
photosynthesis but it is seldom rate of photosynthesis to increase to point D, but then another limiting
likely to be a limiting factor since factor comes in to play from D to E.
all the cells of a plant must contain
it to remain alive. r In experiment 4 we see that, at the higher carbon dioxide
concentration, raising the temperature causes the line to rise to F but
then again another limiting factor has become limiting from F to G.

The level of carbon dioxide in the atmosphere is relatively low and carbon
dioxide is frequently a limiting factor for photosynthesis. Horticulturalists
increase the yield of their crops by maximising the rate of photosynthesis
in their glasshouses.They do this by keeping the air inside warm with
heaters, increasing the intensity of light using lamps and, in some cases,
increasing the concentration of carbon dioxide.

(' >[ i]Z \gVe]h d[ i]Z e]didhnci]Zh^h VXi^dc heZXigjb VcY i]Z X]adgdeaVhi
e^\bZci VWhdgei^dc heZXigjb VgZ hjeZg^bedhZY! l]Vi XVc WZ YZYjXZY4

(( L]Vi ^h bZVci Wn i]Z iZgb Èa^b^i^c\ [VXidgÉ4

() A^hi i]gZZ a^b^i^c\ [VXidgh [dg e]didhnci]Zh^h#

:cY"d["X]VeiZg fjZhi^dch (1)
(1)
1 Which of the following statements is correct? (1)

A Oxidation can involve the removal of oxygen from a compound.
B The solution inside a mitochondrion is called the matrix and the solution inside

a chloroplast is called the stroma.
C The folds of the inner membrane of a mitochondrion are called grana.
D The photosynthetic pigments in a chloroplast are found on the cristae.

2 Which of the following statements about glycolysis is correct?

A It is anaerobic, occurs in the cytoplasm, and includes at least one phosphorylation
reaction.

B It is aerobic and includes a lysis reaction.
C In the final stages, two molecules of ATP are used in the formation of pyruvate.
D It is aerobic and does not include a lysis reaction.

3 Which of the following statements about the link reaction and Krebs cycle is correct?

A Pyruvate in the mitochondrion matrix is oxidised to acetyl CoA.
B At the end of the link reaction, coenzyme A is recycled back into the cytoplasm

to combine with another pyruvate molecule.
C During one rotation of the Krebs cycle there are three decarboxylation reactions.
D The link reaction occurs in the mitochondrial matrix and Krebs cycle occurs on the

mitochondrial cristae.

'&%

4 Which of the following statements about the electron transport chain is correct? (1)
(1)
A As electrons flow along the chain, protons are pumped into the mitochondrial matrix.
B ATP is formed as electrons flow through the enzyme ATP synthase. (1)
C The flow of electrons along the chain causes the pH of the inter-membrane space (1)

to increase.
D When protons diffuse through ATP synthase into the matrix,ATP is formed.

5 Which of the following statements about the light-dependent reaction is correct?

A Photoactivation of photosystem I causes photolysis.
B Cyclic photophosphorylation involves both photosystems I and II.
C Electrons from the photolysis of water are transferred to NADP+ from photosystem I.
D NADP+ becomes oxidised when it combines with electrons and protons.

6 Which of the following statements about the light-independent reaction is correct?

A The enzyme RuBP carboxylase is used to convert ribulose bisphosphate into triose
phosphate.

B The conversion of glycerate 3-phosphate to triose phosphate requires ATP and
NADP+ from the light-dependent reaction.

C At the start of the Calvin cycle, carbon dioxide combines with glycerate 3-phosphate
to form ribulose bisphosphate.

D The formation of ribulose bisphosphate from triose phosphate requires a
phosphorylation reaction.

7 Which of the following statements is correct?

A A limiting factor is one that determines what the end-product of a reaction is.
B A limiting factor is one that determines the rate of a reaction.
C Limiting factors for photosynthesis include light intensity, carbon dioxide

concentration and glucose concentration.
D An absorption spectrum can be obtained by measuring the release of oxygen gas

from pondweed at different wavelengths of light.

8 Explain the reasons for: (2)
a many grana in the chloroplast (2)
b poor growth of plants growing beneath trees (2)
c large amounts of RuBP carboxylase in the chloroplast (total 6 marks)

9 Explain the process of aerobic respiration in a cell starting at the end of glycolysis and including oxidative (8)
phosphorylation.

10 Explain how the light-independent reaction of photosynthesis relies on the light-dependent reaction. (5)

- 8:AA G:HE>G6I>DC 6C9 E=DIDHNCI=:H>H '&&

:conbZ VXi^k^in11 At the start of glycolysis, glucose is phosphorylated to produce glucose 6-phosphate, which is converted into
fructose 6-phosphate.A second phosphorylation reaction is then carried out, in which fructose 6-phosphate
is converted into fructose 1,6-bisphosphate.This reaction is catalysed by the enzyme phosphofructokinase.
Biochemists measured the enzyme activity of phosphofructokinase (the rate at which it catalysed the reaction) at
different concentrations of fructose 6-phosphate.The enzyme activity was measured with a low concentration of
ATP and a high concentration of ATP in the reaction mixture.The graph below shows the results.

adl 6IE XdcXZcigVi^dc

]^\] 6IE XdcXZcigVi^dc

;gjXidhZ +"e]dhe]ViZ XdcXZcigVi^dc

a i Using only the data in the above graph, outline the effect of increasing fructose 6-phosphate (2)
concentration on the activity of phosphofructokinase, at a low ATP concentration. (2)

ii Explain how increases in fructose 6-phosphate concentration affect the activity of the enzyme.

b i Outline the effect of increasing the ATP concentration on the activity of phosphofructokinase. (2)
ii Suggest an advantage to living organisms of the effect of ATP on phosphofructokinase. (1)

(total 7 marks)
© IB Organization 2009

12 There are many abiotic factors that affect the rate of photosynthesis in terrestrial plants.Wheat is an important
cereal crop in many parts of the world.Wheat seedlings were grown at three different concentrations of carbon
dioxide (in parts per million) and the rate of photosynthesis was measured at various light intensities.

GViZ d[ e]didhnci]Zh^h$Ma 8D' b^cÄ& *%
@Zn
&(%% eeb 8D'

)% *%% eeb 8D'
'-% eeb 8D'

(%

'%

&%

%
% * &% &* '%
A^\]i ^ciZch^in$ &%Ä( ajbZc bÄ'

hdjgXZ/ VYVeiZY [gdb ? E @^bb^ch &.., <eh[ij ;Yebe]o 'cY ZY^i^dc e# &+&

'&'

a Describe the relationship between the rate of photosynthesis and light intensity for wheat seedlings (2)
grown at a CO2 concentration of 500 ppm. (3)

b Outline the effect of CO2 concentration on the rate of photosynthesis of the wheat seedlings. (2)

c The normal atmospheric concentration of CO2 is 370 ppm. Deduce the effect of doubling the CO2
concentration to 740 ppm on the growth of wheat plants.

Leaf area and chlorophyll levels were measured in sun leaves and shade leaves of Hedera helix (English ivy)
and Prunus laurocerasus (cherry laurel). Sun leaves developed under maximal sunlight conditions while
shade leaves developed at reduced sunlight levels in the shadow of other leaves.

HeZX^Zh AZV[ ineZ 8]adgde]naa$N\ ba & AZV[ VgZV$Xb'

^kn h]VYZ )#( ,'#+
aVjgZa hjc (#- +'#.
h]VYZ )#, (-#,
hjc )#' '*#,

hdjgXZ/ 9 8jgi^h! eaVci ZXdad\n ^cYZeZcYZci egd_ZXi &..%

d Calculate the percentage increase in the amount of chlorophyll in shade leaves of ivy compared to (1)
sun leaves of ivy.

e Suggest a reason for the differences in chlorophyll concentration and leaf area in sun and shade leaves (2)
in these two species.

(total 10 marks)
© IB Organization 2009

- 8:AA G:HE>G6I>DC 6C9 E=DIDHNCI=:H>H '&(

. EaVci hX^ZcXZ

>cigdYjXi^dc

1MBOUT BSF B WJUBM QBSU PG BMNPTU FWFSZ FDPTZTUFN "T BVUPUSPQIT
UIFZ TUBSU GPPE DIBJOT CZ QSPEVDJOH
DBSCPIZESBUFT BOE PUIFS PSHBOJD NPMFDVMFT UIBU BSF OFFEFE CZ IFUFSPUSPQIT 5IFZ BMTP QSPEVDF
PYZHFO BOE BCTPSC DBSCPO EJPYJEF GSPN UIF BUNPTQIFSF PS GSPN XBUFS 8IFO UIFZ EJF
UIFJS SFNBJOT
DPOUSJCVUF UP UIF IVNVT
XIJDI JT BO JNQPSUBOU QBSU PG TPJM TUSVDUVSF

.#& EaVci higjXijgZ VcY \gdli]

6hhZhhbZci hiViZbZcih

r %SBX BOE MBCFM QMBO EJBHSBNT UP TIPX UIF EJTUSJCVUJPO PG UJTTVFT JO UIF TUFN BOE MFBG PG B EJDPUZMFEPOPVT QMBOU
r 0VUMJOF UISFF EJĄ FSFODFT CFUXFFO UIF TUSVDUVSFT PG EJDPUZMFEPOPVT BOE NPOPDPUZMFEPOPVT QMBOUT
r &YQMBJO UIF SFMBUJPOTIJQ CFUXFFO UIF EJTUSJCVUJPO PG UJTTVFT JO UIF MFBG BOE UIF GVODUJPOT PG UIFTF UJTTVFT
r *EFOUJGZ NPEJê DBUJPOT PG SPPUT
TUFNT BOE MFBWFT GPS EJĄ FSFOU GVODUJPOT CVMCT
TUFN UVCFST
TUPSBHF SPPUT BOE UFOESJMT
r 4UBUF UIBU EJDPUZMFEPOPVT QMBOUT IBWF BQJDBM BOE MBUFSBM NFSJTUFNT
r $PNQBSF HSPXUI EVF UP BQJDBM BOE MBUFSBM NFSJTUFNT JO EJDPUZMFEPOPVT QMBOUT
r &YQMBJO UIF SPMF PG BVYJO JO QIPUPUSPQJTN BT BO FYBNQMF PG UIF DPOUSPM PG QMBOU HSPXUI

Ze^YZgb^h I^hhjZh ^c i]Z hiZb VcY aZV[

e]adZb " UZQJDBM MBOE QMBOU JT NBEF VQ PG UISFF NBKPS PSHBOT UIF SPPUT
TUFNT BOE
mnaZb MFBWFT 3PPUT BODIPS UIF QMBOU JO UIF HSPVOE BOE BCTPSC XBUFS BOE NJOFSBMT
ZcYdYZgb^h GPS QMBOU HSPXUI 'JHVSF 9.1
4PNF SPPUT BMTP TUPSF SFTFSWFT PG GPPE

XdgiZm 5IF TUFN QSPWJEFT TVQQPSU GPS UIF MFBWFT *U BMTP DPOUBJOT UJTTVFT GPS UIF
USBOTQPSU PG NBUFSJBMT GSPN UIF SPPU UP UIF MFBG
BOE GPS UIF EJTUSJCVUJPO
;^\jgZ .#& 6 Xgdhh"hZXi^dc d[ V gddi# I]Z PG UIF QSPEVDUT PG QIPUPTZOUIFTJT GSPN MFBWFT UP UIF HSPXJOH QBSUT PG UIF
Ze^YZgb^h egdiZXih i]Z djiZg aVnZg d[ i]Z QMBOU
BT TIPXO JO 'JHVSF 9.2 0OF PG UIF NPTU EJTUJODUJWF GFBUVSFT PG B
gddi# I]Z XdgiZm XVgg^Zh lViZg id i]Z mnaZb! QMBOU TUFN JT UIF SBOHF PG EJĄ FSFOU UJTTVFT JU DPOUBJOT 5IF PVUFS cortex
l]^X] igVchedgih ^i id i]Z gZhi d[ i]Z eaVci# DPOUBJOT DFMMT UIBU DPOUSJCVUF TUSFOHUI UP UIF TUFN NBJOUBJOJOH JUT FSFDU
I]Z e]adZb XVgg^Zh cjig^Zcih VcY b^cZgVah GPSN &NCFEEFE JO UIF DPSUFY BSF TFWFSBM UJTTVFT
QBSUJDVMBSMZ UIF xylem
VgdjcY i]Z eaVci# BOE phloem WFTTFMT
XIJDI NBLF VQ vascular bundles 5IF DFOUSBM QBSU
PG UIF TUFN JT DBMMFE pith BOE JT DPNQPTFE PG TQPOHZ DFMMT UIBU QSPWJEF BO
BSFB GPS TUPSBHF

4PNF QMBOUT IBWF KVTU B TJOHMF MBSHF MFBG
CVU NPTU QMBOUT IBWF NBOZ
MFBWFT
EJTUSJCVUFE PO TIPPUT PS CSBODIFT UIBU BSJTF GSPN UIF NBJO TUFN
-FBWFT BSF PGUFO BSSBOHFE JO B NPTBJD UP NBYJNJTF UIF Fą DJFODZ PG MJHIU
DBQUVSF BOE TP UIBU OPOF PG UIFN PCTDVSFT PS TIBEFT PUIFS MFBWFT 5IF
HFOFSBM TUSVDUVSF PG QMBOU MFBWFT JT TIPXO JO 'JHVSF 9.3 -FBWFT DPNF JO B
IVHF SBOHF PG TIBQFT BOE TJ[FT
CVU BMM TIBSF TFWFSBM DPNNPO GFBUVSFT

5IF VQQFS epidermis JT DPWFSFE CZ BO PVUFS cuticle PG XBY
XIJDI
MFUT WJTJCMF MJHIU UISPVHI
CVU QSFWFOUT XBUFS MPTT UISPVHI UIF VQQFS

'&)

TVSGBDF 5IF FQJEFSNJT JUTFMG DPOUBJOT B MBZFS PG ë BUUFOFE
SFDUBOHVMBS
kVhXjaVg XVbW^jb
USBOTQBSFOU DFMMT 5IFTF IFMQ QSPUFDU UIF MFBG GSPN JOWBEJOH QBUIPHFOT TVDI XdgiZm
BT GVOHBM TQPSFT #FMPX UIF FQJEFSNJT JT UIF palisade layer
DPOUBJOJOH a^\c^[^ZY [^WgZh
FMPOHBUFE DFMMT XJUI OVNFSPVT DIMPSPQMBTUT 5IF DFMMT BSF DMPTFMZ QBDLFE egdk^YZ
UPHFUIFS UP NBYJNJTF UIF BNPVOU PG QIPUPTZOUIFTJT UIBU DBO UBLF QMBDF hjeedgi
$IMPSPQMBTUT PGUFO NPWF VQ UPXBSET UIF VQQFS QBSU PG UIFTF QBMJTBEF
DFMMT
TP UIFZ DBO SFDFJWF NPSF MJHIU #FMPX UIF QBMJTBEF MBZFS
spongy e]adZb
mesophyll DFMMT
BMTP DPOUBJOJOH TPNF DIMPSPQMBTUT
BSF MPPTFMZ QBDLFE mnaZb
UPHFUIFS XJUI MBSHF air spaces TVSSPVOEJOH UIFN %JĄ VTJPO PG HBTFT UP
BOE GSPN UIF TUPNBUB DBO FBTJMZ PDDVS UISPVHI UIFTF BJS TQBDFT kVhXjaVg WjcYaZ

eVa^hVYZ hedc\n jeeZg Ze^YZgb^h
bZhde]naa bZhde]naa Ze^YZgb^h e^i]
;^\jgZ .#' IgVchkZghZ hZXi^dc i]gdj\] V
ndjc\ hiZb id h]dl i]Z Y^hig^Wji^dc d[
i^hhjZh#

kVhXjaVg WjcYaZ
mnaZb e]adZb

adlZg hidbV
Ze^YZgb^h hjggdjcYZY Wn
V eV^g d[ \jVgY XZaah

;^\jgZ .#( I]Z higjXijgZ d[ V aZV[0 lViZg ZciZgh i]Z aZV[ Vh a^fj^Y lViZg ^c i]Z mnaZb!
VcY Y^[[jhZh dji Vh lViZg kVedjg i]gdj\] i]Z hidbViV#

5IF MPXFS FQJEFSNJT
XIJDI DPWFST UIF MPXFS MFBG TVSGBDF
IBT Advances in plant classification
guard cells FNCFEEFE JO JU
JO NBOZ UZQFT PG MFBG (VBSE DFMMT DPOUBJO
DIMPSPQMBTUT BOE IBWF BO VOFWFO UIJDLFOJOH PG DFMMVMPTF JO UIFJS DFMM 3FDFOU SFTFBSDI JOUP UIF
XBMMT "T UIFZ UBLF JO PS MPTF XBUFS UIFZ DIBOHF TIBQF
PQFOJOH PS DMPTJOH FWPMVUJPOBSZ IJTUPSZ PG
UIF QPSF PS stoma QMVSBM stomata
CFUXFFO UIFN 5IJT BMMPXT DBSCPO BOHJPTQFSNT IBT SFWFBMFE OFX
EJPYJEF
XBUFS WBQPVS BOE PYZHFO UP QBTT JO BOE PVU PG UIF MFBG 4UPNBUB FWJEFODF BCPVU EJĄ FSFODFT CFUXFFO
PO UIF VOEFSTJEF PG B MFBG BSF JO B TIBEFE QPTJUJPO BOE QSPUFDUFE GSPN NFNCFST PG UIF HSPVQ " OFX
FYDFTT IFBU
IFMQJOH UP QSFWFOU UPP NVDI XBUFS CFJOH MPTU UISPVHI UIFN DMBTTJê DBUJPO IBT CFFO EFWJTFE
CZ UIF "OHJPTQFSN 1IZMPHFOZ
-FBWFT BMTP DPOUBJO WBTDVMBS CVOEMFT
XIJDI BSF DPOUJOVPVT XJUI UIPTF (SPVQ *U EJWJEFT BOHJPTQFSNT
JO UIF TUFN "T XFMM BT QSPWJEJOH TVQQPSU GPS UIF MFBG
UIF YZMFN JO UIF JOUP UISFF HSPVQT SBUIFS UIBO KVTU
WBTDVMBS CVOEMFT CSJOHT XBUFS BOE NJOFSBMT UIBU BSF ESBXO VQ GSPN UIF UXP 5IF UISFF OFX HSPVQT BSF
SPPUT EJSFDUMZ JOUP UIF MFBWFT 5IF XBUFS JT OFDFTTBSZ GPS QIPUPTZOUIFTJT
NPOPDPUZMFEPOT
NBHOPMJJET BOE
BOE UIF NJOFSBMT BSF OFDFTTBSZ GPS HSPXUI FVEJDPUT 4PNF QMBOU TDJFOUJTUT IBWF
BMSFBEZ TUBSUFE VTJOH UIF OFX "1(
BdcdXdinaZYdch VcY Y^XdinaZYdch TZTUFN UP PSHBOJTF UIFJS TQFDJNFOT

'MPXFSJOH QMBOUT
PS angiosperms
BSF HSPVQFE JOUP UXP DMBTTFT . EA6CI H8>:C8: '&*
monocotyledonous QMBOUT IBWJOH POF TFFE MFBG
BOE dicotyledonous
QMBOUT IBWJOH UXP TFFE MFBWFT
"QBSU GSPN UIF OVNCFS PG TFFE MFBWFT

UIFSF BSF TFWFSBM PUIFS QIZTJDBM EJĄ FSFODFT CFUXFFO UIF UXP HSPVQT PG
QMBOUT 5BCMF 9.1
PWFSMFBG

;ZVijgZ BdcdXdinaZYdcdjh eaVcih 9^XdinaZYdcdjh eaVcih

hZZY aZVkZh dcZ ild

aZV[ kZ^ch jhjVaan eVgVaaZa gVY^Vi^c\ ^c V cZi"a^`Z eViiZgc

Y^hig^Wji^dc d[ kVhXjaVg hXViiZgZY i]gdj\] i]Z hiZb VggVc\ZY ^c V g^c\ VgdjcY i]Z djih^YZ d[
WjcYaZh ^c i]Z hiZb i]Z hiZb

hidbViV Xdbbdc ^c Wdi] jeeZg VcY adlZg Ze^YZgb^h bdhian [djcY ^c adlZg Ze^YZgb^h

Ó dlZgh hiVbZch VcY di]Zg higjXijgZh ^c i]Z Ó dlZg dXXjg ^c hiVbZch VcY di]Zg higjXijgZh ^c i]Z Ó dlZg
bjai^eaZh d[ i]gZZ dXXjg ^c bjai^eaZh d[ [djg dg Ò kZ

gddih jcWgVcX]ZY! Ò Wgdjh gddih jhjVaan \gdl^c\ [gdb i]Z hiZb bV^c iVe gddi l^i] WgVcX]Zh [gdb ^i

IVWaZ .#& BdcdXdinaZYdch VcY Y^XdinaZYdch XdbeVgZY#

5IFSF BSF NPSF UIBO TQFDJFT PG NPOPDPUZMFEPOT
JODMVEJOH PSDIJET

HSBTTFT BOE MJMJFT %JDPUZMFEPOT BSF B NVDI MBSHFS HSPVQ XJUI BMNPTU
LOPXO TQFDJFT 5IFZ JODMVEF NBHOPMJBT
EBJTJFT
HFOUJBOT BOE
QSPUFBT

6YVeiVi^dch id Y^[[ZgZci Zck^gdcbZcih

*G QMBOUT GSPN EJĄ FSFOU IBCJUBUT BSF DPNQBSFE
UIFZ NBZ XFMM MPPL RVJUF
EJĄ FSFOU 5IFJS SPPUT
TUFNT BOE MFBWFT TFSWF UIF TBNF GVODUJPOT
CVU UIFJS
TUSVDUVSFT NBZ CF NPEJê FE UP TVJU UIFJS FOWJSPONFOUT 4VDI BEBQUBUJPOT
HJWF UIF QMBOU UIF BCJMJUZ UP TVSWJWF JO B QBSUJDVMBS DMJNBUF PS FOBCMF JU UP
BWPJE CFJOH FBUFO CZ IFSCJWPSFT
GPS FYBNQMF

Gddi bdY^Ò XVi^dch

4PNF QMBOUT IBWF MBSHF UBQ SPPUT UIBU BDU BT TUPSBHF PSHBOT GPS GPPE SFTFSWFT
&YBNQMFT PG UIFTF JODMVEF DBSSPUT
DBTTBWB BOE UVSOJQT 'JHVSF 9.4
0UIFST
IBWF TXPMMFO SPPUT UIBU DBO TUPSF XBUFS .BOHSPWFT QSPEVDF BJS SPPUT

XIJDI FYUFOE BCPWF XBUFSMPHHFE TPJM PS XBUFS UP BCTPSC PYZHFO 'JHVSF
9.5
.BOZ DBDUJ IBWF FYUFOTJWF TVSGBDF SPPUT
XIJDI DBO RVJDLMZ BCTPSC
BOZ SBJO UIBU GBMMT CFGPSF JU FWBQPSBUFT JO IPU DPOEJUJPOT

;^\jgZ .#) I]Z XVggdi eaVci ]Vh aVg\Z iVe gddih l]ZgZ ^i hidgZh ;^\jgZ .#* I]Z gddih d[ bVc\gdkZ igZZh ZmiZcY VWdkZ i]Z hd^a dg
[ddY gZhZgkZh# lViZg hd i]Zn XVc VWhdgW dmn\Zc#

'&+

7jaWh Ó Zh]n aZVkZh
4PNF QMBOUT VTF TXPMMFO
VOEFSHSPVOE MFBG CBTFT UP GPSN GPPE TUPSBHF
PSHBOT DBMMFE bulbs 5IFTF FOBCMF QMBOUT UP TVSWJWF PWFS XJOUFS XIFO hiZb
QIPUPTZOUIFTJT NBZ OPU CF QPTTJCMF 0OJPOT BOE EBĄ PEJMT BSF FYBNQMFT PG ;^\jgZ .#+ 6c dc^dc WjaW ^h bVYZ je d[
QMBOUT UIBU QSPEVDF CVMCT 5IF MFBG CBTFT DBO CF TFFO BSSBOHFE PWFS POF bdY^Ò ZY aZVkZh#
BOPUIFS BSPVOE B DFOUSBM TIPPU JO 'JHVSF 9.6

AZVkZh
.BOZ QMBOUT TVSWJWF JO WFSZ BSJE DMJNBUFT XIFSF XBUFS MPTT GSPN MFBWFT
XPVME DBVTF QSPCMFNT 5IFZ TPMWF UIJT JO EJĄ FSFOU XBZT 4PNF IBWF WFSZ
XBYZ MFBWFT UP NJOJNJTF XBUFS MPTT
XIJMF PUIFST IBWF SFEVDFE MFBWFT PS
OP MFBWFT BU BMM
GPS UIF TBNF QVSQPTF

1MBOUT JO CPUI UFNQFSBUF BOE USPQJDBM SFHJPOT IBWF FWPMWFE NPEJê FE
MFBWFT DBMMFE tendrils BT B NFDIBOJTN GPS HFUUJOH UIFJS MFBWFT JOUP TVOMJHIU

FWFO XIFO UIFZ BSF TIBEFE CZ TVSSPVOEJOH WFHFUBUJPO 5FOESJMT FOBCMF
UIF QMBOU UP DMJOH POUP PUIFS QMBOUT PS PCKFDUT
TP UIBU JU JT TVQQPSUFE BT JU
HSPXT BOE DMJNCT VQ UPXBSET UIF MJHIU 'JHVSF 9.7


HiZb ijWZgh
Tubers BSF TUFNT UIBU HSPX CFMPX HSPVOE BOE BSF VTFE UP TUPSF GPPE
1PUBUPFT BSF TUFN UVCFST UIBU TUPSF DBSCPIZESBUF JO UIF GPSN PG TUBSDI
'JHVSF 9.8


[adlZg

aZVkZh

jcYZg\gdjcY hiZb hiZb ;^\jgZ .#, 8jgan iZcYg^ah ^c i]Z \VgYZc
YZkZade^c\ ijWZg VYkZci^i^djh gddih eZV eaVci \g^e dc id hjggdjcY^c\ dW_ZXih!
ZnZ Vaadl^c\ i]Z eaVci id \gdl je ^cid i]Z a^\]i#
ndjc\ ijWZg
hiZb ZcY Potato production
igjZ gddih .PTU DVMUJWBUFE WBSJFUJFT PG QPUBUP
;^\jgZ .#- EdiVid ijWZgh VgZ bdY^Ò ZY hiZbh# BSF EFTDFOEFE GSPN B TQFDJFT ê STU
HSPXO JO $IJMF BCPVU ZFBST
BHP 1PUBUPFT BSF B TUBQMF GPPE JO
NBOZ DPVOUSJFT
BOE BSF UIF XPSME T
MBSHFTU GPPE DSPQ 5PEBZ
B UIJSE PG
BMM QPUBUPFT BSF HSPXO JO $IJOB

. EA6CI H8>:C8: '&,

iZgb^cVa WjY BZg^hiZbh
XdciV^c^c\ i]Z
Ve^XVa bZg^hiZb Meristems BSF UIF HSPXJOH QBSUT PG B ë PXFSJOH QMBOU XIFSF DFMMT NBZ
EJWJEF CZ NJUPTJT UISPVHIPVU UIF MJGF PG UIF QMBOU 5IFSF BSF UXP UZQFT PG
NFSJTUFN JO B EJDPUZMFEPOPVT QMBOU m UIF apical meristems GPVOE BU UIF
UJQ PG UIF SPPU BOE UIF TIPPU
BOE UIF lateral meristems GPVOE JO UIF
WBTDVMBS CVOEMFT PG UIF TUFN (SPXUI JO UIF NBJO TUFN PDDVST BU UIF
BQJDBM PS QSJNBSZ NFSJTUFN
XJUI GSFTI UJTTVF GPSNJOH BU UIF HSPXJOH
UJQ 'JHVSF 9.9
5IJT BMMPXT B QMBOU UP HSPX VQXBSET GSPN UIF TPJM BOE
UPXBSET MJHIU TP UIBU MFBWFT DBO PCUBJO TVą DJFOU MJHIU GPS QIPUPTZOUIFTJT
*O UIF SPPU
HSPXUI PG UIF BQJDBM NFSJTUFN FYUFOET UIF SPPU JOUP UIF TPJM

.BOZ QMBOUT BMTP HSPX BU MBUFSBM NFSJTUFNT JO UIF WBTDVMBS cambium
5IJT NBLFT TUFNT BOE SPPUT UIJDLFS
BOE JT LOPXO BT secondary growth
4JEF HSPXUI NBZ EFWFMPQ GSPN UIF NBJO TUFN BT TIPPUT PS CSBODIFT UP
UBLF BEWBOUBHF PG GBWPVSBCMF DPOEJUJPOT BOE UP BWPJE DPNQFUJUJPO GSPN
PUIFS QMBOUT

*G QMBOUT BSF EBNBHFE BU UIF BQJDBM NFSJTUFNT
PGUFO UIF ê STU MBUFSBM
NFSJTUFN JT JOEVDFE UP HSPX BOE UBLF PWFS UIF SPMF PG UIF BQJDBM
NFSJTUFN *G B ë PXFS PO UIF BQJDBM NFSJTUFN JT DVU PĄ
UIJT XJMM JOEVDF UIF
MBUFSBM NFSJTUFNT UP TXJUDI UP QSPEVDJOH ë PXFST

6jm^c VcY e]didigde^hb

1MBOUT QSPEVDF growth-regulating substances UIBU BDU UP DPOUSPM HSPXUI
BOE EFWFMPQNFOU 5IFTF TVCTUBODFT BSF TPNFUJNFT DBMMFE QMBOU IPSNPOFT

I]Z iZgb^cVa WjY ^h h]dl^c\ Ve^XVa Ydb^cVcXZ ^c
i]^h ZmVbeaZ# <gdli] d[ i]Z iZgb^cVa WjY egZkZcih
hiZb \gdli] [gdb aViZgVa WjYh#

cdYZ
^ciZgcdYZ

aViZgVa WjY GZbdkVa d[ i]Z iZgb^cVa WjY gZbdkZh Ve^XVa Ydb^cVcXZ#
XdciV^c^c\ AViZgVa WjYh XVc cdl \gdl hiZbh#
aViZgVa
bZg^hiZb

;^\jgZ .#. 6e^XVa bZg^hiZbh ZmZgi Vc ^c]^W^idgn Z[[ZXi dc i]Z aViZgVa bZg^hiZbh! XVaaZY Ve^XVa Ydb^cVcXZ#
'&-

,OPXMFEHF PG UIFTF HSPXUI TVCTUBODFT XBT OPUFE CZ $IBSMFT
%BSXJO JO B SFQPSU PG IJT FYQFSJNFOUT UIBU IF QVCMJTIFE JO )F
PCTFSWFE UIBU PBU TIPPUT HSFX UPXBSET MJHIU CFDBVTF PG TPNF AJOë VFODF

XIJDI IF QSPQPTFE XBT USBOTNJUUFE GSPN UIF TIPPU UJQ UP UIF BSFB
JNNFEJBUFMZ CFMPX 8F OPX LOPX UIBU UIF TVCTUBODF UIBU DBVTFT TIPPUT
UP CFOE UPXBSET UIF MJHIU JT auxin
BOE UIF SFTQPOTF JU DBVTFT JT DBMMFE
phototropism "VYJO JT GPVOE JO UIF FNCSZPT PG TFFET BOE JO BQJDBM
NFSJTUFNT
XIFSF JU DPOUSPMT TFWFSBM HSPXUI SFTQPOTFT

"VYJO TFFNT UP BDU CZ MPPTFOJOH UIF CPOET CFUXFFO DFMMVMPTF ê CSFT JO
QMBOU DFMM XBMMT BOE NBLJOH UIFN NPSF ë FYJCMF 5IF FYBDU NFDIBOJTN PG
BVYJO BDUJPO JT OPU GVMMZ VOEFSTUPPE *U IBT CFFO TVHHFTUFE UIBU BVYJO JT
SFEJTUSJCVUFE UP UIF TJEF PG B TIPPU UJQ UIBU JT BXBZ GSPN B MJHIU TPVSDF 5IF
VOFWFO EJTUSJCVUJPO PG BVYJO BMMPXT DFMM FMPOHBUJPO PO UIF TIBEFE TJEF PG B
TIPPU
XIJDI JO UVSO DBVTFT CFOEJOH UPXBSET MJHIU 'JHVSF 9.10


GZXZeidgh GZXZeidgh YZiZXi a^\]i
^c eaVhbV [gdb dcZ h^YZ! XVjh^c\
bZbWgVcZh Vjm^c id WZ igVchedgiZY
YZiZXi a^\]i [gdb XZaa id XZaa id i]Z
ZfjVaan dc h]VYZY h^YZ#
ZVX] h^YZ#
BdgZ Vjm^c ^h igVchedgiZY
Ydlc i]Z h]VYZY h^YZ!
XVjh^c\ i]Z XZaah id
Zadc\ViZ bdgZ dc i]^h h^YZ#

@Zn
Y^gZXi^dc d[ a^\]i
VXi^kZ igVchedgi d[ Vjm^c

;^\jgZ .#&% HdbZ egdiZ^ch ^c i]Z eaVhbV bZbWgVcZh d[ XZgiV^c XZaah ^c eaVci h]ddih
VgZ hZch^i^kZ id a^\]i# L]Zc a^\]i [Vaah dc i]Zb! i]Zn XVjhZ Vjm^c id WZ igVchedgiZY
id i]Z h]VYZY h^YZ d[ i]Z h]ddi! l]^X] ^c ijgc XVjhZh i]Z h]ddi id WZcY idlVgYh i]Z
a^\]i#

& Djia^cZ i]Z Y^[[ZgZcXZh WZilZZc bdcdXdinaZYdch VcY Y^XdinaZYdch#

' Djia^cZ i]Z gdaZ d[ Vjm^c ^c e]didigde^hb#

( 8dbeVgZ i]Z gdaZ d[ Ve^XVa VcY aViZgVa bZg^hiZbh ^c i]Z \gdli] d[ V eaVci#

) 9gVl V eaVc d[ i]Z higjXijgZ d[ V ine^XVa hiZb id h]dl i]Z VggVc\ZbZci
d[ i^hhjZ ^ch^YZ#

. EA6CI H8>:C8: '&.

.#' IgVchedgi ^c Vc\^dheZgbde]niZh

6hhZhhbZci hiViZbZcih

r 0VUMJOF IPX UIF SPPU TZTUFN QSPWJEFT B MBSHF TVSGBDF BSFB GPS NJOFSBM JPO BOE XBUFS VQUBLF CZ NFBOT PG CSBODIJOH BOE

SPPU IBJST

r -JTU XBZT JO XIJDI NJOFSBM JPOT JO UIF TPJM NPWF UP UIF SPPU
r &YQMBJO UIF QSPDFTT PG NJOFSBM JPO BCTPSQUJPO GSPN UIF TPJM JOUP SPPUT CZ BDUJWF USBOTQPSU
r 4UBUF UIBU UFSSFTUSJBM QMBOUT TVQQPSU UIFNTFMWFT CZ NFBOT PG UIJDLFOFE DFMMVMPTF
DFMM UVSHPS BOE MJHOJê FE YZMFN
r %Fê OF AUSBOTQJSBUJPO
r &YQMBJO IPX XBUFS JT DBSSJFE CZ UIF USBOTQJSBUJPO TUSFBN
JODMVEJOH UIF TUSVDUVSF PG YZMFN WFTTFMT
USBOTQJSBUJPO QVMM


DPIFTJPO
BEIFTJPO BOE FWBQPSBUJPO

r 4UBUF UIBU HVBSE DFMMT DBO SFHVMBUF USBOTQJSBUJPO CZ PQFOJOH BOE DMPTJOH TUPNBUB
r 4UBUF UIBU UIF QMBOU IPSNPOF BCTDJTJD BDJE DBVTFT UIF DMPTJOH PG TUPNBUB
r &YQMBJO IPX UIF BCJPUJD GBDUPST MJHIU
UFNQFSBUVSF
XJOE BOE IVNJEJUZ BĄ FDU UIF SBUF PG USBOTQJSBUJPO JO B UZQJDBM

UFSSFTUSJBM QMBOU

r 0VUMJOF GPVS BEBQUBUJPOT PG YFSPQIZUFT UIBU IFMQ UP SFEVDF USBOTQJSBUJPO
r 0VUMJOF UIF SPMF PG QIMPFN JO BDUJWF USBOTMPDBUJPO PG TVHBST TVDSPTF
BOE BNJOP BDJET GSPN TPVSDF QIPUPTZOUIFUJD

UJTTVF BOE TUPSBHF PSHBOT
UP TJOL GSVJUT
TFFET
SPPUT


Gddih

3PPUT BSF SFTQPOTJCMF GPS BCTPSCJOH XBUFS BOE NJOFSBM JPOT GSPN UIF
TPJM .BOZ QMBOUT EFWFMPQ BO FYUFOTJWF
CSBODIJOH SPPU TZTUFN JO PSEFS UP
JODSFBTF UIF TVSGBDF BSFB PG SPPU JO DPOUBDU XJUI UIF TPJM *O BEEJUJPO
BT
OFX SPPUT HSPX
OVNFSPVT SPPU IBJST EFWFMPQ UP JODSFBTF UIF TVSGBDF BSFB
FWFO NPSF 'JHVSF 9.11
3PPU IBJST BSF UFNQPSBSZ BOE EJF BXBZ UP CF
SFQMBDFE CZ OFX POFT OFBS UIF HSPXJOH UJQ

1MBOUT SFRVJSF B OVNCFS PG NJOFSBMT UP NBLF B WBSJFUZ PG TVCTUBODFT
OFDFTTBSZ GPS HSPXUI " GFX PG UIFTF BSF MJTUFE JO 5BCMF 9.2

B^cZgVa ^dc >bedgiVcXZ

XVaX^jb Xdchi^ijZci d[ XZaa lVaah
bV\cZh^jb cZZYZY id bV`Z X]adgde]naa
^gdc gZfj^gZY Vh V Xd[VXidg [dg bVcn ZconbZh

IVWaZ .#' =dl eaVcih jhZ hdbZ ^bedgiVci b^cZgVa ^dch#

;^\jgZ .#&& 6 gddi d[ V ndjc\ gVY^h] .JOFSBMT BSF QSFTFOU JO UIF TPJM BT TBMUT m GPS FYBNQMF
DBMDJVN PDDVST JO
h]dl^c\ i]Z gddi ]V^gh# UIF GPSN PG DBSCPOBUFT 5IFTF EJTTPMWF JO TPJM XBUFS BOE UIF EJTTPMWFE JPOT
DBO NPWF JOUP SPPU DFMMT JO EJĄ FSFOU XBZT
''%
r %JTTPMWFE NJOFSBMT NBZ NPWF JOUP UIF SPPU CZ mass flow PG XBUFS

DBSSZJOH UIF JPOT
PS CZ facilitated diffusion PG JPOT GSPN UIF TPJM
XBUFS JOUP SPPU IBJST
EPXO UIFJS DPODFOUSBUJPO HSBEJFOU 'JHVSF 9.12

#PUI UIFTF QSPDFTTFT BSF QBTTJWF m UIBU JT
UIFZ EP OPU SFRVJSF FOFSHZ JO
UIF GPSN PG "51

mnaZb kZhhZa @Zn
lViZg bdkZbZci

e]adZb

XdgiZm eZg^XnXaZ
ZcYdYZgb^h
gddi ]V^g

lViZg Ze^YZgb^h

;^\jgZ .#&' I]Z eVi]lVn d[ lViZg bdkZbZci [gdb gddi ]V^g id mnaZb# I]Z lViZg
bVn XVggn Y^hhdakZY b^cZgVa ^dch#

r 8IFSF UIF DPODFOUSBUJPO PG B NJOFSBM JT MPXFS JO UIF TPJM XBUFS UIBO JO ;^\jgZ .#&( :aZXigdc b^Xgd\gVe] d[ V [jc\jh
VcY V eaVci ^c V bjijVa^hi^X gZaVi^dch]^e
QMBOU DFMMT
active transport JT OFFEFE UP UBLF JU VQ 1PUBTTJVN
OJUSBUF XVaaZY V bnXdgg]^oV# I]Z i]^c! dgVc\Z i]gZVYh
BOE QIPTQIBUF BSF VTVBMMZ BCTPSCFE CZ BDUJWF USBOTQPSU 3PPU IBJS DFMMT VgZ [jc\Va ]ne]VZ! Zm^hi^c\ l^i]^c i]Z XdgiZm
DPOUBJO NJUPDIPOESJB UP QSPWJEF "51 BOE NPTU SPPUT DBO POMZ UBLF d[ V gddi *)% #
JO NJOFSBMT JG PYZHFO JT BWBJMBCMF GPS BFSPCJD SFTQJSBUJPO
UP QSPWJEF
TVą DJFOU "51 &YQFSJNFOUT IBWF TIPXO UIBU QPUBTTJVN JPOT TUPQ
NPWJOH JOUP SPPU DFMMT GSPN UIF TPJM XIFO QPUBTTJVN DZBOJEF JT BEEFE
$ZBOJEF JT B QPUFOU CMPDLFS PG SFTQJSBUJPO BT JU JOIJCJUT FO[ZNF BDUJPO

BOE TP JU QSFWFOUT BDUJWF USBOTQPSU

r *O PUIFS DBTFT
UIFSF NBZ CF B DMPTF BTTPDJBUJPO
LOPXO BT B mutualistic

relationship
CFUXFFO UIF SPPUT BOE B GVOHVT B NZDPSSIJ[B
'JHVSF
9.13
3PPUT CFDPNF DPWFSFE XJUI BO FYUFOTJWF OFUXPSL PG IZQIBF

XIJDI JODSFBTF UIF TVSGBDF BSFB GPS BCTPSQUJPO PG CPUI XBUFS BOE NJOFSBMT
.JOFSBMT DBO QBTT EJSFDUMZ GSPN GVOHBM IZQIBF UP SPPU DFMMT

Hjeedgi

1MBOUT OFFE UP TVQQPSU UIFJS MFBWFT BOE ë PXFST BOE JU JT PGUFO UIF TUFN

XIJDI DPOOFDUT UIF SPPUT UP UIFTF TUSVDUVSFT
UIBU TVQQPSUT UIFN 4VQQPSU
JT QSPWJEFE CZ DFMMVMPTF DFMM XBMMT
DFMM UVSHPS BOE CZ UIJDLFOJOH DFSUBJO
TUSVDUVSFT XJUI MJHOJO BOE PUIFS NBUFSJBMT

"MM QMBOU DFMMT BSF TVSSPVOEFE CZ B ê SN cellulose DFMM XBMM
XIJDI BMTP
DPOUBJOT IFNJDFMMVMPTFT BOE QFDUJO 0WFS UJNF
TPNF DFMMT NBZ UIJDLFO
UIFJS DFMM XBMMT XJUI PUIFS DBSCPIZESBUFT TVDI BT lignin
XIJDI QSPWJEF
BEEJUJPOBM TUSVDUVSF BSPVOE UIF DFMM

6OEFS OPSNBM FOWJSPONFOUBM DPOEJUJPOT
UIF MBSHF DFOUSBM WBDVPMF
JO QMBOU DFMMT JT ê MMFE XJUI ë VJE DPOUBJOJOH EJTTPMWFE NJOFSBMT 5IJT ë VJE
FYFSUT QSFTTVSF PO UIF DFMM XBMM
TP UIF DFMM CFDPNFT SJHJE BOE QSFTTFT PO
BEKBDFOU DFMMT $FMMT JO UIJT DPOEJUJPO BSF TBJE UP CF turgid
BOE FBDI FYFSUT
turgor pressure PO TVSSPVOEJOH DFMMT 5IJT JT TVą DJFOU UP TVQQPSU MFBWFT

. EA6CI H8>:C8: ''&

Transpiration UIF MPTT PG XBUFS BOE OFX
TPGU UJTTVF *UT FĄ FDU JT NPTU DMFBSMZ TFFO JO QFSJPET PG ESPVHIU
WBQPVS GSPN UIF BFSJBM QBSUT PG XIFO MFBWFT ESPPQ BOE CFDPNF TPGU PS ë BDDJE
QMBOUT UIF MFBWFT BOE TUFNT

#VU UVSHPS QSFTTVSF JT OPU FOPVHI UP TVQQPSU UIF TUFN
FTQFDJBMMZ JG B
QMBOU JT UBMM )FSF
xylem tissue JO UIF WBTDVMBS CVOEMFT OPU POMZ DBSSJFT
XBUFS CVU BMTP QSPWJEFT TVQQPSU
BT TIPXO JO 'JHVSF 9.14 5IF YZMFN
DPOUBJOT FMPOHBUFE DFMMT
XIJDI BSF IPMMPX
BOE CFDPNF UIJDLFOFE XJUI
MJHOJO GPSNJOH B ACBDLCPOF UP TVQQPSU UIF TUFN

-JHOJO JT B DPNQMFY TVCTUBODF UIBU JT WFSZ IBSE BOE SFTJTUBOU UP EFDBZ
1FSFOOJBM QMBOUT MJLF USFFT MBZ EPXO NPSF MJHOJO FBDI ZFBS
GPSNJOH XPPE

IgVche^gVi^dc

Transpiration JT UIF MPTT PG XBUFS WBQPVS GSPN UIF MFBWFT BOE TUFNT PG
QMBOUT 8BUFS JT BCTPSCFE CZ UIF SPPUT
USBWFMT VQ UIF TUFN JO UIF YZMFN
WFTTFMT JO UIF WBTDVMBS CVOEMFT UP UIF MFBWFT
BOE JT MPTU CZ FWBQPSBUJPO
UISPVHI TUPNBUB 'JHVSF 9.15


.PTU QMBOUT HSPX JO BSFBT XIFSF UIF BNPVOU PG XBUFS JO UIF BJS
UIF
humidity
JT MFTT UIBO JO UIF MFBWFT %VSJOH UIF EBZ XIFO UIF TUPNBUB BSF
PQFO
XBUFS WBQPVS MFBWFT UIF BJS TQBDFT JO UIF TQPOHZ NFTPQIZMM UISPVHI
TUPNBUB JO UIF MPXFS FQJEFSNJT BOE UIF TUFN 5IF FWBQPSBUJOH XBUFS JT
ESBXO GSPN UIF WBTDVMBS CVOEMFT JO UIF MFBG BOE TUFN 5IF WBTDVMBS CVOEMFT
BSF DPOUJOVPVT XJUI UIPTF JO UIF YZMFN GSPN UIF SPPUT TP B DPMVNO PG
XBUFS JT GPSNFE DPOOFDUJOH UIF SPPUT
TUFN
MFBWFT BOE BJS TQBDFT 5IJT JT
LOPXO BT UIF transpiration stream

5SBOTQJSBUJPO BMTP DBSSJFT NJOFSBMT UISPVHI UIF QMBOU
BOE TFSWFT UP DPPM
MFBWFT JO XBSN DPOEJUJPOT

8d]Zh^dcÄiZch^dc i]Zdgn

5IF NPWFNFOU PG XBUFS JO UIF YZMFN DBO CF FYQMBJOFE CZ UIF DPIFTJPOm
UFOTJPO UIFPSZ

r -PTT PG XBUFS WBQPVS GSPN UIF TUPNBUB JO UIF MFBWFT SFTVMUT JO AUFOTJPO

PS OFHBUJWF QSFTTVSF JO UIF YZMFN WFTTFMT

IH mnaZb kZhhZa ZaZbZci a^\c^[^ZY IneZh d[ a^\c^[^ZY XZaa AH mnaZb kZhhZa ajbZc
XZaajadhZ lVaa lVaa i]^X`Zc^c\h
XZaajadhZ e^i
lVaa
gZbV^ch d[
e^i ZcY lVaah
d[ VY_VXZci
mnaZb
ZaZbZcih

kZhhZa
ZaZbZci

ajbZc he^gVa VccjaVg gZi^XjaViZ e^iiZY

&% Nb
;^\jgZ .#&) MnaZb kZhhZah VgZ cdi Va^kZ VcY ]VkZ cd eaVhbV bZbWgVcZ! hd lViZg XVc ZVh^an bdkZ ^c VcY dji d[ i]Zb#

'''

+ igVche^gVi^dc d[ lViZg lViZg ZkVedgViZh ^cid V^g
kVedjg i]gdj\] deZc l]^X] ]Vh V adlZg
hidbViV ^cid V^g
XdcXZcigVi^dc d[ lViZg kVedjg
* ZkVedgVi^dc d[ lViZg
^cid aZV[ V^g heVXZh Xdajbc d[ lViZg
^h Xdci^cjdjh YjZ
) lViZg bdkZh [gdb id VY]Zh^dc VcY
mnaZb id aZV[ XZaah Xd]Zh^dc

( lViZg bdkZh je mnaZb

' lViZg ZciZgh mnaZb

lViZg ^h ejaaZY ^cid gddih Vh
kVedjg ^h adhi [gdb aZVkZh

& lViZg jeiV`Z
cZVg gddi i^e

;^\jgZ .#&* I]Z bdkZbZcih d[ lViZg i]gdj\] V eaVci/ lViZg bdkZh [gdb i]Z hd^a id i]Z V^g [gdb l]ZgZ i]ZgZ ^h bdgZ lViZg id l]ZgZ
i]ZgZ ^h aZhh lViZg #

r 8BUFS WBQPVS SF FOUFST UIF BJS TQBDFT JO UIF MFBG GSPN UIF YZMFN WFTTFMT
r $POUJOVPVT DPMVNOT PG XBUFS BSF ESBXO VQ UIF YZMFN EVF UP DPIFTJPO

CFUXFFO XBUFS NPMFDVMFT JO UIF YZMFN BOE GPSDFT PG BEIFTJPO CFUXFFO
UIF XBUFS NPMFDVMFT BOE UIF YZMFN WFTTFM XBMMT Cohesion JT EVF UP
IZESPHFO CPOEJOH CFUXFFO XBUFS NPMFDVMFT BOE adhesion JT DBVTFE
CZ UIF IZESPHFO CPOET CFUXFFO XBUFS NPMFDVMFT BOE NPMFDVMFT JO UIF
XBMMT PG UIF YZMFN WFTTFMT

r 5IF UFOTJPO JO UIF YZMFN JT TUSPOH EVF UP MPTT PG XBUFS BOE UIFSF XPVME

CF B UFOEFODZ GPS YZMFN WFTTFMT UP DPMMBQTF JOXBSET 5IF UIJDLFOJOH
QSPWJEFE CZ MJHOJO QSFWFOUT UIJT IBQQFOJOH

r 8BUFS JT ESBXO JO GSPN UIF DPSUFY JO UIF SPPUT UP SFQMBDF XBUFS UIBU JT

MPTU JO USBOTQJSBUJPO

r 5IF UFOTJPO DBVTFE CZ USBOTQJSBUJPO BMTP DBVTFT XBUFS UP CF ESBXO JOUP

UIF SPPUT GSPN UIF TPJM
5SBOTQJSBUJPO JT MBSHFMZ DPOUSPMMFE CZ UIF QBJST PG HVBSE DFMMT UIBU TVSSPVOE
UIF TUPNBUB Guard cells IBWF VOFWFOMZ TIBQFE DFMM XBMMT XJUI NPSF

. EA6CI H8>:C8: ''(

DFMMVMPTF PO UIF TJEF BEKBDFOU UP UIF TUPNB 5IF JOOFS QBSU PG UIF DFMM XBMM
JT MFTT FMBTUJD
TP UIBU XIFO HVBSE DFMMT UBLF VQ XBUFS BOE CFDPNF UVSHJE

UIFZ UBLF PO B TBVTBHF MJLF TIBQF BOE BO PQFOJOH m UIF stoma m JT GPSNFE
CFUXFFO UIFN 'JHVSF 9.16
8IFO UIF HVBSE DFMMT MPTF XBUFS
UIF DFMM
XBMMT SFMBY BOE UIF TUPNB DMPTFT

5IF PQFOJOH BOE DMPTJOH PG TUPNBUB JT DPOUSPMMFE CZ UIF DPODFOUSBUJPO
PG QPUBTTJVN JPOT *O EBSLOFTT
UIFTF JPOT NPWF PVU PG UIF HVBSE DFMMT
JOUP TVSSPVOEJOH DFMMT *O MJHIU DPOEJUJPOT
QPUBTTJVN JPOT BSF BDUJWFMZ
QVNQFE JOUP UIF WBDVPMFT PG HVBSE DFMMT 5IJT DSFBUFT BO JODSFBTFE TPMVUF
DPODFOUSBUJPO TP UIBU XBUFS FOUFST CZ PTNPTJT
NBLJOH UIF DFMMT UVSHJE
BOE PQFOJOH UIF TUPNBUB " QMBOU IPSNPOF DBMMFE BCTDJTJD BDJE
QSPEVDFE
JO UIF SPPUT EVSJOH UJNFT PG ESPVHIU
BĄ FDUT QPUBTTJVN JPO NPWFNFOU
JO HVBSE DFMMT 8IFO BCTDJTJD BDJE JT QSFTFOU
QPUBTTJVN JPOT MFBL PVU BOE
XBUFS GPMMPXT CZ PTNPTJT 5IJT NFBOT UIBU UIF HVBSE DFMMT MPTF UVSHPS BOE
TUPNBUB DMPTF
UIVT DPOTFSWJOH XBUFS

;VXidgh V[[ZXi^c\ igVche^gVi^dc

4FWFSBM BCJPUJD FOWJSPONFOUBM GBDUPST OPUBCMZ MJHIU
UFNQFSBUVSF
IVNJEJUZ
BOE XJOE TQFFE
JOë VFODF UIF SBUF PG USBOTQJSBUJPO JO QMBOUT

r -JHIU BĄ FDUT USBOTQJSBUJPO EJSFDUMZ CZ DPOUSPMMJOH UIF PQFOJOH BOE

DMPTJOH PG TUPNBUB "T MJHIU JOUFOTJUZ JODSFBTFT
TUPNBUB PQFO
TQFFEJOH
VQ UIF SBUF PG USBOTQJSBUJPO *O EBSLOFTT
TUPNBUB DMPTF
UIVT SFTUSJDUJOH
USBOTQJSBUJPO

r 5FNQFSBUVSF BĄ FDUT USBOTQJSBUJPO CFDBVTF IFBU FOFSHZ JT OFFEFE GPS UIF

FWBQPSBUJPO PG XBUFS "T UIF UFNQFSBUVSF SJTFT
UIF SBUF PG USBOTQJSBUJPO
BMTP SJTFT BT XBUFS FWBQPSBUFT GSPN UIF BJS TQBDFT JO UIF TQPOHZ NFTPQIZMM
BOE EJĄ VTFT PVU PG UIF TUPNBUB

lViZg ZciZgh \jVgY XZaah Wn dhbdh^h0 lViZg aZVkZh \jVgY XZaah Wn dhbdh^h0
\jVgY XZaah WZXdbZ ijg\^Y! deZc^c\ hidbV \jVgY XZaah WZXdbZ [aVXX^Y! Xadh^c\ hidbV

Ze^YZgb^h XZaah hjggdjcY^c\ \jVgY XZaah
;^\jgZ .#&+ I]Z deZc^c\ VcY Xadh^c\ d[ hidbViV# <VhZh XVc Y^[[jhZ ^c VcY dji d[
deZc hidbViV# L]Zc hidbViV VgZ XadhZY! lViZg adhh ^h b^c^b^hZY#

'')

r "O JODSFBTF JO BUNPTQIFSJD IVNJEJUZ SFEVDFT UIF SBUF PG USBOTQJSBUJPO ;^\jgZ .#&, Efkdj_W! dg eg^X`an eZVg! ^h V
XVXijh l^i] Ó ViiZcZY e]didhnci]Zi^X hiZbh
"JS JO UIF NFTPQIZMM BJS TQBDFT UFOET UP CF TBUVSBUFE XJUI XBUFS WBQPVS i]Vi hidgZ lViZg# I]Z aZVkZh VgZ bdY^Ò ZY
TP JG BUNPTQIFSJD BJS CFDPNFT NPSF IVNJE
UIF DPODFOUSBUJPO HSBEJFOU Vh he^cZh! VcY i]^h b^c^b^hZh lViZg adhh
CFUXFFO UIF BJS TQBDF BOE UIF BUNPTQIFSF JT SFEVDFE BOE USBOTQJSBUJPO Wn gZYjX^c\ i]Z hjg[VXZ VgZV [gdb l]^X]
JT TMPXFE EPXO igVche^gVi^dc XVc iV`Z eaVXZ# I]Z he^cZh
Vahd egdiZXi i]Z eaVci [gdb WZ^c\ ZViZc Wn
r "O JODSFBTF JO XJOE TQFFE JODSFBTFT UIF SBUF PG USBOTQJSBUJPO CFDBVTF Vc^bVah#

JU CMPXT BXBZ UIF BJS KVTU PVUTJEF UIF TUPNBUB
XIJDI JT TBUVSBUFE XJUI 4UPSBHF TUSVDUVSFT TVDI BT TFFET BOE
XBUFS WBQPVS 3FEVDFE IVNJEJUZ OFBS UIF TUPNBUB FOBCMFT XBUFS WBQPVS CVMCT BSF TJOLT EVSJOH UIF HSPXJOH
UP EJĄ VTF NPSF SFBEJMZ GSPN UIF TQPOHZ NFTPQIZMM
XIFSF UIF BJS JT WFSZ TFBTPO CVU NBZ BMTP BDU BT TPVSDFT
IVNJE
UP UIF BJS KVTU PVUTJEF UIF MFBG
XIJDI IBT MPXFS IVNJEJUZ XIFO UIFZ CFHJO UP TQSPVU

IgVche^gVi^dc ^c mZgde]niZh

Xerophytes BSF QMBOUT UIBU MJWF JO BSJE DMJNBUFT m BO FYBNQMF JT TIPXO
JO 'JHVSF 9.17 4PNF YFSPQIZUFT HSPX JO BSFBT XIFSF UIFSF JT WFSZ MJUUMF
SBJOGBMM BMM UIF ZFBS
XIJMF PUIFST MJWF JO QMBDFT XIFSF SBJOGBMM JT JOUFOTF CVU
TIPSU MJWFE
XJUI MPOH
ESZ QFSJPET GPS UIF SFTU PG UIF ZFBS *O CPUI DBTFT

QMBOUT IBWF FWPMWFE TQFDJBMJTBUJPOT UIBU FOBCMF UIFN UP TVSWJWF TIPSUBHFT PG
XBUFS CZ SFEVDJOH XBUFS MPTT

.BSSBN HSBTT JT XFMM BEBQUFE UP TVSWJWF JO UIF ESZ DPOEJUJPOT GPVOE JO
TBOE EVOFT *UT MFBWFT BSF SPMMFE JOUP UVCF MJLF TIBQFT
XIJDI BSF QSPUFDUFE
PO UIF PVUTJEF CZ B UIJDL XBYZ DVUJDMF 4UPNBUB PG NBSSBN HSBTT BSF
QSPUFDUFE EFFQ JOTJEF QJUT 'JHVSF 9.18
PWFSMFBG
XIJDI UIFNTFMWFT BSF
SPMMFE VQ JOTJEF UIF MFBG " MJOJOH PG IBJST PO UIF JOOFS TJEF PG UIF MFBG
LFFQT IVNJE BJS USBQQFE JOTJEF UIF SPMMFE VQ MFBWFT )BJST QSFWFOU XBUFS
MPTT CZ EJĄ VTJPO 8IFO UIF IVNJEJUZ PG UIF BJS SJTFT
NBSSBN HSBTT JT BCMF
UP VOSPMM JUT MFBWFT VTJOH TQFDJBMJTFE IJOHF DFMMT 8IFO UIF MFBG JT VOSPMMFE

MFBG IBJST IFMQ DPOTFSWF B TVQQMZ PG XBUFS CZ USBQQJOH NPJTU BJS 5IJT BJS
SFNBJOT JOTJEF UIF MFBG XIFO JU SPMMT VQ BHBJO

5IF $SBTTVMBDFBF
B HSPVQ PG TVDDVMFOU QMBOUT
IBWF FWPMWFE B
NFDIBOJTN BMMPXJOH UIFN UP LFFQ UIFJS TUPNBUB DMPTFE EVSJOH UIF IFBU
PG UIF EBZ
UP SFEVDF XBUFS MPTT "U OJHIU
UIF TUPNBUB PQFO BOE DBSCPO
EJPYJEF EJĄ VTFT JOUP UIF MFBG *U JT ê YFE UFNQPSBSJMZ JO DFMMT
BOE UIFO JT
SFMFBTFE GPS QIPUPTZOUIFTJT EVSJOH UIF EBZ XIFO UIF TUPNBUB BSF DMPTFE
5IJT JT DBMMFE DSBTTVMBDFBO BDJE NFUBCPMJTN $".


IgVchadXVi^dc ^c i]Z e]adZb

Translocation JT UIF NPWFNFOU PG PSHBOJD NPMFDVMFT UISPVHI UIF
QIMPFN UJTTVF PG QMBOUT 5IF QIMPFN DPOTJTUT PG UXP UZQFT PG MJWJOH DFMM
sieve tube cells
XIJDI BSF QFSGPSBUFE UP BMMPX UIF NPWFNFOU PG TPMVUFT
UISPVHI UIFN
BOE companion cells
XIJDI BSF DPOOFDUFE UP UIF TJFWF
UVCF DFMMT BT TIPXO JO 'JHVSF 9.19 QBHF 227


8IFSFBT UIF YZMFN DBSSJFT XBUFS BOE NJOFSBM TBMUT POMZ JO BO VQXBSE
EJSFDUJPO
UIF QIMPFN DBO USBOTQPSU NBUFSJBMT FJUIFS VQ PS EPXO UIF QMBOU
5SBOTMPDBUJPO NPWFT NBUFSJBMT GSPN B source
XIFSF UIFZ BSF NBEF PS
TUPSFE
UP B sink
XIFSF UIFZ BSF VTFE
BT TIPXO JO 'JHVSF 9.20 QBHF 227


. EA6CI H8>:C8: ''*

I]Z aZVkZh XVc gdaa
je! Zmedh^c\ V idj\]!
lViZgegdd[ Xji^XaZ id
i]Z V^g djih^YZ i]Z aZV[#

BVggVb \gVhh ^h dcZ d[ i]Z [Zl eaVcih i]Vi XVc i]g^kZ ^c bdW^aZ hVcY YjcZh!
hjgk^k^c\ i]Z kZgn Ygn XdcY^i^dch i]Vi VgZ [djcY i]ZgZ#

HeZX^Va^hZY XZaah Ä ]^c\Z XZaah Ä XVjhZ i]Z deZc^c\ VcY
Xadh^c\ d[ i]Z bVggVb \gVhh aZV[ ^c gZhedchZ id V^g
]jb^Y^in# AZV[ gdaa^c\ igVeh V^g ^ch^YZ i]Z gdaaZY aZV[# I]^h
V^g XVc gZbV^c ]jb^Y ZkZc ^[ i]Z V^g djih^YZ ^h kZgn Ygn#

I]Z hidbViV VgZ [djcY YZZe ^c i]Z \gddkZh VcY deZc
^cid i]Z ZcXadhZY ]jb^Y heVXZ ^ch^YZ V gdaaZY aZV[#
LViZg ]Vh id Y^[[jhZ V adc\ lVn WZ[dgZ ^i gZVX]Zh
bdk^c\ V^g djih^YZ i]Z aZV[! hadl^c\ lViZg adhh#

6 a^\]i b^Xgd\gVe] d[ V igVchkZghZ hZXi^dc i]gdj\] V bVggVb \gVhh aZV[ &(, #

=V^gh ]Zae id `ZZe i]Z ]jb^Y V^g igVeeZY ^ch^YZ V
gdaaZY aZV[# L]Zc i]Z aZV[ ^h jcgdaaZY! i]Z ]V^gh ]Zae id
igVe V i]^X` aVnZg d[ bd^hi V^g XadhZ id i]Z aZV[ hjg[VXZ!
gZYjX^c\ V^g bdkZbZci# LViZg kVedjg ]Vh id Y^[[jhZ
i]gdj\] i]^h aVnZg WZ[dgZ ^i XVc WZ XVgg^ZY VlVn ^c V^g
bdkZbZcih# I]Z i]^X`Zg i]Z aVnZg! i]Z bdgZ hadlan
lViZg ^h adhi Wn igVche^gVi^dc#

6 hXVcc^c\ ZaZXigdc b^Xgd\gVe] d[ V igVchkZghZ hZXi^dc i]gdj\] eVgi d[ V gdaaZY
aZV[ d[ bVggVb \gVhh .% #
;^\jgZ .#&- 6YVeiVi^dch d[ i]Z mZgde]niZ bVggVb \gVhh 7ccef^_bW Wh[dWh_W id Ygn XdcY^i^dch#

''+

H^ZkZ 8dbeVc^dc HdjgXZ
ZaZbZci XZaa e]didhnci]Zi^X
dg\Vc Z#\# aZV[
h^ZkZ edgZ XZaajadhZ
XZaa lVaa e]didhnci]Zh^h
h^ZkZ eaViZ
eaVhbdYZhbViV b^idX]dcYg^dc hjXgdhZ

b^idX]dcYg^dc gdj\] BVhh [adl VXi^kZ adVY^c\
XZaajadhZ ZcYdeaVhb^X bdkZbZci WZilZZc Vi hdjgXZ
XZaa lVaa gZi^Xjajb hdjgXZ VcY h^c`
XdbeVc^dc
eaVhbV eaVhbV h^ZkZ ijWZ XZaah
bZbWgVcZ bZbWgVcZ
jcadVY^c\
ZcYdeaVhb^X kVXjdaZ Vi h^c`
gZi^Xjajb idcdeaVhi
cjXaZjh

XnideaVhb b^YYaZ H^c` hjXgdhZ
aVbZaaV \gdl^c\ ed^ci dg \ajXdhZ [gjXidhZ
H^ZkZ ZaZbZcih ]VkZ cd hidgV\Z ed^ci
cjXaZjh! idcdeaVhi dg g^WdhdbZh# XnideaVhb Z#\# [gj^i! gddi
;^\jgZ .#&. 6 e]adZb h^ZkZ ijWZ ZaZbZci VcY ^ih XdbeVc^dc XZaa#
gZhe^gVi^dc hiVgX]

5IF QSPEVDUT PG QIPUPTZOUIFTJT
JODMVEJOH TVHBST BOE BNJOP BDJET
;^\jgZ .#'% HdjgXZh! h^c`h VcY bVhh Ó dl
NPWF GSPN MFBG DFMMT
XIJDI BSF B TPVSDF
JOUP UIF QIMPFN 0ODF JO UIF ^c e]adZb#
QIMPFN
UIFZ BSF USBOTMPDBUFE UP TJOL SFHJPOT
TVDI BT HSPXJOH UJTTVF JO UIF
NFSJTUFNT PG SPPUT
CVET BOE TUFNT
PS TUPSBHF PSHBOT MJLF GSVJUT BOE TFFET

"MM UIF NBUFSJBMT UIBU BSF NPWFE CZ USBOTMPDBUJPO BSF EJTTPMWFE JO XBUFS
UP GPSN B TPMVUJPO DBMMFE ATBQ XIJDI BMTP DBSSJFT QMBOU IPSNPOFT 4VHBS JT
VTVBMMZ DBSSJFE BT TVDSPTF
XIJDI FOUFST BOE MFBWFT UIF QIMPFN CZ BDUJWF
USBOTQPSU VTJOH FOFSHZ QSPWJEFE CZ UIF DPNQBOJPO DFMMT 0ODF NBUFSJBMT
IBWF FOUFSFE UIF QIMPFN
UIFZ NPWF QBTTJWFMZ UISPVHIPVU UIF QMBOU

* A^hi lVnh ^c l]^X] V iZggZhig^Va eaVci ^h hjeedgiZY#
+ 8dbeVgZ i]Z higjXijgZ d[ mnaZb VcY e]adZb#
, HiViZ i]Z hjWhiVcXZh i]Vi VgZ XVgg^ZY ^c i]Z mnaZb#
- :meaV^c ]dl b^cZgVa ^dch ZciZg i]Z gddi#
. :meaV^c i]Z ^bedgiVcXZ d[ gddi ]V^gh#
&% A^hi i]Z [VXidgh i]Vi V[[ZXi i]Z gViZ d[ igVche^gVi^dc#

. EA6CI H8>:C8: '',

.#( GZegdYjXi^dc ^c Vc\^dheZgbde]niZh

6hhZhhbZci hiViZbZcih

r %SBX BOE MBCFM B EJBHSBN TIPXJOH UIF TUSVDUVSF PG B EJDPUZMFEPOPVT BOJNBM QPMMJOBUFE ë PXFS
r %JTUJOHVJTI CFUXFFO AQPMMJOBUJPO
AGFSUJMJTBUJPO BOE ATFFE EJTQFSTBM
r %SBX BOE MBCFM B EJBHSBN TIPXJOH UIF FYUFSOBM BOE JOUFSOBM TUSVDUVSF PG B OBNFE EJDPUZMFEPOPVT TFFE
r &YQMBJO UIF DPOEJUJPOT OFFEFE GPS UIF HFSNJOBUJPO PG B UZQJDBM TFFE
r 0VUMJOF UIF NFUBCPMJD QSPDFTTFT EVSJOH UIF HFSNJOBUJPO PG B TUBSDIZ TFFE
r &YQMBJO IPX ë PXFSJOH JT DPOUSPMMFE JO MPOH EBZ BOE TIPSU EBZ QMBOUT
JODMVEJOH UIF SPMF PG QIZUPDISPNF

;adlZgh

5IFSF JT FOPSNPVT WBSJFUZ JO UIF TIBQFT BOE TUSVDUVSFT PG ë PXFST 4PNF
BSF NBMF
TPNF BSF GFNBMF
PUIFST IBWF CPUI NBMF BOE GFNBMF QBSUT 'PS
UIJT SFBTPO
UIFSF JT B IVHF WBSJFUZ JO UIF BQQFBSBODF PG ë PXFST UIBU XF
TFF 'MPXFST BMTP EJĄ FS JO UIF XBZ UIFZ BSF QPMMJOBUFE "OJNBM QPMMJOBUFE
ë PXFST OFFE TUSVDUVSFT UP BUUSBDU B QPMMJOBUPS
XIFSFBT ë PXFST UIBU VTF UIF
XJOE UP DBSSZ UIFJS QPMMFO EP OPU "O FYBNQMF PG BO BOJNBM QPMMJOBUFE
ë PXFS DPOUBJOJOH CPUI NBMF BOE GFNBMF QBSUT JT TIPXO JO 'JHVSF 9.21

8IFO UIF ë PXFS JT JO UIF CVE TUBHF
JU JT TVSSPVOEFE CZ sepals
XIJDI
GPME BSPVOE UIF CVE UP QSPUFDU UIF EFWFMPQJOH ë PXFS "T UIF ë PXFS PQFOT

UIF TFQBMT CFDPNF JOTJHOJê DBOU BOE SFTFNCMF TNBMM ESJFE QFUBMT CFMPX UIF
ë PXFS

Petals PG BOJNBM QPMMJOBUFE ë PXFST BSF PGUFO CSJHIUMZ DPMPVSFE UP BUUSBDU

l]daZ [adlZg

hi^\bV Vci]Zg
hinaZ [^aVbZci
dkVgn
dkjaZ eZiVa

hZeVa

cZXiVgn
hiVa` gZXZeiVXaZ

;^\jgZ .#'& =Va["Ó dlZg d[ lVaaÓ dlZg 9^[_hWdj^ki Y^[_h_ # I]Z Ó dlZg ^h VWdji '#* Xb
^c Y^VbZiZg# >i ^h edaa^cViZY Wn WZZh VcY ]dkZgÓ ^Zh# >ih eZiVah VgZ jhjVaan Wg^\]ian
XdadjgZY VcY [gV\gVci#

''-

JOTFDUT PS PUIFS BOJNBMT UIBU NBZ WJTJU .BOZ IBWF OFDUBS HVJEFT
XIJDI BSF bVaZ \Zgb^cVi^c\
NBSLJOHT PO UIF QFUBMT UIBU UFNQU QPMMJOBUPST EFFQ JOUP UIF ë PXFS \VbZiZh edaaZc \gV^c
hi^\bV
Pollen
DPOUBJOJOH UIF NBMF HBNFUFT
JT QSPEVDFE JO UIF anthers

XIJDI BSF IFME VQ PO MPOH filaments JO NBOZ ë PXFST
TP UIBU BT hinaZ
QPMMJOBUPST FOUFS UIFZ CSVTI QBTU UIF BOUIFST BOE BSF EVTUFE XJUI QPMMFO
edaaZc ijWZ
5IF GFNBMF PSHBOT BSF UIF stigma
style BOE ovary 5IF TUJHNB
SFDFJWFT QPMMFO HSBJOT
XIJDI BSSJWF XJUI QPMMJOBUPST BT UIFZ EFMWF JOUP B dkjaZ
ë PXFS UP PCUBJO OFDUBS 5IF TUJDLZ TUJHNB IBT TVHBST QSFTFOU PO JUT TVSGBDF
UIBU DBVTF QPMMFO HSBJOT UP HFSNJOBUF bVaZ
\VbZiZh
Edaa^cVi^dc VcY [Zgi^a^hVi^dc
b^XgdenaZ
Pollination JT UIF USBOTGFS PG QPMMFO DPOUBJOJOH UIF NBMF HBNFUFT
GSPN
UIF BOUIFS UP UIF TUJHNB 1PMMFO NBZ CF DBSSJFE CZ JOTFDUT
PUIFS BOJNBMT ;^\jgZ .#'' ;Zgi^a^hVi^dc d[ Vc dkjaZ ^c i]Z
TVDI BT CJSET
CBUT PS NJDF

PS CZ UIF XJOE *G QPMMFO USBWFMT GSPN UIF dkVgn d[ V eaVci#
BOUIFST PG POF QMBOU UP UIF TUJHNB PG BOPUIFS QMBOU
UIF QSPDFTT JT LOPXO
BT cross-pollination *G QPMMFO JT EFQPTJUFE PO UIF TUJHNB PG UIF TBNF
QMBOU UIBU QSPEVDFE JU
self-pollination PDDVST 4FMG QPMMJOBUJPO QSPEVDFT
MFTT HFOFUJD WBSJBUJPO UIBO DSPTT QPMMJOBUJPO

Fertilisation PDDVST XIFO NBMF BOE GFNBMF HBNFUFT GVTF UP GPSN B
zygote 5IJT PDDVST JO UIF PWVMF PG UIF ë PXFS 8IFO QPMMFO HSBJOT GSPN B
QMBOU PG UIF SJHIU TQFDJFT BSSJWF PO UIF TUJHNB
UIFZ HFSNJOBUF BOE QSPEVDF
B pollen tube
XIJDI HSPXT EPXO UIF TUZMF UP UIF PWBSZ 'JHVSF 9.22


5IF UVCF FOUFST UIF PWBSZ BOE B QPMMFO OVDMFVT QBTTFT EPXO UIF UVCF UP
GVTF XJUI BOE GFSUJMJTF UIF OVDMFVT PG UIF GFNBMF HBNFUF JO UIF PWVMF

HZZYh

'FSUJMJTFE PWVMFT EFWFMPQ PWFS UJNF JOUP seeds
XIJDI QSPUFDU UIF
EFWFMPQJOH FNCSZP JOTJEF 4FFET BSF IFME XJUIJO B TFFE QPE
GSVJU PS OVU

XIJDI DBO CF EJTQFSTFE UP OFX MPDBUJPOT TP UIBU XIFO UIFZ HFSNJOBUF
UIF
OFX QMBOUT UIBU EFWFMPQ EP OPU DPNQFUF XJUI UIFJS QBSFOUT

1MBOUT IBWF FWPMWFE NBOZ JOHFOJPVT NFBOT CZ XIJDI UP CSJOH BCPVU
seed dispersal " GFX BSF MJTUFE CFMPX

r 4PNF TFFE QPET
TVDI BT UIPTF JO UIF QFB GBNJMZ
NBUVSF BOE ESZ PVU


TP UIFZ FWFOUVBMMZ TOBQ
DBVTJOH UIF TFFE QPE UP PQFO RVJUF TVEEFOMZ

FKFDUJOH UIF TFFET TPNF EJTUBODF GSPN UIF QBSFOU QMBOU

r 'SVJUT DPOUBJOJOH TFFET BSF GSFRVFOUMZ FBUFO CZ CJSET PS BOJNBMT " UBTUZ

GSVJU UFNQUT BO BOJNBM UP FBU BOE EJHFTU JU
CVU UIF UPVHI TFFET JOTJEF JU
QBTT UISPVHI UIF EJHFTUJWF USBDU BOE FNFSHF JO UIF GBFDFT 5IFTF TFFET
NBZ BQQFBS MPOH EJTUBODFT GSPN UIF QBSFOU QMBOU BOE BSF DPOUBJOFE
XJUIJO B SJDI GFSUJMJTFS

r /VUT BSF DPMMFDUFE CZ BOJNBMT MJLF TRVJSSFMT
XIJDI CVSZ UIFN BT B

SFTFSWF PG GPPE GPS UIF XJOUFS 5IFZ NBZ CVSZ TFWFSBM HSPVQT PG OVUT
BOE GBJM UP EJH UIFN BMM VQ EVSJOH UIF XJOUFS 5IF OVUT SFNBJO JO UIF
TPJM SFBEZ UP HFSNJOBUF XIFO DPOEJUJPOT BSF GBWPVSBCMF
4FFET IBWF BMM UIF OFDFTTBSZ DPNQPOFOUT UP FOTVSF TVDDFTTGVM HFSNJOBUJPO
BOE UIF HSPXUI PG B OFX QMBOU 8JUIJO FWFSZ TFFE JT BO FNCSZP SPPU BOE
TIPPU
SFBEZ UP EFWFMPQ XIFO UIF UJNF JT SJHIU 0ODF B TFFE IBT CFFO

. EA6CI H8>:C8: ''.

ZbWgnd gddi GPSNFE JO UIF PWBSZ
JU MPTFT XBUFS TP UIBU JU DBO FOUFS B EPSNBOU QIBTF
BOE OPU EFWFMPQ GVSUIFS VOUJM DPOEJUJPOT GPS HSPXUI BSF GBWPVSBCMF
iZhiV ZbWgnd h]ddi
*OTJEF UIFJS TFFET
EJDPUZMFEPOPVT QMBOUT IBWF UXP TFFE MFBWFT
PS
XdinaZYdch cotyledons
XIJDI TUPSF GPPE SFTFSWFT OFFEFE GPS HFSNJOBUJPO
'JHVSF 9.23
5IF DPUZMFEPOT BSF TVSSPVOEFE CZ B IBSE QSPUFDUJWF TFFE
b^XgdenaZ DPBU DBMMFE UIF testa

;^\jgZ .#'( I]Z bV^c eVgih d[ V .BOZ TFFET IBWF UP FOEVSF RVJUF IBSTI FOWJSPONFOUBM DPOEJUJPOT
TP
Y^XdinaZYdcdjh eaVci hZZY# UIF UFTUB QSPUFDUT UIF EFMJDBUF UJTTVFT JOTJEF *O UIF XBMM PG UIF UFTUB JT B
QPSF DBMMFE UIF micropyle UISPVHI XIJDI XBUFS JT BCTPSCFE UP CFHJO UIF
eajbjaZ l^i] aZVkZh QSPDFTT PG HFSNJOBUJPO

ZbWgnd XdinaZYdc <Zgb^cVi^dc
eaVci
XdinaZYdch Germination JT UIF EFWFMPQNFOU PG UIF TFFE JOUP B OFX QMBOU
'JHVSF 9.24
" EPSNBOU TFFE OFFET UISFF WJUBM GBDUPST UP CF JO QMBDF
iZhiV GPS HFSNJOBUJPO UP PDDVS

hZZY r Temperature m " TVJUBCMF UFNQFSBUVSF JT FTTFOUJBM GPS UIF FO[ZNFT
gVY^XaZ
JO B TFFE UP CFDPNF BDUJWF 5IFZ DBOOPU XPSL JO DPME DPOEJUJPOT
BOE
;^\jgZ .#') <Zgb^cVi^dc VcY ZVgan \gdli] WFSZ IJHI UFNQFSBUVSFT BMTP JOIJCJU UIFJS BDUJWJUZ .BOZ TFFET SFNBJO
^c V Y^XdinaZYdcdjh eaVci# EPSNBOU VOUJM UIF UFNQFSBUVSF JT BU B QBSUJDVMBS MFWFM TP UIBU UIFZ
HFSNJOBUF XIFO UIF TFFEMJOH XJMM IBWF UIF CFTU DIBODF PG TVSWJWBM

r Water m .PTU TFFET DPOUBJO POMZ BCPVU XBUFS
TP XBUFS NVTU CF

UBLFO JO UP TUBSU UIF HFSNJOBUJPO QSPDFTT 8BUFS SFIZESBUFT UIF TFFE BOE
UIF FO[ZNFT DPOUBJOFE XJUIJO JU 5IF FO[ZNFT CSFBL EPXO GPPE TUPSFT
UP QSPWJEF FOFSHZ GPS UIF FNFSHJOH SPPU BOE TUFN

r Oxygen m 5IJT JT FTTFOUJBM UP QSPWJEF FOFSHZ GPS BFSPCJD SFTQJSBUJPO

BZiVWda^hb VcY \Zgb^cVi^dc
(FSNJOBUJPO CFHJOT BT XBUFS JT BCTPSCFE CZ UIF TFFE JO B QSPDFTT LOPXO
BT imbibition 8BUFS FOUFST UISPVHI UIF NJDSPQZMF PG UIF UFTUB

8BUFS SFIZESBUFT TUPSFE GPPE SFTFSWFT JO UIF TFFE BOE
JO B TUBSDIZ
TFFE TVDI BT B CBSMFZ HSBJO
JU USJHHFST UIF FNCSZP QMBOU UP SFMFBTF B QMBOU
HSPXUI IPSNPOF DBMMFE gibberellin 'JHVSF 9.25
5IF HJCCFSFMMJO JO UVSO
TUJNVMBUFT UIF TZOUIFTJT PG amylase CZ UIF DFMMT JO UIF PVUFS aleurone
layer PG UIF TFFE 5IF BNZMBTF IZESPMZTFT TUBSDI NPMFDVMFT JO UIF
endosperm GPPE TUPSF

DPOWFSUJOH UIFN UP TPMVCMF NBMUPTF NPMFDVMFT
5IFTF BSF DPOWFSUFE UP HMVDPTF BOE BSF USBOTQPSUFE UP UIF FNCSZP

QSPWJEJOH B TPVSDF PG DBSCPIZESBUF UIBU DBO CF SFTQJSFE UP QSPWJEF FOFSHZ
BT UIF radicle FNCSZP SPPU
BOE plumule FNCSZP TIPPU
CFHJO UP HSPX

PS VTFE UP QSPEVDF PUIFS NBUFSJBMT OFFEFE GPS HSPXUI
TVDI BT DFMMVMPTF

"CTPSQUJPO PG XBUFS CZ UIF TFFE TQMJUT UIF UFTUB
TP UIBU UIF SBEJDMF BOE
QMVNVMF DBO FNFSHF BOE HSPX 8IFO UIF MFBWFT PG UIF TFFEMJOH IBWF HSPXO
BCPWF HSPVOE
UIFZ DBO CFHJO UP QIPUPTZOUIFTJTF BOE UBLF PWFS GSPN UIF
GPPE TUPSF JO UIF TFFE JO TVQQMZJOH UIF OFFET PG UIF HSPXJOH QMBOU

8dcigda d[ Ó dlZg^c\

"U DFSUBJO UJNFT PG UIF ZFBS
TIPPU NFSJTUFNT QSPEVDF ë PXFST /FBSMZ
ZFBST BHP
QMBOU TDJFOUJTUT EJTDPWFSFE UIBU MJHIU JOë VFODFT UIF UJNJOH
PG ë PXFSJOH JO NBOZ QMBOUT *O UIF NJEEMF PG UIF UI DFOUVSZ
TDJFOUJTUT

'(%

& LViZg jeiV`Z ^c^i^ViZh ( 6aZjgdcZ aVnZg hnci]Zh^hZh
\Zgb^cVi^dc# VbnaVhZ ^c gZhedchZ id
\^WWZgZaa^c#
VaZjgdcZ aVnZg

ZbWgnd

\^WWZgZaa^c VbnaVhZ ) HiVgX] ^h Y^\ZhiZY
id bVaidhZ i]Zc
\ajXdhZ id hjeean
i]Z ZbWgnd#

hiVgX] bVaidhZ

iZhiV ZcYdheZgb i^hhjZ
XdciV^c^c\ hiVgX]
' :bWgnd hnci]Zh^hZh \^WWZgZaa^c ^c gZhedchZ id lViZg jeiV`Z# gZhZgkZh

;^\jgZ .#'* Adc\^ijY^cVa hZXi^dc i]gdj\] V WVgaZn hZZY! h]dl^c\ ]dl hZXgZi^dc
d[ \^WWZgZaa^c Wn i]Z ZbWgnd gZhjaih ^c i]Z bdW^a^hVi^dc d[ hiVgX] gZhZgkZh Yjg^c\
\Zgb^cVi^dc#

TIPXFE UIBU UIF QFSJPE PG EBSLOFTT JT UIF DSJUJDBM GBDUPS JO DPOUSPMMJOH 4PNF TIPSU EBZ QMBOUT
TVDI BT
ë PXFSJOH Photoperiodism JT UIF UFSN HJWFO UP QMBOUT SFTQPOTFT UP UIF QPJOTFUUJBT PS DISZTBOUIFNVNT

SFMBUJWF QFSJPET PG EBSLOFTT BOE MJHIU BSF DPNNFSDJBMMZ QSPEVDFE TP
UIBU UIFZ ë PXFS BU BOZ UJNF PG
r Long-day plants ë PXFS XIFO EBZT BSF MPOHFTU BOE UIF OJHIUT BSF ZFBS )PSUJDVMUVSBMJTUT HSPX UIFN
JO TIBEFE HMBTTIPVTFT XIFSF BO
TIPSU " MPOH EBZ QMBOU SFRVJSFT MFTT UIBO B DFSUBJO OVNCFS PG IPVST PG FYUFOEFE QFSJPE PG EBSLOFTT
EBSLOFTT JO FBDI IPVS QFSJPE UP JOEVDF ë PXFSJOH *O UIF OPSUIFSO JOEVDFT UIFN UP QSPEVDF ë PXFST
IFNJTQIFSF
UIFTF QMBOUT ë PXFS EVSJOH MBUF TQSJOH PS FBSMZ TVNNFS
"QSJM UP +VMZ
BT EBZT CFDPNF MPOHFS BOE QFSJPET PG EBSLOFTT EFDSFBTF . EA6CI H8>:C8: '(&
5IJT TJUVBUJPO JT SFWFSTFE JO UIF TPVUIFSO IFNJTQIFSF
XIFSF MPOH EBZ
QMBOUT ë PXFS CFUXFFO 4FQUFNCFS BOE %FDFNCFS &YBNQMFT PG MPOH EBZ
QMBOUT BSF DBSOBUJPOT
DMPWFS BOE SZFHSBTT

r Short-day plants ë PXFS BT OJHIUT CFDPNF MPOHFS BOE EBZT BSF TIPSUFS

*O UIF OPSUIFSO IFNJTQIFSF UIJT JT EVSJOH UIF MBUF TVNNFS PS BVUVNO
GBMM
5IFZ SFRVJSF B DPOUJOVPVT QFSJPE PG EBSLOFTT CFGPSF ë PXFSJOH
BOE UIF EBSL QFSJPE NVTU CF MPOHFS UIBO B DSJUJDBM MFOHUI 5IF MFOHUI PG
UIF EBSL QFSJPE EJĄ FST CFUXFFO TQFDJFT &YBNQMFT PG TIPSU EBZ QMBOUT
BSF DISZTBOUIFNVN
QPJOTFUUJB
DPĄ FF BOE UPCBDDP
XIJDI SFRVJSF
m IPVST PG EBSLOFTT JO B IPVS QFSJPE CFGPSF UIFZ XJMM ë PXFS
4IPSU EBZ QMBOUT DBOOPU ë PXFS JG UIF QFSJPE PG EBSLOFTT JT JOUFSSVQUFE
CZ B QVMTF PG BSUJê DJBM MJHIU TIPOF PO UIFN FWFO GPS KVTU B GFX NJOVUFT
1MBOUT SFTQPOE UP QFSJPET PG EBSLOFTT VTJOH B MFBG QJHNFOU DBMMFE
phytochrome 5IJT QJHNFOU DBO FYJTU JO UXP JOUFS DPOWFSUJCMF GPSNT m
JOBDUJWF 1r BOE BDUJWF 1GS
"DUJWF 1GS JT QSPEVDFE GSPN JOBDUJWF 1r EVSJOH EBZMJHIU IPVST 5IF
DPOWFSTJPO PDDVST SBQJEMZ JO SFTQPOTF UP BO JODSFBTF JO SFE MJHIU ON


XIJDI JT BCTPSCFE CZ 1r *O EBSLOFTT
1GS SFWFSUT TMPXMZ UP UIF NPSF
TUBCMF 1r

SFE MJHIU ON


Pr 1GS n SFTQPOTF

GBS SFE MJHIU ON


EBSLOFTT

%VSJOH MPOH EBZT
JODSFBTFE BNPVOUT PG 1GS QSPNPUF ë PXFSJOH JO MPOH

EBZ QMBOUT 'MPXFSJOH JO TIPSU EBZ QMBOUT JT JOIJCJUFE CZ 1GS
CVU EVSJOH
MPOH OJHIUT
TVą DJFOU 1GS JT SFNPWFE UP BMMPX UIFN UP ë PXFS

5IF FYBDU NFDIBOJTN PG QIZUPDISPNF BDUJPO JT OPU GVMMZ VOEFSTUPPE
CVU JU JT UIPVHIU UIBU JU DBVTFT DIBOHFT JO UIF FYQSFTTJPO PG HFOFT
DPODFSOFE XJUI ë PXFSJOH

&& :meaV^c l]n iZbeZgVijgZ ^h Vc ^bedgiVci [VXidg ^c i]Z egdXZhh d[
\Zgb^cVi^dc#

&' 9^hi^c\j^h] WZilZZc Èedaa^cVi^dcÉ VcY È[Zgi^a^hVi^dcÉ#

&( CVbZ i]Z bVaZ eVgih d[ Vc Vc\^dheZgb Ó dlZg#

&) Djia^cZ l]n ^i ^h ^bedgiVci [dg hZZYh id WZ Y^heZghZY#

:cY"d["X]VeiZg fjZhi^dch



1 8IJDI PG UIF GPMMPXJOH TUBUFNFOUT DPODFSOJOH QMBOU TUSVDUVSF BOE HSPXUI JT DPSSFDU


" 5IF WFJOT JO B MFBG TFSWF CPUI UP TVQQPSU UIF MFBG BOE BDU BT B USBOTQPSU TZTUFN
# .POPDPUZMFEPOPVT QMBOUT IBWF BQJDBM BOE MBUFSBM NFSJTUFNT
$ *O BO BQJDBM NFSJTUFN
DFMM EJWJTJPO CZ NJUPTJT SFTVMUT JO BO JODSFBTF JO UIF EJBNFUFS

PG UIF TUFN
% 1PTJUJWF QIPUPUSPQJTN JT EVF UP JODSFBTFE HSPXUI BT B SFTVMU PG BVYJO BDDVNVMBUJOH

PO UIF JMMVNJOBUFE TJEF PG B TIPPU

2 8IJDI PG UIF GPMMPXJOH TUBUFNFOUT DPODFSOJOH USBOTQPSU JO BOHJPTQFSNPQIZUFT JT DPSSFDU

" " QMBOU MPTFT TVQQPSU JG JUT DFMMT JODSFBTF UIFJS UVSHPS
# 'VOHBM IZQIBF DBO QMBZ BO JNQPSUBOU QBSU JO UIF VQUBLF PG NJOFSBM JPOT JOUP UIF

SPPU PG B QMBOU
$ .JOFSBM JPOT DBO POMZ NPWF JOUP QMBOU SPPU IBJST BT B SFTVMU PG BDUJWF USBOTQPSU
% 5SBOTQJSBUJPO JT UIF ë PX PG XBUFS UISPVHI UIF QIMPFN UJTTVF PG B QMBOU

3 8IJDI PG UIF GPMMPXJOH TUBUFNFOUT DPODFSOJOH USBOTQPSU JO BOHJPTQFSNPQIZUFT JT DPSSFDU

" $PIFTJPO JT JNQPSUBOU JO NBJOUBJOJOH B DPMVNO PG XBUFS JO YZMFN WFTTFMT XIFO
USBOTQJSBUJPO DBVTFT B USBOTQJSBUJPO QVMM

# 5IF QMBOU IPSNPOF BCTDJTJD BDJE DBVTFT BO JODSFBTF JO USBOTQJSBUJPO
$ "O JODSFBTF JO IVNJEJUZ XJMM MFBE UP BO JODSFBTF JO USBOTQJSBUJPO
% 1IMPFN JT JOWPMWFE JO UIF USBOTQJSBUJPO PG TVHBS

'('

4 8IJDI PG UIF GPMMPXJOH TUBUFNFOUT DPODFSOJOH SFQSPEVDUJPO JO BOHJPTQFSNPQIZUFT JT DPSSFDU


" 5SBOTGFS PG QPMMFO GSPN UIF TUJHNB UP UIF BOUIFS SFTVMUT JO QPMMJOBUJPO
# *O B EJDPUZMFEPOPVT TFFE
UIF NJDSPQZMF JT QBSU PG UIF FNCSZP SPPU
$ %VSJOH HFSNJOBUJPO
QSPEVDUJPO PG HJCCFSFMMJO JO UIF DPUZMFEPOT PQFOT UIF NJDSPQZMF

UP BMMPX XBUFS BCTPSQUJPO
% *O B MPOH EBZ QMBOU
ë PXFSJOH JT QSPNPUFE BT B SFTVMU PG BO JODSFBTF JO UIF QSPQPSUJPO

PG 1GS DPNQBSFE UP 1r

5 &YQMBJO UIF SPMF PG BVYJO JO QIPUPUSPQJTN


6 0VUMJOF UIF NPWFNFOU PG XBUFS JO QMBOUT GSPN SPPU UP MFBG
JODMVEJOH UIF FĄ FDUT PG FOWJSPONFOUBM BCJPUJD

GBDUPST PO UIF SBUF PG USBOTQPSU

7 &YQMBJO IPX NBOJQVMBUJOH EBZ MFOHUI JT VTFE CZ DPNNFSDJBM ë PXFS HSPXFST


8 %FTDSJCF UIF NFUBCPMJD FWFOUT PG HFSNJOBUJPO JO B TUBSDIZ TFFE


9 0VUMJOF UIF SPMF PG UIF QIMPFN JO UIF BDUJWF USBOTMPDBUJPO PG GPPE NPMFDVMFT


10 4FFE EJTQFSTBM JT JNQPSUBOU JO UIF NJHSBUJPO PG QMBOUT GSPN POF BSFB UP BOPUIFS BSFB 1MBOUT IBWF FWPMWFE
NBOZ NFUIPET
CPUI QIZTJDBM BOE CJPMPHJDBM
CZ XIJDI UP EJTQFSTF UIFJS TFFET

NBQMF TFFET
XIJDI BSF XJOE EJTQFSTFE
XFSF ESPQQFE POF BU B UJNF GSPN UXP EJĄ FSFOU IFJHIUT
N
BOE N SFTQFDUJWFMZ 5IF IJTUPHSBNT CFMPX TIPX UIF EJTUSJCVUJPO PG UIF EJTUBODF UIF NBQMF TFFET USBWFMMFE

&- &, &- &,
&+
&+ &* ]Z^\]i 2 %#*) b ]Z^\]i 2 &%#- b

&) &)

&'CjbWZg d[ hZZYh &'
CjbWZg d[ hZZYh
&% &% .
-
- ,

+ * +*
) ) )
'' ( ( ) ((

& ' &&

% %

&&&&&%-)'+%%%%%+')- %%%%%iiiii dddddiiiii ddddd'&&&& %*&(,*.(,&..%.......
&&&*'-.' +(%diiii& k ddddiiii Zddddg &'&& '-*%,)&###'####'...)....)

9^hiVcXZ igVkZaaZY $ Xb 9^hiVcXZ igVkZaaZY $ b

hdjgXZ/ hijYZci ZmeZg^bZci! <jgVac^X`

a *EFOUJGZ UIF EJTUBODF USBWFMMFE CZ UIF HSFBUFTU OVNCFS PG TFFET ESPQQFE GSPN

i IFJHIU N

i i IFJHIU N


b 4UBUF UIF FĄ FDU PG IFJHIU PO TFFE EJTQFSTBM

c 4VHHFTU two SFBTPOT GPS UIF FĄ FDU PG UIF ESPQ IFJHIU PO UIF EJTUBODF USBWFMMFE CZ UIF TFFET

. EA6CI H8>:C8: '((

5IF GPMMPXJOH HSBQIT TIPX UIF SBUF BOE UJNJOH PG TFFE SFMFBTF GSPN EJĄ FSFOU TQFDJFT PG HSBTT JO UIF TBNF BSFB
EVSJOH UIF TVNNFS

&%% &%%
<[ijkYW hkXhW >ebYki bWdWjki

GViZ d[ hZZY [Vaa $ *% *% GViZ d[ hZZY [Vaa $
cjbWZg lZZ`Ä& &%% XbÄ' cjbWZg lZZ`Ä& &%% XbÄ'

% &+ (% % &+ (%
&) '& '- * &' &. '+ ' 6j\jhi &) '& '- * &' &. '+ ' 6j\jhi
?jcZ ?jan ?jcZ ?jan

GViZ d[ hZZY [Vaa $ +%% GViZ d[ hZZY [Vaa $ )%%
cjbWZg lZZ`Ä& &%% XbÄ' 7]heij_i ijebed_\[hW cjbWZg lZZ`Ä& &%% XbÄ' FeW jh_l_Wb_i

)%% (%%

'%% '%%

&%%

% &+ (% % &+ (%
&) '& '- * &' &. '+ ' 6j\jhi &) '& '- * &' &. '+ ' 6j\jhi
?jcZ ?jan ?jcZ ?jan

hdjgXZ/ ? A =VgeZg &.., FefkbWj_ed 8_ebe]o e\ FbWdji! 6XVYZb^X EgZhh =VgXdjgi 7gVXZ ?dkVcdk^X] ! e#*,

d *EFOUJGZ UIF HSBTT TQFDJFT UIBU QSPEVDFT UIF NPTU TFFET JO UIJT BSFB

e *EFOUJGZ UIF HSBTT TQFDJFT UIBU QSPEVDFT UIF NPTU TFFET JO +VOF

f $PNQBSF TFFE QSPEVDUJPO GPS BMM TQFDJFT SFMBUJWF UP UIF UJNJOH PG UIFJS SFMFBTF

g 4VHHFTU two CFOFê UT GPS UIFTF QMBOUT JO UIF UJNJOH PG TFFE SFMFBTF


'()

#JPMPHJDBM TFFE EJTQFSTBM JT VTVBMMZ EFQFOEFOU PO UIF OVUSJUJPOBM DPOUFOU PG UIF TFFE PS GSVJU 5IF GPMMPXJOH
UBCMF HJWFT UIF OVUSJUJPOBM DPOUFOU GPS GSVJUT PG EJĄ FSFOU TQFDJFT JO UFNQFSBUF BOE USPQJDBM DMJNBUFT

8dbbdc cVbZ d[ eaVci EZgXZciV\Z d[ [gj^i Wn Ygn lZ^\]i 9^heZghVa V\Zcih
][dki
EgdiZ^c A^e^Y 8VgWd]nYgViZ

IZbeZgViZ

XgVcWZggn LWYY_d_kc ( + -. W^gYh
]Vli]dgc 9hWjW[]ki ' ' ,( W^gYh
e^c X]Zggn Fhkdki - ( -) W^gYh
ed`ZWZggn F^ojebWYYW &) ' +- W^gYh
higVlWZggn <hW]Wh_W + ) -- W^gYh

Igde^XVa W^gYh
WVih
W^gY eVab 9^WcW[Zeh[W &) &+ ** W^gYh
bdc`Znh
Ò \ <_Yki , ) ,. W^gYh

b^hiaZidZ L_iYkc + *( (-

bdc`Zn [gj^i J[jhW]Wijh_i & ) .)

L^aY cjibZ\ L_hebW ' +( .

hdjgXZ/ = =dlZ VcY A LZhiaZn &.-- ;Yebe]_YWb H[bWj_edi^_f e\ FbWdji WdZ 7d_cWbi! Dm[dgY Jc^kZgh^in EgZhh! e# &'&

h $PNQBSF USPQJDBM GSVJUT UP UFNQFSBUF GSVJUT JO SFMBUJPO UP UIF NFBO WBMVFT GPS MJQJE
DBSCPIZESBUF BOE

QSPUFJO DPOUFOU

i &YQMBJO XIJDI GSVJU XPVME IBWF UIF IJHIFTU FOFSHZ DPOUFOU


j 4VHHFTU one BEWBOUBHF BOE one EJTBEWBOUBHF PG EJTQFSTBM PG TFFET CZ BOJNBMT


(total 17 marks)
¥ *# 0SHBOJ[BUJPO

. EA6CI H8>:C8: '(*

&% <ZcZi^Xh >>

>cigdYjXi^dc

$IBQUFS 4 EFBMU XJUI NFJPTJT
IPX HBNFUFT BSF QSPEVDFE BOE IPX UIF HFOFT UIFZ DBSSZ BĄ FDU
IVNBO DIBSBDUFSJTUJDT 4JOHMF HFOFT BOE NPOPIZCSJE HFOFUJD DSPTTFT QSPEVDF WBSJBUJPO
BOE NVMUJQMF
BMMFMFT
TVDI BT UIPTF UIBU DPOUSPM CMPPE HSPVQT
JODSFBTF UIF QPTTJCMF WBSJFUZ TUJMM GVSUIFS )FSF
XF
DPOTJEFS EJIZCSJE DSPTTFT m UIF TJNVMUBOFPVT JOIFSJUBODF PG UXP QBJST PG DIBSBDUFSJTUJDT
XIJDI
JOWPMWF NPSF UIBO POF HFOF 8F TFF IPX UIF QSPDFTTFT PG SBOEPN BTTPSUNFOU BOE DSPTTJOH PWFS PG
IPNPMPHPVT DISPNPTPNFT SFTVMU JO FOPSNPVT WBSJFUZ BNPOH JOEJWJEVBMT 7FSZ GFX DIBSBDUFSJTUJDT
BSF DPOUSPMMFE CZ TJOHMF HFOFT BOE XIFO B OVNCFS PG HFOFT DPOUSPM B DIBSBDUFSJTUJD
UIF QIFOPUZQF
JT EFUFSNJOFE CZ UIFJS DPNCJOFE FĄ FDU 5IFTF HSPVQT PG HFOFT BSF LOPXO BT QPMZHFOFT
BOE QSPEVDF
UIF WBSJFUZ UIBU JT FTTFOUJBM GPS FWPMVUJPO

&%#& BZ^dh^h

6hhZhhbZci hiViZbZcih

r %FTDSJCF UIF CFIBWJPVS PG UIF DISPNPTPNFT JO UIF QIBTFT PG NFJPTJT
r 0VUMJOF UIF GPSNBUJPO PG DIJBTNBUB JO UIF QSPDFTT PG DSPTTJOH PWFS
r &YQMBJO IPX NFJPTJT SFTVMUT JO BO FĄ FDUJWFMZ JOê OJUF HFOFUJD WBSJFUZ JO HBNFUFT UISPVHI DSPTTJOH PWFS JO QSPQIBTF *

BOE SBOEPN PSJFOUBUJPO JO NFUBQIBTF *

r 4UBUF .FOEFM T MBX PG JOEFQFOEFOU BTTPSUNFOU
r &YQMBJO UIF SFMBUJPOTIJQ CFUXFFO .FOEFM T MBX PG JOEFQFOEFOU BTTPSUNFOU BOE NFJPTJT

;jcXi^dch d[ bZ^dh^h

.FJPTJT JT FTTFOUJBM JO BMM PSHBOJTNT UIBU SFQSPEVDF TFYVBMMZ CFDBVTF BU
GFSUJMJTBUJPO
XIFO UXP IBQMPJE HBNFUFT NFFU
UIF DISPNPTPNF OVNCFS PG
UIF [ZHPUF CFDPNFT UIF EJQMPJE OVNCFS GPS UIF PSHBOJTN

.FJPTJT IBT UXP GVODUJPOT

r Halving the chromosome number m .FJPTJT DPOTJTUT PG UXP

OVDMFBS EJWJTJPOT NFJPTJT * BOE **
CVU UIF DISPNPTPNFT SFQMJDBUF
POMZ PODF
TP UIF GPVS SFTVMUJOH EBVHIUFS DFMMT FBDI IBWF IBMG UIF
DISPNPTPNF OVNCFS PG UIF QBSFOU DFMM

r Producing genetic variety m 5IJT PDDVST JO UXP XBZT UISPVHI

DSPTTJOH PWFS EVSJOH QSPQIBTF *
BOE UISPVHI SBOEPN BTTPSUNFOU
EVSJOH NFUBQIBTF * *O BEEJUJPO
SBOEPN GFSUJMJTBUJPO BMTP QSPEVDFT
WBSJFUZ TJODF BOZ HBNFUF IBT BO FRVBM DIBODF PG DPNCJOJOH XJUI BOZ
PUIFS HBNFUF

'(+

7Z]Vk^djg d[ X]gdbdhdbZh Yjg^c\ bZ^dh^h -PPL CBDL BU 'JHVSF 4.5 PO QBHF
72 UP SFNJOE ZPVSTFMG PG UIF TUBHFT
8gdhh^c\ dkZg PG NFJPTJT

%VSJOH QSPQIBTF *
DISPNPTPNFT TIPSUFO BOE DPJM )PNPMPHPVT QBJST
PG DISPNPTPNFT DPNF UPHFUIFS UP GPSN B CJWBMFOU TP UIBU NBUFSOBM
BOE QBUFSOBM DISPNPTPNFT BSF OFYU UP POF BOPUIFS 'JHVSF 10.1

)PNPMPHPVT DISPNPTPNFT DPOUBJO UIF TBNF HFOFT
CVU TJODF UIFZ
DBNF GSPN EJĄ FSFOU QBSFOUT
UIFZ DBO IBWF EJĄ FSFOU BMMFMFT "T UIFZ MJOF
VQ UPHFUIFS
UIF OPO TJTUFS DISPNBUJET NBZ UPVDI BOE CSFBL 5IF UXP
TFHNFOUT NBZ UIFO SFKPJO BU UIF DPSSFTQPOEJOH QPTJUJPO PO UIF PUIFS

6h lZaa Vh i]Z gZY ]V^g adXjh! X]gdbdhdbZ )
X]gdbdhdbZ ) Vahd ]Vh V adXjh [dg V
\ZcZ XdY^c\ [dg YdeVb^cZ gZXZeidgh# YdeVb^cZ YdeVb^cZ
>bV\^cZ i]Vi i]ZgZ VgZ ild Y^[[ZgZci VaaZaZh gZXZeidg gZXZeidg
d[ i]^h \ZcZ# VaaZaZ & VaaZaZ '

gZY ]V^g VaaZaZ cdi gZY ]V^g VaaZaZ

I]Z X]gdbdhdbZh XdjaY Yd i]^h ½ dg i]Z^g X]gdbVi^Yh XdjaY Xgdhh dkZg a^`Z i]^h ½

I]Z gZhjai d[ i]^h I]Z WgZV`V\Z VcY X]^VhbV
^h i]Vi gZY ]V^g VcY gZ_d^c^c\ d[ X]gdbVi^Yh ^c
YdeVb^cZ gZXZeidg i]^h Xgdhh^c\ dkZg Vaadlh
VaaZaZ & ldjaY cZl XdbW^cVi^dch d[ i]Z
WZ ^c]Zg^iZY VaaZaZh id WZ egdYjXZY#
id\Zi]Zg#

Ild cZl
XdbW^cVi^dch
d[ VaaZaZh dc V
X]gdbdhdbZ#

;^\jgZ &%#& =dl Xgdhh^c\ dkZg egdYjXZh kVg^Vi^dc# >[ V h^c\aZ Xgdhh"dkZg dXXjgh ^c V eV^g d[ X]gdbdhdbZh! [djg Y^[[ZgZci YVj\]iZg
X]gdbVi^Yh VgZ egdYjXZY ^chiZVY d[ ild#

&% <:C:I>8H >> '(,

$SPTTJOH PWFS EPFT OPU DISPNBUJE *O UIJT XBZ
DISPNBUJET BSF GPSNFE UIBU BSF B NJYUVSF PG
PDDVS CFUXFFO UIF 9 BOE : QBUFSOBM BOE NBUFSOBM BMMFMFT 5IF SFHJPO XIFSF UIJT IBQQFOT JT DBMMFE B
DISPNPTPNFT 5IJT JT CFDBVTF NBOZ chiasma QMVSBM chiasmata

PG UIF HFOFT UIFZ DBSSZ EFUFSNJOF
HFOEFS BOE TP OFFE UP SFNBJO PO 5IF QPJOU BU XIJDI B DIJBTNB GPSNT JT MBSHFMZ SBOEPN )PXFWFS

UIFJS SFTQFDUJWF DISPNPTPNFT OPU BMM DISPNBUJET XJMM GPSN DIJBTNBUB BOE UIFZ OFWFS PDDVS BU BMM PO
TPNF DISPNPTPNFT *O UIJT XBZ
TPNF DISPNBUJET XJMM SFUBJO UIFJS GVMM
>bV\^cZ WdYn XZaah XdciV^c^c\ dcZ DPNQMFNFOU PG QBUFSOBM PS NBUFSOBM BMMFMFT 5IJT JT TIPXO JO 'JHVSF 10.1
eV^g d[ VaaZaZh [dg gZY ]V^g $ cdi gZY GPS UXP QBJST PG BMMFMFT GPS B EPQBNJOF SFDFQUPS HFOF BOE B IBJS DPMPVS
]V^g VcY Vcdi]Zg [dg WajZ Xdadjg HFOF
PO IVNBO DISPNPTPNF
Wa^cYcZhh $ cdgbVa WajZ k^h^dc#
8]gdbdhdbZh [gdb i]Z [Vi]Zg GVcYdb dg^ZciVi^dc d[ X]gdbdhdbZh
VgZ h]dlc ^c WajZ VcY [gdb i]Z
bdi]Zg ^c \gZn# %VSJOH NFUBQIBTF *
UIF CJWBMFOUT MJOF VQ PO UIF FRVBUPS BOE TQJOEMF
NJDSPUVCVMFT CFDPNF BUUBDIFE UP UIFJS DFOUSPNFSFT )PXFWFS
UIF XBZ
JO XIJDI UIFZ MJOF VQ JT SBOEPN 5IJT JT TIPXO JO 'JHVSF 10.2
XIJDI
JMMVTUSBUFT UIF QPTTJCJMJUJFT GPS KVTU UXP DISPNPTPNFT
BOE

X]gdbdhdbZ ) X]gdbdhdbZ ,

gZY ]V^g cdi gZY WajZ Xdadjg cdgbVa WajZ
VaaZaZ ]V^g VaaZaZ Wa^cYcZhh VaaZaZ k^h^dc VaaZaZ

6i bZiVe]VhZ >! W^kVaZcih [dg X]gdbdhdbZh ) dg i]Zn XdjaY Va^\c a^`Z i]^h######
VcY , XdjaY Va^\c a^`Z i]^h#####

I]Z gZhjai d[ i]^h ^h i]Vi I]Z gZhjai d[ i]^h ^h i]Vi gZY ]V^g
gZY ]V^g VcY WajZ Xdadjg VcY cdgbVa WajZ k^h^dc \ZcZh
Wa^cYcZhh \ZcZh ldjaY WZ ldjaY WZ ^c]Zg^iZY id\Zi]Zg#
^c]Zg^iZY id\Zi]Zg

;^\jgZ &%#' =dl ^cYZeZcYZci VhhdgibZci egdYjXZh kVg^Vi^dc#
'(-

r 5IF QBUFSOBM DISPNPTPNFT DPVME CPUI MJOF VQ UPHFUIFS PO POF TJEF PG

UIF FRVBUPS XJUI UIF NBUFSOBM POFT PO UIF PUIFS TJEF
BT TIPXO PO UIF
MFGU JO 'JHVSF 10.2 5XP PG UIF HBNFUFT UIBU BSF QSPEVDFE UIFO DPOUBJO
KVTU QBUFSOBM DISPNPTPNFT XIJMF UIF PUIFS UXP DPOUBJO KVTU NBUFSOBM
DISPNPTPNFT

r "OPUIFS QPTTJCJMJUZ JT UIBU UIF DISPNPTPNFT MJOF VQ BT TIPXO PO UIF

SJHIU JO 'JHVSF 10.2
XJUI NBUFSOBM BOE QBUFSOBM DISPNPTPNFT PO CPUI
TJEFT PG UIF FRVBUPS 5IF FOE SFTVMU IFSF JT UIBU BMM GPVS HBNFUFT DPOUBJO
B NJYUVSF PG QBUFSOBM BOE NBUFSOBM DISPNPTPNFT

& Add` XVgZ[jaan Vi i]Z Z^\]i \VbZiZh ^c ;^\jgZ &%#'# =dl bVcn Y^[[ZgZci
\VbZiZh VgZ i]ZgZ4

:PVS BOTXFS TIPVME CF UIBU UIFSF BSF GPVS EJĄ FSFOU HBNFUFT /PX
DPOTJEFS XIBU IBQQFOT JG B UIJSE QBJS PG DISPNPTPNFT JT BEEFE 5IF
OVNCFS PG HFOFUJDBMMZ EJĄ FSFOU HBNFUFT XJMM JODSFBTF UP FJHIU

5IF OVNCFS PG QPTTJCMF HFOFUJD DPNCJOBUJPOT UIBU DBO PDDVS BT B
SFTVMU PG SBOEPN PSJFOUBUJPO PG DISPNPTPNFT JT WBTU *G POMZ DISPNPTPNF
DPNCJOBUJPOT JO B IBQMPJE DFMM BSF DPOTJEFSFE
UIF ê HVSF JT n XIFSF n JT
UIF IBQMPJE OVNCFS 'PS IVNBOT
n TP UIF QPTTJCMF DPNCJOBUJPOT BSF
PWFS NJMMJPO GPS KVTU POF HBNFUF 5IF GPSNVMB DBO CF VTFE UP XPSL PVU
UIF DPNCJOBUJPOT JO 'JHVSF 10.2 m GPS UXP QBJST PG DISPNPTPNFT

n
TP UIF OVNCFS PG QPTTJCMF DPNCJOBUJPOT 8JUI UISFF QBJST
PG DISPNPTPNFT
UIF OVNCFS PG QPTTJCMF DPNCJOBUJPOT

BZ^dh^h VcY kVg^Zin
5IF DBMDVMBUJPO PG UIF OVNCFS PG HFOFUJD QPTTJCJMJUJFT JO HBNFUFT VTJOH
UIF GPSNVMB n DBO POMZ CF BO BQQSPYJNBUJPO *U EPFT OPU BDDPVOU GPS UIF
GBDU UIBU UIFSF BSF UXP UZQFT PG HBNFUFT m NBMF BOE GFNBMF "MTP JU EPFT
OPU JODMVEF UIF FYUSB WBSJBUJPO UIBU BSJTFT GSPN DSPTTJOH PWFS *G B TJOHMF
DSPTT PWFS PDDVST UIFO UIF OVNCFS PG DPNCJOBUJPOT JT EPVCMFE
BT TIPXO
JO 'JHVSF 10.1 4JODF TFWFSBM DSPTTPWFST OPSNBMMZ PDDVS EVSJOH B NFJPUJD
EJWJTJPO
JU JT DMFBS UIBU UIF BNPVOU PG HFOFUJD WBSJFUZ JT BMNPTU JOê OJUF
FWFO JO PSHBOJTNT UIBU POMZ IBWF B TNBMM IBQMPJE OVNCFS

BZ^dh^h VcY BZcYZaÉh aVl d[ ^cYZeZcYZci VhhdgibZci
(SFHPS .FOEFM T AMBX PG JOEFQFOEFOU BTTPSUNFOU TUBUFT UIBU

8IFO HBNFUFT BSF GPSNFE
UIF TFQBSBUJPO PG POF QBJS PG BMMFMFT JOUP UIF
OFX DFMMT JT JOEFQFOEFOU PG UIF TFQBSBUJPO PG BOZ PUIFS QBJS PG BMMFMFT

0S

&JUIFS PG B QBJS PG BMMFMFT JT FRVBMMZ MJLFMZ UP CF JOIFSJUFE XJUI FJUIFS PG
BOPUIFS QBJS

3BOEPN BTTPSUNFOU EVSJOH NFUBQIBTF * DBO QSPEVDF WBSJFUZ JO UIF
HBNFUFT BT TIPXO JO 'JHVSF 10.2 )PX UIJT SFMBUFT UP .FOEFM T MBX PG

&% <:C:I>8H >> '(.

eVgZciVa \ZcdineZ 6V7W 67 VW 6 XZaa XdjaY \d i]gdj\]
6V 67 VW bZ^dh^h VcY egdYjXZ i]ZhZ
\VbZiZh! ^[ Wdi] eViZgcVa
7W \VbZiZh ]dbdad\jZh \d id i]Z hVbZ
ZfjVidg edaZ ^c bZ^dh^h >! VcY Wdi]
bViZgcVa ]dbdad\jZh \d id
i]Z deedh^iZ edaZ#

6V

6W V7 Dg ^i XdjaY egdYjXZ i]ZhZ
\VbZiZh ^[ ZVX] eViZgcVa
]dbdad\jZ VcY ZVX]
bViZgcVa ]dbdad\jZ \dZh
@Zn id Vc deedh^iZ edaZ ^c
bViZgcVa 6W V7 bZ^dh^h >#

eViZgcVa W7

ZfjVidg \VbZiZh

;^\jgZ &%#( BZ^dh^h VcY BZcYZaÉh aVl d[ ^cYZeZcYZci VhhdgibZci#

JOEFQFOEFOU BTTPSUNFOU GPS UXP QBJST PG DISPNPTPNFT DBSSZJOH UIF BMMFMFT
Aa BOE Bb JT TIPXO JO 'JHVSF 10.3

"T B SFTVMU PG UIF SBOEPN BMJHONFOU
UIF A BMMFMF IBT BO FRVBM DIBODF PG
CFJOH JO B HBNFUF XJUI FJUIFS UIF B BMMFMF PS UIF b BMMFMF
BOE TJNJMBSMZ UIF
a BMMFMF IBT BO FRVBM DIBODF PG CFJOH JO B HBNFUF XJUI FJUIFS UIF B BMMFMF
PS UIF b BMMFMF 5IVT
GPVS UZQFT PG HBNFUF DBO CF QSPEVDFE DBSSZJOH UIF
BMMFMFT AB
Ab
aB PS ab 5IFZ XJMM PDDVS JO UIF SBUJP

&%#' 9^]nWg^Y XgdhhZh VcY \ZcZ a^c`V\Z

6hhZhhbZci hiViZbZcih

r $BMDVMBUF BOE QSFEJDU UIF HFOPUZQF BOE QIFOPUZQF SBUJP PG PĄ TQSJOH PG EJIZCSJE DSPTTFT JOWPMWJOH VOMJOLFE

BVUPTPNBM HFOFT

r %JTUJOHVJTI CFUXFFO ABVUPTPNFT BOE ATFY DISPNPTPNFT
r &YQMBJO IPX DSPTTJOH PWFS CFUXFFO OPO TJTUFS DISPNBUJET PG B IPNPMPHPVT QBJS JO QSPQIBTF * DBO SFTVMU JO BO

FYDIBOHF PG BMMFMFT

r %Fê OF AMJOLBHF HSPVQ
r &YQMBJO BO FYBNQMF PG B DSPTT CFUXFFO UXP MJOLFE HFOFT
r *EFOUJGZ XIJDI PG UIF PĄ TQSJOH BSF SFDPNCJOBOUT JO B EJIZCSJE DSPTT JOWPMWJOH MJOLFE HFOFT

')%

<ZcdineZh VcY \VbZiZh

%JIZCSJE DSPTTFT JOWPMWF DIBSBDUFSJTUJDT UIBU BSF DPOUSPMMFE CZ UXP HFOFT *O
B EJIZCSJE HFOPUZQF
UIFSF BSF UXP QBJST PG BMMFMFT UP DPOTJEFS 'JHVSF 10.3
TIPXT XIBU IBQQFOT EVSJOH NFJPTJT JO B QBSFOU XJUI UIF HFOPUZQF AaBb
&BDI QBJS PG BMMFMFT DBO CF DPNCJOFE JO B NJYUVSF PG EPNJOBOU BOE SFDFTTJWF
BOE TPNF FYBNQMFT PG HFOPUZQFT BOE HBNFUFT BSF HJWFO JO 5BCMF 10.1

<ZcdineZ <VbZiZh

6677 Vaa 67
VV77 Vaa V7
6V77 67 VcY V7 ^c V gVi^d d[ & / &
6VWW 6W VcY VW ^c V gVi^d d[ & / &

IVWaZ &%#& HdbZ ZmVbeaZh d[ Y^ead^Y \ZcdineZh VcY i]Z ]Vead^Y \VbZiZh i]Zn
egdYjXZ#

5IFSF BSF NPSF QPTTJCMF HFOPUZQFT UIBO UIPTF TIPXO JO 5BCMF 10.1
CVU
FBDI HFOPUZQF DBO POMZ QSPEVDF FJUIFS POF UZQF PG HBNFUF
PS UXP
PS
GPVS /P HFOPUZQF QSPEVDFT UISFF UZQFT PG HBNFUF BOE POMZ UIF EPVCMF
IFUFSP[ZHPVT HFOPUZQF BT JO 'JHVSF 10.3
GPS FYBNQMF
DBO QSPEVDF GPVS
UZQFT PG HBNFUF *U JT IFMQGVM UP LFFQ UIJT JO NJOE XIFO XPSLJOH PVU UIF
QPTTJCMF PĄ TQSJOH PG EJIZCSJE DSPTTFT

' L]Vi VgZ i]Z \VbZiZh egdYjXZY Wn i]Z \ZcdineZh Iigg VcY =]<\4

( L]Vi ^h i]Z cVbZ d[ i]Z \g^Y jhZY id YZiZgb^cZ d[[heg^c\ \ZcdineZh VcY
e]ZcdineZh4

I]Z Y^]nWg^Y Xgdhh Parental generation UIF PSJHJOBM

"MUIPVHI UIF EJIZCSJE DSPTT JOWPMWFT UXP QBJST PG HFOFT JOTUFBE PG KVTU QBSFOU JOEJWJEVBMT JO B TFSJFT PG
POF
UIF QSJODJQMFT PG TFUUJOH PVU B HFOFUJD DSPTT EJBHSBN UP QSFEJDU
UIF PĄ TQSJOH UIBU XJMM CF QSPEVDFE BSF FYBDUMZ UIF TBNF BT GPS UIF FYQFSJNFOUBM DSPTTFT
NPOPIZCSJE DSPTTFT ZPV TBX JO $IBQUFS 4 5IF HFOFUJD EJBHSBNT TIPVME
JODMVEF QBSFOUBM QIFOPUZQFT
QBSFOUBM HFOPUZQFT
HBNFUFT JO DJSDMFT BOE B F1 generation UIF PĄ TQSJOH PG
1VOOFUU HSJE GPS UIF F1 PS F2 generation UIF QBSFOUBM HFOFSBUJPO

F2 generation UIF PĄ TQSJOH PG B
DSPTT CFUXFFO ' JOEJWJEVBMT

Ldg`ZY ZmVbeaZ &

'VS DPMPVS JO NJDF JT EFUFSNJOFE CZ B TJOHMF HFOF #SPXO GVS JT EPNJOBOU UP XIJUF &BS TJ[F JT BMTP EFUFSNJOFE CZ
B TJOHMF HFOF 3PVOEFE FBST BSF EPNJOBOU UP QPJOUFE FBST

" NPVTF IPNP[ZHPVT GPS CSPXO GVS BOE SPVOEFE FBST XBT DSPTTFE XJUI B XIJUF NPVTF XJUI QPJOUFE FBST
%FUFSNJOF UIF QPTTJCMF QIFOPUZQFT BOE HFOPUZQFT PG UIF PĄ TQSJOH

&% <:C:I>8H >> ')&

Step 1 $IPPTF TVJUBCMF MFUUFST UP SFQSFTFOU UIF eVgZciVa e]ZcdineZh/ Wgdlc [jg! l]^iZ [jg!
BMMFMFT #SPXO GVS JT EPNJOBOU
TP MFU gdjcYZY ZVgh ed^ciZY ZVgh
B CSPXO GVS BOE b XIJUF GVS eVgZciVa \ZcdineZh/ WWgg
3PVOEFE FBST JT EPNJOBOU
TP MFU 77GG
R SPVOEFE BOE r QPJOUFE \VbZiZh/ Vaa 7G Vaa Wg

Step 2 5IF CSPXO NPVTF XJUI SPVOEFE FBST EjccZii \g^Y [dg ;&/ \VbZiZh [gdb
JT IPNP[ZHPVT TP JUT HFOPUZQF NVTU CF Wgdlc! gdjcY"
BBRR ZVgZY eVgZci

4JODF XIJUF BOE QPJOUFE BSF SFDFTTJWF
UIF \VbZiZh [gdb 7G
HFOPUZQF PG UIF XIJUF NPVTF XJUI QPJOUFE l]^iZ! ed^ciZY"
FBST NVTU CF bbrr 7WGg
ZVgZY eVgZci
Step 3 4FU PVU UIF HFOFUJD EJBHSBN BT TIPXO Wg Wgdlc!
Step 4 "MM UIF ' NJDF IBWF CSPXO GVS BOE gdjcYZY

SPVOEFE FBST ZVgh

CdiZ i]Vi Vai]dj\] i]Z \VbZiZ 7G ^h XdbW^cZY l^i] i]Z
\VbZiZ Wg! i]Z VaaZaZh ^c i]Z d[[heg^c\ VgZ ValVnh eV^gZY je!
hd i]Z \ZcdineZ d[ i]Z ;& ^h lg^iiZc Vh 7WGg cdi 7GWg #

Ldg`ZY ZmVbeaZ '

.FOEFM DBSSJFE PVU HFOFUJD TUVEJFT XJUI UIF HBSEFO QFB 5BMM QMBOUT BSF EPNJOBOU UP TIPSU
BOE HSFFO TFFET BSF
EPNJOBOU UP ZFMMPX " IPNP[ZHPVT UBMM QMBOU XJUI ZFMMPX TFFET XBT DSPTTFE XJUI B TIPSU QMBOU IPNP[ZHPVT GPS
HSFFO TFFET %FUFSNJOF UIF QPTTJCMF HFOPUZQFT BOE QIFOPUZQFT JO UIF PĄ TQSJOH

Step 1 5BMM JT EPNJOBOU UP TIPSU
TP T UBMM BOE eVgZciVa e]ZcdineZh/ iVaa! nZaadl h]dgi! \gZZc
t TIPSU (SFFO JT EPNJOBOU UP ZFMMPX TP hZZYh hZZYh
G HSFFO BOE g ZFMMPX eVgZciVa \ZcdineZh/
II\\ ii<<
Step 2 &BDI QBSFOU IBT POF EPNJOBOU BOE POF \VbZiZh/ Vaa I\
SFDFTTJWF DIBSBDUFSJTUJD CVU XF BSF UPME UIF i<
EPNJOBOU DIBSBDUFSJTUJD JT IPNP[ZHPVT EjccZii \g^Y [dg ;&/
\VbZiZh [gdb iVaa!
5IF UBMM
ZFMMPX TFFEFE QMBOU UIFSFGPSF IBT nZaadl"hZZYZY
HFOPUZQF TTgg
BOE UIF TIPSU
HSFFO TFFEFE eVgZci
QMBOU JT ttGG
\VbZiZh [gdb I\
Step 3 4FU PVU UIF HFOFUJD EJBHSBN BT TIPXO h]dgi! \gZZc"
Step 4 "MM UIF PĄ TQSJOH BSF UBMM QMBOUT XJUI HSFFO hZZYZY eVgZci Ii<\
i< iVaa! \gZZc
TFFET
*U XBT GPSUVOBUF UIBU .FOEFM DIPTF UIFTF UXP hZZYh
DIBSBDUFSJTUJDT GPS IJT DSPTTFT 4FFE DPMPVS BOE IFJHIU
BSF VOMJOLFE HFOFT PO EJĄ FSFOU DISPNPTPNFT )BE
UIFZ CFFO PO UIF TBNF DISPNPTPNF BOE MJOLFE
UIF
SFTVMUT XPVME IBWF CFFO EJĄ FSFOU

')'