Unit 4-Photosynthesis Questions

1.

Photosynthesis is a complex metabolic process whic h can be influenced by many different environmental factors. (a) (a)

Expl Explai ain n the the term term limiting factor with reference to photosynthesis. ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… (2)

(b)

An investig investigation ation into into the effect effect of of light light intensity intensity and and carbon carbon dioxide dioxide concentration concentration on  photosynthesis was carried out using pond weed. The pond weed was placed in a test tube that contained pond water and a quantity of sodium hydrogencarbonate. The light was  provided by a lamp. The oxygen bubbles produced by the pond weed were directed into a length of capillary tubing.

The graph below shows how the rate of oxygen production of the pond weed changed with light intensity when immersed in two different concentrations of sodium hydrogencarbonate. 0 .8 0 . 5 m o l d m  – 3 s o d i u m hydrogencarbonate

0 .7 R a te o f o x y g e n p r o d u c t io n 0 .6 / c m 3 m in –1 0 .5 0 .4

0 . 1 m o l d m  – 3 s o d i u m hydrogencarbonate

0 .3 0 .2 0 .1 0 0

50

100

150

200

250

300

350

400

L ig h t in t e n s i ty / a r b i tr a r y u n i t s

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(i)

Explain Explain the the shape shape of the the graph graph between between a light light intensi intensity ty of 0 and and 400 400 arbitrar arbitrary y  –3 units in the sodium hydrogencarbonate concentration of 0.5 mol dm . ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… (4)

(ii)

Describe Describe and and explain explain the the effect effect of increasing increasing the concen concentratio tration n of sodium sodium hydrogencarbonate, on the rate of oxygen production. ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… (3)

(iii)

A number of precautions precautions would need to be taken while carrying out this investigation in order to obtain reliable data. Describe one precaution and explain why this precaution is necessary. ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… ……………………………………………….…………………………..…… (2)

(c)

During the light-de light-depende pendent nt stage stage of photosy photosynthes nthesis, is, oxygen oxygen is is produced produced by by photolysi photolysis. s. Describe the process of photolysis and explain its role. ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… (3) (Total 14 marks)

(a)

2.

The rate of photos photosynthe ynthesis sis can be be limited limited by a number number of factors. factors.

Explain why temperature can be a limiting factor in photosynthesis. ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… (2)

(b)

The diagram diagram below shows the structure structure of a chloro chloroplast plast..

3

 Name the parts labelled A, B and C. A …………………………………………….……………………………………… B …………………………………………….……………………………………… C …………………………………………….……………………………………… (2)

(c)

The flow flow diagram diagram below shows shows some some of the the process processes es which which occur occur in the light light independent reaction of photosynthesis. 5 c a rb o n c o m p o u n d + X

R e g e n e r a tio n

Y N A D PH + H AT P

+

T rio s e p h o s p h a t e

G lu c o s e p h o s p h a te

(i)

Name the substance substancess represented represented by the letters letters X and Y. X ..…………………………………….……………………………………… Y ..…………………………………….……………………………………… (2)

(ii) (ii)

State State the origin origin of the NADPH NADPH + H+ and the ATP used in the light-independent reaction. …..…………………………………….……………………………………… (1)

(d)

Describe Describe how how the products products of photosy photosynthes nthesis is are transported transported in the plant. ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… ……………………………………………….……………………………………… (5) (Total 12 marks)

3.

The diagram below shows an outline of the light-independent stage of photosynthesis, together  with some of the products.

C

2O

X

Y N

o

T k T p P

h G

o l u

r i o s e h o s p h

s p c

h o

o s e

r y

t e

r i o s e n o w n

p

6

g

h a

o s

s G

a t e l a

t e

d S

u

C c

s u r o

a

r

s e

5 

(a)

Using the informa information tion provided provided in the diagram, diagram, identify identify substances substances X and Y and and state state the number of carbon atoms present in each. X .......................................................................... ................................................................................................................ .............................................................. ........................ Y .......................................................................... ................................................................................................................ ........................................................... ..................... (2)

(b)

Explain Explain how substance substance Y is is converted converted to triose phosphate. phosphate. .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ (2)

(c)

Triose Triose phosphate phosphate is converted converted to a phosph phosphorylat orylated ed 6-carbon 6-carbon sugar which in in turn can be converted to a number of products such as sucrose and glucose. Sucrose is translocated around the plant in phloem. Describe how phloem tissue is adapted for this function. .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ .......................................................................... ................................................................................................................ .................................................................. ............................ (6) (Total 10 marks)

4.

The diagram below shows one pair of electrons being passed between the molecules of the electron carrier system (A, B, C and D) during part of the light-dependent reactions of   photosynthesis.

7 

(a) (a)

(i) Expl Explai ain n how the the pair air of elec electtrons rons move ove from rom chlo chloro roph phyl ylll to the the electron carrier system. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2)

(ii)

Explain Explain how electrons electrons lost from chlorophyl chlorophylll are are replace replaced. d. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2)

(iii)

Explain how how ATP is synthesised synthesised when electrons pass between between electron carriers B and C. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2)

(b)

Describe the Calvin cycle. You should answer this question in continuous prose. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (6) (Total 12 marks)

5.

Simazine is a herbicide that kills plants by disrupting the flow of elect rons in the membranes of  chloroplasts. An investigation was carried out into the effects of Simazine on photosynthesis. Two samples of   plants were grown under the same controlled conditions. One sample was treated with water and the other with a solution of Simazine. Both samples were supplied with radioactive carbon dioxide (14CO2) in a well lit, sealed chamber for an hour. The plants were removed from the chamber and killed immediately. The mass of radioactive carbon fixed in the plants was measured.

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(a) (a)

Sug Suggest gest one condition which should have been controlled while the plants were growing. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (1)

(b)

Explain Explain why the plants plants were killed killed immediately immediately after after they they were were removed removed from the chamber. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (1)

(c)

The results results of the experiment experiment are given in the table below. Radioactive carbon fixed / mg Plants Plants treated treated with water water

Plants Plants treate treated d with with Simazin Simazinee

10.6

1.4

Suggest an explanation for the effect of Simazine on the mass of radioactive carbon fixed in the plants. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (5) (Total 7 marks)

6.

The carbohydrates in green plants are formed during the light-independent stage of   photosynthesis. They are synthesised from glycerate 3-phosphate (GP). (a)

State precis precisely ely where where the the synthes synthesis is of carbohydra carbohydrates tes takes takes place place during during the lightlightindependent stage of photosynthesis. .......................................................................... ................................................................................................................ ............................................................ ...................... (1)

(b)

Name the products of the light-dependent stage of photosynthesis used during the synthesis of carbohydrates. .......................................................................... ................................................................................................................ ............................................................ ...................... .......................................................................... ................................................................................................................ ............................................................ ...................... (2)

(c)

Describe Describe the the role of ribulose ribulose bisphospha bisphosphate te (RuBP) (RuBP) in in the light-indep light-independen endentt stage stage of   photosynthesis. .......................................................................... ................................................................................................................ ............................................................ ...................... .......................................................................... ................................................................................................................ ............................................................ ...................... .......................................................................... ................................................................................................................ ............................................................ ...................... .......................................................................... ................................................................................................................ ............................................................ ...................... .......................................................................... ................................................................................................................ ............................................................ ...................... .......................................................................... ................................................................................................................ ............................................................ ...................... (2)

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(d)

An investig investigation ation of of photosyn photosynthesis thesis in cells taken from a green alga was was carried carried out. out. Samples of the algal cells were taken at 1 minute intervals over a period of 6 minutes. The quantities of GP and RuBP in these cell samples were measured. At the start of the investigation, the algal cells were kept in an atmosphere with 1% carbon dioxide. After 3 minutes, the concentration of carbon dioxide was decreased to 0.003%. The graph below shows the results of this investigation.

C

1

%

c a

r b

a

o

r b

n

o

d

n

d

i o

x

i o

x 0 i . d0 e0

i d

3

e

d

%

c

Q u a n t i t i e s o f R u B P a n d G P / a r b i t r a r y u n i t s

0

(i)

1 Time / minutes

e

c

a

r e

r b

a

o

s

n

R

u

G

P

2

Describe Describe the the effects effects of the the decreas decreasee in the concentration concentration of carbon carbon dioxide dioxide on the quantities of GP and RuBP. ......................................................................... ............................................................................................................... ...................................................... ................ ......................................................................... ............................................................................................................... ...................................................... ................ ......................................................................... ............................................................................................................... ...................................................... ................ ......................................................................... ............................................................................................................... ...................................................... ................ ......................................................................... ............................................................................................................... ...................................................... ................ ......................................................................... ............................................................................................................... ...................................................... ................ (2)

(ii)

Suggest Suggest explanatio explanations ns for for the effects effects you you have have described described in part part (i). (i). ......................................................................... ............................................................................................................... ...................................................... ................ ......................................................................... ............................................................................................................... ...................................................... ................ ......................................................................... ............................................................................................................... ...................................................... ................ ......................................................................... ............................................................................................................... ...................................................... ................ ......................................................................... ............................................................................................................... ...................................................... ................ ......................................................................... ............................................................................................................... ...................................................... ................ (2) (Total 9 marks)

7.

An experiment was carried out to investigate the effect of light i ntensity on the rate of   photosynthesis of an aquatic plant, using t he apparatus shown below.

S

L

i g

h

t

C

a p

G

a

s

A

q

u

p

e

T w

e

c

a l e

i n

i l l a r y b

u

b

b

m

m

t u b e S y r i n

g

l e s

a t i c p l a n t i n r f o r a t e d t u b e

s t i t h

t u w

b e f i l l e d a t e r

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(a)

Explai Explain n what what is meant meant by the term term limiting factor. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (2)

(b)

State two environmental conditions, other than light intensity, which would need to be controlled. Describe how each of these environmental conditions could be controlled. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (4)

(c)

The aquatic aquatic plant was allowed allowed to carry carry out out photosy photosynthes nthesis is for for 10 minutes. minutes. Describ Describee how 3

 – 

this apparatus could be used to determine the rate of oxygen production (mm min 1). .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (4)

(d)

Describe Describe how how you could modify this appara apparatus tus to to determine determine the effect effect of differen differentt wavelengths of light on photosynthesis. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (2) (Total 12 marks)

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8.

The diagram below shows some of the stages in the Calvin cycle.

C R

F

G

S

(a)

l u

u

c

c

B

P

o

s e

r o

s e

u

B

P

a s e

P

P

G

A

2O

G

L

Some stages stages of the the Calvin Calvin cycle cycle require require energy from ATP. Describ Describee in outline outline how ATP ATP is made available by reactions in the chloroplast. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (5)

FBPase is an enzyme involved in one step of the pathway used to re-form the CO 2 acceptor  molecule RuBP. In an investigation, plants were modified by introducing a gene which reduces the activity of  FBPase. The graph below shows the effect of this treatment on the sucrose content of the leaves of treated and untreated plants.

2

5

2 o 1

0 0 r m 5 0

% o f n s u c r o s e c o n t e n t1

0

0 5

a l

0 0

0 U

n p

(b)

t r eT a r t e e a d t e d l a n tp s l a n t s

Describe Describe the the effect effect of reduced reduced FBPase FBPase activit activity y on the sucrose sucrose content content of leaves. leaves. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (2)

(c)

Suggest Suggest an explana explanation tion for for the differ difference ence in sucrose sucrose content content of the leaves of treated treated and and untreated plants. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (2)

17 

(d)

Suggest Suggest potential potential benefits benefits of plants modified modified in this way. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (2) (Total 11 marks)

9.

The diagram below shows a root hair cell.

(a)

Describe how the the shape shape of of a root hair cell increases the efficiency of absorption absorption of water  and mineral ions from the soil solution. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (1)

(b)

Mineral Mineral ions can be be taken taken up by root root hair hair cells cells and may accumu accumulate late at at higher  higher  concentrations than in the soil solution. Explain how mineral ions are taken up by root hair cells. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (4)

(c)

Phosphate Phosphate ions ions are are required required for the the synthes synthesis is of many important important molecu molecules les in plants. plants.  Name two products of the light-dependent stage of photosynthesis that require phosphate ions in their molecular structure. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (1)

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(d)

Describe a simple simple procedure procedure by which which you you could could use use mineral mineral culture solutions to find the effect of a lack of phosphate ions on plant growth. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (3) (Total 9 marks)

10.

(a) In the the space space below, below, draw draw a diagram diagram of a chloroplas chloroplastt showing showing the the main main features features of  this organelle. On your diagram indicate the location of the light-dependent reactions and the lightindependent reactions.

(4)

21

(b)

photophosphorylation. Descri Describe be the proces processs of non-cyclic photophosphorylation

.......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (4)

(c)

photophosphorylation. Describe Describe what happens happens to the products products of  non-cyclic photophosphorylation

.......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (2) (Total 10 marks)

11.

The diagram below shows a chloroplast.

A

B C

D

(a)

(i)

Name the parts labelled A, B, C and D.

A ........................................ B ......................................... C ........................................ D ........................................ (2)

(ii)

State the the part of of the chlorop chloroplast, last, shown shown on on the diagra diagram, m, where where oxygen oxygen is produc produced. ed. ......................................................................... ............................................................................................................... .................................................. ............ (1)

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(iii)

Explain how oxygen is produced in chloroplasts during photosynthesis. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (3)

(b)

Oxygen Oxygen inhibits inhibits the enzyme enzyme that catalys catalyses es the the fixing fixing of of carbon carbon dioxide dioxide.. High concentrations of oxygen, within a chloroplast, can reduce the rate of photosynthesis. Describe and explain the effect of high concentrations of oxygen on the rate of  carbohydrate production in a chloroplast. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (3)

(c) (c)

Sug Suggest gest two environmental conditions which could increase the rate of oxygen  production by plants. 1 ....................................................................... ............................................................................................................. ........................................................... ..................... 2 ....................................................................... ............................................................................................................. ........................................................... ..................... (2) (Total 11 marks)

12.

One of the reactions of photosynthesis can be summarised as shown below. water

(a)

    →

hydrogen ions + oxygen gas + electrons

Name Name the reactio reaction n shown. shown. .......................................................................... ................................................................................................................ ........................................................... ..................... (1)

(b)

Give one other factor, not shown above, that would be required for this reaction to occur  in a chloroplast. .......................................................................... ................................................................................................................ ........................................................... ..................... (1)

(c)

Describe Describe the the role of the the electrons electrons in the light dependent dependent reactio reaction n of photosynth photosynthesis esis.. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (4)

25 

(d)

Describe Describe and explain explain how the the products products of the light dependent dependent reaction reaction are involved involved in in the  production of glyceraldehyde-3-phosphate (GALP). .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (4)

(e)

GALP does does not not accumula accumulate te in a chloroplas chloroplastt during during photos photosynthe ynthesis. sis. Explain Explain how GALP is is used following its production. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (2) (Total 12 marks)

13.

The diagrams below show the absorption spectra and the action spectrum that were produced in an investigation of photosynthesis in a flowering plant. A

b

s o r p

t i o

n

s p

e c t r a

c a A b s o r p t i o / a r b i t r a r y

4

0

c t i o

R p /

n

a

s p

t e

f

o

i d

c h u

n

0

i t s

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e c t r u

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A

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c h

l o

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e

r bo

p

h

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l e n

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s

l o y

t h

r ao

p

l l

/

7

0

n

m

7

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n

m

m

 

h o t o s y n t h e s i s a r b i t r a r y u n i t s

4

0

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a v h

e t

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0 g

t h r e d

/

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27 

(a)

Using the informa information tion in the two two graphs, graphs, explain explain the relationship relationship between between the absorption absorption and action spectra for this flowering plant. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (3)

(b)

State precis precisely ely where where the the chloroph chlorophyll yll pigment pigmentss would would be found in a chlorop chloroplast last of of a flowering plant. .......................................................................... ................................................................................................................ ........................................................... ..................... (1)

(c)

Describe Describe how how chromato chromatography graphy could be used used to identify identify the the chloroplas chloroplastt pigments pigments from from the leaves of a flowering plant. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (4)

(d)

Explain Explain why flowerin flowering g plants plants grown grown in soil soil which which is defici deficient ent in magnes magnesium ium ions ions often often have leaves with pale yellow patches between the veins. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (2) (Total 10 marks)

14.

The diagram below summarises the light dependent reactions of photosynthesis.

L

C

(a)

I G

h

l o

H

T

r o

p

P

h

e

l e c y l l

t r o

n s E l e

r o

c

d

u

c

t r o

n

t

A

c

e l e c t r o n s a r r i e r s P r o

d

u

c

Give the the precise precise location location within within a chloroplast chloroplast where this sequence sequence of of reactions reactions occurs. occurs. .......................................................................... ................................................................................................................ ........................................................... ..................... (2)

(b)

Give the names of product product A and product product B. Product A ........................................................................... ................................................................................................................. ......................................... ... Product B ....................................................................... ............................................................................................................. ............................................. ....... (2)

(c)

Give the the name of the process process that that provides provides electron electronss to replace replace those those lost by chlorophyll chlorophyll.. .......................................................................... ................................................................................................................ ........................................................... ..................... (1)

(d)

A chemical chemical called called atrazin atrazinee prevents prevents the the flow flow of electrons electrons to to the electron electron carriers carriers.. Describe and explain the likely effect of atrazine on the production of carbohydrate in a 29

chloroplast. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (4)

(e)

Atrazine Atrazine can be used as a weedkiller. weedkiller. (i)

Explain Explain how how the the presen presence ce of of weeds weeds can reduce the yield of crop crop plants. plants. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2)

(ii)

A change change in a single single gene gene can can alter alter the electron electron carrier carrierss so that atrazin atrazinee is ineffective. Suggest how crop plants unaffected by atrazine could be used to increase crop yields. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2) (Total 13 marks)

15. 15.

Data Data for for use use wit with h the the ques questi tion onss that that fol follo low. w. Figure Figure 1. Micros Microscop copic ic phytopla phytoplank nkton ton..

Phytoplankton are microscopic single-celled plant-like organisms which live in vast numbers in the sea floating just below the surface where they carry out photosynthesis. Marine phytoplankton account for over 50% of the world’s primary productivity.

Figure 2.

Calanus

is a herbivorous small animal which makes up most of the zooplankton of the North Sea and feeds on phytoplankton. Calanus appears in the North Sea in March and starts to breed, but its numbers do not reach a maximum until July. Between late August to early October they leave the North Sea and return to the deep waters of the North Atlantic Ocean to spend the winter. Calanus are the main food source of many small fish as well as the young of larger fish such as herring and cod.

31

Figur Figuree 3. Sand Sandee eels ls.. Sandeels are small fish which make up almost a half of the mass of fish in the North Sea. They feed on zooplankton, particularly Calanus. They are an important part of the diet of many of the larger fish such as cod and herrings caught for human food. Sandeels are also important in the diet of many sea birds such as puffins and kittiwakes. Sandeels are caught in vast numbers to make fish-meal food used for farm animals.

Figu Figure re 4. period.

    2   –

Prod Produc ucti tivi vity ty due due to to phy phyto topl plan ankt kton on in Nort North h Sea Sea over over a twe twelv lvee mon month th

3

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5 0

J

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Figu Figure re 5. period.

   e    r    u     t    a    r    e    p    m    e     t     C    a    s    e    e    s    e    r    y     l    g     h    e     t     d    n    o

Mean Mean sea sea sur surfa face ce temp temper erat atur uree of of the the Nort North h Sea Sea over over a twe twelv lvee mon month th

2

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Figure Figure 6. Breeding Breeding stock biomas biomasss of two species species of fish in the North North Sea. Herring Herring stocks stocks fell so low that from 1978 until 1982, fishing for this species in the North Sea was banned. In 2000 the EU negotiated a reduction in fishing for cod but scientists believed that the ‘fishing quotas’ agreed by the EU were too high to allow cod to recover to a sustainable level.

        s         g         e         n         n            i         n            d         o         e           t         e            /         r            b         s         s            l         a         a           t         m         o         o            i            T            b

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33

Figure 7. Location map.

   o      N

N S U

   a rw

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K

Acknowledgements

Based on data in ‘Phytoplankton, biomass a nd production in the southern North Sea’.  Joint , I. and Pomroy , A. (1993) Marine Ecology Progress Series. 99: 169–182. Based on Zhihong Li, Holt M. and Osborne, J. (2000) ‘A baroclinic model of the NW European shelf seas’. http://www.google.co.uk/search?sourceid=navclient&ie=UTF8&rls=GGLG,GGLG:2006-16,GGLG:en&q=north+sea+temperature+annual+cycle http://www.aslo.org/photopost/showphoto.php?photo=1007&papass=&sort=1&thecat=500 http://www.statistics.gov.uk/cci/nugget.asp?id=367

Read and use the data above, and your own knowledge, to answer the following questions. (a)

(i) Construct an appropriat iate food web diag iagram to show the feeding ing relationships between the organisms referred to in the data booklet and which shows the trophic levels each organism occupies.

(3)

(ii)

Explain Explain why the total total biomass biomass of cod in the North North Sea is normally normally much less less than than the total biomass of sand eels. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2)

(b)

(i) Suggest two advantages to the phytoplankton of being concentrated  just below the sea surface (Figures 1 and 4). ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2)

35 

(ii)

Like land plants, phytoplankton require mineral salts. Suggest why phosphates are essential for the growth of phytoplankton. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (1)

(c) (c)

(i) In Figu Figure re 4, the the unit unitss used used to exp expres ress prim primaary produ roduct ctiv ivit ity y are are abbreviated as gCm –2. Given that ‘C’ stands for organic carbon and the other letters are common  –2

metric units, suggest what gCm

stands for by writing it out in full.

......................................................................... ............................................................................................................... .................................................. ............ (1)

(ii)

With referen reference ce to Figure Figuress 4 and 5, discuss discuss the the extent extent to which which mean mean sea sea surface surface temperature controls the primary productivity of phytoplankton. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (3)

(iii)

Measurements show that the mean light intensity for the months May and July July is the same, but the mean sea surface temperature is 8oC higher in July than in May. Suggest why, in spite of this, primary productivity is similar in these two months. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2)

(d) (d)

The The numb number erss of Calanus in the North Sea have been decreasing since 1960 and there is some evidence that this may be due to climate change. The distribution of  Calanus  finmarchicus, one of the most abundant species, seems to be shifting northwards,  becoming more common off the coast of Norway. Suggest why Calanus may not succeed so well in warmer water. .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... .......................................................................... ................................................................................................................ ........................................................... ..................... (2)

37 

(e) (e)

(i) Ther Theree are sever everaal reaso easons ns why why comm commer erci ciaally lly impo import rtan antt stock tockss of fish ish, such as cod and herring, are under threat in the North Sea. Using information in Figure 6 explain why over-fishing by humans is almost certainly part of the  problem. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2)

(ii)

Nets used used by by fishermen fishermen in the North Sea are are required required to to have have a mesh mesh size size which which catches larger fish but allows the smaller (younger) fish to escape. This acts as a selection pressure on the cod population. Explain the effects this selection pressure might have on the phenotypes of these cod in future generations. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2) (Total 20 marks)

(a)

16.

The electron electron microsc microscope ope image below shows shows part part of of a chloroplas chloroplast. t.

The table below gives one function of each of the three structures labelled A, B and C on the electron microscope image. Complete the table below by writing in the appropriate letter and the name of each structure. Function

Label letter

Name of structure

Photophosphorylation Stores non-carbohydrate organic material Carbon fixation (3)

(b)

The equatio equation n below below summari summarises ses the the proces processs of photolysis photolysis of water. water. +

 – 

2H2O → 4H + 4e + O2 (i)

Explain Explain what happens happens to the electrons electrons released released by photolysis photolysis.. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2)

39

(ii)

The electron electronss are later later involved involved in the reduc reduction tion of NADP. Explain Explain the the importanc importancee of reduced NADP in the light-independent reactions of photosynthesis. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (3)

(c)

The rate rate at which plants produce produce carbohy carbohydrate drate by photosy photosynthes nthesis is is known as gross gross  primary productivity. Put a cross in the box next to the equation that shows the relationship between gross  primary productivity (GPP), net primary productivity (NPP) and respiration (R). GPP + R = NPP GPP + NPP = R  GPP = NPP + R  GPP = NPP – R  (1)

(d)

The table table below below shows shows the net net primary primary productiv productivity ity in four four differ different ent ecosyste ecosystems. ms. The The ecosystems in the table are listed in order of increasing distance from the equator, starting with tropical rainforest.

Ecosystem

Net primary productivity  –2

/ kJ m

 –1

year

Tropical rainforest

37 800

Temperate forest

25 200

Boreal forest

14 700

Polar tundra

2 400

(i)

It is estimated estimated that that 85% 85% of the energy energy available available to to primary primary consumers consumers will not be be available to secondary consumers. Calculate the energy that will be available to the secondary consumers in the tropical rainforest. Show your working.

 –2

Answer ................................. kJ m

 –1

year 

(2)

(ii) (ii)

Sugg Sugges estt two reasons for the differences in the net primary productivity as the distance from the equator increases. ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ ......................................................................... ............................................................................................................... .................................................. ............ (2) (Total 13 marks)

41