as long paper unit 2

1. The table below refers to four membrane transport processes: diffusion, facilitated diffusion, osmosis and active transport. If the statement is correct, place a tick ( ) in the appropriate box and if the statement is incorrect, place a cross (X) in the appropriate box.

Process Takes place against aconcentration gradient

Requires energy in the form of ATP

Diffusion

Facilitated diffusion

Osmosis

Active transport

(Total 4 marks)

2. Give an account of the structure and functions of the cell surface membrane.

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(Allow three lined pages)(Total 10 marks)

Hammersmith and West London College 1

3. The table below refers to two disaccharides, sucrose and maltose. If the statement is correct, place a tick ( ) in the appropriate box and if the statement is incorrect, place a cross ( ) in the appropriate box.

Statement Sucrose Maltose

Contains glucose

Is a reducing sugar

Contains glycosidic bonds

Is transported in the phloem of flowering plants

(Total 4 marks)

4. The diagram below shows cells from a root tip, prepared by the root tip squash method.


(a) Describe how you would prepare a root tip squash so that mitosis can be studied.

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(b) State which of the cells labelled A–E is in:

(i) metaphase ...................

(ii) anaphase .....................(2)

(c) State two events that take place during interphase.

1. ……………………………………………………………………………………..

2. ……………………………………………………………………………………..(2)

(Total 8 marks)

5. (a) (i) Explain what is meant by the term facilitated diffusion.

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(ii) State two ways in which active transport differs from facilitated diffusion.

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2 .........................................................................................................................

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(b) In an investigation into the effects of osmosis on red blood cells, seven samples of red blood cells were placed in potassium chloride solutions of different concentrations. After two hours, each sample was examined to find the percentage of cells that had swollen and burst (lysed). The results are shown in the graph below.

1 0 0

9 0

8 0

7 0

6 0

5 0

4 0

3 0

2 0

1 0

00 .0 4 0 .0 5 0 .0 6 0 .0 7 0 .0 8

C o n c en tra tio n o f p o ta ssiu m c h lo r id e /m o l dm

P e rce n ta ge o fred b lo o dce lls th a th ad b u rs t

–3


(i) Calculate the difference between the percentage of red blood cells that burst in 0.05 mol dm–1 and 0.07 mol dm–1 potassium chloride solutions.Show your working.

Answer ................................(2)

(ii) With reference to water potential, explain why most of the cells burst when placed in 0.05 mol dm–3 potassium chloride solution.

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(iii) Suggest what would happen if red blood cells were placed in a 0 1 mol dm–3 solution of potassium chloride.

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(c) Explain why plant cells do not burst when placed in distilled water.

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……..……………………………………………….……………………………….(2)

(Total 12 marks)’

6. An experiment was carried out to compare the uptake of two substances, A and B, by Amoeba. Amoeba is a single-celled aquatic organism.

Cells of Amoeba were placed in a solution containing equal concentrations of both substances and kept at 15 °C. The concentration of each substance in the cytoplasm of the cells was measured every 30 minutes over a period of 6 hours.

The results of this experiment are shown in the graph below.

S u bs tan c e A

S u b s tan ce B

1 4

1 2

1 0

8

6

4

2

00 1 2 3 4 5 6

Tim e / h o u rs

C on c en tra tio nin cy to p lasm /

g c m –3


(a) Compare the uptake of substance A by the cells with the uptake of substance B during the period of 6 hours.

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(b) Substance B enters the cells by diffusion. Describe and explain how the results of this experiment support this statement.

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(c) Explain why an increase in temperature to 25 °C would increase the rate of diffusion of substance B into the cells.

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(d) Substance A is taken into Amoeba by active transport. Describe the process of active transport.

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(Total 13 marks)

7. The photograph below shows a group of cacti, plants which are adapted to living in hot deserts.


Suggest how each of the following features helps a cactus to survive in desert conditions.

(a) A shallow, extensive root system.

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(b) Fleshy stems, containing large, thin-walled cells.

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(c) Leaves reduced to spines.

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(Total 7 marks)


8. The siting of a new sewage treatment works and the discharge of its effluent need careful consideration in order to minimise ecological damage. Figure 1 shows two possible sites for a new sewage works near to the coast in North Devon.

Figure 1 – Plan of proposed sites for sewage treatment works, undergroundpipelines and marine discharge pipelines

Site 2 p = field Site 1 a = fieldq = field b = conservation arear = fields = cliff grasslandt = rocky shore

This development would involve the permanent siting of the buildings for the main sewage treatment plant, an underground pipeline and a marine discharge pipe. A strip of land 10 metres wide would need to be removed during the laying of the underground pipeline. The land would be returned to its previous condition after the work is completed.

An ecological assessment must be carried out before any development can go ahead. The assessment compares the possible effects of the development on the terrestrial areas of the two sites. The first stage is to assign each area to a particular ecological category, using the criteria in Figure 2.


Figure 2 – Criteria for assigning ecological categories to an area

Criteria

Very high species diversity and highest number of different habitats or rare habitats

———►

Very low species diversity and lowest number of different habitats or rare habitats

Ecological category

5 ———► 1

The second stage is to calculate the impact of the proposed development within each area using the following formula:

area (m2) × ecological category = units of damage

Finally, consideration is given to whether the damage is reversible or irreversible. Figure 3 shows the results of this ecological assessment survey for Site 1 and Site 2.

Figure 3 – A comparison of the results of the ecological assessment survey for Site 1 and Site 2

Site 1

Area Type ofdevelopment

Area/m2 Ecologicalcategory

Units ofdamage

Reversibledamage

Irreversibledamage

a Building 10 500 2 21 000 – 21 000

b* Pipeline 150 000 5 750 000 750 000 –

Totals 771 000 750 000 21 000

Site 2

Area Type ofdevelopment

Area/m2 Ecologicalcategory

Units ofdamage

Reversibledamage

Irreversibledamage

p Building 21 000 2

q* Pipeline 2 500 1

r* Pipeline 3 000 1

s* Pipeline 500 5

t* Pipeline 2 000 5 10 000

Totals

* involves laying of underground pipeline only.

Data adapted from JBE Vol 32 Number 2 Summer 1998


(a) Suggest why some damage is considered to be reversible and some damage is considered to be irreversible.

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(b) Complete the data for Site 2 in Figure 3.(3)

(c) Using the data in Figure 3, compare the ecological effect that the development of the sewage treatment works would have at Site 1 and Site 2.

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(d) State what is meant by species diversity.

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(e) The ecological impact on the marine environment also needs to be considered. Using information from Figure 1, suggest three factors affecting the marine environment that should be considered when comparing Site 1 with Site 2.

1 ………………………………………………………………………………………...

2 ………………………………………………………………………………………...

3 ………………………………………………………………………………………...(3)

(f) Suggest why an accidental discharge of raw sewage from the treatment works might lead to an increase in the numbers of carnivorous fish around the discharge pipe.

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(Total 16 marks)

9. Plant cells have a cell wall made of cellulose, whereas animal cells do not have a cell wall.

(a) State three other structural features found in plant cells but not in animal cells.

1 ..................................................................................................................................

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2 ..................................................................................................................................

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3 ..................................................................................................................................

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(b) The photograph below shows a transverse section through the stem of a stinging nettle (Urtica dioica), as seen through a light microscope. Diagrams P and Q show some cells from two regions of the section.

Alfred Pasieka /Science Photo Library

(i) Name the type of cell found at P and at Q.

P ........................................................................................................................

Q ........................................................................................................................(2)

(ii) Explain how the structure of the cell walls found at P and Q provides the strength to help support the whole plant.

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(c) Stinging nettles can be grown on land unsuitable for crops.


(i) Suggest one possible use of harvested nettle stems.

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(ii) Explain how crops of nettles could be used as a sustainable resource.

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(Total 11 marks)

10. (a) Explain why penicillin is classed as an antibiotic.

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(b) Explain what is meant by the term antibiotic resistance.

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(c) Give two factors which have contributed to the spread of antibiotic resistance.

1 .........................................................................................................................................

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(Total 6 marks)

11. (a) The table below summarises four processes by which molecules can pass across membranes.

Complete each box in the table with a if the statement is correct or a x if the statement is incorrect.

Process Requires energy from respiration (ATP)

Requires a concentration gradient

Passive diffusion


Osmosis

Active transport

(4)


(b) Explain how the structure of the lung makes it effective for gaseous exchange by diffusion.

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(Total 8 marks)

12. (a) The diagram below shows the results of two different types of cell division, A and B, in an animal cell with six chromosomes.

A

B

A n im a lce ll

N ew sk ince ll

G am ete

Name the types of cell division indicated by A and B.

A ..................................................................................................................................

B ..................................................................................................................................(2)


(b) The diagram below shows the fusion of two gametes.

G am ete

G am ete

(i) Name the process by which gametes fuse.

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(ii) Name the type of cell formed by this process.

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(c) The diagram below shows a sperm cell.

X Y Z

Name the organelles labelled X, Y, and Z.

X ..................................................................................................................................

Y ..................................................................................................................................

Z ..................................................................................................................................(3)

(Total 7 marks)

13. Garlic is known to contain an antibacterial substance called allicin.

(a) Suggest an advantage to a plant in producing antibacterial substances in its cells.

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(b) The presence of antibacterial substances in garlic can be demonstrated by grinding garlic in ethanol to produce an extract. A sample of this extract is then applied to a small disc of filter paper.

(i) Describe how you would demonstrate that this disc contained an antibacterial substance.

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(ii) A newly discovered rainforest plant is thought to contain a powerful antibacterial substance. Explain how you would compare the effectiveness of this new substance with allicin in garlic.

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(c) Suggest how this newly discovered plant substance might have a useful application which does not involve genetic modification.

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(Total 9 marks)

14. Read through the following account of mitosis in an animal cell, then write on the dotted lines the most appropriate word or words to complete the account.

During prophase, the ................................................ breaks down and the

................................................ migrate to opposite poles of the cell.

During ................................................, the chromosomes are visible as pairs of

chromatids, lined up along the equator of the cell. Spindle fibres extend from the poles

of the cell and attach to the ................................................ .

In ................................................, the spindle fibres contract, pulling the chromatids

apart.(Total 5 marks)

15. Eukaryotic cells contain organelles, many of which are bound by a membrane. Some organelles have a double membrane, often called an envelope.

(a) (i) Describe two structural differences between the double membrane surrounding a mitochondrion and the double membrane surrounding a nucleus.

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(ii) Name one other organelle that has a double membrane.

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(b) Centrioles are an example of organelles that are not membrane-bound. Describe the structure and function of centrioles.

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(Total 6 marks)


16. Beetroots are root vegetables. They appear red because their cells contain a water soluble red pigment in their vacuoles, which cannot pass through membranes.

An experiment was carried out to investigate the effect of bile salts on the permeability of beetroot membranes. Bile salts disrupt the structure of the membranes. Several beetroot discs were cut of equal dimensions. Each disc was rinsed in distilled water and dried using absorbent tissue.

Five beetroot discs were then placed in a tube containing 25 cm3 of 2% bile salt solution and left for 30 minutes at 20 °C. The procedure was repeated for different concentrations of bile salts and one set of discs was left in distilled water.

After 30 minutes, each set of beetroot discs was removed from the solutions and from the water. Each bile salt solution had become red and the discs were slightly pink. There was no change in the colour of the discs in the water and the water remained colourless.

Each bile salt solution was stirred and a sample removed and placed in a colorimeter. The intensity of red coloration (absorbance) was determined by the colorimeter.

The results of the investigation are shown in the graph below.

In ten s ity o fred co lo ra tion(ab so rb an c e )/ A rb itra ry u n its

C o n cen tra tio n o f b ile sa lts (%)

2 .0 –

1 .8 –

1 .6 –

1 .4 –

1 .2 –

1 .0 –

0 .8 –

0 .6 –

0 .4 –

0 .2 –

0 – –––––––––––

0

0 .2 0 .4 0 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .00 .6


(a) Explain why the cell membrane is described as having a fluid mosaic structure.

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(b) Suggest why it was necessary to rinse the beetroot discs before they were added to the bile salt solution.

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(c) Describe the effect of increasing bile salt concentration on the intensity of the red colour (absorbance) of the solution.

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(d) Suggest an explanation for these results.

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(e) The experiment was repeated using a second beetroot. Suggest why the readings obtained might be slightly different from those for the first beetroot.

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(Total 11 marks)


17. The diagram below shows the sequence of stages in meiosis.

Te lo p h ase II

A n ap h ase II

M e tap h ase II

P ro p h ase II

Te lo p h ase I

A n ap h ase I

M e tap h ase I

P ro p h ase I

(a) Describe what is happening to the chromosomes during the following stages.

(i) Prophase I

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(ii) Metaphase I

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(iii) Anaphase II

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(b) Meiosis in humans results in the production of gametes. Name the type of cell produced by each of the following stages.

(i) Meiosis I in oogenesis.

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(ii) Meiosis I in spermatogenesis.

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(Total 8 marks)


18. The photograph below shows a transverse section through part of a leaf of Nymphaea, as seen using a light microscope. Nymphaea is a hydrophyte (a plant which lives in water).The upper epidermis and air spaces are labelled.

(a) Suggest one function of the tissue labelled A, giving an explanation for your answer.

Function ........................................................................................................................

Explanation ...................................................................................................................

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(b) Suggest two functions of the large air spaces in this leaf.

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(c) Suggest why stomata are found only in the upper epidermis of this leaf.

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(Total 7 marks)

19. Agrostis tenuis is a grass that grows near old copper mines in North Wales. Copper is usually very toxic to plants, but some Agrostis plants can tolerate copper in the soil and grow on the waste tips from the copper mines.

(a) Suggest a method for measuring tolerance to copper in a sample of Agrostis plants.

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(b) Agrostis plants were sampled from three sites close to a copper mine. Site B was on the waste tip from the mine, Site Awas up-wind of the tip and Site C was down-wind, as shown below. The tolerance to copper of each of the samples was measured and the results are shown in the graph below.

M a in w in d d irec tio n

H ig h

To le ran cetoC o p p e r

L o w

S ite A S ite B S ite C

S ite A S ite B S ite C

U p -w in d s iteN o co p p e r p re sen t in so il

C o p p e r m in e w as te tipC o p p e r p re sen t in so il

D o w n -w in d s iteN o co p p e r p re sen t in so il

Suggest an explanation for the difference in tolerance between plants in the up-wind site (A) and plants in the down-wind site (C).

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(c) Samples of tolerant and non-tolerant plants were grown in three trays of soil that contained no copper. Tray 1 contained only tolerant plants, Tray 3 contained only non-tolerant plants and Tray 2 had a mixture of equal numbers of both types. The total dry mass of the plants in each tray was measured. The arrangement of the plants and the results are summarised below.

Tray 1A ll to le ran t p lan ts

Tray 2M ix ed to le ran t an dn o n -to le ran t p lan ts

Tray 3A ll n o n -to le ran t

p lan ts

Total dry massof tolerant plants 46 g 12 g ___

Total dry massof non-tolerant ___ 30 g 47 gplants

Suggest an explanation for the results obtained in Tray 2.

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(d) Suggest and explain how the abundance of copper-tolerant Agrostis plants would be likely to change if the copper were removed from the soil on the mine waste tip (Site B).

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(Total 11 marks)

20. The diagrams below show the structures of a leaf palisade cell and a bacterial cell, as seenusing an electron microscope.

Leaf palisade cell Bacterial cell(Magnification × 100000) (Magnification × 18000)

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

A ...................................................................................................................................

B ...................................................................................................................................

C ...................................................................................................................................(3)

(b) Give one difference between the cell wall of a leaf palisade cell and the cell wall of a bacterial cell.

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(c) Describe the function of part D.


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(Total 6 marks)

21. An investigation was performed to determine the length of time that a cell in an onion root tip spends in each stage of mitosis.

A growing root from an onion was selected and a root tip squash was made. This was examined under a light microscope and the percentage of cells in each stage of mitosis was determined.

The results are shown in the table below.

Stage of mitosisPercentage of cells in this

stage

Prophase 2.43

Metaphase 1.40

Anaphase 0.70

Telophase 2.78


(a) Describe how you would prepare a root tip squash so that mitosis could be studied.

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(b) The percentage of cells in a stage of mitosis is proportional to the duration of that stage. Use this information to compare the duration of each stage of mitosis in these root tip cells.

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(c) The duration of each stage of mitosis can be calculated using the equation below.

Duration of a stage = 100

timecycle cell stagein that cells of Percentage

The cell cycle time for these cells is 1200 minutes.Describe how you would use this data to determine the total duration of mitosis.

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(Total 9 marks)

22. The diagram below shows a stage in the division of a cell from the male part of a flower.The diploid number of chromosomes for this plant is 14.

(a) State the exact location of such a cell in the male part of a flower.

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(b) Identify the stage of meiosis shown in the diagram.

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(c) Fertilisation in a plant involves different types of cells and nuclei.State the number of chromosomes present in each of the following in this plant.

A pollen tube nucleus ..........................

A female gamete (egg cell) .................

A zygote nucleus .................................

An endosperm cell ...............................(4)

(Total 7 marks)

23. (a) The diagram below shows some of the stages during the development of a human ovum.


(i) On the diagram, write the letter M to show when the first division of meiosis is complete.

(1)

(ii) Name structure Q, shown in the diagram.

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(iii) After ovulation, structure Q develops to form a corpus luteum. Name two hormones that are secreted by the corpus luteum.

1 .............................................................................................................................

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(b) Describe the process of fertilisation in humans.

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(Total 7 marks)


24. Cell A in the diagram below has two pairs of chromosomes. Cell B is one of four cells that were produced from cell A by cell division.

(a) State the type of cell division which has occurred to produce cell B, and give a reason for your answer.

Type of cell division .....................................................................................................

Reason ..........................................................................................................................

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(b) Explain what happened during this cell division which resulted in the different appearance of chromosome P.

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(c) Give the exact location in a human male where this type of cell division occurs.

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(Total 6 marks)

25. The table below lists some features of a typical plant cell and a typical animal cell.

Complete the table with a tick ( ) if you would expect the feature to be usually present or a cross ( ) if you would expect it to be absent.Do not leave any boxes empty.The first line has been done for you.

Typical plant cell Typical animal cell

Cellulose cell wall

Chloroplasts

Cell membrane

Large central vacuole

Chromosomes

Centrioles

Cytoplasm

Stored starch

(Total 7 marks)

26. The diagrams below show cells from a garlic plant at five different stages of mitosis as seen using a light microscope. These stages are in the wrong order.

A B C D E


(a) Give the correct order in which the five stages take place by using the letters A–E.

1st stage ............ 2nd stage ............ 3rd stage ............

4th stage ............ 5th stage ............(2)

(b) (i) Name the part of a garlic plant which is used to prepare a slide showing the stages of mitosis.

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(ii) Name a stain which is used to make the chromosomes easy to see.

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(c) Name the process which must occur in the genetic material before the chromosomes become visible.

(i) Name of the process .........................................................................................(1)

(ii) State what happens to the genetic material during this process.

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(Total 6 marks)


27. Complete the following by filling in the spaces with the most appropriate word or words.

Plant cell walls are largely made up of cellulose. Cellulose molecules consist of

.................................... molecules joined together in very long chains. These

cellulose molecules lie parallel, bound together by .................................... bonds

making up ..................................... A xylem vessel is a tube which forms when a

long row of cells dies and the end walls of the cells break down. As well as

containing cellulose the walls of xylem vessels contain lignin, which makes them

.................................... and .....................................(Total 5 marks)

28. The diagram below shows a bacterium.

A

C

D

B

(a) Name the four structures labelled in the diagram.

A ..................................................................................................................................

B ..................................................................................................................................

C ..................................................................................................................................

D ..................................................................................................................................(2)


(b) Give three features of a virus which distinguishes it from a bacterium.

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(c) Give two reasons for selecting some features but not others when classifying living organisms.

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(Total 7 marks)

29. The diagram below shows a mayfly nymph, an invertebrate which lives in freshwater streams.


(a) Give two features, visible in the diagram, which show how mayfly nymphs are adapted for living in an aquatic habitat. In each case, explain how the feature helps the mayfly nymphs to live in water.

1 ..................................................................................................................................

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2 ..................................................................................................................................

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(b) Freshwater streams may be polluted with organic effluents. One of the effects of an organic effluent is to reduce the concentration of dissolved oxygen in the water. The graph below shows the distribution of larvae of Chironomus, a freshwater invertebrate, at increasing distances downstream from the source of an organic effluent.

N u m b e rs o f

la rv a eC h iro n o m u s

D is tan ce d o w n stre am fro m e fflu en t

P o in t a t w h ic h e ff lu en te n te rs th e s tre am


(i) Suggest and explain two ways in which Chironomus larvae could be adapted to living in water with a low concentration of dissolved oxygen.

1 ........................................................................................................................

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2 ........................................................................................................................

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(ii) Immediately after the point at which the effluent enters the stream, numbers of Chironomus larvae decrease and then increase.

Suggest an explanation for this increase in the numbers of Chironomus larvae.

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(Total 10 marks)


30. Although zoos have changed considerably since London Zoo first showed imported animals to the public, their role in animal conservation is criticised by some.

(a) Describe two activities of zoos which can be used to justify keeping animals in captivity.

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(b) The small numbers of animals typically found in zoos can be a problem for maintaining populations of healthy captive animals over several generations.Describe and explain steps taken to avoid such problems.

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(Total 6 marks)


31. The photograph below shows a chloroplast as seen using an electron microscope. It has been magnified 5000 times.

Magnification × 5000


A ..................................................................................................................................

B ..................................................................................................................................

C ..................................................................................................................................(3)

(b) The magnification of this chloroplast is ×5000. Measure the width of the chloroplast between points X and Y on the photograph.

Calculate the actual width of the chloroplast, expressing the answer in m (micrometres). Show your working.

Answer ............................. m(3)


(c) Name two types of cells which contain chloroplasts and are found in a leaf.

1 ...................................................................................................................................

2 ...................................................................................................................................(2)

(Total 8 marks)

32. The diagram below shows the stages in the cell cycle of a plant root cell.

C y to k in e s is

Te lo p h ase

A n ap h ase

M eta p h ase

P ro p h a se

In te rp h a se

(a) The cell had 2 arbitrary units of DNA at the start of interphase. State the number of arbitrary units of DNA in this cell in each of the following stages.

(i) at the end of prophase

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

(ii) during anaphase

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


(b) Describe how you would prepare a root tip squash to observe the stages of mitosis.

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(c) Two onion bulbs were grown to obtain some roots. One onion bulb was grown in water, the other in a solution of a drug called vincristine, as shown below.

O n io n b u lb

R o o ts

S o lu tio n o fv in c ris tin e

W ate r

Vincristine is a drug used in the treatment of cancer. It prevents spindle formation during mitosis. The result of a root tip squash on the roots grown in a solution of vincristine showed an increase in the percentage of cells found in one of the phases compared with roots grown in water.

(i) Suggest in which phase of mitosis this increase occurs.

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


(ii) Give an explanation for your answer.

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(Total 10 marks)

33. The photograph below shows four germinating pollen grains, as seen using a light microscope.

Maginification ×100

(a) Name the part labelled A.

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


(b) Part A contains a tube nucleus and two male nuclei. Describe the roles of the two male nuclei in the process of fertilisation in a flowering plant.

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(c) An experiment was carried out to investigate the effect of sucrose concentration on the germination of pollen grains from Camellia flowers. The results graph below.

3 0

2 5

2 0

1 5

1 0

5

00 5 1 0 1 5 2 0 2 5 3 0

S u c ro se co n cen tra tio n (% )

P ercen tag eg e rm in a tio no f p o lleng ra in s (% )


(i) From the graph, find the expected percentage germination in a 16% sucrose concentration.

……………………… %(1)

(ii) Describe the relationship between the percentage germination and the sucrose concentration, as shown in the graph.

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(Total 8 marks)

34. The diagrams below show some of the stages of meiosis I in an animal cell.


(a) State the diploid (2n) number of this cell.

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

(b) Write the letters in the correct order to show the sequence of stages in meiosis I.

.....................................................................................................................................(2)

(c) Explain the importance of meiosis in spermatogenesis.

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(d) Semen contains about 100 million sperm per cm3. Suggest why the chances of

fertilisation are significantly reduced if this number falls below about 30 million per cm3.

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(Total 9 marks)

35. The diagram below shows the fluid mosaic model of the cell surface membrane.

B

C

A


A ..................................................................................................................................

B ..................................................................................................................................

C ..................................................................................................................................(3)


(b) Suggest two properties that drugs should possess if they are to enter a cell rapidly.

1 ..................................................................................................................................

2 ..................................................................................................................................(2)

(c) Facilitated diffusion and active transport are two ways in which molecules are transported across cell membranes. Describe one similarity and one difference between facilitated diffusion and active transport.

(i) Similarity

...........................................................................................................................

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

(ii) Difference

...........................................................................................................................

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(Total 7 marks)


36. Read through the following account relating to sexual reproduction. Write on each dotted line the most appropriate word to complete the account.

A sperm is produced by a special kind of nuclear division called......................................

In this type of division the chromosome number of the normal body cell is

..................................... The chromosomes are .................................... assorted which

increases genetic variation.

A sperm can only fertilise an egg by penetrating the jelly surrounding the egg

membrane. The head of the sperm releases .................................... which allow the

sperm to reach the egg membrane. This process is called the ....................................

reaction. Fertilisation produces a diploid cell called a .................................... which

divides by ..................................... to form an embryo.(Total 7 marks)

37. (a) Identify the organelles (structures inside a cell) which fit the descriptions given in the table below. The first one has been done for you.

Description Name of organelle

iWhere photosynthesis takes place and carbon dioxideis converted into sugar chloroplast

ii Where aerobic respiration takes place

iiiWhere amino acids are joined together to formproteins

ivPackages proteins into vesicles so that they can bereleased from the cell by exocytosis

vA large space inside a plant cell surrounded by atonoplast and helping to maintain cell turgidity

viDivides and organises a spindle in an animal cell as itstarts to undergo mitosis

(5)


(b) Describe the structure of pits in plant cells and explain their function.

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.....................................................................................................................................(2)

(c) Give two ways in which the structure of a prokaryotic cell differs from a eukaryotic cell.

1 ..................................................................................................................................

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2 ..................................................................................................................................

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(Total 9 marks)

38. Many plants are grown for their fibres for use in making cloth. For example, nettle fibres can be used for this purpose. In the future nettle fibres may be developed in the United Kingdom as an alternative to imported cotton plant fibres.

A student investigated the strength of plant fibres to find out if they could be made into cloth.

The following method was used.

Step 1. Harvest nettle plants and remove leaves from stems

Step 2. Place stems in buckets and cover with water. Leave for ten days

Step 3. Remove stems and wash fibres under running water


(a) Suggest and explain the changes that take place in the nettle stems during Step 2.

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(b) Describe a reliable method for measuring the strength of these plant fibres.

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(c) Suggest why, in the United Kingdom, cloth made from nettle fibres could be made more cheaply than cloth made from cotton.

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(Total 8 marks)


39. A newspaper recently published the following report.

‘Scientists find gene to halt ovarian cancer’

A gene that can stop the development of cancer of the ovary has been identified. This gene acts as a tumour suppressor. If the gene is switched off then a tumour develops.Scientists have switched the gene back on in mice and the cancer cells stopped developing.

Scientists hope to be able to find a drug to turn this gene back on. This could provide a means of treating ovarian cancer in humans.

(a) (i) If a suitable drug is found it will have to be carefully tested in clinical trials.Describe the methods that would be used to trial a new drug to treat ovarian cancer.

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(ii) William Withering carried out trials of the digitalis soup which he used to treat patients. Explain why his methods could not be used as part of a modern clinical trial.

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(b) In the future, it may be possible to treat ovarian cancer by transplanting healthy stem cells into a diseased ovary. Some people think that stem cell research should not be carried out.

State whether you are for or against the use of stem cells to treat ovarian cancer.

For or against? ........................

Present an argument to explain why you hold this point of view (for or against) using your biological knowledge of stem cell research and the ethical issues connected with it.

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(Total 9 marks)


40. A study of mammals in West Africa has found that populations have decreased by up to 76% in 41 different species. Some species have become extinct in the area, reducing the biodiversity.

Is lan d o f A g ad ir

A tlan ticO cean

M A U R ITA N IA

Source: www.news.bbc.co.uk

(a) Explain why extinction of species reduces biodiversity.

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(b) It is thought that this loss of biodiversity is an indirect result of European legislation which limits fishing in European waters. Rather than lose their way of life, European fishermen now fish off the West African coast, and this has reduced fish stocks dramatically. The highest density of human populations in West Africa is along the coast.

(i) Suggest one reason why fish stocks are important for the human population in West Africa.

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(ii) Suggest reasons why changes in European legislation have had an effect on the wild mammal populations of West Africa.

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(c) With reference to the information given, describe the importance of considering cultural issues when using legislation for conservation of organisms.

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(d) Explain why local legislation is likely to be less effective than international agreements for major conservation projects.

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(Total 10 marks)


41. Research has been carried out on the effect of amphetamines on sporting performance.The table below shows data from a study of volunteers taking part in swimming trials over a fixed distance. Each time is the average for 3 swimmers racing on 4 separate occasions.

Average Performance

Event After takingplacebo /seconds

After takingamphetamines

seconds

Percentage (%)improvement

Freestyle 136.88 135.94 0.69

Backstroke 159.80 158.32 0.93

Breaststroke 171.87 170.22 –

(a) (i) Calculate the percentage improvement for breaststroke, using the space below.Show your working.

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

(ii) State two variables that should have been controlled in this study.

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(iii) Suggest the importance of using a placebo (inactive substance) rather than no drug being given.

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(b) Amphetamines are similar in chemical structure to certain neurotransmitters. One effect of amphetamines can be to reduce blood flow through the skin during exercise.

(i) Suggest how this reduction in blood flow might occur.

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(ii) Suggest the effect of reduced blood flow through the skin on body temperature regulation.

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(iii) Apart from changes in blood flow through the skin, explain how the body controls its temperature when generating heat through exercise, such as running.

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(c) Do you think that the use of amphetamines as a performance-enhancing drug should be made legal?

Explain your views.

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(Total 10 marks)

42. The table below describes some structures found in eukaryotic cells.

Complete the table below by writing the name of the structure in the box next to its description.

Description Name of structure

Cylindrical organelle made up of microtubules,involved in spindle organisation.

Site where ribosomal RNA is made and thesubunits of the ribosomes are assembled.

Organelle consisting of stacks of cisternae andvesicles, concerned with the modification ofproteins.

Small spherical structures surrounded by a singlemembrane, containing hydrolytic enzymes.

(Total 4 marks)


43. The antibiotic penicillin acts on a bacterium by weakening its cell wall so that it bursts.The antibiotic tetracycline interferes with a bacterium’s protein synthesis, preventing the production of new proteins by the bacterium.

(a) Suggest one reason why each antibiotic is not effective against viruses.

Penicillin

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Tetracycline

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(b) Describe and explain how each of these antibiotics would affect the numbers of living bacterial cells in a laboratory culture.

Penicillin

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Tetracycline

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(c) Suggest how tetracycline helps a person to overcome a bacterial infection.

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(Total 9 marks)

44. (a) Describe the roles of protein molecules in facilitated diffusion and active transport.

Facilitated diffusion ....................................................................................................

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Active transport ...........................................................................................................

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(b) Experiments were carried out to compare the uptake by cells of a substance (substance X) in the presence and absence of a respiratory inhibitor. A respiratory inhibitor is a substance that prevents the formation of ATP.

In each experiment the cells were incubated in a solution of substance X for five hours.

The concentration of substance X in the cytoplasm was measured throughout.

The graph below shows the changes in the concentration of substance X in the cell cytoplasm during the experiments.

1 4

1 2

1 0

8

6

4

2

Con

cent

rati

on o

f su

bsta

nce

Xin

side

the

cell

/ g

cm

–3

0 1 2 3 4 5Tim e / h o u rs

C e lls in cu b a ted w ithsu b s tan ce X o n ly

C e lls in cu b a ted w ithsu b s tan ce X an d th ere sp ira to ry in h ib ito r


(i) Describe the changes in the concentration of substance X in the cytoplasm of the cells incubated with the respiratory inhibitor present, during the five hours of the experiments.

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(ii) Suggest an explanation for the changes you have described.

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(Total 9 marks)


45. (a) The diagram below shows some of the stages and cells involved in the process of spermatogenesis.

S p erm a to g o n ia

S p e rm a to zo a

C e lls A

S eco n d a ry sp e rm a to cy te s

P rim ary sp e rm a to cy te s

(i) Name Cells A shown in the diagram above.

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

(ii) State which of the cells named in the diagram are diploid (2n).

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(b) The graph below shows the changes in the DNA content of cells in the testes, during the formation of spermatozoa.

D N A co n ten t p e r ce ll

4 n

2 n

n

Tim e

Name the type of nuclear division shown by the graph and explain why it is important to reduce the DNA content from diploid (2n) to haploid (n), during the formation of spermatozoa.

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(Total 6 marks)


46. The photograph below shows a transverse section through a leaf of Ammophila, as seen using a light microscope. Ammophila is an example of a plant with xeromorphic adaptations.

(a) Explain what is meant by the term xeromorphic adaptations.

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(b) Describe and explain two features, visible in the photograph, that show how Ammophila is adapted to its environment.

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(Total 5 marks)


47. The diagram below shows the steps needed to produce human tissues from embryonic stem cells. This procedure has not yet been successfully carried out although some scientists hope that it will soon be possible. Perhaps one day new nervous tissue will be produced that will enable people with spinal injuries to walk again.

S tep 1

S tep 2

S tep 3

S tep 4

S tep 5

S tep 6

S tep 7

fe rtilisa tio n

‘sp a re ’ em b ry o

g ro w n to fo rm b la s to cy st

s tem ce lls iso la ted , rem a in so f b la s to cy s t d isca rd ed

stem ce lls cu ltu red

ce ll d iffe ren tia tio n

h u m an tissu es fo r tran sp lan ta tio n

(a) (i) Describe how scientists might obtain a supply of ‘spare embryos’ (Step 2) to produce tissues.

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(ii) After fertilisation, cells are totipotent but by the time a blastocyst has formed the cells are pluripotent. Explain what is meant by the terms totipotent and pluripotent.

totipotent ..........................................................................................................

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pluripotent .......................................................................................................

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(b) Explain why the following are important in producing tissues from stem cells.

(i) stem cells cultured (Step 5)

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(ii) cell differentiation (Step 6)

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(c) The use of embryonic stem cells to produce tissues in this way is controversial. Some people think that it should be banned, whilst other people think that it would be wrong not to try this technique. State whether you are for or against using embryonic stem cells to produce new tissues.

For or against?.............................................

Use your knowledge of stem cell research issues to justify your view.

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(Total 11 marks)

48. The tolerance of plants to copper ions in the soil is under genetic control. The frequency of an allele, which causes a plant to be more tolerant of copper, was measured at two different sites A and B.

The table below shows the percentage frequencies of the tolerance and non-tolerance alleles in plant populations at the two sites.

Site Percentage frequencies of

Tolerance allele Non-tolerance allele

A 30 70

B 80 20


(a) Explain what is meant by the frequency of an allele in a population.

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(b) Describe how natural selection could have brought about the different allele frequencies at the two sites.

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(c) Suggest why bacteria often adapt to changing conditions much more quickly than plants.

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(Total 8 marks)


49. Answer the following essay question.

You are expected to answer in continuous prose. You should use examples from the biology course you have studied but need not restrict yourself to the course content.

You should spend approximately 45 minutes answering this question including planning time.

Marks will be awarded for the following areas:

Breadth: selection of a range of relevant examples (up to 6 marks)

Depth: Further description and discussion of the examples (up to 8 marks)

Balance: Have you answered the question asked; for example have you recognised the advantages and disadvantages or benefits and risks (up to 6 marks)

Style: Coherence, clarity and expression (up to 4 marks)

Some people claim that many medical problems, such as the shortage of suitable organs needed for transplant surgery, may become a thing of the past. The use of stem cells, which may have had a specific gene or genes inserted, could give rise to many new treatments.

Write an essay on: ‘Manipulating stem cells: a miracle cure or a dangerous development?’(Total 20 marks)

50. (a) The cell cycle includes interphase and mitosis. Mitosis has four phases: prophase, metaphase, anaphase and telophase. The photograph below shows plant root cells at various stages of the cell cycle.

(i) Draw a line to indicate a cell in the photograph that is undergoing anaphase and label this line A.

(1)

(ii) Draw a line to indicate a cell in the photograph that is undergoing telophase and label this line T.

(1)

(iii) How many of the cells shown in the photograph are in telophase?

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(b) Give an account of the events that take place during prophase and metaphase of mitosis.

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(Total 8 marks)


51. (a) In the space below, draw and label a diagram to show the structure of a chloroplast, as seen using an electron microscope.

(4)

(b) The photograph below shows a group of mitochondria in a liver cell, as seen using an electron microscope. The magnification is ×50 000.


(i) Measure the length of the mitochondrion labelled A between X and Y. Calculate the actual length of this mitochondrion in μm. Show your working.

Actual length of A ......................µm.(3)

(ii) Suggest one other structure that might be visible in the cytoplasm of this liver cell if the magnification used was higher.

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(iii) Suggest one reason why the double membrane is not clearly visible all around the mitochondrion labelled A.

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(Total 9 marks)


52. (a) Some invertebrates, such as insect larvae, show various adaptations to living in freshwater with a low concentration of dissolved oxygen. Some other invertebrates are adapted to living in fast-flowing water.

(i) Describe and explain two ways in which invertebrates are adapted to living in fresh water with a low concentration of dissolved oxygen.

1 ........................................................................................................................

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2 ........................................................................................................................

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(ii) Suggest and explain one way in which an invertebrate might be adapted to living in fast-flowing water.

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(b) An experiment was carried out to investigate the relationship between temperature and the concentration of dissolved oxygen in freshwater. The results are shown in the table below.

Temperature / °C Concentration of dissolved oxygen / mg dm–3

5 12.8

10 11.3

15 10.2

20 9.2

25 8.2

30 7.5

Describe the relationship between temperature and the concentration of dissolved oxygen, as shown by the data.

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(Total 8 marks)


53. (a) The diagrams below show some of the stages of meiosis I in an animal cell. The diploid number (2n) of this cell is 4.

A B C

D E

Write the letters in the correct order to show the sequence of stages in meiosis I.

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(b) The diploid number of chromosomes in a human cell is 46. State the number of chromosomes present in each of the following.

(i) A spermatogonium ...................

(ii) A spermatid ..............................(2)


(c) Describe the process of oogenesis.

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(Total 8 marks)

54. The table below refers to four processes by which molecules can cross a cell surface (plasma) membrane. If the statement is correct, place a tick ( ) in the appropriate box and if the statement is incorrect, place a cross ( ) in the appropriate box.

Process Requires carrier proteinsRequires energy

in the form of ATP

Simple diffusion


Osmosis

Active transport

(Total 4 marks)


55. All cells have a cell surface (plasma) membrane. The diagram below shows the structure of this membrane.

P ro te in s

P h o sp h o lip id b ilay e r

Explain how the properties of phospholipids result in the formation of a bilayer.

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56. The table below refers to some cell structures. Complete the table by inserting the correct word, words or diagram in the appropriate boxes. Leave the shaded grey boxes empty.

Name of cell structure Description of cell structure Diagram of cell structure

(1)

1. Darkly-stained region in the nucleus.

2. Where ribosomal RNA is made.

Centriole

(2)

Lysosome

1.

2.

(2)

(1)

1. Hollow cylinders made of protein.

2. Form spindle fibres.

(Total 6 marks)


57. The graphs below show changes in the DNA content of cells during the cell cycle in two different plants, A and B.

P la n t A

DN

A c

onte

nt in

eac

h ce

ll / a

rbitr

ary

unit

s

6

3

Tim e / h o u rs

3 63 43 23 02 82 62 42 22 01 81 61 41 21 086420

P la n t B

DN

A c

onte

nt in

eac

h ce

ll /

arbi

trar

y un

its

6

3

Tim e / h o u rs

3 63 43 23 02 82 62 42 22 01 81 61 41 21 086420


(a) Compare the cell cycle of plant A with the cell cycle of plant B.

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(b) The DNA content of the cells of plant A doubles between 4 and 8 hours. Give an explanation for this change in DNA content.

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(c) Describe the events that are occurring inside the cells of plant A between 11 and 13 hours.

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(Total 7 marks)

58. The photograph below shows a transverse section through part of a leaf of Ammophila, as seen using a light microscope. Ammophila is a plant which is adapted to living in a dry environment.

Magnification ×100


(a) Describe and explain three ways in which the leaves of plants, such as Ammophila, are adapted to their environment.

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(b) Suggest one way in which the structure of a leaf of a hydrophyte might differ from the structure of a leaf of Ammophila.

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(Total 7 marks)

59. The table below refers to some structures of microorganisms. Complete the table by writing the name of the type of microorganism possessing each structure in the empty boxes.

Structure Type of microorganism

Nucleus

Capsid

Flagellum

Peptidoglycan (murein) cell wall

(Total 4 marks)


60. The table below compares the features of typical plant, animal and bacterial cells.Complete the table by placing a tick ( ) in the appropriate box if the feature is usually present or a cross ( ) if the feature is usually absent.Do not leave any boxes empty.

The first line has been done for you.

Plant(eukaryotic) cell

Animal(eukaryotic) cell

Bacterial(prokaryotic) cell

Cell wall

Chloroplasts

Nuclear membrane

Cell (unit) membrane

Ribosomes

Centrioles

(Total 5 marks)

61. (a) Mammalian gametes are formed by meiosis and have the ability to fuse to form a zygote. Explain why it is important that gametes are produced by meiosis.

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(b) Explain how the genetic material from a mammalian sperm cell is able to enter an ovum to bring about the process of fertilisation.

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(c) (i) Calculate the number of cells that will be present in the embryo after the first four mitotic divisions of the zygote.

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(ii) Suggest why, during the first four mitotic divisions, the embryo does not increase in volume even though the total number of cells increases.

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(iii) Outline the events that occur in mitosis from the start of prophase up to the end of metaphase.

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(Total 9 marks)

62. (a) A single stem cell can give rise to many genetically identical cells of different types.There are, for example, adult stem cells in the human brain which are capable of producing the different types of brain cells including nerve cells (neurones).

Scientists are trying to find ways of growing such adult brain stem cells in the laboratory.

(i) Name the type of cell division by which a stem cell can give rise to many genetically identical cells.

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(ii) Explain how cells produced from stem cells can have the same genes yet be of different types.

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(iii) Suggest why it might be useful to keep a supply of live stem cells from your brain in a laboratory.

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(b) Much research remains to be done and so it will be some time before adult stem cell treatments will be available to those who might benefit from them. However, research using embryonic stem cells is much further advanced.

(i) Suggest why research with embryonic stem cells is further advanced than research with adult stem cells.

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(ii) Some people hold the view that research into and the medical use of embryonic stem cells is unethical and that we should await the results of research on adult stem cells.

Are you for or against embryonic stem cell research? .....................................

Using your scientific knowledge and your understanding of the ethical issues associated with embryonic stem cell research, explain why you hold this view.

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(Total 11 marks)


63. The graph below shows the changes in population size of bacterial cultures grown in the presence of three antibiotics, A, B and C. In each case the antibiotic was added at 7 hours.

6 0 0 0

5 0 0 0

4 0 0 0

3 0 0 0

2 0 0 0

1 0 0 0

01 51 050

Pop

ulat

ion

size

/ ar

bitr

ary

unit

s

T im e / h o u rs

an tib io tic ad d ed

A n tib io tic A

A n tib io tic B

A n tib io tic C

(a) Use examples from the graph to explain the differences between bacteriocidal and bacteriostatic antibiotics.

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(b) A previous investigation on the same bacterium using antibiotic A had produced a curve similar to that for antibiotic B. Suggest an explanation for the change in the response to antibiotic A.

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(c) Outline a technique that could demonstrate the effectiveness of antibiotics on bacteria.

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(Total 11 marks)


64. Chimpanzees and humans share about 98.4% of their DNA and it is thought that they had a common ancestor about four million years ago. One gene that shows differences is ‘Fox P2’ which is involved in speech. All modern humans have the same allele for this gene which is different from that found in chimpanzees.

(a) Explain how the frequency of the Fox P2 allele could have increased as humans evolved.

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(b) (i) Until 1968 it was illegal to teach evolution in schools in a number of states in the USA. Suggest two reasons why it was thought necessary to make the teaching of evolution illegal in these schools.

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(ii) Suggest why the teaching of natural selection has less opposition than the teaching of evolution.

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(Total 7 marks)

65. (a) The diagrams A and B below show cells from the same organism. Both cells are in the same stage of nuclear division. One cell is undergoing mitosis and the other cell is undergoing meiosis.

A B

Z

(i) Which cell is undergoing mitosis? Put a cross in the correct box.

A B (1)

(ii) Give the name of the structure labelled Z.

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(iii) Name the stage of mitosis shown.

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(b) Describe how you would prepare cells in order to observe mitosis.

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(Total 7 marks)

66. (a) Independent assortment and crossing over both result in genetic variation.

(i) Explain how independent assortment leads to genetic variation.

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(ii) Describe how crossing over further increases genetic variation.

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(b) The graph below shows changes in mean height of men in Japan from 1950 to 1980.

1 6 3

1 9 4 5 1 9 5 0 1 9 5 5 1 9 6 0 1 9 6 5 1 9 7 0 1 97 5 1 9 8 0

1 6 4

1 6 5

1 6 6

1 6 7

1 6 8

1 6 9

1 7 0

1 7 1

1 7 2

1 7 3

M ea n h e igh t o f m en a ged 20

/cm

Yea r

Describe the changes in height between 1950 and 1980.

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(c) The graph below shows changes in the major components of the diet of men in Japan over the same period.

1 9 5 0 1 9 6 0 1 9 7 0 1 9 8 0

Yea r

ca rb o h y d ra te

fa t

an im a l p ro te in

8 0

7 0

6 0

5 0

4 0

3 0

2 0

1 0

0Rel

ativ

e p

rop

orti

on o

f d

ieta

ry c

omp

onen

t /

arb

itra

ry u

nit

s

The evidence from both graphs suggests that a combination of genetic and environmental factors influence the height of men in Japan. Give an explanation for this.

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(Total 10 marks)

67. (a) Three structures found in mammalian sperm cells are described in the table below.Give the name of each structure being described.

Description Structure

Releases digestive enzymes to penetrate egg

Allows the sperm to swim to the egg cell

Provides the energy required for swimming

(3)


(b) Give the term that describes the ability of a stem cell from an embryo to produce all cell types.

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(c) Describe how a cell loses the ability to produce other cell types and becomes specialised.

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(d) Embryos have been produced from human egg cells which have not been fertilised by sperm. These embryos never survive past a few days. This is because some of the genes needed for development are only active in chromosomes from the sperm.

It has been suggested that there will be less opposition to the medical use of stem cells from these embryos than from normal embryos. Suggest reasons for this.

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(Total 10 marks)


68. Taxonomy is the branch of biology concerned with the classification of organisms. In the taxonomic system first developed by Linnaeus, organisms are given a two-part Latin name.

(a) State one advantage of the binomial system developed by Linnaeus.

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(b) The table below shows the classification of the blue whale, Balaenoptera musculus together with some of the classification of the fin whale, Balaenoptera physalus.

Complete the table by suggesting appropriate names for the class, order and family of the fin whale.

Classification taxon Blue whale Fin whale

Kingdom Animalia Animalia

Phylum Chordata Chordata

Class Mammalia

Order Cetacea

Family Balaenopteridae

Genus Balaenoptera Balaenoptera

Species Balaenoptera musculus Balaenoptera physalus

(1)


(c) Below are four features, A, B, C and D, used in the classification of organisms. Put a cross in the box or boxes next to the features which are shared by both blue whales and fin whales.

A – feed by heterotrophism on organic material

B – multicellular

C – cells surrounded by cell wall

D – cytoplasm of cells contain circular DNA(2)

(d) Suggest reasons for the classification of the blue whale and the fin whale within the same genus, Balaenoptera, but as different species.

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(Total 7 marks)

69. (a) State what is meant by the term species richness.

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(b) In a survey, the mean species richness for the vegetation found in roadside verges and hedgerows in England and Wales was measured in 1990 and again in 1998. The results of this survey are shown in the graphs below.

14 .0

14 .5

15 .0

15 .5

16 .0

16 .5

17 .0

17 .5

199 0 1998

R o a d sid e ve rg e s

Sp

ecie

s ri

chn

ess

11 . 5

1 2 . 0

1 2 . 5

1 3 . 0

1 3 . 5

1 4 . 0

1 4 . 5

1 9 9 0 1 9 9 8

H e d g e ro w s

Sp

ecie

s ri

chn

ess


Compare the species richness shown by the survey for the vegetation in the roadside verges with that of the hedgerows over this study period.

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(c) Other information would be needed, in addition to species richness, to measure the biodiversity of the vegetation in the two types of habitat. Give an explanation for this.

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(d) Seed banks, such as the Millennium Seed Bank Project (MSBP), are an effective means of conserving plant species.

Write a short briefing, intended for a government committee, describing how seed banks work and why their funding should be continued.

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(Total 12 marks)


70. Sisal is a material used to make rope. It is made from the sclerenchyma fibres found in the leaves of the plant, Agave sisalana.

After extraction of the fibres, the waste leaf material can be used in the production of organic fertiliser.

The four countries that produce most of the world’s sisal are Brazil, Kenya, Tanzania and Madagascar. The table below shows the annual harvest of freshly-cut Agave sisalana leaves together with the total annual production of sisal.

CountryAnnual harvest of freshly-

cut leaves / tonnes × 103Annual production of sisal /

tonnes × 103

Brazil 995 199

Kenya 196 40

Tanzania 145 28

Madagascar 96 20

TOTAL 1432

(a) (i) Complete the table to show the total annual production of sisal.(1)

(ii) Calculate the total percentage of sisal produced from freshly-cut leaves. Show your working.

Answer ..................... %(2)


(b) Nylon is a synthetic (man-made) fibre which can be used to make ropes. Nylon ropes are lighter and stronger than those made using sisal. Suggest two advantages of using sisal rather than nylon to make ropes.

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(c) (i) Explain what is meant by the term tensile strength of a fibre.

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(ii) Suggest how you could carry out a practical investigation to compare the tensile strength of sisal and nylon fibres.

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(d) Describe two ways in which the structure of xylem vessels is similar to that of sclerenchyma fibres.

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(Total 12 marks)


as long paper unit 2

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