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Paper Reference(s)

4325/03 4437/07

London Examinations IGCSE

Biology – 4325

Paper 3

Science (Double Award) – 4437

Paper 7

Foundation and Higher Tiers

Monday 22 November 2010 – Morning

Time: 1 hour 15 minutes

Materials required for examination Items included with question papers

  Nil Nil

Instructions to Candidates

In the boxes above, write your centre number, candidate number, your surname, initial(s), the paper reference and your signature.The paper references are shown above. Write the one for which you have been entered. Check thatyou have the correct question paper.Answer ALL the questions. Write your answers in the spaces provided in this question paper.Do not use pencil. Use blue or black ink.Show all stages in any calculations and state the units. Calculators may be used.

Information for Candidates

The marks for individual questions and the parts of questions are shown in round brackets: e.g. (2).There are 5 questions in this question paper. The total mark for this paper is 50.There are 16 pages in this question paper. Any blank pages are indicated.

Advice to Candidates

Write your answers neatly and in good English.

Examiner’s use only

Team Leader’s use only

Question Leave

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1

2

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Total

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Signature

Centre

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Paper Reference

This publication may be reproduced only in accordance with

Edexcel Limited copyright policy.©2010 Edexcel Limited.

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Answer ALL the questions. Write your answers in the spaces provided.

1. Fernando wanted to find out how wind affected transpiration (water loss) from a leafy

shoot. To do this Fernando had to set up a potometer.

The apparatus he used to set up his potometer is shown below.

(a) Complete the table below to identify the letter that labels each piece of apparatus. Thefirst one has been done for you.

Name of apparatus Letter of apparatus

Rubber tube F

Elastic band

Glass tube

Knife

Beaker 

Ruler 

(5)

A C

FED

B

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(b) Fernando used the apparatus to make his potometer. He filled the rubber tube, the

 beaker and the glass tube with water. The stem of a plant was attached to the rubber 

tube. One end of the glass tube was attached to the rubber tube and the other end was

 put into the water in the beaker. He then put an air bubble in the water inside the glass

tube.

Fernando wanted to estimate transpiration by measuring how far the bubble moved in

an hour. To help him to do this he used the elastic band to attach the ruler to the glass

tube.

Fernando made a drawing of his potometer as shown below. The drawing is not

finished.

(i) Complete the drawing.

(3)

 plant

rubber tube

glass tube

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(ii) Fernando wanted to create a stream of moving air (wind) around the plant.

Suggest how he could do this.

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

(1)

(c) Fernando estimated transpiration by measuring the movement of the bubble in still air 

and in moving air (wind). The table shows the results he obtained.

Movement of bubble in cm per hour

In still air In moving air

8 12

Describe the effect that moving air had on the rate of transpiration.

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

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(2) Q1

(Total 11 marks)

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2. Nicola investigated the digestion of lactose, a sugar found in milk.

The diagram shows the apparatus she used.

The beads contained an enzyme called lactase. This enzyme digests lactose into twosugars called glucose and galactose.

The outer coat of the beads allows milk to enter and sugars to leave. The outer coat also

 prevents the enzyme from leaving.

An experiment was carried out in which milk was allowed to flow through the apparatus

at different speeds. The speed of flow was changed using the clamp on the exit tube.

The milk collected in the beaker was tested for the concentration of glucose it contained

at each flow speed. The table shows the results.

Speed of milk flow through

apparatus

in cm3 per minute

Glucose concentration in

beaker milk 

in mmol per litre

4 156

6 132

10 100

18 55

32 25

milk 

containing

lactose

milk containing

glucose

 beads

clamp

 beaker 

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(a) (i) Use the information in the table to plot a line graph on the grid below.

Join the points with straight lines.

(5)

(ii) Describe the relationship between the speed of flow and the concentration of 

glucose.

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

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

(1)

(iii) Suggest an explanation for the relationship between the speed of flow and the

concentration of glucose.

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(2)

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(b) The investigation was carried out at 20 °C.

(i) Name two variables, apart from temperature, that needed to be kept the same

during the investigation.

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

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

(2)

(ii) Suggest how the results would be different if the investigation had been carried

out at 25 °C. Explain your answer.

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

(2)

(c) How would the concentration of glucose in the beaker be different if the beads used

were bigger in size?

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

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

(1)

(d) Give one way in which the results in this investigation could be made more reliable.

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(1) Q2

(Total 14 marks)

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3. The diagrams show a male and a female fruit fly.

Male Female

John carried out a breeding investigation using these fruit flies. He placed a male and

a female fly in a tube containing some food (a food tube) and allowed them to breed.

The food tube he used is shown in the diagram.

(a) The flies produced 60 offspring as shown on the next page.

Count the number of male and female offspring and use a tally system to write your 

answers in the table below.

Sex of fly Tally count Number counted

Male

Female

(4)

food

flies

sponge

 bung

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(b) John had expected to get 30 males and 30 females.

(i) Draw a genetic diagram to show why he expected to get equal numbers of males

and females. Use your knowledge of how sex is inherited in humans to help

you.

(3)

(ii) Suggest why the numbers of male and female flies obtained were not equal.

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

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

(1)

(c) John repeated the breeding investigation four more times using different food tubes

and different males and females.

The results are in the table.

Food tube Number of male offspring Number of female offspring

1 32 28

2 29 33

3 10 6

4 36 32

Total

(i) Complete the table by writing in the total number of male and female flies

obtained in the four food tubes.

(1)

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(ii) Which food tube produced an anomalous (unexpected) result?

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

(1)

(iii) Suggest one reason why this food tube produced an anomalous result.

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

(1) Q3

(Total 11 marks)

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4. The energy released by cell respiration is trapped in a molecule called ATP.

Verity wanted to find out how a solution of ATP affected the contraction (shortening) of 

muscle tissue.

She placed a long strip of muscle tissue on a glass microscope slide.

She then added a solution of ATP.

The diagram shows the result of Verity’s experiment.

She used the formula below to calculate the percentage change in length that had taken

 place.

% change in length =

length of muscle tissue before ATP addded

length of muscle tissue after ATP added

length of m

−

uuscle tissue before ATP added100×

(a) Use the diagram and the formula to calculate the percentage change in length.

Show your working.

Answer .......................................... %

(2)

after adding ATP

glass slide muscle tissue

before adding ATP

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(b) Michael was another student in the same class as Verity.

Michael did the same experiment five times with an ATP solution and five times with

 pure water.

He wrote his answers in his notebook as shown below.

(i) Put Michael’s results into a suitable table.

(4)

(ii) Explain why Michael’s investigation was better than Verity’s.

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

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

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

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

(2) Q4

(Total 8 marks)

with ATP15%

17.6%16.6%

15.2%16.4%

without ATP

3.2%2.5%

0.8%4.2%

3.6%

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5. Rivers are sometimes polluted by warm water from power station outflows.

This is known as thermal pollution and can affect the growth of plants.

Design an experiment to investigate the effect of water temperature on the growth of 

 plants.

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TOTAL FOR PAPER: 50 MARKS

END

Q5

(Total 6 marks)