INSTRUCTIONS TO CANDIDATES

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1 Candidate Name Centre Number 0 Candidate Number GCSE 239/02 ADDITIONAL SCIENCE HIGHER TIER BIOLOGY 2 A.M. FRIDAY, 21 May minutes For s use ADDITIONAL MATERIALS In addition to this paper you may require a calculator and a ruler. Question Maximum Mark Total 50 Mark Awarded INSTRUCTIONS TO CANDIDATES Write your name, centre number and candidate number in the spaces at the top of this page. Answer all questions. Write your answers in the spaces provided in this booklet. INFORMATION FOR CANDIDATES The number of marks is given in brackets at the end of each question or part-question. You are reminded of the necessity for good English and orderly presentation in your answers. VP*(S )

2 2 Answer all questions. 1. The cell below is carrying out aerobic respiration. glucose oxygen water carbon dioxide (a) Draw arrows, to or from the boxes, to indicate the direction in which glucose, oxygen, water and carbon dioxide move, into or out of the cell. [4] (b) Why is respiration important to all cells? [1] 5

3 3 2. (a) The following food chain was found in a garden. lettuce greenfly ladybird blue tit (i) Name the producer in this food chain. [1]... (ii) The following data was collected on this food chain. Organism Number in the food chain Mass of each organism/g Total biomass of organisms/ g lettuce greenfly ladybird blue tit 1 8 I. Complete the table by calculating the total biomass for each of the organisms in the food chain. One has been done for you. [1] II. On the chart below use the total biomass of each of the organisms to construct, to scale, a pyramid of biomass for this food chain. Label each level of the pyramid with the name of the organism. [3] (b) Give one way in which energy is lost from the food chain. [1] Turn over. 6

4 4 3. Floating pennywort is an alien plant species in Britain. It grows in slow flowing waterways such as canals and lakes where it forms dense mats which grow at the rate of 20cm a day. Floating pennywort out-competes native plants, reduces the oxygen content of water and has a damaging effect on flood control. A waterway choked with floating pennywort Centre for aquatic plant management (a) What is meant by an alien species? [1] (b) State one harmful effect that floating pennywort could have on native wildlife. [1] (c) In Florida the southern army worm is known to eat floating pennywort and in Argentina there is a weevil (an insect) that eats floating pennywort. What advice would you give the Environment Agency about the dangers of introducing these organisms into Britain as methods of biological control against floating pennywort? [2] 4

5 5 4. The diagram represents a section of the small intestine containing three different large food molecules, X, Y and Z. glucose molecules wall of small intestine amino acid molecules (a) (i) Complete the diagram to show the effect of the action of lipase on molecule X. Include labels in your drawing. [2] (ii) Name the enzyme that acted on molecule Y to break it down into glucose molecules. [1]... (iii) How does the body use the amino acids produced from molecule Z? [1] (b) Name the stage in dealing with food that results in molecules moving (diffusing) through the wall of the small intestine into the bloodstream. [1]... Turn over. 5

6 6 5. PhotoMax is a chemical spray which is used to increase the rate of photosynthesis in crop plants. It does this by increasing the amount of carbon dioxide which leaves can absorb. It has been successfully used in New Zealand to increase fruit size in grapevines. The rate of photosynthesis in grapevines in a test area was measured over a 28 day period. On two separate days within this 28 day period PhotoMax was sprayed onto grapevines on days 7 and 21. The results are shown in the graph below. Photomax sprayed Photomax sprayed Rate of photosynthesis /arbitrary units Time/days (a) Apart from environmental factors, suggest why the rate of photosynthesis fell between days 10 and 21. [1] (b) Based on the results above, suggest a suitable re-spray time interval that would both maximise the size of the grapes and be economic to the farmer. [1]... (c) During the testing period a control spray was used instead of PhotoMax. Suggest what substance was in the spray. [1]

7 7 (d) In another experiment: the concentration of carbon dioxide in the air remained the same over the 28 days the concentration of PhotoMax was the same on both sprayings. In this experiment the scientists noticed that the increase in the rate of photosynthesis was greater after the first spraying than after the second spraying. Use your knowledge of photosynthesis to suggest reasons for this decrease. [2] Turn over. 5

8 8 6. Students investigated the effect of sugar solution on potato tissue in the following way. Cylinders of constant size were cut from the potatoes and covered by a range of sugar solutions of different concentrations. cylinders of potato sugar solution concentration of sugar solution /mol per dm 3 Their lengths were measured at the start and after 30 minutes in the solutions. The graph shows the changes in the length after 30 minutes in the solutions. Change in length of cylinder / mm Key: + = increase in length = decrease in length Sugar concentration /mol per dm 3

9 9 (a) (i) What concentration of sugar solution is the same as the concentration of the cell sap of the potatoes? [1]... mol per dm 3 (ii) Explain your answer. [1] (b) What would be the expected change in length in sugar solution at a concentration of 0.25 mol per dm 3? [1]... (c) Explain the change in length of the potato cylinders when they were placed in sugar solution of concentration 0.5 mol per dm 3. [4] Turn over. 7

10 10 7. The map shows the main pollution levels in some rivers which enter the North Sea. Key: Thousands of tonnes per year of: N nitrogen P phosphorus Cu Pb Zn copper lead zinc } Heavy metals (a) Use the data on the map to suggest how agriculture and industry cause water pollution. (i) Agriculture [2] (ii) Industry [1]

11 11 (b) (i) In which river would you expect to have the lowest concentration of oxygen? [1]... (ii) Explain, in detail, why this river would have the lowest concentration of oxygen. [5] (c) It was noted that many birds that eat fish have been found dead near the mouth of the rivers Elbe and Rhine. Suggest two possible reasons for the death of these birds. [2] (i)... (ii)... Turn over. 11

12 12 8. Some plants, like the pitcher plant shown below, collect rain water in their modified cup-like leaves. Insects and small frogs collect in the water. Modified leaf The inside of the leaf of a pitcher plant Insects and small frogs Decaying plants and animals The dead and decaying insects and other animals contain protein. The frogs which live in the water excrete urea. (a) Use your knowledge of the nitrogen cycle to explain how nitrate, used by the plant, can be produced in the water in the cup-like leaves. [3]

13 13 (b) Scientists have investigated the processes taking place in the cup-like leaves. They took samples of liquid from the cup-like leaves and added them to urea in two specimen tubes as shown in the diagrams. The specimen tubes were kept at 25 C for 12 hours. A B Moist indicator paper sample of liquid and urea boiled cooled sample of liquid and urea Colour key for indicator ph Red Yellow Green At the start of the investigation the indicator paper in both specimen tubes was yellow. After 12 hours, the indicator paper in A was green but, in B it was still yellow. (i) Underline the correct answer below: [1] In tube A, after 12 hours, the liquid was Neutral Acid Alkaline (ii) Explain how the results for tube B show that an enzyme was responsible for the change in tube A. [1] (iii) Name the enzyme which acted on the urea. [1]... (iv) Suggest the type of organism which could produce this enzyme. [1]... 7