Cambridge IGCSE Biology - 0610 - Supplement Paper 4 2018 Summer Zone 2

(a) Red pandas, Ailurus fulgens, and humans have a similar arrangement of teeth.

Fig. 1.1 shows a section through one tooth of a red panda. Fig. 1.2 shows the side view of the lower jaw of a red panda.


(i) State the names of the structures labelled A to F in Fig. 1.1 and Fig. 1.2.
A ......................................................................................................................................................
B ......................................................................................................................................................
C ......................................................................................................................................................
D ......................................................................................................................................................
E ......................................................................................................................................................
F ...................................................................................................................................................... [3]

(ii) State the type of digestion that breaks down large pieces of food.
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(b) Food that sticks to the teeth can be used by bacteria for anaerobic respiration.

This type of respiration releases a substance that can cause tooth decay.

(i) State the type of substance released by the bacteria, during respiration, that causes tooth decay.
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(ii) State the names of the two parts of a tooth that are dissolved by the substance released by bacterial respiration.
1 ...................................................................................................................................................
2 ................................................................................................................................................... [2]

(c) The teeth of red pandas do not decay as much as human teeth.

Suggest the component of a human diet that causes teeth to decay as a result of bacterial respiration.
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Mangrove trees are hydrophytes because they grow in water.
Fig. 2.1 shows a young mangrove tree.

(a) An adaptive feature is a feature that increases the fitness of an organism.
(i) Define the term fitness.
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(ii) Mangrove trees have many aerial roots and floating seeds. Suggest how these adaptive features allow mangrove trees to survive in water.
many aerial roots ..........................................................................................................................
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floating seeds ..........................................................................................................................
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(b) Fig. 2.2 shows a food chain in a mangrove forest.
mangrove tree → fiddler crab → seagull
Fig. 2.2
Table 2.1 gives the number of organisms and their biomass in a mangrove forest.
[Table_1]
| organism | number of organisms | biomass of organisms / kg |
|--------------|--------------------|----------------------------|
| mangrove trees | 1000 | 450000 |
| fiddler crabs | 7500000 | 8000 |
| seagulls | 150000 | 1200 |
(i) Estimate the biomass of one fiddler crab in grams. Write your answer to two significant figures. Show your working.
.................................................. g [2]
(ii) Sketch a pyramid of numbers, using the information in Table 2.1, for the food chain shown in Fig. 2.2.
Write the number of each trophic level on the appropriate part of your pyramid. [3]
(iii) Explain why the shape of a pyramid of biomass, for the information given in Table 2.1, would be different from the shape of your pyramid of numbers.
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Aphids are insects that feed on the phloem sap in plants.
Fig. 3.1 shows a diagram of an aphid with its mouth parts inserted into the stem of a plant.

Fig. 3.1
(a) The mouth parts of the aphid reach the phloem tissue of the stem.
(i) State the name of the foods the aphid could suck out of the phloem tissue.
1 ..................................................................................................................................................
2 .................................................................................................................................................. [2]
(ii) Explain the role of phloem in plant transport. Use the words source and sink in your answer.
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(b) Fig. 3.1 shows some of the features of xylem.
Describe how xylem is adapted for its functions.
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(c) Some farmers spray their crops with insecticides to kill pests such as aphids.
Explain the benefits of killing pests.
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One of the roles of the Centers for Disease Control and Prevention (CDC) in Atlanta, US, is to try to reduce the number of people who are infected with pathogens.
The CDC conducted a survey. They asked women which, if any, contraceptive methods they used.

(a) Suggest why the CDC collected data on contraceptive methods.
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Fig. 4.1 shows the results of the survey.


(b) (i) State two hormones that are used in contraceptive pills.
1 .........................................................................................................................................................................
2 ......................................................................................................................................................................... [2]

(ii) Suggest why contraceptive pills do not contain FSH.
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(iii) Give one example of ‘other chemical methods’ (fourth bar) that could be included in the bar in Fig. 4.1.
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(iv) State two methods of birth control that were not listed in the survey.
1 .........................................................................................................................................................................
2 ......................................................................................................................................................................... [2]

(v) The percentage of the last three bars in Fig. 4.1 added together is 90%.
Suggest why the percentage of women who used any type of contraceptive method (first bar) is not equal to the sum of the last three bars.
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(a) State three visible features from Fig. 5.1 that could be used to distinguish adult insects from other arthropods.
1 ........................................................
2 ........................................................
3 ........................................................ [3]

(b) Fly larvae are immature insects that are often used in experiments on respiration.
Give the balanced chemical equation for aerobic respiration.
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(c) A respirometer is shown in Fig. 5.2. It can be used to estimate an organism’s rate of respiration.
(i) Complete the sentences:
A respirometer can be used to calculate the .............................. of oxygen used by the fly larvae by measuring the .............................. the droplet of oil moves in one minute. A water-bath is used to .............................. the temperature of the apparatus. [3]
(ii) The soda lime in the respirometer absorbs carbon dioxide.
Explain why this is important in this investigation.
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(iii) Fly larvae respire to release energy.
State two uses of energy in a fly larva.
1 ........................................................
2 ........................................................ [2]

(d) A student used a respirometer to investigate the effect of temperature on the rate of respiration of germinating seeds.
Predict the results of this investigation and explain your prediction.
prediction ..........................................
explanation .......................................... [4]

Bacteria are useful in biotechnology and genetic engineering.
Fig. 6.1 shows a photomicrograph of a bacterium.

[Image_1: Photomicrograph with magnification ×27,000]

(a) State the name of the process that is taking place in Fig. 6.1.
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(b) (i) Write the formula that would be used to calculate the actual width of the bacterium.
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(ii) The actual width of the bacterium is 0.0008 mm.
Convert this value to micrometres (µm).
Space for working.
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(c) Genetically modified bacteria can produce human insulin.
(i) State the name of the disease that can be treated with insulin injections.
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(ii) Insulin is a protein.
Describe the process of using bacteria in genetic engineering to produce human proteins.
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(d) Genetically modified bacteria are often grown in fermenters.
(i) Suggest why steam is used to clean fermenters.
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(ii) State three conditions inside a fermenter that are measured and controlled.
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(iii) State the name of one commercial product, other than insulin, that is made in fermenters.
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(e) Crop plants can also be genetically modified.
Describe the advantages of genetically modifying crops.
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