Cambridge IGCSE Biology - 0610 - Core Paper 3 2012 Winter Zone 2

Animals without backbones are classified into a number of groups.
Draw one line from each of the named groups to its description.


(a) (i) State what is meant by the term excretion.
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(ii) Name the main substance that is excreted in expired air.
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(iii) Urine contains water. Name two other excretory products found in the urine of a healthy person.
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(b) Fig. 2.1 shows the kidneys and associated structures.



Fig. 2.1
Name the structures labelled A and B.

A ......................................................................................................................
B ...................................................................................................................... [2]

(c) In the digestive system, proteins are digested into amino acids.
Describe what happens to any of these amino acids that are in excess, and how their breakdown product is removed from the body.
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(a) Fig. 3.1 shows the fruits of two species of plants.
[Image_1: Fig. 3.1]

Suggest and explain how seeds from each of these two plants are transported away from the parent plant.

tomato ..................................................................................................................
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dandelion ..................................................................................................................
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(b) Explain why it is important that seeds are transported well away from the parent plant.
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Table 4.1 shows the percentage of each of the gases present in the atmosphere and in expired air.

[Table_1]

(a) Identify gas X.
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(b) Fig. 4.1 shows the volume of air exchanged during each breath at rest and during vigorous exercise.



(i) State the volume of air inhaled in each breath at rest.
......................................... dm$^3$ [1]
(ii) State how many breaths are taken in one minute at rest.
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(iii) Calculate the volume of air exchanged in one minute at rest.
......................................... dm$^3$ [1]
(iv) Using information from Table 4.1, calculate the volume of oxygen absorbed in one minute at rest.
Show your working.
......................................... dm$^3$ [2]

(c) (i) Describe what happens to both the rate and depth of breathing during vigorous exercise.
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(ii) Suggest why the changes in the rate and depth of breathing are important for the person doing exercise.
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(iii) Suggest why the person's heart rate also changes during exercise.
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Fig. 5.1 shows a food web that is part of an ecosystem in the Amazon rainforest.

(a) (i) Explain why the whole food web depends on the producers such as the grass and trees.
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[3]

(ii) Name two herbivores in this food web.
1 ......................................................................................................................
2 ......................................................................................................................
[1]

(iii) State the trophic level of the frog.
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[1]

(iv) Complete a food chain of five stages from this food web.

[2]

(b) Jaguars are big cats that are hunted for their fur. Suggest and explain how the numbers of eagles might be affected if the jaguars were removed from this food web.
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[2]

(c) Suggest how humans who live in the Amazon rainforest might be affected if large areas of trees are removed.
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[2]

Fig. 6.1 shows a human fetus developing inside a uterus.

(a) (i) Name the structures labelled S and T.
S ..............................................................................................
T .............................................................................................. [1]
(ii) Explain the function of the placenta in the healthy development of the fetus.
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(iii) The blood supply of the mother and of the fetus are kept separate from each other at the placenta.
Suggest and explain two reasons why these two blood systems must not be joined to each other.
1 ..............................................................................................
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2 ..............................................................................................
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Fig. 6.2 shows a family tree in which the inherited condition beta thalassaemia occurs.
Beta thalassaemia is caused by a recessive allele, b. It results in the formation of haemoglobin that carries less oxygen than normal haemoglobin.

(b) Complete the diagram to show the phenotype of child 1. [1]
(c) Use the symbols B and b to complete the diagram to show:
(i) the genotype of child 2; [1]
(ii) the genotype of the father; [1]
(iii) the genotype of the mother. [1]
(d) State which two people in this family are heterozygous for the condition.
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Fig. 7.1 shows the water cycle.



(a) Name the processes that are happening at points 1, 2 and 3 in the water cycle.

1 ..............................................................................................................................................................
2 ..............................................................................................................................................................
3 .............................................................................................................................................................. [3]

(b) On mountains, rainwater drains over the surface and sinks into the soil.

Explain why the soil on mountainsides may be poor for agriculture.

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(a) (i) Name layers A and B.
A .................................................................
B ................................................................. [2]
(ii) State a function of layer A.
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(iii) Describe the function of C.
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(b) Measurements were made of the mass of water taken in and lost by a plant every two hours for 24 hours.
Fig. 8.2 is a graph showing the mass of water lost from the plant by transpiration.

(i) Use the graph, Fig. 8.2, to state the time when the mass of water lost was greatest.
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Table 8.1 shows the mass of water taken in by the plant every two hours.
Some of the data has been plotted in Fig. 8.3.
[Table_1]
Fig. 8.3 shows the mass of water lost and the mass of water taken in by the plant during the same period.

(ii) Complete the graph, Fig. 8.3, to show the mass of water taken in by the plant from 8 am to 10 pm.
Draw your graph on Fig. 8.3. [2]
(iii) State the period of time during which water taken in was less than water lost.
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(iv) Describe the state of the stomata between 6 am and 2 pm.
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(v) Suggest one factor that caused the state in (b)(iv).
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(vi) Name and explain one factor, other than your answer to (b)(v), that might increase the loss of water from a leaf during the day.
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Table 9.1 shows the percentage of the main types of foods in the diet of two teenage girls. One girl lives in Great Britain and the other girl in sub-Saharan Africa.

Table 9.1

[Table_1]

(a) Compare the percentage of foods rich in fats in the two diets. ............................................................................................................................................ ............................................................................................................................................ [1]

(b) Suggest how the lack of sweets and sugar in the diet of the African girl might benefit her health. ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ [2]

(c) The diet of the African girl contains much less protein than that of the British girl. Suggest and explain one way in which a diet containing little protein might affect her physical development. ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ [2]