Cambridge IGCSE Biology - 0610 - Core Paper 3 2013 Winter Zone 2

(a) Define the term photosynthesis.
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(b) Some plants store starch in underground storage organs.
(i) Explain how starch in a leaf is transported to an underground storage organ.
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(ii) Suggest one advantage to the plant of storing starch in an underground storage organ.
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(c) Fig. 1.1 shows the underground storage organs of five plants.



Use the key to identify which storage organ, shown in Fig. 1.1, is produced by which plant.
Write the letter of each storage organ on the correct line in the key.

Key

[Table_1]
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Fig. 2.1 shows an external view of a human heart seen from the front.



(a) (i) Name blood vessel A.
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(ii) Blood vessel B supplies blood to the muscle of the heart wall. Name blood vessel B.
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(iii) State what happens if blood vessel B becomes blocked.
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(iv) Describe and explain how the structure of the left ventricle differs from the structure of the right ventricle.
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(b) Exercise affects pulse rate. Describe how you would measure a person’s pulse rate.
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Fig. 3.1 shows the relative growth of the brain, reproductive organs and the whole body.



(a) (i) State the age at which the whole body has made 50% of its total growth.
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(ii) Suggest why the growth of the brain is so rapid in the early years of life.
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(iii) Between which two ages does the rapid increase in the size of the reproductive organs occur?
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(b) Name the hormone which controls the start of puberty in:
(i) males;
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(ii) females.
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(iii) Reproductive organs are affected by an increase of the male sex hormone.
Name two other structures affected by this increase.
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(c) Some athletes use the male sex hormone as a drug.
They inject this hormone.
The use of such drugs is banned in athletics.
Suggest two ways that the male sex hormone could improve the performance of an athlete.
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(a) Explain why the cells of the fruit pod, as shown in Fig. 4.1, are genetically different from the cells of the embryo in the seeds.


(b)(i) Fig. 4.2 shows a pea seedling after germination has begun.

Name the structures labelled A and B.
Write your answers on Fig. 4.2.

(ii) State three external conditions that are always required for germination.
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(c) Define the terms growth and development.
growth .................................................................................................
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(a) (i) Name the structures labelled A, B, C and D, shown in Fig. 5.1.
A ........................................................
B ........................................................
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(a) (ii) State the function of structure E.
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(a) (iii) Give one reason why area X is called the blind spot.
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(b) A girl looks at a distant tree and then looks at a small plant very close to her.
Describe the changes that take place in the ciliary muscles, the suspensory ligaments and the lens to allow the girl to focus on the small plant.
ciliary muscles ............................................................................................
suspensory ligaments ...................................................................................
lens ...........................................................................................................

(a) In Table 6.1, write the letter from Fig. 6.1 which labels the structure that carries out each of the functions.

One has been completed for you.

Table 6.1

| function | letter |
|-------------------------------------------|--------|
| helps to prevent dehydration of the body | B |
| detects changes in the external temperature| |
| dilates when body temperature rises | |
| prevents most heat loss from the body | |
| produces a fluid to help the body lose heat| |

(b) Name the structure labelled X on Fig. 6.1.

X ........................................................................................ [1]

(a) Explain what is shown by a food web.
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(b) Fig. 7.1 shows part of the food web in the arctic tundra.



Fig. 7.1

(i) Name one organism, shown in Fig. 7.1, that feeds on both animals and plants.
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(ii) The arctic wolf is sometimes described as a top carnivore.
Define the term carnivore.
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(iii) Suggest why top carnivores, such as the arctic wolf, are usually only present in very small numbers in an area.
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(c) The number of lemmings in an area undergoes a rapid decrease every few years.
Explain how a decrease in lemmings may affect the number of arctic foxes and arctic hares.

(i) arctic foxes
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(ii) arctic hares
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Table 8.1 shows the effect of the use of nitrate fertilisers on the yield of a crop.

(a) Plot the data from Table 8.1 as a line graph using the axes provided on Fig. 8.1.

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Table 8.1
[Table_1]

(b) (i) Calculate by how much the crop yield increased when 50 kg per ha of nitrate fertiliser was added.
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(ii) Use your graph to determine how much nitrate fertiliser must be added to double the unfertilised crop yield.
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(iii) Some farmers add more than 150 kg per ha of nitrate fertiliser.
Suggest two reasons why this is not a good idea.
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(iv) A farmer has only 100 kg of nitrate fertiliser available, but 2 ha of land.
He has to decide whether to put all of the fertiliser on one field of 1 ha or to spread it evenly over both fields of 1 ha each.
Use the data in Table 8.1 to calculate which decision would give the farmer the highest yield, in total.
calculation ..................................................................................................................
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(c) Explain why the yield of a crop can be increased by adding nitrate fertilisers.
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When a mass of still air becomes trapped over a city, pollutants build up in the air next to the ground.
(a) (i) Name two chemical pollutants that might build up over a busy city centre.
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(ii) Vehicles such as cars burn fossil fuels.
Explain why vehicles may be banned from the city if pollution becomes severe.
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(b) If air pollution is very severe, warnings may be given not to take young babies into the city centre and for any people with heart and respiratory problems to stay inside.
Suggest two reasons for this advice.
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